NetworkManager/libnm/nm-device.c

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// SPDX-License-Identifier: LGPL-2.1+
/*
* Copyright (C) 2007 - 2008 Novell, Inc.
* Copyright (C) 2007 - 2018 Red Hat, Inc.
*/
#include "nm-default.h"
#include "nm-device.h"
#include <libudev.h>
#include "nm-glib-aux/nm-dbus-aux.h"
#include "nm-dbus-interface.h"
#include "nm-active-connection.h"
#include "nm-device-bt.h"
#include "nm-dhcp4-config.h"
#include "nm-dhcp6-config.h"
#include "nm-ip4-config.h"
#include "nm-ip6-config.h"
#include "nm-object-private.h"
#include "nm-remote-connection.h"
#include "nm-core-internal.h"
#include "nm-utils.h"
#include "nm-dbus-helpers.h"
2015-09-04 18:11:15 +02:00
#include "nm-device-tun.h"
#include "nm-setting-connection.h"
#include "nm-udev-aux/nm-udev-utils.h"
/*****************************************************************************/
libnm: refactor caching of D-Bus objects in NMClient No longer use GDBusObjectMangaerClient and gdbus-codegen generated classes for the NMClient cache. Instead, use GDBusConnection directly and a custom implementation (NMLDBusObject) for caching D-Bus' ObjectManager data. CHANGES ------- - This is a complete rework. I think the previous implementation was difficult to understand. There were unfixed bugs and nobody understood the code well enough to fix them. Maybe somebody out there understood the code, but I certainly did not. At least nobody provided patches to fix those issues. I do believe that this implementation is more straightforward and easier to understand. It removes a lot of layers of code. Whether this claim of simplicity is true, each reader must decide for himself/herself. Note that it is still fairly complex. - There was a lingering performance issue with large number of D-Bus objects. The patch tries hard that the implementation scales well. Of course, when we cache N objects that have N-to-M references to other, we still are fundamentally O(N*M) for runtime and memory consumption (with M being the number of references between objects). But each part should behave efficiently and well. - Play well with GMainContext. libnm code (NMClient) is generally not thread safe. However, it should work to use multiple instances in parallel, as long as each access to a NMClient is through the caller's GMainContext. This follows glib's style and effectively allows to use NMClient in a multi threaded scenario. This implies to stick to a main context upon construction and ensure that callbacks are only invoked when iterating that context. Also, NMClient itself shall never iterate the caller's context. This also means, libnm must never use g_idle_add() or g_timeout_add(), as those enqueue sources in the g_main_context_default() context. - Get ordering of messages right. All events are consistently enqueued in a GMainContext and processed strictly in order. For example, previously "nm-object.c" tried to combine signals and emit them on an idle handler. That is wrong, signals must be emitted in the right order and when they happen. Note that when using GInitable's synchronous initialization to initialize the NMClient instance, NMClient internally still operates fully asynchronously. In that case NMClient has an internal main context. - NMClient takes over most of the functionality. When using D-Bus' ObjectManager interface, one needs to handle basically the entire state of the D-Bus interface. That cannot be separated well into distinct parts, and even if you try, you just end up having closely related code in different source files. Spreading related code does not make it easier to understand, on the contrary. That means, NMClient is inherently complex as it contains most of the logic. I think that is not avoidable, but it's not as bad as it sounds. - NMClient processes D-Bus messages and state changes in separate steps. First NMClient unpacks the message (e.g. _dbus_handle_properties_changed()) and keeps track of the changed data. Then we update the GObject instances (_dbus_handle_obj_changed_dbus()) without emitting any signals yet. Finally, we emit all signals and notifications that were collected (_dbus_handle_changes_commit()). Note that for example during the initial GetManagedObjects() reply, NMClient receive a large amount of state at once. But we first apply all the changes to our GObject instances before emitting any signals. The result is that signals are always emitted in a moment when the cache is consistent. The unavoidable downside is that when you receive a property changed signal, possibly many other properties changed already and more signals are about to be emitted. - NMDeviceWifi no longer modifies the content of the cache from client side during poke_wireless_devices_with_rf_status(). The content of the cache should be determined by D-Bus alone and follow what NetworkManager service exposes. Local modifications should be avoided. - This aims to bring no API/ABI change, though it does of course bring various subtle changes in behavior. Those should be all for the better, but the goal is not to break any existing clients. This does change internal (albeit externally visible) API, like dropping NM_OBJECT_DBUS_OBJECT_MANAGER property and NMObject no longer implementing GInitableIface and GAsyncInitableIface. - Some uses of gdbus-codegen classes remain in NMVpnPluginOld, NMVpnServicePlugin and NMSecretAgentOld. These are independent of NMClient/NMObject and should be reworked separately. - While we no longer use generated classes from gdbus-codegen, we don't need more glue code than before. Also before we constructed NMPropertiesInfo and a had large amount of code to propagate properties from NMDBus* to NMObject. That got completely reworked, but did not fundamentally change. You still need about the same effort to create the NMLDBusMetaIface. Not using generated bindings did not make anything worse (which tells about the usefulness of generated code, at least in the way it was used). - NMLDBusMetaIface and other meta data is static and immutable. This avoids copying them around. Also, macros like NML_DBUS_META_PROPERTY_INIT_U() have compile time checks to ensure the property types matches. It's pretty hard to misuse them because it won't compile. - The meta data now explicitly encodes the expected D-Bus types and makes sure never to accept wrong data. That would only matter when the server (accidentally or intentionally) exposes unexpected types on D-Bus. I don't think that was previously ensured in all cases. For example, demarshal_generic() only cared about the GObject property type, it didn't know the expected D-Bus type. - Previously GDBusObjectManager would sometimes emit warnings (g_log()). Those probably indicated real bugs. In any case, it prevented us from running CI with G_DEBUG=fatal-warnings, because there would be just too many unrelated crashes. Now we log debug messages that can be enabled with "LIBNM_CLIENT_DEBUG=trace". Some of these messages can also be turned into g_warning()/g_critical() by setting LIBNM_CLIENT_DEBUG=warning,error. Together with G_DEBUG=fatal-warnings, this turns them into assertions. Note that such "assertion failures" might also happen because of a server bug (or change). Thus these are not common assertions that indicate a bug in libnm and are thus not armed unless explicitly requested. In our CI we should now always run with LIBNM_CLIENT_DEBUG=warning,error and G_DEBUG=fatal-warnings and to catch bugs. Note that currently NetworkManager has bugs in this regard, so enabling this will result in assertion failures. That should be fixed first. - Note that this changes the order in which we emit "notify:devices" and "device-added" signals. I think it makes the most sense to emit first "device-removed", then "notify:devices", and finally "device-added" signals. This changes behavior for commit 52ae28f6e5bf ('libnm: queue added/removed signals and suppress uninitialized notifications'), but I don't think that users should actually rely on the order. Still, the new order makes the most sense to me. - In NetworkManager, profiles can be invisible to the user by setting "connection.permissions". Such profiles would be hidden by NMClient's nm_client_get_connections() and their "connection-added"/"connection-removed" signals. Note that NMActiveConnection's nm_active_connection_get_connection() and NMDevice's nm_device_get_available_connections() still exposes such hidden NMRemoteConnection instances. This behavior was preserved. NUMBERS ------- I compared 3 versions of libnm. [1] 962297f9085d, current tip of nm-1-20 branch [2] 4fad8c7c642e, current master, immediate parent of this patch [3] this patch All tests were done on Fedora 31, x86_64, gcc 9.2.1-1.fc31. The libraries were build with $ ./contrib/fedora/rpm/build_clean.sh -g -w test -W debug Note that RPM build already stripped the library. --- N1) File size of libnm.so.0.1.0 in bytes. There currently seems to be a issue on Fedora 31 generating wrong ELF notes. Usually, libnm is smaller but in these tests it had large (and bogus) ELF notes. Anyway, the point is to show the relative sizes, so it doesn't matter). [1] 4075552 (102.7%) [2] 3969624 (100.0%) [3] 3705208 ( 93.3%) --- N2) `size /usr/lib64/libnm.so.0.1.0`: text data bss dec hex filename [1] 1314569 (102.0%) 69980 ( 94.8%) 10632 ( 80.4%) 1395181 (101.4%) 1549ed /usr/lib64/libnm.so.0.1.0 [2] 1288410 (100.0%) 73796 (100.0%) 13224 (100.0%) 1375430 (100.0%) 14fcc6 /usr/lib64/libnm.so.0.1.0 [3] 1229066 ( 95.4%) 65248 ( 88.4%) 13400 (101.3%) 1307714 ( 95.1%) 13f442 /usr/lib64/libnm.so.0.1.0 --- N3) Performance test with test-client.py. With checkout of [2], run ``` prepare_checkout() { rm -rf /tmp/nm-test && \ git checkout -B test 4fad8c7c642e && \ git clean -fdx && \ ./autogen.sh --prefix=/tmp/nm-test && \ make -j 5 install && \ make -j 5 check-local-clients-tests-test-client } prepare_test() { NM_TEST_REGENERATE=1 NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v } do_test() { for i in {1..10}; do NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v || return -1 done echo "done!" } prepare_checkout prepare_test time do_test ``` [1] real 2m14.497s (101.3%) user 5m26.651s (100.3%) sys 1m40.453s (101.4%) [2] real 2m12.800s (100.0%) user 5m25.619s (100.0%) sys 1m39.065s (100.0%) [3] real 1m54.915s ( 86.5%) user 4m18.585s ( 79.4%) sys 1m32.066s ( 92.9%) --- N4) Performance. Run NetworkManager from build [2] and setup a large number of profiles (551 profiles and 515 devices, mostly unrealized). This setup is already at the edge of what NetworkManager currently can handle. Of course, that is a different issue. Here we just check how long plain `nmcli` takes on the system. ``` do_cleanup() { for UUID in $(nmcli -g NAME,UUID connection show | sed -n 's/^xx-c-.*:\([^:]\+\)$/\1/p'); do nmcli connection delete uuid "$UUID" done for DEVICE in $(nmcli -g DEVICE device status | grep '^xx-i-'); do nmcli device delete "$DEVICE" done } do_setup() { do_cleanup for i in {1..30}; do nmcli connection add type bond autoconnect no con-name xx-c-bond-$i ifname xx-i-bond-$i ipv4.method disabled ipv6.method ignore for j in $(seq $i 30); do nmcli connection add type vlan autoconnect no con-name xx-c-vlan-$i-$j vlan.id $j ifname xx-i-vlan-$i-$j vlan.parent xx-i-bond-$i ipv4.method disabled ipv6.method ignore done done systemctl restart NetworkManager.service sleep 5 } do_test() { perf stat -r 50 -B nmcli 1>/dev/null } do_test ``` [1] Performance counter stats for 'nmcli' (50 runs): 456.33 msec task-clock:u # 1.093 CPUs utilized ( +- 0.44% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,900 page-faults:u # 0.013 M/sec ( +- 0.02% ) 1,408,675,453 cycles:u # 3.087 GHz ( +- 0.48% ) 1,594,741,060 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 368,744,018 branches:u # 808.061 M/sec ( +- 0.02% ) 4,566,058 branch-misses:u # 1.24% of all branches ( +- 0.76% ) 0.41761 +- 0.00282 seconds time elapsed ( +- 0.68% ) [2] Performance counter stats for 'nmcli' (50 runs): 477.99 msec task-clock:u # 1.088 CPUs utilized ( +- 0.36% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,948 page-faults:u # 0.012 M/sec ( +- 0.03% ) 1,471,133,482 cycles:u # 3.078 GHz ( +- 0.36% ) 1,655,275,369 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 382,595,152 branches:u # 800.433 M/sec ( +- 0.02% ) 4,746,070 branch-misses:u # 1.24% of all branches ( +- 0.49% ) 0.43923 +- 0.00242 seconds time elapsed ( +- 0.55% ) [3] Performance counter stats for 'nmcli' (50 runs): 352.36 msec task-clock:u # 1.027 CPUs utilized ( +- 0.32% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 4,790 page-faults:u # 0.014 M/sec ( +- 0.26% ) 1,092,341,186 cycles:u # 3.100 GHz ( +- 0.26% ) 1,209,045,283 instructions:u # 1.11 insn per cycle ( +- 0.02% ) 281,708,462 branches:u # 799.499 M/sec ( +- 0.01% ) 3,101,031 branch-misses:u # 1.10% of all branches ( +- 0.61% ) 0.34296 +- 0.00120 seconds time elapsed ( +- 0.35% ) --- N5) same setup as N4), but run `PAGER= /bin/time -v nmcli`: [1] Command being timed: "nmcli" User time (seconds): 0.42 System time (seconds): 0.04 Percent of CPU this job got: 107% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.43 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34456 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6128 Voluntary context switches: 1298 Involuntary context switches: 1106 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [2] Command being timed: "nmcli" User time (seconds): 0.44 System time (seconds): 0.04 Percent of CPU this job got: 108% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.44 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34452 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6169 Voluntary context switches: 1849 Involuntary context switches: 142 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [3] Command being timed: "nmcli" User time (seconds): 0.32 System time (seconds): 0.02 Percent of CPU this job got: 102% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.34 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 29196 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 5059 Voluntary context switches: 919 Involuntary context switches: 685 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 --- N6) same setup as N4), but run `nmcli monitor` and look at `ps aux` for the RSS size. USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND [1] me 1492900 21.0 0.2 461348 33248 pts/10 Sl+ 15:02 0:00 nmcli monitor [2] me 1490721 5.0 0.2 461496 33548 pts/10 Sl+ 15:00 0:00 nmcli monitor [3] me 1495801 16.5 0.1 459476 28692 pts/10 Sl+ 15:04 0:00 nmcli monitor
2019-10-30 11:42:58 +01:00
NM_GOBJECT_PROPERTIES_DEFINE (NMDevice,
PROP_INTERFACE,
PROP_UDI,
PROP_PATH,
PROP_DRIVER,
PROP_DRIVER_VERSION,
PROP_FIRMWARE_VERSION,
PROP_CAPABILITIES,
PROP_REAL,
PROP_MANAGED,
PROP_AUTOCONNECT,
PROP_FIRMWARE_MISSING,
PROP_NM_PLUGIN_MISSING,
PROP_IP4_CONFIG,
PROP_DHCP4_CONFIG,
PROP_IP6_CONFIG,
PROP_STATE,
PROP_STATE_REASON,
PROP_PRODUCT,
PROP_VENDOR,
PROP_DHCP6_CONFIG,
PROP_IP_INTERFACE,
PROP_DEVICE_TYPE,
PROP_ACTIVE_CONNECTION,
PROP_AVAILABLE_CONNECTIONS,
PROP_PHYSICAL_PORT_ID,
PROP_MTU,
PROP_METERED,
PROP_LLDP_NEIGHBORS,
PROP_IP4_CONNECTIVITY,
PROP_IP6_CONNECTIVITY,
PROP_INTERFACE_FLAGS,
PROP_HW_ADDRESS,
);
enum {
STATE_CHANGED,
LAST_SIGNAL
};
static guint signals[LAST_SIGNAL] = { 0 };
libnm: refactor caching of D-Bus objects in NMClient No longer use GDBusObjectMangaerClient and gdbus-codegen generated classes for the NMClient cache. Instead, use GDBusConnection directly and a custom implementation (NMLDBusObject) for caching D-Bus' ObjectManager data. CHANGES ------- - This is a complete rework. I think the previous implementation was difficult to understand. There were unfixed bugs and nobody understood the code well enough to fix them. Maybe somebody out there understood the code, but I certainly did not. At least nobody provided patches to fix those issues. I do believe that this implementation is more straightforward and easier to understand. It removes a lot of layers of code. Whether this claim of simplicity is true, each reader must decide for himself/herself. Note that it is still fairly complex. - There was a lingering performance issue with large number of D-Bus objects. The patch tries hard that the implementation scales well. Of course, when we cache N objects that have N-to-M references to other, we still are fundamentally O(N*M) for runtime and memory consumption (with M being the number of references between objects). But each part should behave efficiently and well. - Play well with GMainContext. libnm code (NMClient) is generally not thread safe. However, it should work to use multiple instances in parallel, as long as each access to a NMClient is through the caller's GMainContext. This follows glib's style and effectively allows to use NMClient in a multi threaded scenario. This implies to stick to a main context upon construction and ensure that callbacks are only invoked when iterating that context. Also, NMClient itself shall never iterate the caller's context. This also means, libnm must never use g_idle_add() or g_timeout_add(), as those enqueue sources in the g_main_context_default() context. - Get ordering of messages right. All events are consistently enqueued in a GMainContext and processed strictly in order. For example, previously "nm-object.c" tried to combine signals and emit them on an idle handler. That is wrong, signals must be emitted in the right order and when they happen. Note that when using GInitable's synchronous initialization to initialize the NMClient instance, NMClient internally still operates fully asynchronously. In that case NMClient has an internal main context. - NMClient takes over most of the functionality. When using D-Bus' ObjectManager interface, one needs to handle basically the entire state of the D-Bus interface. That cannot be separated well into distinct parts, and even if you try, you just end up having closely related code in different source files. Spreading related code does not make it easier to understand, on the contrary. That means, NMClient is inherently complex as it contains most of the logic. I think that is not avoidable, but it's not as bad as it sounds. - NMClient processes D-Bus messages and state changes in separate steps. First NMClient unpacks the message (e.g. _dbus_handle_properties_changed()) and keeps track of the changed data. Then we update the GObject instances (_dbus_handle_obj_changed_dbus()) without emitting any signals yet. Finally, we emit all signals and notifications that were collected (_dbus_handle_changes_commit()). Note that for example during the initial GetManagedObjects() reply, NMClient receive a large amount of state at once. But we first apply all the changes to our GObject instances before emitting any signals. The result is that signals are always emitted in a moment when the cache is consistent. The unavoidable downside is that when you receive a property changed signal, possibly many other properties changed already and more signals are about to be emitted. - NMDeviceWifi no longer modifies the content of the cache from client side during poke_wireless_devices_with_rf_status(). The content of the cache should be determined by D-Bus alone and follow what NetworkManager service exposes. Local modifications should be avoided. - This aims to bring no API/ABI change, though it does of course bring various subtle changes in behavior. Those should be all for the better, but the goal is not to break any existing clients. This does change internal (albeit externally visible) API, like dropping NM_OBJECT_DBUS_OBJECT_MANAGER property and NMObject no longer implementing GInitableIface and GAsyncInitableIface. - Some uses of gdbus-codegen classes remain in NMVpnPluginOld, NMVpnServicePlugin and NMSecretAgentOld. These are independent of NMClient/NMObject and should be reworked separately. - While we no longer use generated classes from gdbus-codegen, we don't need more glue code than before. Also before we constructed NMPropertiesInfo and a had large amount of code to propagate properties from NMDBus* to NMObject. That got completely reworked, but did not fundamentally change. You still need about the same effort to create the NMLDBusMetaIface. Not using generated bindings did not make anything worse (which tells about the usefulness of generated code, at least in the way it was used). - NMLDBusMetaIface and other meta data is static and immutable. This avoids copying them around. Also, macros like NML_DBUS_META_PROPERTY_INIT_U() have compile time checks to ensure the property types matches. It's pretty hard to misuse them because it won't compile. - The meta data now explicitly encodes the expected D-Bus types and makes sure never to accept wrong data. That would only matter when the server (accidentally or intentionally) exposes unexpected types on D-Bus. I don't think that was previously ensured in all cases. For example, demarshal_generic() only cared about the GObject property type, it didn't know the expected D-Bus type. - Previously GDBusObjectManager would sometimes emit warnings (g_log()). Those probably indicated real bugs. In any case, it prevented us from running CI with G_DEBUG=fatal-warnings, because there would be just too many unrelated crashes. Now we log debug messages that can be enabled with "LIBNM_CLIENT_DEBUG=trace". Some of these messages can also be turned into g_warning()/g_critical() by setting LIBNM_CLIENT_DEBUG=warning,error. Together with G_DEBUG=fatal-warnings, this turns them into assertions. Note that such "assertion failures" might also happen because of a server bug (or change). Thus these are not common assertions that indicate a bug in libnm and are thus not armed unless explicitly requested. In our CI we should now always run with LIBNM_CLIENT_DEBUG=warning,error and G_DEBUG=fatal-warnings and to catch bugs. Note that currently NetworkManager has bugs in this regard, so enabling this will result in assertion failures. That should be fixed first. - Note that this changes the order in which we emit "notify:devices" and "device-added" signals. I think it makes the most sense to emit first "device-removed", then "notify:devices", and finally "device-added" signals. This changes behavior for commit 52ae28f6e5bf ('libnm: queue added/removed signals and suppress uninitialized notifications'), but I don't think that users should actually rely on the order. Still, the new order makes the most sense to me. - In NetworkManager, profiles can be invisible to the user by setting "connection.permissions". Such profiles would be hidden by NMClient's nm_client_get_connections() and their "connection-added"/"connection-removed" signals. Note that NMActiveConnection's nm_active_connection_get_connection() and NMDevice's nm_device_get_available_connections() still exposes such hidden NMRemoteConnection instances. This behavior was preserved. NUMBERS ------- I compared 3 versions of libnm. [1] 962297f9085d, current tip of nm-1-20 branch [2] 4fad8c7c642e, current master, immediate parent of this patch [3] this patch All tests were done on Fedora 31, x86_64, gcc 9.2.1-1.fc31. The libraries were build with $ ./contrib/fedora/rpm/build_clean.sh -g -w test -W debug Note that RPM build already stripped the library. --- N1) File size of libnm.so.0.1.0 in bytes. There currently seems to be a issue on Fedora 31 generating wrong ELF notes. Usually, libnm is smaller but in these tests it had large (and bogus) ELF notes. Anyway, the point is to show the relative sizes, so it doesn't matter). [1] 4075552 (102.7%) [2] 3969624 (100.0%) [3] 3705208 ( 93.3%) --- N2) `size /usr/lib64/libnm.so.0.1.0`: text data bss dec hex filename [1] 1314569 (102.0%) 69980 ( 94.8%) 10632 ( 80.4%) 1395181 (101.4%) 1549ed /usr/lib64/libnm.so.0.1.0 [2] 1288410 (100.0%) 73796 (100.0%) 13224 (100.0%) 1375430 (100.0%) 14fcc6 /usr/lib64/libnm.so.0.1.0 [3] 1229066 ( 95.4%) 65248 ( 88.4%) 13400 (101.3%) 1307714 ( 95.1%) 13f442 /usr/lib64/libnm.so.0.1.0 --- N3) Performance test with test-client.py. With checkout of [2], run ``` prepare_checkout() { rm -rf /tmp/nm-test && \ git checkout -B test 4fad8c7c642e && \ git clean -fdx && \ ./autogen.sh --prefix=/tmp/nm-test && \ make -j 5 install && \ make -j 5 check-local-clients-tests-test-client } prepare_test() { NM_TEST_REGENERATE=1 NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v } do_test() { for i in {1..10}; do NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v || return -1 done echo "done!" } prepare_checkout prepare_test time do_test ``` [1] real 2m14.497s (101.3%) user 5m26.651s (100.3%) sys 1m40.453s (101.4%) [2] real 2m12.800s (100.0%) user 5m25.619s (100.0%) sys 1m39.065s (100.0%) [3] real 1m54.915s ( 86.5%) user 4m18.585s ( 79.4%) sys 1m32.066s ( 92.9%) --- N4) Performance. Run NetworkManager from build [2] and setup a large number of profiles (551 profiles and 515 devices, mostly unrealized). This setup is already at the edge of what NetworkManager currently can handle. Of course, that is a different issue. Here we just check how long plain `nmcli` takes on the system. ``` do_cleanup() { for UUID in $(nmcli -g NAME,UUID connection show | sed -n 's/^xx-c-.*:\([^:]\+\)$/\1/p'); do nmcli connection delete uuid "$UUID" done for DEVICE in $(nmcli -g DEVICE device status | grep '^xx-i-'); do nmcli device delete "$DEVICE" done } do_setup() { do_cleanup for i in {1..30}; do nmcli connection add type bond autoconnect no con-name xx-c-bond-$i ifname xx-i-bond-$i ipv4.method disabled ipv6.method ignore for j in $(seq $i 30); do nmcli connection add type vlan autoconnect no con-name xx-c-vlan-$i-$j vlan.id $j ifname xx-i-vlan-$i-$j vlan.parent xx-i-bond-$i ipv4.method disabled ipv6.method ignore done done systemctl restart NetworkManager.service sleep 5 } do_test() { perf stat -r 50 -B nmcli 1>/dev/null } do_test ``` [1] Performance counter stats for 'nmcli' (50 runs): 456.33 msec task-clock:u # 1.093 CPUs utilized ( +- 0.44% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,900 page-faults:u # 0.013 M/sec ( +- 0.02% ) 1,408,675,453 cycles:u # 3.087 GHz ( +- 0.48% ) 1,594,741,060 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 368,744,018 branches:u # 808.061 M/sec ( +- 0.02% ) 4,566,058 branch-misses:u # 1.24% of all branches ( +- 0.76% ) 0.41761 +- 0.00282 seconds time elapsed ( +- 0.68% ) [2] Performance counter stats for 'nmcli' (50 runs): 477.99 msec task-clock:u # 1.088 CPUs utilized ( +- 0.36% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,948 page-faults:u # 0.012 M/sec ( +- 0.03% ) 1,471,133,482 cycles:u # 3.078 GHz ( +- 0.36% ) 1,655,275,369 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 382,595,152 branches:u # 800.433 M/sec ( +- 0.02% ) 4,746,070 branch-misses:u # 1.24% of all branches ( +- 0.49% ) 0.43923 +- 0.00242 seconds time elapsed ( +- 0.55% ) [3] Performance counter stats for 'nmcli' (50 runs): 352.36 msec task-clock:u # 1.027 CPUs utilized ( +- 0.32% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 4,790 page-faults:u # 0.014 M/sec ( +- 0.26% ) 1,092,341,186 cycles:u # 3.100 GHz ( +- 0.26% ) 1,209,045,283 instructions:u # 1.11 insn per cycle ( +- 0.02% ) 281,708,462 branches:u # 799.499 M/sec ( +- 0.01% ) 3,101,031 branch-misses:u # 1.10% of all branches ( +- 0.61% ) 0.34296 +- 0.00120 seconds time elapsed ( +- 0.35% ) --- N5) same setup as N4), but run `PAGER= /bin/time -v nmcli`: [1] Command being timed: "nmcli" User time (seconds): 0.42 System time (seconds): 0.04 Percent of CPU this job got: 107% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.43 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34456 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6128 Voluntary context switches: 1298 Involuntary context switches: 1106 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [2] Command being timed: "nmcli" User time (seconds): 0.44 System time (seconds): 0.04 Percent of CPU this job got: 108% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.44 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34452 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6169 Voluntary context switches: 1849 Involuntary context switches: 142 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [3] Command being timed: "nmcli" User time (seconds): 0.32 System time (seconds): 0.02 Percent of CPU this job got: 102% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.34 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 29196 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 5059 Voluntary context switches: 919 Involuntary context switches: 685 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 --- N6) same setup as N4), but run `nmcli monitor` and look at `ps aux` for the RSS size. USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND [1] me 1492900 21.0 0.2 461348 33248 pts/10 Sl+ 15:02 0:00 nmcli monitor [2] me 1490721 5.0 0.2 461496 33548 pts/10 Sl+ 15:00 0:00 nmcli monitor [3] me 1495801 16.5 0.1 459476 28692 pts/10 Sl+ 15:04 0:00 nmcli monitor
2019-10-30 11:42:58 +01:00
enum {
PROPERTY_O_IDX_ACTIVE_CONNECTION,
PROPERTY_O_IDX_IP4_CONFIG,
PROPERTY_O_IDX_IP6_CONFIG,
PROPERTY_O_IDX_DHCP4_CONFIG,
PROPERTY_O_IDX_DHCP6_CONFIG,
_PROPERTY_O_IDX_NUM,
};
libnm: refactor caching of D-Bus objects in NMClient No longer use GDBusObjectMangaerClient and gdbus-codegen generated classes for the NMClient cache. Instead, use GDBusConnection directly and a custom implementation (NMLDBusObject) for caching D-Bus' ObjectManager data. CHANGES ------- - This is a complete rework. I think the previous implementation was difficult to understand. There were unfixed bugs and nobody understood the code well enough to fix them. Maybe somebody out there understood the code, but I certainly did not. At least nobody provided patches to fix those issues. I do believe that this implementation is more straightforward and easier to understand. It removes a lot of layers of code. Whether this claim of simplicity is true, each reader must decide for himself/herself. Note that it is still fairly complex. - There was a lingering performance issue with large number of D-Bus objects. The patch tries hard that the implementation scales well. Of course, when we cache N objects that have N-to-M references to other, we still are fundamentally O(N*M) for runtime and memory consumption (with M being the number of references between objects). But each part should behave efficiently and well. - Play well with GMainContext. libnm code (NMClient) is generally not thread safe. However, it should work to use multiple instances in parallel, as long as each access to a NMClient is through the caller's GMainContext. This follows glib's style and effectively allows to use NMClient in a multi threaded scenario. This implies to stick to a main context upon construction and ensure that callbacks are only invoked when iterating that context. Also, NMClient itself shall never iterate the caller's context. This also means, libnm must never use g_idle_add() or g_timeout_add(), as those enqueue sources in the g_main_context_default() context. - Get ordering of messages right. All events are consistently enqueued in a GMainContext and processed strictly in order. For example, previously "nm-object.c" tried to combine signals and emit them on an idle handler. That is wrong, signals must be emitted in the right order and when they happen. Note that when using GInitable's synchronous initialization to initialize the NMClient instance, NMClient internally still operates fully asynchronously. In that case NMClient has an internal main context. - NMClient takes over most of the functionality. When using D-Bus' ObjectManager interface, one needs to handle basically the entire state of the D-Bus interface. That cannot be separated well into distinct parts, and even if you try, you just end up having closely related code in different source files. Spreading related code does not make it easier to understand, on the contrary. That means, NMClient is inherently complex as it contains most of the logic. I think that is not avoidable, but it's not as bad as it sounds. - NMClient processes D-Bus messages and state changes in separate steps. First NMClient unpacks the message (e.g. _dbus_handle_properties_changed()) and keeps track of the changed data. Then we update the GObject instances (_dbus_handle_obj_changed_dbus()) without emitting any signals yet. Finally, we emit all signals and notifications that were collected (_dbus_handle_changes_commit()). Note that for example during the initial GetManagedObjects() reply, NMClient receive a large amount of state at once. But we first apply all the changes to our GObject instances before emitting any signals. The result is that signals are always emitted in a moment when the cache is consistent. The unavoidable downside is that when you receive a property changed signal, possibly many other properties changed already and more signals are about to be emitted. - NMDeviceWifi no longer modifies the content of the cache from client side during poke_wireless_devices_with_rf_status(). The content of the cache should be determined by D-Bus alone and follow what NetworkManager service exposes. Local modifications should be avoided. - This aims to bring no API/ABI change, though it does of course bring various subtle changes in behavior. Those should be all for the better, but the goal is not to break any existing clients. This does change internal (albeit externally visible) API, like dropping NM_OBJECT_DBUS_OBJECT_MANAGER property and NMObject no longer implementing GInitableIface and GAsyncInitableIface. - Some uses of gdbus-codegen classes remain in NMVpnPluginOld, NMVpnServicePlugin and NMSecretAgentOld. These are independent of NMClient/NMObject and should be reworked separately. - While we no longer use generated classes from gdbus-codegen, we don't need more glue code than before. Also before we constructed NMPropertiesInfo and a had large amount of code to propagate properties from NMDBus* to NMObject. That got completely reworked, but did not fundamentally change. You still need about the same effort to create the NMLDBusMetaIface. Not using generated bindings did not make anything worse (which tells about the usefulness of generated code, at least in the way it was used). - NMLDBusMetaIface and other meta data is static and immutable. This avoids copying them around. Also, macros like NML_DBUS_META_PROPERTY_INIT_U() have compile time checks to ensure the property types matches. It's pretty hard to misuse them because it won't compile. - The meta data now explicitly encodes the expected D-Bus types and makes sure never to accept wrong data. That would only matter when the server (accidentally or intentionally) exposes unexpected types on D-Bus. I don't think that was previously ensured in all cases. For example, demarshal_generic() only cared about the GObject property type, it didn't know the expected D-Bus type. - Previously GDBusObjectManager would sometimes emit warnings (g_log()). Those probably indicated real bugs. In any case, it prevented us from running CI with G_DEBUG=fatal-warnings, because there would be just too many unrelated crashes. Now we log debug messages that can be enabled with "LIBNM_CLIENT_DEBUG=trace". Some of these messages can also be turned into g_warning()/g_critical() by setting LIBNM_CLIENT_DEBUG=warning,error. Together with G_DEBUG=fatal-warnings, this turns them into assertions. Note that such "assertion failures" might also happen because of a server bug (or change). Thus these are not common assertions that indicate a bug in libnm and are thus not armed unless explicitly requested. In our CI we should now always run with LIBNM_CLIENT_DEBUG=warning,error and G_DEBUG=fatal-warnings and to catch bugs. Note that currently NetworkManager has bugs in this regard, so enabling this will result in assertion failures. That should be fixed first. - Note that this changes the order in which we emit "notify:devices" and "device-added" signals. I think it makes the most sense to emit first "device-removed", then "notify:devices", and finally "device-added" signals. This changes behavior for commit 52ae28f6e5bf ('libnm: queue added/removed signals and suppress uninitialized notifications'), but I don't think that users should actually rely on the order. Still, the new order makes the most sense to me. - In NetworkManager, profiles can be invisible to the user by setting "connection.permissions". Such profiles would be hidden by NMClient's nm_client_get_connections() and their "connection-added"/"connection-removed" signals. Note that NMActiveConnection's nm_active_connection_get_connection() and NMDevice's nm_device_get_available_connections() still exposes such hidden NMRemoteConnection instances. This behavior was preserved. NUMBERS ------- I compared 3 versions of libnm. [1] 962297f9085d, current tip of nm-1-20 branch [2] 4fad8c7c642e, current master, immediate parent of this patch [3] this patch All tests were done on Fedora 31, x86_64, gcc 9.2.1-1.fc31. The libraries were build with $ ./contrib/fedora/rpm/build_clean.sh -g -w test -W debug Note that RPM build already stripped the library. --- N1) File size of libnm.so.0.1.0 in bytes. There currently seems to be a issue on Fedora 31 generating wrong ELF notes. Usually, libnm is smaller but in these tests it had large (and bogus) ELF notes. Anyway, the point is to show the relative sizes, so it doesn't matter). [1] 4075552 (102.7%) [2] 3969624 (100.0%) [3] 3705208 ( 93.3%) --- N2) `size /usr/lib64/libnm.so.0.1.0`: text data bss dec hex filename [1] 1314569 (102.0%) 69980 ( 94.8%) 10632 ( 80.4%) 1395181 (101.4%) 1549ed /usr/lib64/libnm.so.0.1.0 [2] 1288410 (100.0%) 73796 (100.0%) 13224 (100.0%) 1375430 (100.0%) 14fcc6 /usr/lib64/libnm.so.0.1.0 [3] 1229066 ( 95.4%) 65248 ( 88.4%) 13400 (101.3%) 1307714 ( 95.1%) 13f442 /usr/lib64/libnm.so.0.1.0 --- N3) Performance test with test-client.py. With checkout of [2], run ``` prepare_checkout() { rm -rf /tmp/nm-test && \ git checkout -B test 4fad8c7c642e && \ git clean -fdx && \ ./autogen.sh --prefix=/tmp/nm-test && \ make -j 5 install && \ make -j 5 check-local-clients-tests-test-client } prepare_test() { NM_TEST_REGENERATE=1 NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v } do_test() { for i in {1..10}; do NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v || return -1 done echo "done!" } prepare_checkout prepare_test time do_test ``` [1] real 2m14.497s (101.3%) user 5m26.651s (100.3%) sys 1m40.453s (101.4%) [2] real 2m12.800s (100.0%) user 5m25.619s (100.0%) sys 1m39.065s (100.0%) [3] real 1m54.915s ( 86.5%) user 4m18.585s ( 79.4%) sys 1m32.066s ( 92.9%) --- N4) Performance. Run NetworkManager from build [2] and setup a large number of profiles (551 profiles and 515 devices, mostly unrealized). This setup is already at the edge of what NetworkManager currently can handle. Of course, that is a different issue. Here we just check how long plain `nmcli` takes on the system. ``` do_cleanup() { for UUID in $(nmcli -g NAME,UUID connection show | sed -n 's/^xx-c-.*:\([^:]\+\)$/\1/p'); do nmcli connection delete uuid "$UUID" done for DEVICE in $(nmcli -g DEVICE device status | grep '^xx-i-'); do nmcli device delete "$DEVICE" done } do_setup() { do_cleanup for i in {1..30}; do nmcli connection add type bond autoconnect no con-name xx-c-bond-$i ifname xx-i-bond-$i ipv4.method disabled ipv6.method ignore for j in $(seq $i 30); do nmcli connection add type vlan autoconnect no con-name xx-c-vlan-$i-$j vlan.id $j ifname xx-i-vlan-$i-$j vlan.parent xx-i-bond-$i ipv4.method disabled ipv6.method ignore done done systemctl restart NetworkManager.service sleep 5 } do_test() { perf stat -r 50 -B nmcli 1>/dev/null } do_test ``` [1] Performance counter stats for 'nmcli' (50 runs): 456.33 msec task-clock:u # 1.093 CPUs utilized ( +- 0.44% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,900 page-faults:u # 0.013 M/sec ( +- 0.02% ) 1,408,675,453 cycles:u # 3.087 GHz ( +- 0.48% ) 1,594,741,060 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 368,744,018 branches:u # 808.061 M/sec ( +- 0.02% ) 4,566,058 branch-misses:u # 1.24% of all branches ( +- 0.76% ) 0.41761 +- 0.00282 seconds time elapsed ( +- 0.68% ) [2] Performance counter stats for 'nmcli' (50 runs): 477.99 msec task-clock:u # 1.088 CPUs utilized ( +- 0.36% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,948 page-faults:u # 0.012 M/sec ( +- 0.03% ) 1,471,133,482 cycles:u # 3.078 GHz ( +- 0.36% ) 1,655,275,369 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 382,595,152 branches:u # 800.433 M/sec ( +- 0.02% ) 4,746,070 branch-misses:u # 1.24% of all branches ( +- 0.49% ) 0.43923 +- 0.00242 seconds time elapsed ( +- 0.55% ) [3] Performance counter stats for 'nmcli' (50 runs): 352.36 msec task-clock:u # 1.027 CPUs utilized ( +- 0.32% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 4,790 page-faults:u # 0.014 M/sec ( +- 0.26% ) 1,092,341,186 cycles:u # 3.100 GHz ( +- 0.26% ) 1,209,045,283 instructions:u # 1.11 insn per cycle ( +- 0.02% ) 281,708,462 branches:u # 799.499 M/sec ( +- 0.01% ) 3,101,031 branch-misses:u # 1.10% of all branches ( +- 0.61% ) 0.34296 +- 0.00120 seconds time elapsed ( +- 0.35% ) --- N5) same setup as N4), but run `PAGER= /bin/time -v nmcli`: [1] Command being timed: "nmcli" User time (seconds): 0.42 System time (seconds): 0.04 Percent of CPU this job got: 107% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.43 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34456 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6128 Voluntary context switches: 1298 Involuntary context switches: 1106 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [2] Command being timed: "nmcli" User time (seconds): 0.44 System time (seconds): 0.04 Percent of CPU this job got: 108% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.44 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34452 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6169 Voluntary context switches: 1849 Involuntary context switches: 142 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [3] Command being timed: "nmcli" User time (seconds): 0.32 System time (seconds): 0.02 Percent of CPU this job got: 102% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.34 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 29196 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 5059 Voluntary context switches: 919 Involuntary context switches: 685 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 --- N6) same setup as N4), but run `nmcli monitor` and look at `ps aux` for the RSS size. USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND [1] me 1492900 21.0 0.2 461348 33248 pts/10 Sl+ 15:02 0:00 nmcli monitor [2] me 1490721 5.0 0.2 461496 33548 pts/10 Sl+ 15:00 0:00 nmcli monitor [3] me 1495801 16.5 0.1 459476 28692 pts/10 Sl+ 15:04 0:00 nmcli monitor
2019-10-30 11:42:58 +01:00
typedef struct _NMDevicePrivate {
NMLDBusPropertyO property_o[_PROPERTY_O_IDX_NUM];
NMLDBusPropertyAO available_connections;
GPtrArray *lldp_neighbors;
char *driver;
char *driver_version;
char *hw_address;
libnm: refactor caching of D-Bus objects in NMClient No longer use GDBusObjectMangaerClient and gdbus-codegen generated classes for the NMClient cache. Instead, use GDBusConnection directly and a custom implementation (NMLDBusObject) for caching D-Bus' ObjectManager data. CHANGES ------- - This is a complete rework. I think the previous implementation was difficult to understand. There were unfixed bugs and nobody understood the code well enough to fix them. Maybe somebody out there understood the code, but I certainly did not. At least nobody provided patches to fix those issues. I do believe that this implementation is more straightforward and easier to understand. It removes a lot of layers of code. Whether this claim of simplicity is true, each reader must decide for himself/herself. Note that it is still fairly complex. - There was a lingering performance issue with large number of D-Bus objects. The patch tries hard that the implementation scales well. Of course, when we cache N objects that have N-to-M references to other, we still are fundamentally O(N*M) for runtime and memory consumption (with M being the number of references between objects). But each part should behave efficiently and well. - Play well with GMainContext. libnm code (NMClient) is generally not thread safe. However, it should work to use multiple instances in parallel, as long as each access to a NMClient is through the caller's GMainContext. This follows glib's style and effectively allows to use NMClient in a multi threaded scenario. This implies to stick to a main context upon construction and ensure that callbacks are only invoked when iterating that context. Also, NMClient itself shall never iterate the caller's context. This also means, libnm must never use g_idle_add() or g_timeout_add(), as those enqueue sources in the g_main_context_default() context. - Get ordering of messages right. All events are consistently enqueued in a GMainContext and processed strictly in order. For example, previously "nm-object.c" tried to combine signals and emit them on an idle handler. That is wrong, signals must be emitted in the right order and when they happen. Note that when using GInitable's synchronous initialization to initialize the NMClient instance, NMClient internally still operates fully asynchronously. In that case NMClient has an internal main context. - NMClient takes over most of the functionality. When using D-Bus' ObjectManager interface, one needs to handle basically the entire state of the D-Bus interface. That cannot be separated well into distinct parts, and even if you try, you just end up having closely related code in different source files. Spreading related code does not make it easier to understand, on the contrary. That means, NMClient is inherently complex as it contains most of the logic. I think that is not avoidable, but it's not as bad as it sounds. - NMClient processes D-Bus messages and state changes in separate steps. First NMClient unpacks the message (e.g. _dbus_handle_properties_changed()) and keeps track of the changed data. Then we update the GObject instances (_dbus_handle_obj_changed_dbus()) without emitting any signals yet. Finally, we emit all signals and notifications that were collected (_dbus_handle_changes_commit()). Note that for example during the initial GetManagedObjects() reply, NMClient receive a large amount of state at once. But we first apply all the changes to our GObject instances before emitting any signals. The result is that signals are always emitted in a moment when the cache is consistent. The unavoidable downside is that when you receive a property changed signal, possibly many other properties changed already and more signals are about to be emitted. - NMDeviceWifi no longer modifies the content of the cache from client side during poke_wireless_devices_with_rf_status(). The content of the cache should be determined by D-Bus alone and follow what NetworkManager service exposes. Local modifications should be avoided. - This aims to bring no API/ABI change, though it does of course bring various subtle changes in behavior. Those should be all for the better, but the goal is not to break any existing clients. This does change internal (albeit externally visible) API, like dropping NM_OBJECT_DBUS_OBJECT_MANAGER property and NMObject no longer implementing GInitableIface and GAsyncInitableIface. - Some uses of gdbus-codegen classes remain in NMVpnPluginOld, NMVpnServicePlugin and NMSecretAgentOld. These are independent of NMClient/NMObject and should be reworked separately. - While we no longer use generated classes from gdbus-codegen, we don't need more glue code than before. Also before we constructed NMPropertiesInfo and a had large amount of code to propagate properties from NMDBus* to NMObject. That got completely reworked, but did not fundamentally change. You still need about the same effort to create the NMLDBusMetaIface. Not using generated bindings did not make anything worse (which tells about the usefulness of generated code, at least in the way it was used). - NMLDBusMetaIface and other meta data is static and immutable. This avoids copying them around. Also, macros like NML_DBUS_META_PROPERTY_INIT_U() have compile time checks to ensure the property types matches. It's pretty hard to misuse them because it won't compile. - The meta data now explicitly encodes the expected D-Bus types and makes sure never to accept wrong data. That would only matter when the server (accidentally or intentionally) exposes unexpected types on D-Bus. I don't think that was previously ensured in all cases. For example, demarshal_generic() only cared about the GObject property type, it didn't know the expected D-Bus type. - Previously GDBusObjectManager would sometimes emit warnings (g_log()). Those probably indicated real bugs. In any case, it prevented us from running CI with G_DEBUG=fatal-warnings, because there would be just too many unrelated crashes. Now we log debug messages that can be enabled with "LIBNM_CLIENT_DEBUG=trace". Some of these messages can also be turned into g_warning()/g_critical() by setting LIBNM_CLIENT_DEBUG=warning,error. Together with G_DEBUG=fatal-warnings, this turns them into assertions. Note that such "assertion failures" might also happen because of a server bug (or change). Thus these are not common assertions that indicate a bug in libnm and are thus not armed unless explicitly requested. In our CI we should now always run with LIBNM_CLIENT_DEBUG=warning,error and G_DEBUG=fatal-warnings and to catch bugs. Note that currently NetworkManager has bugs in this regard, so enabling this will result in assertion failures. That should be fixed first. - Note that this changes the order in which we emit "notify:devices" and "device-added" signals. I think it makes the most sense to emit first "device-removed", then "notify:devices", and finally "device-added" signals. This changes behavior for commit 52ae28f6e5bf ('libnm: queue added/removed signals and suppress uninitialized notifications'), but I don't think that users should actually rely on the order. Still, the new order makes the most sense to me. - In NetworkManager, profiles can be invisible to the user by setting "connection.permissions". Such profiles would be hidden by NMClient's nm_client_get_connections() and their "connection-added"/"connection-removed" signals. Note that NMActiveConnection's nm_active_connection_get_connection() and NMDevice's nm_device_get_available_connections() still exposes such hidden NMRemoteConnection instances. This behavior was preserved. NUMBERS ------- I compared 3 versions of libnm. [1] 962297f9085d, current tip of nm-1-20 branch [2] 4fad8c7c642e, current master, immediate parent of this patch [3] this patch All tests were done on Fedora 31, x86_64, gcc 9.2.1-1.fc31. The libraries were build with $ ./contrib/fedora/rpm/build_clean.sh -g -w test -W debug Note that RPM build already stripped the library. --- N1) File size of libnm.so.0.1.0 in bytes. There currently seems to be a issue on Fedora 31 generating wrong ELF notes. Usually, libnm is smaller but in these tests it had large (and bogus) ELF notes. Anyway, the point is to show the relative sizes, so it doesn't matter). [1] 4075552 (102.7%) [2] 3969624 (100.0%) [3] 3705208 ( 93.3%) --- N2) `size /usr/lib64/libnm.so.0.1.0`: text data bss dec hex filename [1] 1314569 (102.0%) 69980 ( 94.8%) 10632 ( 80.4%) 1395181 (101.4%) 1549ed /usr/lib64/libnm.so.0.1.0 [2] 1288410 (100.0%) 73796 (100.0%) 13224 (100.0%) 1375430 (100.0%) 14fcc6 /usr/lib64/libnm.so.0.1.0 [3] 1229066 ( 95.4%) 65248 ( 88.4%) 13400 (101.3%) 1307714 ( 95.1%) 13f442 /usr/lib64/libnm.so.0.1.0 --- N3) Performance test with test-client.py. With checkout of [2], run ``` prepare_checkout() { rm -rf /tmp/nm-test && \ git checkout -B test 4fad8c7c642e && \ git clean -fdx && \ ./autogen.sh --prefix=/tmp/nm-test && \ make -j 5 install && \ make -j 5 check-local-clients-tests-test-client } prepare_test() { NM_TEST_REGENERATE=1 NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v } do_test() { for i in {1..10}; do NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v || return -1 done echo "done!" } prepare_checkout prepare_test time do_test ``` [1] real 2m14.497s (101.3%) user 5m26.651s (100.3%) sys 1m40.453s (101.4%) [2] real 2m12.800s (100.0%) user 5m25.619s (100.0%) sys 1m39.065s (100.0%) [3] real 1m54.915s ( 86.5%) user 4m18.585s ( 79.4%) sys 1m32.066s ( 92.9%) --- N4) Performance. Run NetworkManager from build [2] and setup a large number of profiles (551 profiles and 515 devices, mostly unrealized). This setup is already at the edge of what NetworkManager currently can handle. Of course, that is a different issue. Here we just check how long plain `nmcli` takes on the system. ``` do_cleanup() { for UUID in $(nmcli -g NAME,UUID connection show | sed -n 's/^xx-c-.*:\([^:]\+\)$/\1/p'); do nmcli connection delete uuid "$UUID" done for DEVICE in $(nmcli -g DEVICE device status | grep '^xx-i-'); do nmcli device delete "$DEVICE" done } do_setup() { do_cleanup for i in {1..30}; do nmcli connection add type bond autoconnect no con-name xx-c-bond-$i ifname xx-i-bond-$i ipv4.method disabled ipv6.method ignore for j in $(seq $i 30); do nmcli connection add type vlan autoconnect no con-name xx-c-vlan-$i-$j vlan.id $j ifname xx-i-vlan-$i-$j vlan.parent xx-i-bond-$i ipv4.method disabled ipv6.method ignore done done systemctl restart NetworkManager.service sleep 5 } do_test() { perf stat -r 50 -B nmcli 1>/dev/null } do_test ``` [1] Performance counter stats for 'nmcli' (50 runs): 456.33 msec task-clock:u # 1.093 CPUs utilized ( +- 0.44% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,900 page-faults:u # 0.013 M/sec ( +- 0.02% ) 1,408,675,453 cycles:u # 3.087 GHz ( +- 0.48% ) 1,594,741,060 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 368,744,018 branches:u # 808.061 M/sec ( +- 0.02% ) 4,566,058 branch-misses:u # 1.24% of all branches ( +- 0.76% ) 0.41761 +- 0.00282 seconds time elapsed ( +- 0.68% ) [2] Performance counter stats for 'nmcli' (50 runs): 477.99 msec task-clock:u # 1.088 CPUs utilized ( +- 0.36% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,948 page-faults:u # 0.012 M/sec ( +- 0.03% ) 1,471,133,482 cycles:u # 3.078 GHz ( +- 0.36% ) 1,655,275,369 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 382,595,152 branches:u # 800.433 M/sec ( +- 0.02% ) 4,746,070 branch-misses:u # 1.24% of all branches ( +- 0.49% ) 0.43923 +- 0.00242 seconds time elapsed ( +- 0.55% ) [3] Performance counter stats for 'nmcli' (50 runs): 352.36 msec task-clock:u # 1.027 CPUs utilized ( +- 0.32% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 4,790 page-faults:u # 0.014 M/sec ( +- 0.26% ) 1,092,341,186 cycles:u # 3.100 GHz ( +- 0.26% ) 1,209,045,283 instructions:u # 1.11 insn per cycle ( +- 0.02% ) 281,708,462 branches:u # 799.499 M/sec ( +- 0.01% ) 3,101,031 branch-misses:u # 1.10% of all branches ( +- 0.61% ) 0.34296 +- 0.00120 seconds time elapsed ( +- 0.35% ) --- N5) same setup as N4), but run `PAGER= /bin/time -v nmcli`: [1] Command being timed: "nmcli" User time (seconds): 0.42 System time (seconds): 0.04 Percent of CPU this job got: 107% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.43 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34456 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6128 Voluntary context switches: 1298 Involuntary context switches: 1106 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [2] Command being timed: "nmcli" User time (seconds): 0.44 System time (seconds): 0.04 Percent of CPU this job got: 108% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.44 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34452 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6169 Voluntary context switches: 1849 Involuntary context switches: 142 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [3] Command being timed: "nmcli" User time (seconds): 0.32 System time (seconds): 0.02 Percent of CPU this job got: 102% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.34 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 29196 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 5059 Voluntary context switches: 919 Involuntary context switches: 685 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 --- N6) same setup as N4), but run `nmcli monitor` and look at `ps aux` for the RSS size. USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND [1] me 1492900 21.0 0.2 461348 33248 pts/10 Sl+ 15:02 0:00 nmcli monitor [2] me 1490721 5.0 0.2 461496 33548 pts/10 Sl+ 15:00 0:00 nmcli monitor [3] me 1495801 16.5 0.1 459476 28692 pts/10 Sl+ 15:04 0:00 nmcli monitor
2019-10-30 11:42:58 +01:00
char *interface;
char *ip_interface;
char *firmware_version;
libnm: refactor caching of D-Bus objects in NMClient No longer use GDBusObjectMangaerClient and gdbus-codegen generated classes for the NMClient cache. Instead, use GDBusConnection directly and a custom implementation (NMLDBusObject) for caching D-Bus' ObjectManager data. CHANGES ------- - This is a complete rework. I think the previous implementation was difficult to understand. There were unfixed bugs and nobody understood the code well enough to fix them. Maybe somebody out there understood the code, but I certainly did not. At least nobody provided patches to fix those issues. I do believe that this implementation is more straightforward and easier to understand. It removes a lot of layers of code. Whether this claim of simplicity is true, each reader must decide for himself/herself. Note that it is still fairly complex. - There was a lingering performance issue with large number of D-Bus objects. The patch tries hard that the implementation scales well. Of course, when we cache N objects that have N-to-M references to other, we still are fundamentally O(N*M) for runtime and memory consumption (with M being the number of references between objects). But each part should behave efficiently and well. - Play well with GMainContext. libnm code (NMClient) is generally not thread safe. However, it should work to use multiple instances in parallel, as long as each access to a NMClient is through the caller's GMainContext. This follows glib's style and effectively allows to use NMClient in a multi threaded scenario. This implies to stick to a main context upon construction and ensure that callbacks are only invoked when iterating that context. Also, NMClient itself shall never iterate the caller's context. This also means, libnm must never use g_idle_add() or g_timeout_add(), as those enqueue sources in the g_main_context_default() context. - Get ordering of messages right. All events are consistently enqueued in a GMainContext and processed strictly in order. For example, previously "nm-object.c" tried to combine signals and emit them on an idle handler. That is wrong, signals must be emitted in the right order and when they happen. Note that when using GInitable's synchronous initialization to initialize the NMClient instance, NMClient internally still operates fully asynchronously. In that case NMClient has an internal main context. - NMClient takes over most of the functionality. When using D-Bus' ObjectManager interface, one needs to handle basically the entire state of the D-Bus interface. That cannot be separated well into distinct parts, and even if you try, you just end up having closely related code in different source files. Spreading related code does not make it easier to understand, on the contrary. That means, NMClient is inherently complex as it contains most of the logic. I think that is not avoidable, but it's not as bad as it sounds. - NMClient processes D-Bus messages and state changes in separate steps. First NMClient unpacks the message (e.g. _dbus_handle_properties_changed()) and keeps track of the changed data. Then we update the GObject instances (_dbus_handle_obj_changed_dbus()) without emitting any signals yet. Finally, we emit all signals and notifications that were collected (_dbus_handle_changes_commit()). Note that for example during the initial GetManagedObjects() reply, NMClient receive a large amount of state at once. But we first apply all the changes to our GObject instances before emitting any signals. The result is that signals are always emitted in a moment when the cache is consistent. The unavoidable downside is that when you receive a property changed signal, possibly many other properties changed already and more signals are about to be emitted. - NMDeviceWifi no longer modifies the content of the cache from client side during poke_wireless_devices_with_rf_status(). The content of the cache should be determined by D-Bus alone and follow what NetworkManager service exposes. Local modifications should be avoided. - This aims to bring no API/ABI change, though it does of course bring various subtle changes in behavior. Those should be all for the better, but the goal is not to break any existing clients. This does change internal (albeit externally visible) API, like dropping NM_OBJECT_DBUS_OBJECT_MANAGER property and NMObject no longer implementing GInitableIface and GAsyncInitableIface. - Some uses of gdbus-codegen classes remain in NMVpnPluginOld, NMVpnServicePlugin and NMSecretAgentOld. These are independent of NMClient/NMObject and should be reworked separately. - While we no longer use generated classes from gdbus-codegen, we don't need more glue code than before. Also before we constructed NMPropertiesInfo and a had large amount of code to propagate properties from NMDBus* to NMObject. That got completely reworked, but did not fundamentally change. You still need about the same effort to create the NMLDBusMetaIface. Not using generated bindings did not make anything worse (which tells about the usefulness of generated code, at least in the way it was used). - NMLDBusMetaIface and other meta data is static and immutable. This avoids copying them around. Also, macros like NML_DBUS_META_PROPERTY_INIT_U() have compile time checks to ensure the property types matches. It's pretty hard to misuse them because it won't compile. - The meta data now explicitly encodes the expected D-Bus types and makes sure never to accept wrong data. That would only matter when the server (accidentally or intentionally) exposes unexpected types on D-Bus. I don't think that was previously ensured in all cases. For example, demarshal_generic() only cared about the GObject property type, it didn't know the expected D-Bus type. - Previously GDBusObjectManager would sometimes emit warnings (g_log()). Those probably indicated real bugs. In any case, it prevented us from running CI with G_DEBUG=fatal-warnings, because there would be just too many unrelated crashes. Now we log debug messages that can be enabled with "LIBNM_CLIENT_DEBUG=trace". Some of these messages can also be turned into g_warning()/g_critical() by setting LIBNM_CLIENT_DEBUG=warning,error. Together with G_DEBUG=fatal-warnings, this turns them into assertions. Note that such "assertion failures" might also happen because of a server bug (or change). Thus these are not common assertions that indicate a bug in libnm and are thus not armed unless explicitly requested. In our CI we should now always run with LIBNM_CLIENT_DEBUG=warning,error and G_DEBUG=fatal-warnings and to catch bugs. Note that currently NetworkManager has bugs in this regard, so enabling this will result in assertion failures. That should be fixed first. - Note that this changes the order in which we emit "notify:devices" and "device-added" signals. I think it makes the most sense to emit first "device-removed", then "notify:devices", and finally "device-added" signals. This changes behavior for commit 52ae28f6e5bf ('libnm: queue added/removed signals and suppress uninitialized notifications'), but I don't think that users should actually rely on the order. Still, the new order makes the most sense to me. - In NetworkManager, profiles can be invisible to the user by setting "connection.permissions". Such profiles would be hidden by NMClient's nm_client_get_connections() and their "connection-added"/"connection-removed" signals. Note that NMActiveConnection's nm_active_connection_get_connection() and NMDevice's nm_device_get_available_connections() still exposes such hidden NMRemoteConnection instances. This behavior was preserved. NUMBERS ------- I compared 3 versions of libnm. [1] 962297f9085d, current tip of nm-1-20 branch [2] 4fad8c7c642e, current master, immediate parent of this patch [3] this patch All tests were done on Fedora 31, x86_64, gcc 9.2.1-1.fc31. The libraries were build with $ ./contrib/fedora/rpm/build_clean.sh -g -w test -W debug Note that RPM build already stripped the library. --- N1) File size of libnm.so.0.1.0 in bytes. There currently seems to be a issue on Fedora 31 generating wrong ELF notes. Usually, libnm is smaller but in these tests it had large (and bogus) ELF notes. Anyway, the point is to show the relative sizes, so it doesn't matter). [1] 4075552 (102.7%) [2] 3969624 (100.0%) [3] 3705208 ( 93.3%) --- N2) `size /usr/lib64/libnm.so.0.1.0`: text data bss dec hex filename [1] 1314569 (102.0%) 69980 ( 94.8%) 10632 ( 80.4%) 1395181 (101.4%) 1549ed /usr/lib64/libnm.so.0.1.0 [2] 1288410 (100.0%) 73796 (100.0%) 13224 (100.0%) 1375430 (100.0%) 14fcc6 /usr/lib64/libnm.so.0.1.0 [3] 1229066 ( 95.4%) 65248 ( 88.4%) 13400 (101.3%) 1307714 ( 95.1%) 13f442 /usr/lib64/libnm.so.0.1.0 --- N3) Performance test with test-client.py. With checkout of [2], run ``` prepare_checkout() { rm -rf /tmp/nm-test && \ git checkout -B test 4fad8c7c642e && \ git clean -fdx && \ ./autogen.sh --prefix=/tmp/nm-test && \ make -j 5 install && \ make -j 5 check-local-clients-tests-test-client } prepare_test() { NM_TEST_REGENERATE=1 NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v } do_test() { for i in {1..10}; do NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v || return -1 done echo "done!" } prepare_checkout prepare_test time do_test ``` [1] real 2m14.497s (101.3%) user 5m26.651s (100.3%) sys 1m40.453s (101.4%) [2] real 2m12.800s (100.0%) user 5m25.619s (100.0%) sys 1m39.065s (100.0%) [3] real 1m54.915s ( 86.5%) user 4m18.585s ( 79.4%) sys 1m32.066s ( 92.9%) --- N4) Performance. Run NetworkManager from build [2] and setup a large number of profiles (551 profiles and 515 devices, mostly unrealized). This setup is already at the edge of what NetworkManager currently can handle. Of course, that is a different issue. Here we just check how long plain `nmcli` takes on the system. ``` do_cleanup() { for UUID in $(nmcli -g NAME,UUID connection show | sed -n 's/^xx-c-.*:\([^:]\+\)$/\1/p'); do nmcli connection delete uuid "$UUID" done for DEVICE in $(nmcli -g DEVICE device status | grep '^xx-i-'); do nmcli device delete "$DEVICE" done } do_setup() { do_cleanup for i in {1..30}; do nmcli connection add type bond autoconnect no con-name xx-c-bond-$i ifname xx-i-bond-$i ipv4.method disabled ipv6.method ignore for j in $(seq $i 30); do nmcli connection add type vlan autoconnect no con-name xx-c-vlan-$i-$j vlan.id $j ifname xx-i-vlan-$i-$j vlan.parent xx-i-bond-$i ipv4.method disabled ipv6.method ignore done done systemctl restart NetworkManager.service sleep 5 } do_test() { perf stat -r 50 -B nmcli 1>/dev/null } do_test ``` [1] Performance counter stats for 'nmcli' (50 runs): 456.33 msec task-clock:u # 1.093 CPUs utilized ( +- 0.44% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,900 page-faults:u # 0.013 M/sec ( +- 0.02% ) 1,408,675,453 cycles:u # 3.087 GHz ( +- 0.48% ) 1,594,741,060 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 368,744,018 branches:u # 808.061 M/sec ( +- 0.02% ) 4,566,058 branch-misses:u # 1.24% of all branches ( +- 0.76% ) 0.41761 +- 0.00282 seconds time elapsed ( +- 0.68% ) [2] Performance counter stats for 'nmcli' (50 runs): 477.99 msec task-clock:u # 1.088 CPUs utilized ( +- 0.36% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,948 page-faults:u # 0.012 M/sec ( +- 0.03% ) 1,471,133,482 cycles:u # 3.078 GHz ( +- 0.36% ) 1,655,275,369 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 382,595,152 branches:u # 800.433 M/sec ( +- 0.02% ) 4,746,070 branch-misses:u # 1.24% of all branches ( +- 0.49% ) 0.43923 +- 0.00242 seconds time elapsed ( +- 0.55% ) [3] Performance counter stats for 'nmcli' (50 runs): 352.36 msec task-clock:u # 1.027 CPUs utilized ( +- 0.32% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 4,790 page-faults:u # 0.014 M/sec ( +- 0.26% ) 1,092,341,186 cycles:u # 3.100 GHz ( +- 0.26% ) 1,209,045,283 instructions:u # 1.11 insn per cycle ( +- 0.02% ) 281,708,462 branches:u # 799.499 M/sec ( +- 0.01% ) 3,101,031 branch-misses:u # 1.10% of all branches ( +- 0.61% ) 0.34296 +- 0.00120 seconds time elapsed ( +- 0.35% ) --- N5) same setup as N4), but run `PAGER= /bin/time -v nmcli`: [1] Command being timed: "nmcli" User time (seconds): 0.42 System time (seconds): 0.04 Percent of CPU this job got: 107% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.43 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34456 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6128 Voluntary context switches: 1298 Involuntary context switches: 1106 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [2] Command being timed: "nmcli" User time (seconds): 0.44 System time (seconds): 0.04 Percent of CPU this job got: 108% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.44 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34452 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6169 Voluntary context switches: 1849 Involuntary context switches: 142 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [3] Command being timed: "nmcli" User time (seconds): 0.32 System time (seconds): 0.02 Percent of CPU this job got: 102% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.34 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 29196 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 5059 Voluntary context switches: 919 Involuntary context switches: 685 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 --- N6) same setup as N4), but run `nmcli monitor` and look at `ps aux` for the RSS size. USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND [1] me 1492900 21.0 0.2 461348 33248 pts/10 Sl+ 15:02 0:00 nmcli monitor [2] me 1490721 5.0 0.2 461496 33548 pts/10 Sl+ 15:00 0:00 nmcli monitor [3] me 1495801 16.5 0.1 459476 28692 pts/10 Sl+ 15:04 0:00 nmcli monitor
2019-10-30 11:42:58 +01:00
char *physical_port_id;
char *udi;
char *path;
libnm: refactor caching of D-Bus objects in NMClient No longer use GDBusObjectMangaerClient and gdbus-codegen generated classes for the NMClient cache. Instead, use GDBusConnection directly and a custom implementation (NMLDBusObject) for caching D-Bus' ObjectManager data. CHANGES ------- - This is a complete rework. I think the previous implementation was difficult to understand. There were unfixed bugs and nobody understood the code well enough to fix them. Maybe somebody out there understood the code, but I certainly did not. At least nobody provided patches to fix those issues. I do believe that this implementation is more straightforward and easier to understand. It removes a lot of layers of code. Whether this claim of simplicity is true, each reader must decide for himself/herself. Note that it is still fairly complex. - There was a lingering performance issue with large number of D-Bus objects. The patch tries hard that the implementation scales well. Of course, when we cache N objects that have N-to-M references to other, we still are fundamentally O(N*M) for runtime and memory consumption (with M being the number of references between objects). But each part should behave efficiently and well. - Play well with GMainContext. libnm code (NMClient) is generally not thread safe. However, it should work to use multiple instances in parallel, as long as each access to a NMClient is through the caller's GMainContext. This follows glib's style and effectively allows to use NMClient in a multi threaded scenario. This implies to stick to a main context upon construction and ensure that callbacks are only invoked when iterating that context. Also, NMClient itself shall never iterate the caller's context. This also means, libnm must never use g_idle_add() or g_timeout_add(), as those enqueue sources in the g_main_context_default() context. - Get ordering of messages right. All events are consistently enqueued in a GMainContext and processed strictly in order. For example, previously "nm-object.c" tried to combine signals and emit them on an idle handler. That is wrong, signals must be emitted in the right order and when they happen. Note that when using GInitable's synchronous initialization to initialize the NMClient instance, NMClient internally still operates fully asynchronously. In that case NMClient has an internal main context. - NMClient takes over most of the functionality. When using D-Bus' ObjectManager interface, one needs to handle basically the entire state of the D-Bus interface. That cannot be separated well into distinct parts, and even if you try, you just end up having closely related code in different source files. Spreading related code does not make it easier to understand, on the contrary. That means, NMClient is inherently complex as it contains most of the logic. I think that is not avoidable, but it's not as bad as it sounds. - NMClient processes D-Bus messages and state changes in separate steps. First NMClient unpacks the message (e.g. _dbus_handle_properties_changed()) and keeps track of the changed data. Then we update the GObject instances (_dbus_handle_obj_changed_dbus()) without emitting any signals yet. Finally, we emit all signals and notifications that were collected (_dbus_handle_changes_commit()). Note that for example during the initial GetManagedObjects() reply, NMClient receive a large amount of state at once. But we first apply all the changes to our GObject instances before emitting any signals. The result is that signals are always emitted in a moment when the cache is consistent. The unavoidable downside is that when you receive a property changed signal, possibly many other properties changed already and more signals are about to be emitted. - NMDeviceWifi no longer modifies the content of the cache from client side during poke_wireless_devices_with_rf_status(). The content of the cache should be determined by D-Bus alone and follow what NetworkManager service exposes. Local modifications should be avoided. - This aims to bring no API/ABI change, though it does of course bring various subtle changes in behavior. Those should be all for the better, but the goal is not to break any existing clients. This does change internal (albeit externally visible) API, like dropping NM_OBJECT_DBUS_OBJECT_MANAGER property and NMObject no longer implementing GInitableIface and GAsyncInitableIface. - Some uses of gdbus-codegen classes remain in NMVpnPluginOld, NMVpnServicePlugin and NMSecretAgentOld. These are independent of NMClient/NMObject and should be reworked separately. - While we no longer use generated classes from gdbus-codegen, we don't need more glue code than before. Also before we constructed NMPropertiesInfo and a had large amount of code to propagate properties from NMDBus* to NMObject. That got completely reworked, but did not fundamentally change. You still need about the same effort to create the NMLDBusMetaIface. Not using generated bindings did not make anything worse (which tells about the usefulness of generated code, at least in the way it was used). - NMLDBusMetaIface and other meta data is static and immutable. This avoids copying them around. Also, macros like NML_DBUS_META_PROPERTY_INIT_U() have compile time checks to ensure the property types matches. It's pretty hard to misuse them because it won't compile. - The meta data now explicitly encodes the expected D-Bus types and makes sure never to accept wrong data. That would only matter when the server (accidentally or intentionally) exposes unexpected types on D-Bus. I don't think that was previously ensured in all cases. For example, demarshal_generic() only cared about the GObject property type, it didn't know the expected D-Bus type. - Previously GDBusObjectManager would sometimes emit warnings (g_log()). Those probably indicated real bugs. In any case, it prevented us from running CI with G_DEBUG=fatal-warnings, because there would be just too many unrelated crashes. Now we log debug messages that can be enabled with "LIBNM_CLIENT_DEBUG=trace". Some of these messages can also be turned into g_warning()/g_critical() by setting LIBNM_CLIENT_DEBUG=warning,error. Together with G_DEBUG=fatal-warnings, this turns them into assertions. Note that such "assertion failures" might also happen because of a server bug (or change). Thus these are not common assertions that indicate a bug in libnm and are thus not armed unless explicitly requested. In our CI we should now always run with LIBNM_CLIENT_DEBUG=warning,error and G_DEBUG=fatal-warnings and to catch bugs. Note that currently NetworkManager has bugs in this regard, so enabling this will result in assertion failures. That should be fixed first. - Note that this changes the order in which we emit "notify:devices" and "device-added" signals. I think it makes the most sense to emit first "device-removed", then "notify:devices", and finally "device-added" signals. This changes behavior for commit 52ae28f6e5bf ('libnm: queue added/removed signals and suppress uninitialized notifications'), but I don't think that users should actually rely on the order. Still, the new order makes the most sense to me. - In NetworkManager, profiles can be invisible to the user by setting "connection.permissions". Such profiles would be hidden by NMClient's nm_client_get_connections() and their "connection-added"/"connection-removed" signals. Note that NMActiveConnection's nm_active_connection_get_connection() and NMDevice's nm_device_get_available_connections() still exposes such hidden NMRemoteConnection instances. This behavior was preserved. NUMBERS ------- I compared 3 versions of libnm. [1] 962297f9085d, current tip of nm-1-20 branch [2] 4fad8c7c642e, current master, immediate parent of this patch [3] this patch All tests were done on Fedora 31, x86_64, gcc 9.2.1-1.fc31. The libraries were build with $ ./contrib/fedora/rpm/build_clean.sh -g -w test -W debug Note that RPM build already stripped the library. --- N1) File size of libnm.so.0.1.0 in bytes. There currently seems to be a issue on Fedora 31 generating wrong ELF notes. Usually, libnm is smaller but in these tests it had large (and bogus) ELF notes. Anyway, the point is to show the relative sizes, so it doesn't matter). [1] 4075552 (102.7%) [2] 3969624 (100.0%) [3] 3705208 ( 93.3%) --- N2) `size /usr/lib64/libnm.so.0.1.0`: text data bss dec hex filename [1] 1314569 (102.0%) 69980 ( 94.8%) 10632 ( 80.4%) 1395181 (101.4%) 1549ed /usr/lib64/libnm.so.0.1.0 [2] 1288410 (100.0%) 73796 (100.0%) 13224 (100.0%) 1375430 (100.0%) 14fcc6 /usr/lib64/libnm.so.0.1.0 [3] 1229066 ( 95.4%) 65248 ( 88.4%) 13400 (101.3%) 1307714 ( 95.1%) 13f442 /usr/lib64/libnm.so.0.1.0 --- N3) Performance test with test-client.py. With checkout of [2], run ``` prepare_checkout() { rm -rf /tmp/nm-test && \ git checkout -B test 4fad8c7c642e && \ git clean -fdx && \ ./autogen.sh --prefix=/tmp/nm-test && \ make -j 5 install && \ make -j 5 check-local-clients-tests-test-client } prepare_test() { NM_TEST_REGENERATE=1 NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v } do_test() { for i in {1..10}; do NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v || return -1 done echo "done!" } prepare_checkout prepare_test time do_test ``` [1] real 2m14.497s (101.3%) user 5m26.651s (100.3%) sys 1m40.453s (101.4%) [2] real 2m12.800s (100.0%) user 5m25.619s (100.0%) sys 1m39.065s (100.0%) [3] real 1m54.915s ( 86.5%) user 4m18.585s ( 79.4%) sys 1m32.066s ( 92.9%) --- N4) Performance. Run NetworkManager from build [2] and setup a large number of profiles (551 profiles and 515 devices, mostly unrealized). This setup is already at the edge of what NetworkManager currently can handle. Of course, that is a different issue. Here we just check how long plain `nmcli` takes on the system. ``` do_cleanup() { for UUID in $(nmcli -g NAME,UUID connection show | sed -n 's/^xx-c-.*:\([^:]\+\)$/\1/p'); do nmcli connection delete uuid "$UUID" done for DEVICE in $(nmcli -g DEVICE device status | grep '^xx-i-'); do nmcli device delete "$DEVICE" done } do_setup() { do_cleanup for i in {1..30}; do nmcli connection add type bond autoconnect no con-name xx-c-bond-$i ifname xx-i-bond-$i ipv4.method disabled ipv6.method ignore for j in $(seq $i 30); do nmcli connection add type vlan autoconnect no con-name xx-c-vlan-$i-$j vlan.id $j ifname xx-i-vlan-$i-$j vlan.parent xx-i-bond-$i ipv4.method disabled ipv6.method ignore done done systemctl restart NetworkManager.service sleep 5 } do_test() { perf stat -r 50 -B nmcli 1>/dev/null } do_test ``` [1] Performance counter stats for 'nmcli' (50 runs): 456.33 msec task-clock:u # 1.093 CPUs utilized ( +- 0.44% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,900 page-faults:u # 0.013 M/sec ( +- 0.02% ) 1,408,675,453 cycles:u # 3.087 GHz ( +- 0.48% ) 1,594,741,060 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 368,744,018 branches:u # 808.061 M/sec ( +- 0.02% ) 4,566,058 branch-misses:u # 1.24% of all branches ( +- 0.76% ) 0.41761 +- 0.00282 seconds time elapsed ( +- 0.68% ) [2] Performance counter stats for 'nmcli' (50 runs): 477.99 msec task-clock:u # 1.088 CPUs utilized ( +- 0.36% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,948 page-faults:u # 0.012 M/sec ( +- 0.03% ) 1,471,133,482 cycles:u # 3.078 GHz ( +- 0.36% ) 1,655,275,369 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 382,595,152 branches:u # 800.433 M/sec ( +- 0.02% ) 4,746,070 branch-misses:u # 1.24% of all branches ( +- 0.49% ) 0.43923 +- 0.00242 seconds time elapsed ( +- 0.55% ) [3] Performance counter stats for 'nmcli' (50 runs): 352.36 msec task-clock:u # 1.027 CPUs utilized ( +- 0.32% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 4,790 page-faults:u # 0.014 M/sec ( +- 0.26% ) 1,092,341,186 cycles:u # 3.100 GHz ( +- 0.26% ) 1,209,045,283 instructions:u # 1.11 insn per cycle ( +- 0.02% ) 281,708,462 branches:u # 799.499 M/sec ( +- 0.01% ) 3,101,031 branch-misses:u # 1.10% of all branches ( +- 0.61% ) 0.34296 +- 0.00120 seconds time elapsed ( +- 0.35% ) --- N5) same setup as N4), but run `PAGER= /bin/time -v nmcli`: [1] Command being timed: "nmcli" User time (seconds): 0.42 System time (seconds): 0.04 Percent of CPU this job got: 107% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.43 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34456 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6128 Voluntary context switches: 1298 Involuntary context switches: 1106 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [2] Command being timed: "nmcli" User time (seconds): 0.44 System time (seconds): 0.04 Percent of CPU this job got: 108% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.44 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34452 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6169 Voluntary context switches: 1849 Involuntary context switches: 142 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [3] Command being timed: "nmcli" User time (seconds): 0.32 System time (seconds): 0.02 Percent of CPU this job got: 102% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.34 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 29196 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 5059 Voluntary context switches: 919 Involuntary context switches: 685 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 --- N6) same setup as N4), but run `nmcli monitor` and look at `ps aux` for the RSS size. USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND [1] me 1492900 21.0 0.2 461348 33248 pts/10 Sl+ 15:02 0:00 nmcli monitor [2] me 1490721 5.0 0.2 461496 33548 pts/10 Sl+ 15:00 0:00 nmcli monitor [3] me 1495801 16.5 0.1 459476 28692 pts/10 Sl+ 15:04 0:00 nmcli monitor
2019-10-30 11:42:58 +01:00
guint32 capabilities;
guint32 device_type;
guint32 ip4_connectivity;
guint32 ip6_connectivity;
guint32 metered;
guint32 mtu;
guint32 state;
guint32 state_reason;
guint32 interface_flags;
bool firmware_missing;
bool nm_plugin_missing;
bool autoconnect;
bool managed;
bool real;
bool hw_address_is_new:1;
libnm: refactor caching of D-Bus objects in NMClient No longer use GDBusObjectMangaerClient and gdbus-codegen generated classes for the NMClient cache. Instead, use GDBusConnection directly and a custom implementation (NMLDBusObject) for caching D-Bus' ObjectManager data. CHANGES ------- - This is a complete rework. I think the previous implementation was difficult to understand. There were unfixed bugs and nobody understood the code well enough to fix them. Maybe somebody out there understood the code, but I certainly did not. At least nobody provided patches to fix those issues. I do believe that this implementation is more straightforward and easier to understand. It removes a lot of layers of code. Whether this claim of simplicity is true, each reader must decide for himself/herself. Note that it is still fairly complex. - There was a lingering performance issue with large number of D-Bus objects. The patch tries hard that the implementation scales well. Of course, when we cache N objects that have N-to-M references to other, we still are fundamentally O(N*M) for runtime and memory consumption (with M being the number of references between objects). But each part should behave efficiently and well. - Play well with GMainContext. libnm code (NMClient) is generally not thread safe. However, it should work to use multiple instances in parallel, as long as each access to a NMClient is through the caller's GMainContext. This follows glib's style and effectively allows to use NMClient in a multi threaded scenario. This implies to stick to a main context upon construction and ensure that callbacks are only invoked when iterating that context. Also, NMClient itself shall never iterate the caller's context. This also means, libnm must never use g_idle_add() or g_timeout_add(), as those enqueue sources in the g_main_context_default() context. - Get ordering of messages right. All events are consistently enqueued in a GMainContext and processed strictly in order. For example, previously "nm-object.c" tried to combine signals and emit them on an idle handler. That is wrong, signals must be emitted in the right order and when they happen. Note that when using GInitable's synchronous initialization to initialize the NMClient instance, NMClient internally still operates fully asynchronously. In that case NMClient has an internal main context. - NMClient takes over most of the functionality. When using D-Bus' ObjectManager interface, one needs to handle basically the entire state of the D-Bus interface. That cannot be separated well into distinct parts, and even if you try, you just end up having closely related code in different source files. Spreading related code does not make it easier to understand, on the contrary. That means, NMClient is inherently complex as it contains most of the logic. I think that is not avoidable, but it's not as bad as it sounds. - NMClient processes D-Bus messages and state changes in separate steps. First NMClient unpacks the message (e.g. _dbus_handle_properties_changed()) and keeps track of the changed data. Then we update the GObject instances (_dbus_handle_obj_changed_dbus()) without emitting any signals yet. Finally, we emit all signals and notifications that were collected (_dbus_handle_changes_commit()). Note that for example during the initial GetManagedObjects() reply, NMClient receive a large amount of state at once. But we first apply all the changes to our GObject instances before emitting any signals. The result is that signals are always emitted in a moment when the cache is consistent. The unavoidable downside is that when you receive a property changed signal, possibly many other properties changed already and more signals are about to be emitted. - NMDeviceWifi no longer modifies the content of the cache from client side during poke_wireless_devices_with_rf_status(). The content of the cache should be determined by D-Bus alone and follow what NetworkManager service exposes. Local modifications should be avoided. - This aims to bring no API/ABI change, though it does of course bring various subtle changes in behavior. Those should be all for the better, but the goal is not to break any existing clients. This does change internal (albeit externally visible) API, like dropping NM_OBJECT_DBUS_OBJECT_MANAGER property and NMObject no longer implementing GInitableIface and GAsyncInitableIface. - Some uses of gdbus-codegen classes remain in NMVpnPluginOld, NMVpnServicePlugin and NMSecretAgentOld. These are independent of NMClient/NMObject and should be reworked separately. - While we no longer use generated classes from gdbus-codegen, we don't need more glue code than before. Also before we constructed NMPropertiesInfo and a had large amount of code to propagate properties from NMDBus* to NMObject. That got completely reworked, but did not fundamentally change. You still need about the same effort to create the NMLDBusMetaIface. Not using generated bindings did not make anything worse (which tells about the usefulness of generated code, at least in the way it was used). - NMLDBusMetaIface and other meta data is static and immutable. This avoids copying them around. Also, macros like NML_DBUS_META_PROPERTY_INIT_U() have compile time checks to ensure the property types matches. It's pretty hard to misuse them because it won't compile. - The meta data now explicitly encodes the expected D-Bus types and makes sure never to accept wrong data. That would only matter when the server (accidentally or intentionally) exposes unexpected types on D-Bus. I don't think that was previously ensured in all cases. For example, demarshal_generic() only cared about the GObject property type, it didn't know the expected D-Bus type. - Previously GDBusObjectManager would sometimes emit warnings (g_log()). Those probably indicated real bugs. In any case, it prevented us from running CI with G_DEBUG=fatal-warnings, because there would be just too many unrelated crashes. Now we log debug messages that can be enabled with "LIBNM_CLIENT_DEBUG=trace". Some of these messages can also be turned into g_warning()/g_critical() by setting LIBNM_CLIENT_DEBUG=warning,error. Together with G_DEBUG=fatal-warnings, this turns them into assertions. Note that such "assertion failures" might also happen because of a server bug (or change). Thus these are not common assertions that indicate a bug in libnm and are thus not armed unless explicitly requested. In our CI we should now always run with LIBNM_CLIENT_DEBUG=warning,error and G_DEBUG=fatal-warnings and to catch bugs. Note that currently NetworkManager has bugs in this regard, so enabling this will result in assertion failures. That should be fixed first. - Note that this changes the order in which we emit "notify:devices" and "device-added" signals. I think it makes the most sense to emit first "device-removed", then "notify:devices", and finally "device-added" signals. This changes behavior for commit 52ae28f6e5bf ('libnm: queue added/removed signals and suppress uninitialized notifications'), but I don't think that users should actually rely on the order. Still, the new order makes the most sense to me. - In NetworkManager, profiles can be invisible to the user by setting "connection.permissions". Such profiles would be hidden by NMClient's nm_client_get_connections() and their "connection-added"/"connection-removed" signals. Note that NMActiveConnection's nm_active_connection_get_connection() and NMDevice's nm_device_get_available_connections() still exposes such hidden NMRemoteConnection instances. This behavior was preserved. NUMBERS ------- I compared 3 versions of libnm. [1] 962297f9085d, current tip of nm-1-20 branch [2] 4fad8c7c642e, current master, immediate parent of this patch [3] this patch All tests were done on Fedora 31, x86_64, gcc 9.2.1-1.fc31. The libraries were build with $ ./contrib/fedora/rpm/build_clean.sh -g -w test -W debug Note that RPM build already stripped the library. --- N1) File size of libnm.so.0.1.0 in bytes. There currently seems to be a issue on Fedora 31 generating wrong ELF notes. Usually, libnm is smaller but in these tests it had large (and bogus) ELF notes. Anyway, the point is to show the relative sizes, so it doesn't matter). [1] 4075552 (102.7%) [2] 3969624 (100.0%) [3] 3705208 ( 93.3%) --- N2) `size /usr/lib64/libnm.so.0.1.0`: text data bss dec hex filename [1] 1314569 (102.0%) 69980 ( 94.8%) 10632 ( 80.4%) 1395181 (101.4%) 1549ed /usr/lib64/libnm.so.0.1.0 [2] 1288410 (100.0%) 73796 (100.0%) 13224 (100.0%) 1375430 (100.0%) 14fcc6 /usr/lib64/libnm.so.0.1.0 [3] 1229066 ( 95.4%) 65248 ( 88.4%) 13400 (101.3%) 1307714 ( 95.1%) 13f442 /usr/lib64/libnm.so.0.1.0 --- N3) Performance test with test-client.py. With checkout of [2], run ``` prepare_checkout() { rm -rf /tmp/nm-test && \ git checkout -B test 4fad8c7c642e && \ git clean -fdx && \ ./autogen.sh --prefix=/tmp/nm-test && \ make -j 5 install && \ make -j 5 check-local-clients-tests-test-client } prepare_test() { NM_TEST_REGENERATE=1 NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v } do_test() { for i in {1..10}; do NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v || return -1 done echo "done!" } prepare_checkout prepare_test time do_test ``` [1] real 2m14.497s (101.3%) user 5m26.651s (100.3%) sys 1m40.453s (101.4%) [2] real 2m12.800s (100.0%) user 5m25.619s (100.0%) sys 1m39.065s (100.0%) [3] real 1m54.915s ( 86.5%) user 4m18.585s ( 79.4%) sys 1m32.066s ( 92.9%) --- N4) Performance. Run NetworkManager from build [2] and setup a large number of profiles (551 profiles and 515 devices, mostly unrealized). This setup is already at the edge of what NetworkManager currently can handle. Of course, that is a different issue. Here we just check how long plain `nmcli` takes on the system. ``` do_cleanup() { for UUID in $(nmcli -g NAME,UUID connection show | sed -n 's/^xx-c-.*:\([^:]\+\)$/\1/p'); do nmcli connection delete uuid "$UUID" done for DEVICE in $(nmcli -g DEVICE device status | grep '^xx-i-'); do nmcli device delete "$DEVICE" done } do_setup() { do_cleanup for i in {1..30}; do nmcli connection add type bond autoconnect no con-name xx-c-bond-$i ifname xx-i-bond-$i ipv4.method disabled ipv6.method ignore for j in $(seq $i 30); do nmcli connection add type vlan autoconnect no con-name xx-c-vlan-$i-$j vlan.id $j ifname xx-i-vlan-$i-$j vlan.parent xx-i-bond-$i ipv4.method disabled ipv6.method ignore done done systemctl restart NetworkManager.service sleep 5 } do_test() { perf stat -r 50 -B nmcli 1>/dev/null } do_test ``` [1] Performance counter stats for 'nmcli' (50 runs): 456.33 msec task-clock:u # 1.093 CPUs utilized ( +- 0.44% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,900 page-faults:u # 0.013 M/sec ( +- 0.02% ) 1,408,675,453 cycles:u # 3.087 GHz ( +- 0.48% ) 1,594,741,060 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 368,744,018 branches:u # 808.061 M/sec ( +- 0.02% ) 4,566,058 branch-misses:u # 1.24% of all branches ( +- 0.76% ) 0.41761 +- 0.00282 seconds time elapsed ( +- 0.68% ) [2] Performance counter stats for 'nmcli' (50 runs): 477.99 msec task-clock:u # 1.088 CPUs utilized ( +- 0.36% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,948 page-faults:u # 0.012 M/sec ( +- 0.03% ) 1,471,133,482 cycles:u # 3.078 GHz ( +- 0.36% ) 1,655,275,369 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 382,595,152 branches:u # 800.433 M/sec ( +- 0.02% ) 4,746,070 branch-misses:u # 1.24% of all branches ( +- 0.49% ) 0.43923 +- 0.00242 seconds time elapsed ( +- 0.55% ) [3] Performance counter stats for 'nmcli' (50 runs): 352.36 msec task-clock:u # 1.027 CPUs utilized ( +- 0.32% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 4,790 page-faults:u # 0.014 M/sec ( +- 0.26% ) 1,092,341,186 cycles:u # 3.100 GHz ( +- 0.26% ) 1,209,045,283 instructions:u # 1.11 insn per cycle ( +- 0.02% ) 281,708,462 branches:u # 799.499 M/sec ( +- 0.01% ) 3,101,031 branch-misses:u # 1.10% of all branches ( +- 0.61% ) 0.34296 +- 0.00120 seconds time elapsed ( +- 0.35% ) --- N5) same setup as N4), but run `PAGER= /bin/time -v nmcli`: [1] Command being timed: "nmcli" User time (seconds): 0.42 System time (seconds): 0.04 Percent of CPU this job got: 107% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.43 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34456 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6128 Voluntary context switches: 1298 Involuntary context switches: 1106 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [2] Command being timed: "nmcli" User time (seconds): 0.44 System time (seconds): 0.04 Percent of CPU this job got: 108% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.44 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34452 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6169 Voluntary context switches: 1849 Involuntary context switches: 142 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [3] Command being timed: "nmcli" User time (seconds): 0.32 System time (seconds): 0.02 Percent of CPU this job got: 102% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.34 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 29196 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 5059 Voluntary context switches: 919 Involuntary context switches: 685 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 --- N6) same setup as N4), but run `nmcli monitor` and look at `ps aux` for the RSS size. USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND [1] me 1492900 21.0 0.2 461348 33248 pts/10 Sl+ 15:02 0:00 nmcli monitor [2] me 1490721 5.0 0.2 461496 33548 pts/10 Sl+ 15:00 0:00 nmcli monitor [3] me 1495801 16.5 0.1 459476 28692 pts/10 Sl+ 15:04 0:00 nmcli monitor
2019-10-30 11:42:58 +01:00
guint32 old_state;
struct udev *udev;
libnm: refactor caching of D-Bus objects in NMClient No longer use GDBusObjectMangaerClient and gdbus-codegen generated classes for the NMClient cache. Instead, use GDBusConnection directly and a custom implementation (NMLDBusObject) for caching D-Bus' ObjectManager data. CHANGES ------- - This is a complete rework. I think the previous implementation was difficult to understand. There were unfixed bugs and nobody understood the code well enough to fix them. Maybe somebody out there understood the code, but I certainly did not. At least nobody provided patches to fix those issues. I do believe that this implementation is more straightforward and easier to understand. It removes a lot of layers of code. Whether this claim of simplicity is true, each reader must decide for himself/herself. Note that it is still fairly complex. - There was a lingering performance issue with large number of D-Bus objects. The patch tries hard that the implementation scales well. Of course, when we cache N objects that have N-to-M references to other, we still are fundamentally O(N*M) for runtime and memory consumption (with M being the number of references between objects). But each part should behave efficiently and well. - Play well with GMainContext. libnm code (NMClient) is generally not thread safe. However, it should work to use multiple instances in parallel, as long as each access to a NMClient is through the caller's GMainContext. This follows glib's style and effectively allows to use NMClient in a multi threaded scenario. This implies to stick to a main context upon construction and ensure that callbacks are only invoked when iterating that context. Also, NMClient itself shall never iterate the caller's context. This also means, libnm must never use g_idle_add() or g_timeout_add(), as those enqueue sources in the g_main_context_default() context. - Get ordering of messages right. All events are consistently enqueued in a GMainContext and processed strictly in order. For example, previously "nm-object.c" tried to combine signals and emit them on an idle handler. That is wrong, signals must be emitted in the right order and when they happen. Note that when using GInitable's synchronous initialization to initialize the NMClient instance, NMClient internally still operates fully asynchronously. In that case NMClient has an internal main context. - NMClient takes over most of the functionality. When using D-Bus' ObjectManager interface, one needs to handle basically the entire state of the D-Bus interface. That cannot be separated well into distinct parts, and even if you try, you just end up having closely related code in different source files. Spreading related code does not make it easier to understand, on the contrary. That means, NMClient is inherently complex as it contains most of the logic. I think that is not avoidable, but it's not as bad as it sounds. - NMClient processes D-Bus messages and state changes in separate steps. First NMClient unpacks the message (e.g. _dbus_handle_properties_changed()) and keeps track of the changed data. Then we update the GObject instances (_dbus_handle_obj_changed_dbus()) without emitting any signals yet. Finally, we emit all signals and notifications that were collected (_dbus_handle_changes_commit()). Note that for example during the initial GetManagedObjects() reply, NMClient receive a large amount of state at once. But we first apply all the changes to our GObject instances before emitting any signals. The result is that signals are always emitted in a moment when the cache is consistent. The unavoidable downside is that when you receive a property changed signal, possibly many other properties changed already and more signals are about to be emitted. - NMDeviceWifi no longer modifies the content of the cache from client side during poke_wireless_devices_with_rf_status(). The content of the cache should be determined by D-Bus alone and follow what NetworkManager service exposes. Local modifications should be avoided. - This aims to bring no API/ABI change, though it does of course bring various subtle changes in behavior. Those should be all for the better, but the goal is not to break any existing clients. This does change internal (albeit externally visible) API, like dropping NM_OBJECT_DBUS_OBJECT_MANAGER property and NMObject no longer implementing GInitableIface and GAsyncInitableIface. - Some uses of gdbus-codegen classes remain in NMVpnPluginOld, NMVpnServicePlugin and NMSecretAgentOld. These are independent of NMClient/NMObject and should be reworked separately. - While we no longer use generated classes from gdbus-codegen, we don't need more glue code than before. Also before we constructed NMPropertiesInfo and a had large amount of code to propagate properties from NMDBus* to NMObject. That got completely reworked, but did not fundamentally change. You still need about the same effort to create the NMLDBusMetaIface. Not using generated bindings did not make anything worse (which tells about the usefulness of generated code, at least in the way it was used). - NMLDBusMetaIface and other meta data is static and immutable. This avoids copying them around. Also, macros like NML_DBUS_META_PROPERTY_INIT_U() have compile time checks to ensure the property types matches. It's pretty hard to misuse them because it won't compile. - The meta data now explicitly encodes the expected D-Bus types and makes sure never to accept wrong data. That would only matter when the server (accidentally or intentionally) exposes unexpected types on D-Bus. I don't think that was previously ensured in all cases. For example, demarshal_generic() only cared about the GObject property type, it didn't know the expected D-Bus type. - Previously GDBusObjectManager would sometimes emit warnings (g_log()). Those probably indicated real bugs. In any case, it prevented us from running CI with G_DEBUG=fatal-warnings, because there would be just too many unrelated crashes. Now we log debug messages that can be enabled with "LIBNM_CLIENT_DEBUG=trace". Some of these messages can also be turned into g_warning()/g_critical() by setting LIBNM_CLIENT_DEBUG=warning,error. Together with G_DEBUG=fatal-warnings, this turns them into assertions. Note that such "assertion failures" might also happen because of a server bug (or change). Thus these are not common assertions that indicate a bug in libnm and are thus not armed unless explicitly requested. In our CI we should now always run with LIBNM_CLIENT_DEBUG=warning,error and G_DEBUG=fatal-warnings and to catch bugs. Note that currently NetworkManager has bugs in this regard, so enabling this will result in assertion failures. That should be fixed first. - Note that this changes the order in which we emit "notify:devices" and "device-added" signals. I think it makes the most sense to emit first "device-removed", then "notify:devices", and finally "device-added" signals. This changes behavior for commit 52ae28f6e5bf ('libnm: queue added/removed signals and suppress uninitialized notifications'), but I don't think that users should actually rely on the order. Still, the new order makes the most sense to me. - In NetworkManager, profiles can be invisible to the user by setting "connection.permissions". Such profiles would be hidden by NMClient's nm_client_get_connections() and their "connection-added"/"connection-removed" signals. Note that NMActiveConnection's nm_active_connection_get_connection() and NMDevice's nm_device_get_available_connections() still exposes such hidden NMRemoteConnection instances. This behavior was preserved. NUMBERS ------- I compared 3 versions of libnm. [1] 962297f9085d, current tip of nm-1-20 branch [2] 4fad8c7c642e, current master, immediate parent of this patch [3] this patch All tests were done on Fedora 31, x86_64, gcc 9.2.1-1.fc31. The libraries were build with $ ./contrib/fedora/rpm/build_clean.sh -g -w test -W debug Note that RPM build already stripped the library. --- N1) File size of libnm.so.0.1.0 in bytes. There currently seems to be a issue on Fedora 31 generating wrong ELF notes. Usually, libnm is smaller but in these tests it had large (and bogus) ELF notes. Anyway, the point is to show the relative sizes, so it doesn't matter). [1] 4075552 (102.7%) [2] 3969624 (100.0%) [3] 3705208 ( 93.3%) --- N2) `size /usr/lib64/libnm.so.0.1.0`: text data bss dec hex filename [1] 1314569 (102.0%) 69980 ( 94.8%) 10632 ( 80.4%) 1395181 (101.4%) 1549ed /usr/lib64/libnm.so.0.1.0 [2] 1288410 (100.0%) 73796 (100.0%) 13224 (100.0%) 1375430 (100.0%) 14fcc6 /usr/lib64/libnm.so.0.1.0 [3] 1229066 ( 95.4%) 65248 ( 88.4%) 13400 (101.3%) 1307714 ( 95.1%) 13f442 /usr/lib64/libnm.so.0.1.0 --- N3) Performance test with test-client.py. With checkout of [2], run ``` prepare_checkout() { rm -rf /tmp/nm-test && \ git checkout -B test 4fad8c7c642e && \ git clean -fdx && \ ./autogen.sh --prefix=/tmp/nm-test && \ make -j 5 install && \ make -j 5 check-local-clients-tests-test-client } prepare_test() { NM_TEST_REGENERATE=1 NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v } do_test() { for i in {1..10}; do NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v || return -1 done echo "done!" } prepare_checkout prepare_test time do_test ``` [1] real 2m14.497s (101.3%) user 5m26.651s (100.3%) sys 1m40.453s (101.4%) [2] real 2m12.800s (100.0%) user 5m25.619s (100.0%) sys 1m39.065s (100.0%) [3] real 1m54.915s ( 86.5%) user 4m18.585s ( 79.4%) sys 1m32.066s ( 92.9%) --- N4) Performance. Run NetworkManager from build [2] and setup a large number of profiles (551 profiles and 515 devices, mostly unrealized). This setup is already at the edge of what NetworkManager currently can handle. Of course, that is a different issue. Here we just check how long plain `nmcli` takes on the system. ``` do_cleanup() { for UUID in $(nmcli -g NAME,UUID connection show | sed -n 's/^xx-c-.*:\([^:]\+\)$/\1/p'); do nmcli connection delete uuid "$UUID" done for DEVICE in $(nmcli -g DEVICE device status | grep '^xx-i-'); do nmcli device delete "$DEVICE" done } do_setup() { do_cleanup for i in {1..30}; do nmcli connection add type bond autoconnect no con-name xx-c-bond-$i ifname xx-i-bond-$i ipv4.method disabled ipv6.method ignore for j in $(seq $i 30); do nmcli connection add type vlan autoconnect no con-name xx-c-vlan-$i-$j vlan.id $j ifname xx-i-vlan-$i-$j vlan.parent xx-i-bond-$i ipv4.method disabled ipv6.method ignore done done systemctl restart NetworkManager.service sleep 5 } do_test() { perf stat -r 50 -B nmcli 1>/dev/null } do_test ``` [1] Performance counter stats for 'nmcli' (50 runs): 456.33 msec task-clock:u # 1.093 CPUs utilized ( +- 0.44% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,900 page-faults:u # 0.013 M/sec ( +- 0.02% ) 1,408,675,453 cycles:u # 3.087 GHz ( +- 0.48% ) 1,594,741,060 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 368,744,018 branches:u # 808.061 M/sec ( +- 0.02% ) 4,566,058 branch-misses:u # 1.24% of all branches ( +- 0.76% ) 0.41761 +- 0.00282 seconds time elapsed ( +- 0.68% ) [2] Performance counter stats for 'nmcli' (50 runs): 477.99 msec task-clock:u # 1.088 CPUs utilized ( +- 0.36% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,948 page-faults:u # 0.012 M/sec ( +- 0.03% ) 1,471,133,482 cycles:u # 3.078 GHz ( +- 0.36% ) 1,655,275,369 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 382,595,152 branches:u # 800.433 M/sec ( +- 0.02% ) 4,746,070 branch-misses:u # 1.24% of all branches ( +- 0.49% ) 0.43923 +- 0.00242 seconds time elapsed ( +- 0.55% ) [3] Performance counter stats for 'nmcli' (50 runs): 352.36 msec task-clock:u # 1.027 CPUs utilized ( +- 0.32% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 4,790 page-faults:u # 0.014 M/sec ( +- 0.26% ) 1,092,341,186 cycles:u # 3.100 GHz ( +- 0.26% ) 1,209,045,283 instructions:u # 1.11 insn per cycle ( +- 0.02% ) 281,708,462 branches:u # 799.499 M/sec ( +- 0.01% ) 3,101,031 branch-misses:u # 1.10% of all branches ( +- 0.61% ) 0.34296 +- 0.00120 seconds time elapsed ( +- 0.35% ) --- N5) same setup as N4), but run `PAGER= /bin/time -v nmcli`: [1] Command being timed: "nmcli" User time (seconds): 0.42 System time (seconds): 0.04 Percent of CPU this job got: 107% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.43 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34456 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6128 Voluntary context switches: 1298 Involuntary context switches: 1106 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [2] Command being timed: "nmcli" User time (seconds): 0.44 System time (seconds): 0.04 Percent of CPU this job got: 108% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.44 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34452 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6169 Voluntary context switches: 1849 Involuntary context switches: 142 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [3] Command being timed: "nmcli" User time (seconds): 0.32 System time (seconds): 0.02 Percent of CPU this job got: 102% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.34 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 29196 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 5059 Voluntary context switches: 919 Involuntary context switches: 685 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 --- N6) same setup as N4), but run `nmcli monitor` and look at `ps aux` for the RSS size. USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND [1] me 1492900 21.0 0.2 461348 33248 pts/10 Sl+ 15:02 0:00 nmcli monitor [2] me 1490721 5.0 0.2 461496 33548 pts/10 Sl+ 15:00 0:00 nmcli monitor [3] me 1495801 16.5 0.1 459476 28692 pts/10 Sl+ 15:04 0:00 nmcli monitor
2019-10-30 11:42:58 +01:00
char *type_description;
char *product;
libnm: refactor caching of D-Bus objects in NMClient No longer use GDBusObjectMangaerClient and gdbus-codegen generated classes for the NMClient cache. Instead, use GDBusConnection directly and a custom implementation (NMLDBusObject) for caching D-Bus' ObjectManager data. CHANGES ------- - This is a complete rework. I think the previous implementation was difficult to understand. There were unfixed bugs and nobody understood the code well enough to fix them. Maybe somebody out there understood the code, but I certainly did not. At least nobody provided patches to fix those issues. I do believe that this implementation is more straightforward and easier to understand. It removes a lot of layers of code. Whether this claim of simplicity is true, each reader must decide for himself/herself. Note that it is still fairly complex. - There was a lingering performance issue with large number of D-Bus objects. The patch tries hard that the implementation scales well. Of course, when we cache N objects that have N-to-M references to other, we still are fundamentally O(N*M) for runtime and memory consumption (with M being the number of references between objects). But each part should behave efficiently and well. - Play well with GMainContext. libnm code (NMClient) is generally not thread safe. However, it should work to use multiple instances in parallel, as long as each access to a NMClient is through the caller's GMainContext. This follows glib's style and effectively allows to use NMClient in a multi threaded scenario. This implies to stick to a main context upon construction and ensure that callbacks are only invoked when iterating that context. Also, NMClient itself shall never iterate the caller's context. This also means, libnm must never use g_idle_add() or g_timeout_add(), as those enqueue sources in the g_main_context_default() context. - Get ordering of messages right. All events are consistently enqueued in a GMainContext and processed strictly in order. For example, previously "nm-object.c" tried to combine signals and emit them on an idle handler. That is wrong, signals must be emitted in the right order and when they happen. Note that when using GInitable's synchronous initialization to initialize the NMClient instance, NMClient internally still operates fully asynchronously. In that case NMClient has an internal main context. - NMClient takes over most of the functionality. When using D-Bus' ObjectManager interface, one needs to handle basically the entire state of the D-Bus interface. That cannot be separated well into distinct parts, and even if you try, you just end up having closely related code in different source files. Spreading related code does not make it easier to understand, on the contrary. That means, NMClient is inherently complex as it contains most of the logic. I think that is not avoidable, but it's not as bad as it sounds. - NMClient processes D-Bus messages and state changes in separate steps. First NMClient unpacks the message (e.g. _dbus_handle_properties_changed()) and keeps track of the changed data. Then we update the GObject instances (_dbus_handle_obj_changed_dbus()) without emitting any signals yet. Finally, we emit all signals and notifications that were collected (_dbus_handle_changes_commit()). Note that for example during the initial GetManagedObjects() reply, NMClient receive a large amount of state at once. But we first apply all the changes to our GObject instances before emitting any signals. The result is that signals are always emitted in a moment when the cache is consistent. The unavoidable downside is that when you receive a property changed signal, possibly many other properties changed already and more signals are about to be emitted. - NMDeviceWifi no longer modifies the content of the cache from client side during poke_wireless_devices_with_rf_status(). The content of the cache should be determined by D-Bus alone and follow what NetworkManager service exposes. Local modifications should be avoided. - This aims to bring no API/ABI change, though it does of course bring various subtle changes in behavior. Those should be all for the better, but the goal is not to break any existing clients. This does change internal (albeit externally visible) API, like dropping NM_OBJECT_DBUS_OBJECT_MANAGER property and NMObject no longer implementing GInitableIface and GAsyncInitableIface. - Some uses of gdbus-codegen classes remain in NMVpnPluginOld, NMVpnServicePlugin and NMSecretAgentOld. These are independent of NMClient/NMObject and should be reworked separately. - While we no longer use generated classes from gdbus-codegen, we don't need more glue code than before. Also before we constructed NMPropertiesInfo and a had large amount of code to propagate properties from NMDBus* to NMObject. That got completely reworked, but did not fundamentally change. You still need about the same effort to create the NMLDBusMetaIface. Not using generated bindings did not make anything worse (which tells about the usefulness of generated code, at least in the way it was used). - NMLDBusMetaIface and other meta data is static and immutable. This avoids copying them around. Also, macros like NML_DBUS_META_PROPERTY_INIT_U() have compile time checks to ensure the property types matches. It's pretty hard to misuse them because it won't compile. - The meta data now explicitly encodes the expected D-Bus types and makes sure never to accept wrong data. That would only matter when the server (accidentally or intentionally) exposes unexpected types on D-Bus. I don't think that was previously ensured in all cases. For example, demarshal_generic() only cared about the GObject property type, it didn't know the expected D-Bus type. - Previously GDBusObjectManager would sometimes emit warnings (g_log()). Those probably indicated real bugs. In any case, it prevented us from running CI with G_DEBUG=fatal-warnings, because there would be just too many unrelated crashes. Now we log debug messages that can be enabled with "LIBNM_CLIENT_DEBUG=trace". Some of these messages can also be turned into g_warning()/g_critical() by setting LIBNM_CLIENT_DEBUG=warning,error. Together with G_DEBUG=fatal-warnings, this turns them into assertions. Note that such "assertion failures" might also happen because of a server bug (or change). Thus these are not common assertions that indicate a bug in libnm and are thus not armed unless explicitly requested. In our CI we should now always run with LIBNM_CLIENT_DEBUG=warning,error and G_DEBUG=fatal-warnings and to catch bugs. Note that currently NetworkManager has bugs in this regard, so enabling this will result in assertion failures. That should be fixed first. - Note that this changes the order in which we emit "notify:devices" and "device-added" signals. I think it makes the most sense to emit first "device-removed", then "notify:devices", and finally "device-added" signals. This changes behavior for commit 52ae28f6e5bf ('libnm: queue added/removed signals and suppress uninitialized notifications'), but I don't think that users should actually rely on the order. Still, the new order makes the most sense to me. - In NetworkManager, profiles can be invisible to the user by setting "connection.permissions". Such profiles would be hidden by NMClient's nm_client_get_connections() and their "connection-added"/"connection-removed" signals. Note that NMActiveConnection's nm_active_connection_get_connection() and NMDevice's nm_device_get_available_connections() still exposes such hidden NMRemoteConnection instances. This behavior was preserved. NUMBERS ------- I compared 3 versions of libnm. [1] 962297f9085d, current tip of nm-1-20 branch [2] 4fad8c7c642e, current master, immediate parent of this patch [3] this patch All tests were done on Fedora 31, x86_64, gcc 9.2.1-1.fc31. The libraries were build with $ ./contrib/fedora/rpm/build_clean.sh -g -w test -W debug Note that RPM build already stripped the library. --- N1) File size of libnm.so.0.1.0 in bytes. There currently seems to be a issue on Fedora 31 generating wrong ELF notes. Usually, libnm is smaller but in these tests it had large (and bogus) ELF notes. Anyway, the point is to show the relative sizes, so it doesn't matter). [1] 4075552 (102.7%) [2] 3969624 (100.0%) [3] 3705208 ( 93.3%) --- N2) `size /usr/lib64/libnm.so.0.1.0`: text data bss dec hex filename [1] 1314569 (102.0%) 69980 ( 94.8%) 10632 ( 80.4%) 1395181 (101.4%) 1549ed /usr/lib64/libnm.so.0.1.0 [2] 1288410 (100.0%) 73796 (100.0%) 13224 (100.0%) 1375430 (100.0%) 14fcc6 /usr/lib64/libnm.so.0.1.0 [3] 1229066 ( 95.4%) 65248 ( 88.4%) 13400 (101.3%) 1307714 ( 95.1%) 13f442 /usr/lib64/libnm.so.0.1.0 --- N3) Performance test with test-client.py. With checkout of [2], run ``` prepare_checkout() { rm -rf /tmp/nm-test && \ git checkout -B test 4fad8c7c642e && \ git clean -fdx && \ ./autogen.sh --prefix=/tmp/nm-test && \ make -j 5 install && \ make -j 5 check-local-clients-tests-test-client } prepare_test() { NM_TEST_REGENERATE=1 NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v } do_test() { for i in {1..10}; do NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v || return -1 done echo "done!" } prepare_checkout prepare_test time do_test ``` [1] real 2m14.497s (101.3%) user 5m26.651s (100.3%) sys 1m40.453s (101.4%) [2] real 2m12.800s (100.0%) user 5m25.619s (100.0%) sys 1m39.065s (100.0%) [3] real 1m54.915s ( 86.5%) user 4m18.585s ( 79.4%) sys 1m32.066s ( 92.9%) --- N4) Performance. Run NetworkManager from build [2] and setup a large number of profiles (551 profiles and 515 devices, mostly unrealized). This setup is already at the edge of what NetworkManager currently can handle. Of course, that is a different issue. Here we just check how long plain `nmcli` takes on the system. ``` do_cleanup() { for UUID in $(nmcli -g NAME,UUID connection show | sed -n 's/^xx-c-.*:\([^:]\+\)$/\1/p'); do nmcli connection delete uuid "$UUID" done for DEVICE in $(nmcli -g DEVICE device status | grep '^xx-i-'); do nmcli device delete "$DEVICE" done } do_setup() { do_cleanup for i in {1..30}; do nmcli connection add type bond autoconnect no con-name xx-c-bond-$i ifname xx-i-bond-$i ipv4.method disabled ipv6.method ignore for j in $(seq $i 30); do nmcli connection add type vlan autoconnect no con-name xx-c-vlan-$i-$j vlan.id $j ifname xx-i-vlan-$i-$j vlan.parent xx-i-bond-$i ipv4.method disabled ipv6.method ignore done done systemctl restart NetworkManager.service sleep 5 } do_test() { perf stat -r 50 -B nmcli 1>/dev/null } do_test ``` [1] Performance counter stats for 'nmcli' (50 runs): 456.33 msec task-clock:u # 1.093 CPUs utilized ( +- 0.44% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,900 page-faults:u # 0.013 M/sec ( +- 0.02% ) 1,408,675,453 cycles:u # 3.087 GHz ( +- 0.48% ) 1,594,741,060 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 368,744,018 branches:u # 808.061 M/sec ( +- 0.02% ) 4,566,058 branch-misses:u # 1.24% of all branches ( +- 0.76% ) 0.41761 +- 0.00282 seconds time elapsed ( +- 0.68% ) [2] Performance counter stats for 'nmcli' (50 runs): 477.99 msec task-clock:u # 1.088 CPUs utilized ( +- 0.36% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,948 page-faults:u # 0.012 M/sec ( +- 0.03% ) 1,471,133,482 cycles:u # 3.078 GHz ( +- 0.36% ) 1,655,275,369 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 382,595,152 branches:u # 800.433 M/sec ( +- 0.02% ) 4,746,070 branch-misses:u # 1.24% of all branches ( +- 0.49% ) 0.43923 +- 0.00242 seconds time elapsed ( +- 0.55% ) [3] Performance counter stats for 'nmcli' (50 runs): 352.36 msec task-clock:u # 1.027 CPUs utilized ( +- 0.32% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 4,790 page-faults:u # 0.014 M/sec ( +- 0.26% ) 1,092,341,186 cycles:u # 3.100 GHz ( +- 0.26% ) 1,209,045,283 instructions:u # 1.11 insn per cycle ( +- 0.02% ) 281,708,462 branches:u # 799.499 M/sec ( +- 0.01% ) 3,101,031 branch-misses:u # 1.10% of all branches ( +- 0.61% ) 0.34296 +- 0.00120 seconds time elapsed ( +- 0.35% ) --- N5) same setup as N4), but run `PAGER= /bin/time -v nmcli`: [1] Command being timed: "nmcli" User time (seconds): 0.42 System time (seconds): 0.04 Percent of CPU this job got: 107% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.43 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34456 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6128 Voluntary context switches: 1298 Involuntary context switches: 1106 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [2] Command being timed: "nmcli" User time (seconds): 0.44 System time (seconds): 0.04 Percent of CPU this job got: 108% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.44 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34452 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6169 Voluntary context switches: 1849 Involuntary context switches: 142 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [3] Command being timed: "nmcli" User time (seconds): 0.32 System time (seconds): 0.02 Percent of CPU this job got: 102% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.34 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 29196 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 5059 Voluntary context switches: 919 Involuntary context switches: 685 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 --- N6) same setup as N4), but run `nmcli monitor` and look at `ps aux` for the RSS size. USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND [1] me 1492900 21.0 0.2 461348 33248 pts/10 Sl+ 15:02 0:00 nmcli monitor [2] me 1490721 5.0 0.2 461496 33548 pts/10 Sl+ 15:00 0:00 nmcli monitor [3] me 1495801 16.5 0.1 459476 28692 pts/10 Sl+ 15:04 0:00 nmcli monitor
2019-10-30 11:42:58 +01:00
char *vendor;
char *short_vendor;
char *description;
char *bus_name;
} NMDevicePrivate;
G_DEFINE_ABSTRACT_TYPE (NMDevice, nm_device, NM_TYPE_OBJECT);
#define NM_DEVICE_GET_PRIVATE(self) _NM_GET_PRIVATE_PTR(self, NMDevice, NM_IS_DEVICE, NMObject)
/*****************************************************************************/
static gboolean connection_compatible (NMDevice *device, NMConnection *connection, GError **error);
static NMLldpNeighbor *nm_lldp_neighbor_dup (NMLldpNeighbor *neighbor);
/*****************************************************************************/
struct _NMLldpNeighbor {
guint refcount;
GHashTable *attrs;
};
G_DEFINE_BOXED_TYPE (NMLldpNeighbor, nm_lldp_neighbor, nm_lldp_neighbor_dup, nm_lldp_neighbor_unref)
libnm: refactor caching of D-Bus objects in NMClient No longer use GDBusObjectMangaerClient and gdbus-codegen generated classes for the NMClient cache. Instead, use GDBusConnection directly and a custom implementation (NMLDBusObject) for caching D-Bus' ObjectManager data. CHANGES ------- - This is a complete rework. I think the previous implementation was difficult to understand. There were unfixed bugs and nobody understood the code well enough to fix them. Maybe somebody out there understood the code, but I certainly did not. At least nobody provided patches to fix those issues. I do believe that this implementation is more straightforward and easier to understand. It removes a lot of layers of code. Whether this claim of simplicity is true, each reader must decide for himself/herself. Note that it is still fairly complex. - There was a lingering performance issue with large number of D-Bus objects. The patch tries hard that the implementation scales well. Of course, when we cache N objects that have N-to-M references to other, we still are fundamentally O(N*M) for runtime and memory consumption (with M being the number of references between objects). But each part should behave efficiently and well. - Play well with GMainContext. libnm code (NMClient) is generally not thread safe. However, it should work to use multiple instances in parallel, as long as each access to a NMClient is through the caller's GMainContext. This follows glib's style and effectively allows to use NMClient in a multi threaded scenario. This implies to stick to a main context upon construction and ensure that callbacks are only invoked when iterating that context. Also, NMClient itself shall never iterate the caller's context. This also means, libnm must never use g_idle_add() or g_timeout_add(), as those enqueue sources in the g_main_context_default() context. - Get ordering of messages right. All events are consistently enqueued in a GMainContext and processed strictly in order. For example, previously "nm-object.c" tried to combine signals and emit them on an idle handler. That is wrong, signals must be emitted in the right order and when they happen. Note that when using GInitable's synchronous initialization to initialize the NMClient instance, NMClient internally still operates fully asynchronously. In that case NMClient has an internal main context. - NMClient takes over most of the functionality. When using D-Bus' ObjectManager interface, one needs to handle basically the entire state of the D-Bus interface. That cannot be separated well into distinct parts, and even if you try, you just end up having closely related code in different source files. Spreading related code does not make it easier to understand, on the contrary. That means, NMClient is inherently complex as it contains most of the logic. I think that is not avoidable, but it's not as bad as it sounds. - NMClient processes D-Bus messages and state changes in separate steps. First NMClient unpacks the message (e.g. _dbus_handle_properties_changed()) and keeps track of the changed data. Then we update the GObject instances (_dbus_handle_obj_changed_dbus()) without emitting any signals yet. Finally, we emit all signals and notifications that were collected (_dbus_handle_changes_commit()). Note that for example during the initial GetManagedObjects() reply, NMClient receive a large amount of state at once. But we first apply all the changes to our GObject instances before emitting any signals. The result is that signals are always emitted in a moment when the cache is consistent. The unavoidable downside is that when you receive a property changed signal, possibly many other properties changed already and more signals are about to be emitted. - NMDeviceWifi no longer modifies the content of the cache from client side during poke_wireless_devices_with_rf_status(). The content of the cache should be determined by D-Bus alone and follow what NetworkManager service exposes. Local modifications should be avoided. - This aims to bring no API/ABI change, though it does of course bring various subtle changes in behavior. Those should be all for the better, but the goal is not to break any existing clients. This does change internal (albeit externally visible) API, like dropping NM_OBJECT_DBUS_OBJECT_MANAGER property and NMObject no longer implementing GInitableIface and GAsyncInitableIface. - Some uses of gdbus-codegen classes remain in NMVpnPluginOld, NMVpnServicePlugin and NMSecretAgentOld. These are independent of NMClient/NMObject and should be reworked separately. - While we no longer use generated classes from gdbus-codegen, we don't need more glue code than before. Also before we constructed NMPropertiesInfo and a had large amount of code to propagate properties from NMDBus* to NMObject. That got completely reworked, but did not fundamentally change. You still need about the same effort to create the NMLDBusMetaIface. Not using generated bindings did not make anything worse (which tells about the usefulness of generated code, at least in the way it was used). - NMLDBusMetaIface and other meta data is static and immutable. This avoids copying them around. Also, macros like NML_DBUS_META_PROPERTY_INIT_U() have compile time checks to ensure the property types matches. It's pretty hard to misuse them because it won't compile. - The meta data now explicitly encodes the expected D-Bus types and makes sure never to accept wrong data. That would only matter when the server (accidentally or intentionally) exposes unexpected types on D-Bus. I don't think that was previously ensured in all cases. For example, demarshal_generic() only cared about the GObject property type, it didn't know the expected D-Bus type. - Previously GDBusObjectManager would sometimes emit warnings (g_log()). Those probably indicated real bugs. In any case, it prevented us from running CI with G_DEBUG=fatal-warnings, because there would be just too many unrelated crashes. Now we log debug messages that can be enabled with "LIBNM_CLIENT_DEBUG=trace". Some of these messages can also be turned into g_warning()/g_critical() by setting LIBNM_CLIENT_DEBUG=warning,error. Together with G_DEBUG=fatal-warnings, this turns them into assertions. Note that such "assertion failures" might also happen because of a server bug (or change). Thus these are not common assertions that indicate a bug in libnm and are thus not armed unless explicitly requested. In our CI we should now always run with LIBNM_CLIENT_DEBUG=warning,error and G_DEBUG=fatal-warnings and to catch bugs. Note that currently NetworkManager has bugs in this regard, so enabling this will result in assertion failures. That should be fixed first. - Note that this changes the order in which we emit "notify:devices" and "device-added" signals. I think it makes the most sense to emit first "device-removed", then "notify:devices", and finally "device-added" signals. This changes behavior for commit 52ae28f6e5bf ('libnm: queue added/removed signals and suppress uninitialized notifications'), but I don't think that users should actually rely on the order. Still, the new order makes the most sense to me. - In NetworkManager, profiles can be invisible to the user by setting "connection.permissions". Such profiles would be hidden by NMClient's nm_client_get_connections() and their "connection-added"/"connection-removed" signals. Note that NMActiveConnection's nm_active_connection_get_connection() and NMDevice's nm_device_get_available_connections() still exposes such hidden NMRemoteConnection instances. This behavior was preserved. NUMBERS ------- I compared 3 versions of libnm. [1] 962297f9085d, current tip of nm-1-20 branch [2] 4fad8c7c642e, current master, immediate parent of this patch [3] this patch All tests were done on Fedora 31, x86_64, gcc 9.2.1-1.fc31. The libraries were build with $ ./contrib/fedora/rpm/build_clean.sh -g -w test -W debug Note that RPM build already stripped the library. --- N1) File size of libnm.so.0.1.0 in bytes. There currently seems to be a issue on Fedora 31 generating wrong ELF notes. Usually, libnm is smaller but in these tests it had large (and bogus) ELF notes. Anyway, the point is to show the relative sizes, so it doesn't matter). [1] 4075552 (102.7%) [2] 3969624 (100.0%) [3] 3705208 ( 93.3%) --- N2) `size /usr/lib64/libnm.so.0.1.0`: text data bss dec hex filename [1] 1314569 (102.0%) 69980 ( 94.8%) 10632 ( 80.4%) 1395181 (101.4%) 1549ed /usr/lib64/libnm.so.0.1.0 [2] 1288410 (100.0%) 73796 (100.0%) 13224 (100.0%) 1375430 (100.0%) 14fcc6 /usr/lib64/libnm.so.0.1.0 [3] 1229066 ( 95.4%) 65248 ( 88.4%) 13400 (101.3%) 1307714 ( 95.1%) 13f442 /usr/lib64/libnm.so.0.1.0 --- N3) Performance test with test-client.py. With checkout of [2], run ``` prepare_checkout() { rm -rf /tmp/nm-test && \ git checkout -B test 4fad8c7c642e && \ git clean -fdx && \ ./autogen.sh --prefix=/tmp/nm-test && \ make -j 5 install && \ make -j 5 check-local-clients-tests-test-client } prepare_test() { NM_TEST_REGENERATE=1 NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v } do_test() { for i in {1..10}; do NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v || return -1 done echo "done!" } prepare_checkout prepare_test time do_test ``` [1] real 2m14.497s (101.3%) user 5m26.651s (100.3%) sys 1m40.453s (101.4%) [2] real 2m12.800s (100.0%) user 5m25.619s (100.0%) sys 1m39.065s (100.0%) [3] real 1m54.915s ( 86.5%) user 4m18.585s ( 79.4%) sys 1m32.066s ( 92.9%) --- N4) Performance. Run NetworkManager from build [2] and setup a large number of profiles (551 profiles and 515 devices, mostly unrealized). This setup is already at the edge of what NetworkManager currently can handle. Of course, that is a different issue. Here we just check how long plain `nmcli` takes on the system. ``` do_cleanup() { for UUID in $(nmcli -g NAME,UUID connection show | sed -n 's/^xx-c-.*:\([^:]\+\)$/\1/p'); do nmcli connection delete uuid "$UUID" done for DEVICE in $(nmcli -g DEVICE device status | grep '^xx-i-'); do nmcli device delete "$DEVICE" done } do_setup() { do_cleanup for i in {1..30}; do nmcli connection add type bond autoconnect no con-name xx-c-bond-$i ifname xx-i-bond-$i ipv4.method disabled ipv6.method ignore for j in $(seq $i 30); do nmcli connection add type vlan autoconnect no con-name xx-c-vlan-$i-$j vlan.id $j ifname xx-i-vlan-$i-$j vlan.parent xx-i-bond-$i ipv4.method disabled ipv6.method ignore done done systemctl restart NetworkManager.service sleep 5 } do_test() { perf stat -r 50 -B nmcli 1>/dev/null } do_test ``` [1] Performance counter stats for 'nmcli' (50 runs): 456.33 msec task-clock:u # 1.093 CPUs utilized ( +- 0.44% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,900 page-faults:u # 0.013 M/sec ( +- 0.02% ) 1,408,675,453 cycles:u # 3.087 GHz ( +- 0.48% ) 1,594,741,060 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 368,744,018 branches:u # 808.061 M/sec ( +- 0.02% ) 4,566,058 branch-misses:u # 1.24% of all branches ( +- 0.76% ) 0.41761 +- 0.00282 seconds time elapsed ( +- 0.68% ) [2] Performance counter stats for 'nmcli' (50 runs): 477.99 msec task-clock:u # 1.088 CPUs utilized ( +- 0.36% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,948 page-faults:u # 0.012 M/sec ( +- 0.03% ) 1,471,133,482 cycles:u # 3.078 GHz ( +- 0.36% ) 1,655,275,369 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 382,595,152 branches:u # 800.433 M/sec ( +- 0.02% ) 4,746,070 branch-misses:u # 1.24% of all branches ( +- 0.49% ) 0.43923 +- 0.00242 seconds time elapsed ( +- 0.55% ) [3] Performance counter stats for 'nmcli' (50 runs): 352.36 msec task-clock:u # 1.027 CPUs utilized ( +- 0.32% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 4,790 page-faults:u # 0.014 M/sec ( +- 0.26% ) 1,092,341,186 cycles:u # 3.100 GHz ( +- 0.26% ) 1,209,045,283 instructions:u # 1.11 insn per cycle ( +- 0.02% ) 281,708,462 branches:u # 799.499 M/sec ( +- 0.01% ) 3,101,031 branch-misses:u # 1.10% of all branches ( +- 0.61% ) 0.34296 +- 0.00120 seconds time elapsed ( +- 0.35% ) --- N5) same setup as N4), but run `PAGER= /bin/time -v nmcli`: [1] Command being timed: "nmcli" User time (seconds): 0.42 System time (seconds): 0.04 Percent of CPU this job got: 107% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.43 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34456 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6128 Voluntary context switches: 1298 Involuntary context switches: 1106 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [2] Command being timed: "nmcli" User time (seconds): 0.44 System time (seconds): 0.04 Percent of CPU this job got: 108% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.44 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34452 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6169 Voluntary context switches: 1849 Involuntary context switches: 142 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [3] Command being timed: "nmcli" User time (seconds): 0.32 System time (seconds): 0.02 Percent of CPU this job got: 102% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.34 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 29196 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 5059 Voluntary context switches: 919 Involuntary context switches: 685 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 --- N6) same setup as N4), but run `nmcli monitor` and look at `ps aux` for the RSS size. USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND [1] me 1492900 21.0 0.2 461348 33248 pts/10 Sl+ 15:02 0:00 nmcli monitor [2] me 1490721 5.0 0.2 461496 33548 pts/10 Sl+ 15:00 0:00 nmcli monitor [3] me 1495801 16.5 0.1 459476 28692 pts/10 Sl+ 15:04 0:00 nmcli monitor
2019-10-30 11:42:58 +01:00
/*****************************************************************************/
static void
nm_device_init (NMDevice *self)
{
NMDevicePrivate *priv;
priv = G_TYPE_INSTANCE_GET_PRIVATE (self, NM_TYPE_DEVICE, NMDevicePrivate);
self->_priv = priv;
libnm: refactor caching of D-Bus objects in NMClient No longer use GDBusObjectMangaerClient and gdbus-codegen generated classes for the NMClient cache. Instead, use GDBusConnection directly and a custom implementation (NMLDBusObject) for caching D-Bus' ObjectManager data. CHANGES ------- - This is a complete rework. I think the previous implementation was difficult to understand. There were unfixed bugs and nobody understood the code well enough to fix them. Maybe somebody out there understood the code, but I certainly did not. At least nobody provided patches to fix those issues. I do believe that this implementation is more straightforward and easier to understand. It removes a lot of layers of code. Whether this claim of simplicity is true, each reader must decide for himself/herself. Note that it is still fairly complex. - There was a lingering performance issue with large number of D-Bus objects. The patch tries hard that the implementation scales well. Of course, when we cache N objects that have N-to-M references to other, we still are fundamentally O(N*M) for runtime and memory consumption (with M being the number of references between objects). But each part should behave efficiently and well. - Play well with GMainContext. libnm code (NMClient) is generally not thread safe. However, it should work to use multiple instances in parallel, as long as each access to a NMClient is through the caller's GMainContext. This follows glib's style and effectively allows to use NMClient in a multi threaded scenario. This implies to stick to a main context upon construction and ensure that callbacks are only invoked when iterating that context. Also, NMClient itself shall never iterate the caller's context. This also means, libnm must never use g_idle_add() or g_timeout_add(), as those enqueue sources in the g_main_context_default() context. - Get ordering of messages right. All events are consistently enqueued in a GMainContext and processed strictly in order. For example, previously "nm-object.c" tried to combine signals and emit them on an idle handler. That is wrong, signals must be emitted in the right order and when they happen. Note that when using GInitable's synchronous initialization to initialize the NMClient instance, NMClient internally still operates fully asynchronously. In that case NMClient has an internal main context. - NMClient takes over most of the functionality. When using D-Bus' ObjectManager interface, one needs to handle basically the entire state of the D-Bus interface. That cannot be separated well into distinct parts, and even if you try, you just end up having closely related code in different source files. Spreading related code does not make it easier to understand, on the contrary. That means, NMClient is inherently complex as it contains most of the logic. I think that is not avoidable, but it's not as bad as it sounds. - NMClient processes D-Bus messages and state changes in separate steps. First NMClient unpacks the message (e.g. _dbus_handle_properties_changed()) and keeps track of the changed data. Then we update the GObject instances (_dbus_handle_obj_changed_dbus()) without emitting any signals yet. Finally, we emit all signals and notifications that were collected (_dbus_handle_changes_commit()). Note that for example during the initial GetManagedObjects() reply, NMClient receive a large amount of state at once. But we first apply all the changes to our GObject instances before emitting any signals. The result is that signals are always emitted in a moment when the cache is consistent. The unavoidable downside is that when you receive a property changed signal, possibly many other properties changed already and more signals are about to be emitted. - NMDeviceWifi no longer modifies the content of the cache from client side during poke_wireless_devices_with_rf_status(). The content of the cache should be determined by D-Bus alone and follow what NetworkManager service exposes. Local modifications should be avoided. - This aims to bring no API/ABI change, though it does of course bring various subtle changes in behavior. Those should be all for the better, but the goal is not to break any existing clients. This does change internal (albeit externally visible) API, like dropping NM_OBJECT_DBUS_OBJECT_MANAGER property and NMObject no longer implementing GInitableIface and GAsyncInitableIface. - Some uses of gdbus-codegen classes remain in NMVpnPluginOld, NMVpnServicePlugin and NMSecretAgentOld. These are independent of NMClient/NMObject and should be reworked separately. - While we no longer use generated classes from gdbus-codegen, we don't need more glue code than before. Also before we constructed NMPropertiesInfo and a had large amount of code to propagate properties from NMDBus* to NMObject. That got completely reworked, but did not fundamentally change. You still need about the same effort to create the NMLDBusMetaIface. Not using generated bindings did not make anything worse (which tells about the usefulness of generated code, at least in the way it was used). - NMLDBusMetaIface and other meta data is static and immutable. This avoids copying them around. Also, macros like NML_DBUS_META_PROPERTY_INIT_U() have compile time checks to ensure the property types matches. It's pretty hard to misuse them because it won't compile. - The meta data now explicitly encodes the expected D-Bus types and makes sure never to accept wrong data. That would only matter when the server (accidentally or intentionally) exposes unexpected types on D-Bus. I don't think that was previously ensured in all cases. For example, demarshal_generic() only cared about the GObject property type, it didn't know the expected D-Bus type. - Previously GDBusObjectManager would sometimes emit warnings (g_log()). Those probably indicated real bugs. In any case, it prevented us from running CI with G_DEBUG=fatal-warnings, because there would be just too many unrelated crashes. Now we log debug messages that can be enabled with "LIBNM_CLIENT_DEBUG=trace". Some of these messages can also be turned into g_warning()/g_critical() by setting LIBNM_CLIENT_DEBUG=warning,error. Together with G_DEBUG=fatal-warnings, this turns them into assertions. Note that such "assertion failures" might also happen because of a server bug (or change). Thus these are not common assertions that indicate a bug in libnm and are thus not armed unless explicitly requested. In our CI we should now always run with LIBNM_CLIENT_DEBUG=warning,error and G_DEBUG=fatal-warnings and to catch bugs. Note that currently NetworkManager has bugs in this regard, so enabling this will result in assertion failures. That should be fixed first. - Note that this changes the order in which we emit "notify:devices" and "device-added" signals. I think it makes the most sense to emit first "device-removed", then "notify:devices", and finally "device-added" signals. This changes behavior for commit 52ae28f6e5bf ('libnm: queue added/removed signals and suppress uninitialized notifications'), but I don't think that users should actually rely on the order. Still, the new order makes the most sense to me. - In NetworkManager, profiles can be invisible to the user by setting "connection.permissions". Such profiles would be hidden by NMClient's nm_client_get_connections() and their "connection-added"/"connection-removed" signals. Note that NMActiveConnection's nm_active_connection_get_connection() and NMDevice's nm_device_get_available_connections() still exposes such hidden NMRemoteConnection instances. This behavior was preserved. NUMBERS ------- I compared 3 versions of libnm. [1] 962297f9085d, current tip of nm-1-20 branch [2] 4fad8c7c642e, current master, immediate parent of this patch [3] this patch All tests were done on Fedora 31, x86_64, gcc 9.2.1-1.fc31. The libraries were build with $ ./contrib/fedora/rpm/build_clean.sh -g -w test -W debug Note that RPM build already stripped the library. --- N1) File size of libnm.so.0.1.0 in bytes. There currently seems to be a issue on Fedora 31 generating wrong ELF notes. Usually, libnm is smaller but in these tests it had large (and bogus) ELF notes. Anyway, the point is to show the relative sizes, so it doesn't matter). [1] 4075552 (102.7%) [2] 3969624 (100.0%) [3] 3705208 ( 93.3%) --- N2) `size /usr/lib64/libnm.so.0.1.0`: text data bss dec hex filename [1] 1314569 (102.0%) 69980 ( 94.8%) 10632 ( 80.4%) 1395181 (101.4%) 1549ed /usr/lib64/libnm.so.0.1.0 [2] 1288410 (100.0%) 73796 (100.0%) 13224 (100.0%) 1375430 (100.0%) 14fcc6 /usr/lib64/libnm.so.0.1.0 [3] 1229066 ( 95.4%) 65248 ( 88.4%) 13400 (101.3%) 1307714 ( 95.1%) 13f442 /usr/lib64/libnm.so.0.1.0 --- N3) Performance test with test-client.py. With checkout of [2], run ``` prepare_checkout() { rm -rf /tmp/nm-test && \ git checkout -B test 4fad8c7c642e && \ git clean -fdx && \ ./autogen.sh --prefix=/tmp/nm-test && \ make -j 5 install && \ make -j 5 check-local-clients-tests-test-client } prepare_test() { NM_TEST_REGENERATE=1 NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v } do_test() { for i in {1..10}; do NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v || return -1 done echo "done!" } prepare_checkout prepare_test time do_test ``` [1] real 2m14.497s (101.3%) user 5m26.651s (100.3%) sys 1m40.453s (101.4%) [2] real 2m12.800s (100.0%) user 5m25.619s (100.0%) sys 1m39.065s (100.0%) [3] real 1m54.915s ( 86.5%) user 4m18.585s ( 79.4%) sys 1m32.066s ( 92.9%) --- N4) Performance. Run NetworkManager from build [2] and setup a large number of profiles (551 profiles and 515 devices, mostly unrealized). This setup is already at the edge of what NetworkManager currently can handle. Of course, that is a different issue. Here we just check how long plain `nmcli` takes on the system. ``` do_cleanup() { for UUID in $(nmcli -g NAME,UUID connection show | sed -n 's/^xx-c-.*:\([^:]\+\)$/\1/p'); do nmcli connection delete uuid "$UUID" done for DEVICE in $(nmcli -g DEVICE device status | grep '^xx-i-'); do nmcli device delete "$DEVICE" done } do_setup() { do_cleanup for i in {1..30}; do nmcli connection add type bond autoconnect no con-name xx-c-bond-$i ifname xx-i-bond-$i ipv4.method disabled ipv6.method ignore for j in $(seq $i 30); do nmcli connection add type vlan autoconnect no con-name xx-c-vlan-$i-$j vlan.id $j ifname xx-i-vlan-$i-$j vlan.parent xx-i-bond-$i ipv4.method disabled ipv6.method ignore done done systemctl restart NetworkManager.service sleep 5 } do_test() { perf stat -r 50 -B nmcli 1>/dev/null } do_test ``` [1] Performance counter stats for 'nmcli' (50 runs): 456.33 msec task-clock:u # 1.093 CPUs utilized ( +- 0.44% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,900 page-faults:u # 0.013 M/sec ( +- 0.02% ) 1,408,675,453 cycles:u # 3.087 GHz ( +- 0.48% ) 1,594,741,060 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 368,744,018 branches:u # 808.061 M/sec ( +- 0.02% ) 4,566,058 branch-misses:u # 1.24% of all branches ( +- 0.76% ) 0.41761 +- 0.00282 seconds time elapsed ( +- 0.68% ) [2] Performance counter stats for 'nmcli' (50 runs): 477.99 msec task-clock:u # 1.088 CPUs utilized ( +- 0.36% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,948 page-faults:u # 0.012 M/sec ( +- 0.03% ) 1,471,133,482 cycles:u # 3.078 GHz ( +- 0.36% ) 1,655,275,369 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 382,595,152 branches:u # 800.433 M/sec ( +- 0.02% ) 4,746,070 branch-misses:u # 1.24% of all branches ( +- 0.49% ) 0.43923 +- 0.00242 seconds time elapsed ( +- 0.55% ) [3] Performance counter stats for 'nmcli' (50 runs): 352.36 msec task-clock:u # 1.027 CPUs utilized ( +- 0.32% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 4,790 page-faults:u # 0.014 M/sec ( +- 0.26% ) 1,092,341,186 cycles:u # 3.100 GHz ( +- 0.26% ) 1,209,045,283 instructions:u # 1.11 insn per cycle ( +- 0.02% ) 281,708,462 branches:u # 799.499 M/sec ( +- 0.01% ) 3,101,031 branch-misses:u # 1.10% of all branches ( +- 0.61% ) 0.34296 +- 0.00120 seconds time elapsed ( +- 0.35% ) --- N5) same setup as N4), but run `PAGER= /bin/time -v nmcli`: [1] Command being timed: "nmcli" User time (seconds): 0.42 System time (seconds): 0.04 Percent of CPU this job got: 107% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.43 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34456 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6128 Voluntary context switches: 1298 Involuntary context switches: 1106 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [2] Command being timed: "nmcli" User time (seconds): 0.44 System time (seconds): 0.04 Percent of CPU this job got: 108% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.44 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34452 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6169 Voluntary context switches: 1849 Involuntary context switches: 142 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [3] Command being timed: "nmcli" User time (seconds): 0.32 System time (seconds): 0.02 Percent of CPU this job got: 102% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.34 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 29196 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 5059 Voluntary context switches: 919 Involuntary context switches: 685 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 --- N6) same setup as N4), but run `nmcli monitor` and look at `ps aux` for the RSS size. USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND [1] me 1492900 21.0 0.2 461348 33248 pts/10 Sl+ 15:02 0:00 nmcli monitor [2] me 1490721 5.0 0.2 461496 33548 pts/10 Sl+ 15:00 0:00 nmcli monitor [3] me 1495801 16.5 0.1 459476 28692 pts/10 Sl+ 15:04 0:00 nmcli monitor
2019-10-30 11:42:58 +01:00
priv->old_state = NM_DEVICE_STATE_UNKNOWN;
}
libnm: refactor caching of D-Bus objects in NMClient No longer use GDBusObjectMangaerClient and gdbus-codegen generated classes for the NMClient cache. Instead, use GDBusConnection directly and a custom implementation (NMLDBusObject) for caching D-Bus' ObjectManager data. CHANGES ------- - This is a complete rework. I think the previous implementation was difficult to understand. There were unfixed bugs and nobody understood the code well enough to fix them. Maybe somebody out there understood the code, but I certainly did not. At least nobody provided patches to fix those issues. I do believe that this implementation is more straightforward and easier to understand. It removes a lot of layers of code. Whether this claim of simplicity is true, each reader must decide for himself/herself. Note that it is still fairly complex. - There was a lingering performance issue with large number of D-Bus objects. The patch tries hard that the implementation scales well. Of course, when we cache N objects that have N-to-M references to other, we still are fundamentally O(N*M) for runtime and memory consumption (with M being the number of references between objects). But each part should behave efficiently and well. - Play well with GMainContext. libnm code (NMClient) is generally not thread safe. However, it should work to use multiple instances in parallel, as long as each access to a NMClient is through the caller's GMainContext. This follows glib's style and effectively allows to use NMClient in a multi threaded scenario. This implies to stick to a main context upon construction and ensure that callbacks are only invoked when iterating that context. Also, NMClient itself shall never iterate the caller's context. This also means, libnm must never use g_idle_add() or g_timeout_add(), as those enqueue sources in the g_main_context_default() context. - Get ordering of messages right. All events are consistently enqueued in a GMainContext and processed strictly in order. For example, previously "nm-object.c" tried to combine signals and emit them on an idle handler. That is wrong, signals must be emitted in the right order and when they happen. Note that when using GInitable's synchronous initialization to initialize the NMClient instance, NMClient internally still operates fully asynchronously. In that case NMClient has an internal main context. - NMClient takes over most of the functionality. When using D-Bus' ObjectManager interface, one needs to handle basically the entire state of the D-Bus interface. That cannot be separated well into distinct parts, and even if you try, you just end up having closely related code in different source files. Spreading related code does not make it easier to understand, on the contrary. That means, NMClient is inherently complex as it contains most of the logic. I think that is not avoidable, but it's not as bad as it sounds. - NMClient processes D-Bus messages and state changes in separate steps. First NMClient unpacks the message (e.g. _dbus_handle_properties_changed()) and keeps track of the changed data. Then we update the GObject instances (_dbus_handle_obj_changed_dbus()) without emitting any signals yet. Finally, we emit all signals and notifications that were collected (_dbus_handle_changes_commit()). Note that for example during the initial GetManagedObjects() reply, NMClient receive a large amount of state at once. But we first apply all the changes to our GObject instances before emitting any signals. The result is that signals are always emitted in a moment when the cache is consistent. The unavoidable downside is that when you receive a property changed signal, possibly many other properties changed already and more signals are about to be emitted. - NMDeviceWifi no longer modifies the content of the cache from client side during poke_wireless_devices_with_rf_status(). The content of the cache should be determined by D-Bus alone and follow what NetworkManager service exposes. Local modifications should be avoided. - This aims to bring no API/ABI change, though it does of course bring various subtle changes in behavior. Those should be all for the better, but the goal is not to break any existing clients. This does change internal (albeit externally visible) API, like dropping NM_OBJECT_DBUS_OBJECT_MANAGER property and NMObject no longer implementing GInitableIface and GAsyncInitableIface. - Some uses of gdbus-codegen classes remain in NMVpnPluginOld, NMVpnServicePlugin and NMSecretAgentOld. These are independent of NMClient/NMObject and should be reworked separately. - While we no longer use generated classes from gdbus-codegen, we don't need more glue code than before. Also before we constructed NMPropertiesInfo and a had large amount of code to propagate properties from NMDBus* to NMObject. That got completely reworked, but did not fundamentally change. You still need about the same effort to create the NMLDBusMetaIface. Not using generated bindings did not make anything worse (which tells about the usefulness of generated code, at least in the way it was used). - NMLDBusMetaIface and other meta data is static and immutable. This avoids copying them around. Also, macros like NML_DBUS_META_PROPERTY_INIT_U() have compile time checks to ensure the property types matches. It's pretty hard to misuse them because it won't compile. - The meta data now explicitly encodes the expected D-Bus types and makes sure never to accept wrong data. That would only matter when the server (accidentally or intentionally) exposes unexpected types on D-Bus. I don't think that was previously ensured in all cases. For example, demarshal_generic() only cared about the GObject property type, it didn't know the expected D-Bus type. - Previously GDBusObjectManager would sometimes emit warnings (g_log()). Those probably indicated real bugs. In any case, it prevented us from running CI with G_DEBUG=fatal-warnings, because there would be just too many unrelated crashes. Now we log debug messages that can be enabled with "LIBNM_CLIENT_DEBUG=trace". Some of these messages can also be turned into g_warning()/g_critical() by setting LIBNM_CLIENT_DEBUG=warning,error. Together with G_DEBUG=fatal-warnings, this turns them into assertions. Note that such "assertion failures" might also happen because of a server bug (or change). Thus these are not common assertions that indicate a bug in libnm and are thus not armed unless explicitly requested. In our CI we should now always run with LIBNM_CLIENT_DEBUG=warning,error and G_DEBUG=fatal-warnings and to catch bugs. Note that currently NetworkManager has bugs in this regard, so enabling this will result in assertion failures. That should be fixed first. - Note that this changes the order in which we emit "notify:devices" and "device-added" signals. I think it makes the most sense to emit first "device-removed", then "notify:devices", and finally "device-added" signals. This changes behavior for commit 52ae28f6e5bf ('libnm: queue added/removed signals and suppress uninitialized notifications'), but I don't think that users should actually rely on the order. Still, the new order makes the most sense to me. - In NetworkManager, profiles can be invisible to the user by setting "connection.permissions". Such profiles would be hidden by NMClient's nm_client_get_connections() and their "connection-added"/"connection-removed" signals. Note that NMActiveConnection's nm_active_connection_get_connection() and NMDevice's nm_device_get_available_connections() still exposes such hidden NMRemoteConnection instances. This behavior was preserved. NUMBERS ------- I compared 3 versions of libnm. [1] 962297f9085d, current tip of nm-1-20 branch [2] 4fad8c7c642e, current master, immediate parent of this patch [3] this patch All tests were done on Fedora 31, x86_64, gcc 9.2.1-1.fc31. The libraries were build with $ ./contrib/fedora/rpm/build_clean.sh -g -w test -W debug Note that RPM build already stripped the library. --- N1) File size of libnm.so.0.1.0 in bytes. There currently seems to be a issue on Fedora 31 generating wrong ELF notes. Usually, libnm is smaller but in these tests it had large (and bogus) ELF notes. Anyway, the point is to show the relative sizes, so it doesn't matter). [1] 4075552 (102.7%) [2] 3969624 (100.0%) [3] 3705208 ( 93.3%) --- N2) `size /usr/lib64/libnm.so.0.1.0`: text data bss dec hex filename [1] 1314569 (102.0%) 69980 ( 94.8%) 10632 ( 80.4%) 1395181 (101.4%) 1549ed /usr/lib64/libnm.so.0.1.0 [2] 1288410 (100.0%) 73796 (100.0%) 13224 (100.0%) 1375430 (100.0%) 14fcc6 /usr/lib64/libnm.so.0.1.0 [3] 1229066 ( 95.4%) 65248 ( 88.4%) 13400 (101.3%) 1307714 ( 95.1%) 13f442 /usr/lib64/libnm.so.0.1.0 --- N3) Performance test with test-client.py. With checkout of [2], run ``` prepare_checkout() { rm -rf /tmp/nm-test && \ git checkout -B test 4fad8c7c642e && \ git clean -fdx && \ ./autogen.sh --prefix=/tmp/nm-test && \ make -j 5 install && \ make -j 5 check-local-clients-tests-test-client } prepare_test() { NM_TEST_REGENERATE=1 NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v } do_test() { for i in {1..10}; do NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v || return -1 done echo "done!" } prepare_checkout prepare_test time do_test ``` [1] real 2m14.497s (101.3%) user 5m26.651s (100.3%) sys 1m40.453s (101.4%) [2] real 2m12.800s (100.0%) user 5m25.619s (100.0%) sys 1m39.065s (100.0%) [3] real 1m54.915s ( 86.5%) user 4m18.585s ( 79.4%) sys 1m32.066s ( 92.9%) --- N4) Performance. Run NetworkManager from build [2] and setup a large number of profiles (551 profiles and 515 devices, mostly unrealized). This setup is already at the edge of what NetworkManager currently can handle. Of course, that is a different issue. Here we just check how long plain `nmcli` takes on the system. ``` do_cleanup() { for UUID in $(nmcli -g NAME,UUID connection show | sed -n 's/^xx-c-.*:\([^:]\+\)$/\1/p'); do nmcli connection delete uuid "$UUID" done for DEVICE in $(nmcli -g DEVICE device status | grep '^xx-i-'); do nmcli device delete "$DEVICE" done } do_setup() { do_cleanup for i in {1..30}; do nmcli connection add type bond autoconnect no con-name xx-c-bond-$i ifname xx-i-bond-$i ipv4.method disabled ipv6.method ignore for j in $(seq $i 30); do nmcli connection add type vlan autoconnect no con-name xx-c-vlan-$i-$j vlan.id $j ifname xx-i-vlan-$i-$j vlan.parent xx-i-bond-$i ipv4.method disabled ipv6.method ignore done done systemctl restart NetworkManager.service sleep 5 } do_test() { perf stat -r 50 -B nmcli 1>/dev/null } do_test ``` [1] Performance counter stats for 'nmcli' (50 runs): 456.33 msec task-clock:u # 1.093 CPUs utilized ( +- 0.44% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,900 page-faults:u # 0.013 M/sec ( +- 0.02% ) 1,408,675,453 cycles:u # 3.087 GHz ( +- 0.48% ) 1,594,741,060 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 368,744,018 branches:u # 808.061 M/sec ( +- 0.02% ) 4,566,058 branch-misses:u # 1.24% of all branches ( +- 0.76% ) 0.41761 +- 0.00282 seconds time elapsed ( +- 0.68% ) [2] Performance counter stats for 'nmcli' (50 runs): 477.99 msec task-clock:u # 1.088 CPUs utilized ( +- 0.36% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,948 page-faults:u # 0.012 M/sec ( +- 0.03% ) 1,471,133,482 cycles:u # 3.078 GHz ( +- 0.36% ) 1,655,275,369 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 382,595,152 branches:u # 800.433 M/sec ( +- 0.02% ) 4,746,070 branch-misses:u # 1.24% of all branches ( +- 0.49% ) 0.43923 +- 0.00242 seconds time elapsed ( +- 0.55% ) [3] Performance counter stats for 'nmcli' (50 runs): 352.36 msec task-clock:u # 1.027 CPUs utilized ( +- 0.32% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 4,790 page-faults:u # 0.014 M/sec ( +- 0.26% ) 1,092,341,186 cycles:u # 3.100 GHz ( +- 0.26% ) 1,209,045,283 instructions:u # 1.11 insn per cycle ( +- 0.02% ) 281,708,462 branches:u # 799.499 M/sec ( +- 0.01% ) 3,101,031 branch-misses:u # 1.10% of all branches ( +- 0.61% ) 0.34296 +- 0.00120 seconds time elapsed ( +- 0.35% ) --- N5) same setup as N4), but run `PAGER= /bin/time -v nmcli`: [1] Command being timed: "nmcli" User time (seconds): 0.42 System time (seconds): 0.04 Percent of CPU this job got: 107% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.43 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34456 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6128 Voluntary context switches: 1298 Involuntary context switches: 1106 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [2] Command being timed: "nmcli" User time (seconds): 0.44 System time (seconds): 0.04 Percent of CPU this job got: 108% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.44 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34452 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6169 Voluntary context switches: 1849 Involuntary context switches: 142 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [3] Command being timed: "nmcli" User time (seconds): 0.32 System time (seconds): 0.02 Percent of CPU this job got: 102% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.34 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 29196 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 5059 Voluntary context switches: 919 Involuntary context switches: 685 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 --- N6) same setup as N4), but run `nmcli monitor` and look at `ps aux` for the RSS size. USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND [1] me 1492900 21.0 0.2 461348 33248 pts/10 Sl+ 15:02 0:00 nmcli monitor [2] me 1490721 5.0 0.2 461496 33548 pts/10 Sl+ 15:00 0:00 nmcli monitor [3] me 1495801 16.5 0.1 459476 28692 pts/10 Sl+ 15:04 0:00 nmcli monitor
2019-10-30 11:42:58 +01:00
/*****************************************************************************/
libnm: refactor caching of D-Bus objects in NMClient No longer use GDBusObjectMangaerClient and gdbus-codegen generated classes for the NMClient cache. Instead, use GDBusConnection directly and a custom implementation (NMLDBusObject) for caching D-Bus' ObjectManager data. CHANGES ------- - This is a complete rework. I think the previous implementation was difficult to understand. There were unfixed bugs and nobody understood the code well enough to fix them. Maybe somebody out there understood the code, but I certainly did not. At least nobody provided patches to fix those issues. I do believe that this implementation is more straightforward and easier to understand. It removes a lot of layers of code. Whether this claim of simplicity is true, each reader must decide for himself/herself. Note that it is still fairly complex. - There was a lingering performance issue with large number of D-Bus objects. The patch tries hard that the implementation scales well. Of course, when we cache N objects that have N-to-M references to other, we still are fundamentally O(N*M) for runtime and memory consumption (with M being the number of references between objects). But each part should behave efficiently and well. - Play well with GMainContext. libnm code (NMClient) is generally not thread safe. However, it should work to use multiple instances in parallel, as long as each access to a NMClient is through the caller's GMainContext. This follows glib's style and effectively allows to use NMClient in a multi threaded scenario. This implies to stick to a main context upon construction and ensure that callbacks are only invoked when iterating that context. Also, NMClient itself shall never iterate the caller's context. This also means, libnm must never use g_idle_add() or g_timeout_add(), as those enqueue sources in the g_main_context_default() context. - Get ordering of messages right. All events are consistently enqueued in a GMainContext and processed strictly in order. For example, previously "nm-object.c" tried to combine signals and emit them on an idle handler. That is wrong, signals must be emitted in the right order and when they happen. Note that when using GInitable's synchronous initialization to initialize the NMClient instance, NMClient internally still operates fully asynchronously. In that case NMClient has an internal main context. - NMClient takes over most of the functionality. When using D-Bus' ObjectManager interface, one needs to handle basically the entire state of the D-Bus interface. That cannot be separated well into distinct parts, and even if you try, you just end up having closely related code in different source files. Spreading related code does not make it easier to understand, on the contrary. That means, NMClient is inherently complex as it contains most of the logic. I think that is not avoidable, but it's not as bad as it sounds. - NMClient processes D-Bus messages and state changes in separate steps. First NMClient unpacks the message (e.g. _dbus_handle_properties_changed()) and keeps track of the changed data. Then we update the GObject instances (_dbus_handle_obj_changed_dbus()) without emitting any signals yet. Finally, we emit all signals and notifications that were collected (_dbus_handle_changes_commit()). Note that for example during the initial GetManagedObjects() reply, NMClient receive a large amount of state at once. But we first apply all the changes to our GObject instances before emitting any signals. The result is that signals are always emitted in a moment when the cache is consistent. The unavoidable downside is that when you receive a property changed signal, possibly many other properties changed already and more signals are about to be emitted. - NMDeviceWifi no longer modifies the content of the cache from client side during poke_wireless_devices_with_rf_status(). The content of the cache should be determined by D-Bus alone and follow what NetworkManager service exposes. Local modifications should be avoided. - This aims to bring no API/ABI change, though it does of course bring various subtle changes in behavior. Those should be all for the better, but the goal is not to break any existing clients. This does change internal (albeit externally visible) API, like dropping NM_OBJECT_DBUS_OBJECT_MANAGER property and NMObject no longer implementing GInitableIface and GAsyncInitableIface. - Some uses of gdbus-codegen classes remain in NMVpnPluginOld, NMVpnServicePlugin and NMSecretAgentOld. These are independent of NMClient/NMObject and should be reworked separately. - While we no longer use generated classes from gdbus-codegen, we don't need more glue code than before. Also before we constructed NMPropertiesInfo and a had large amount of code to propagate properties from NMDBus* to NMObject. That got completely reworked, but did not fundamentally change. You still need about the same effort to create the NMLDBusMetaIface. Not using generated bindings did not make anything worse (which tells about the usefulness of generated code, at least in the way it was used). - NMLDBusMetaIface and other meta data is static and immutable. This avoids copying them around. Also, macros like NML_DBUS_META_PROPERTY_INIT_U() have compile time checks to ensure the property types matches. It's pretty hard to misuse them because it won't compile. - The meta data now explicitly encodes the expected D-Bus types and makes sure never to accept wrong data. That would only matter when the server (accidentally or intentionally) exposes unexpected types on D-Bus. I don't think that was previously ensured in all cases. For example, demarshal_generic() only cared about the GObject property type, it didn't know the expected D-Bus type. - Previously GDBusObjectManager would sometimes emit warnings (g_log()). Those probably indicated real bugs. In any case, it prevented us from running CI with G_DEBUG=fatal-warnings, because there would be just too many unrelated crashes. Now we log debug messages that can be enabled with "LIBNM_CLIENT_DEBUG=trace". Some of these messages can also be turned into g_warning()/g_critical() by setting LIBNM_CLIENT_DEBUG=warning,error. Together with G_DEBUG=fatal-warnings, this turns them into assertions. Note that such "assertion failures" might also happen because of a server bug (or change). Thus these are not common assertions that indicate a bug in libnm and are thus not armed unless explicitly requested. In our CI we should now always run with LIBNM_CLIENT_DEBUG=warning,error and G_DEBUG=fatal-warnings and to catch bugs. Note that currently NetworkManager has bugs in this regard, so enabling this will result in assertion failures. That should be fixed first. - Note that this changes the order in which we emit "notify:devices" and "device-added" signals. I think it makes the most sense to emit first "device-removed", then "notify:devices", and finally "device-added" signals. This changes behavior for commit 52ae28f6e5bf ('libnm: queue added/removed signals and suppress uninitialized notifications'), but I don't think that users should actually rely on the order. Still, the new order makes the most sense to me. - In NetworkManager, profiles can be invisible to the user by setting "connection.permissions". Such profiles would be hidden by NMClient's nm_client_get_connections() and their "connection-added"/"connection-removed" signals. Note that NMActiveConnection's nm_active_connection_get_connection() and NMDevice's nm_device_get_available_connections() still exposes such hidden NMRemoteConnection instances. This behavior was preserved. NUMBERS ------- I compared 3 versions of libnm. [1] 962297f9085d, current tip of nm-1-20 branch [2] 4fad8c7c642e, current master, immediate parent of this patch [3] this patch All tests were done on Fedora 31, x86_64, gcc 9.2.1-1.fc31. The libraries were build with $ ./contrib/fedora/rpm/build_clean.sh -g -w test -W debug Note that RPM build already stripped the library. --- N1) File size of libnm.so.0.1.0 in bytes. There currently seems to be a issue on Fedora 31 generating wrong ELF notes. Usually, libnm is smaller but in these tests it had large (and bogus) ELF notes. Anyway, the point is to show the relative sizes, so it doesn't matter). [1] 4075552 (102.7%) [2] 3969624 (100.0%) [3] 3705208 ( 93.3%) --- N2) `size /usr/lib64/libnm.so.0.1.0`: text data bss dec hex filename [1] 1314569 (102.0%) 69980 ( 94.8%) 10632 ( 80.4%) 1395181 (101.4%) 1549ed /usr/lib64/libnm.so.0.1.0 [2] 1288410 (100.0%) 73796 (100.0%) 13224 (100.0%) 1375430 (100.0%) 14fcc6 /usr/lib64/libnm.so.0.1.0 [3] 1229066 ( 95.4%) 65248 ( 88.4%) 13400 (101.3%) 1307714 ( 95.1%) 13f442 /usr/lib64/libnm.so.0.1.0 --- N3) Performance test with test-client.py. With checkout of [2], run ``` prepare_checkout() { rm -rf /tmp/nm-test && \ git checkout -B test 4fad8c7c642e && \ git clean -fdx && \ ./autogen.sh --prefix=/tmp/nm-test && \ make -j 5 install && \ make -j 5 check-local-clients-tests-test-client } prepare_test() { NM_TEST_REGENERATE=1 NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v } do_test() { for i in {1..10}; do NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v || return -1 done echo "done!" } prepare_checkout prepare_test time do_test ``` [1] real 2m14.497s (101.3%) user 5m26.651s (100.3%) sys 1m40.453s (101.4%) [2] real 2m12.800s (100.0%) user 5m25.619s (100.0%) sys 1m39.065s (100.0%) [3] real 1m54.915s ( 86.5%) user 4m18.585s ( 79.4%) sys 1m32.066s ( 92.9%) --- N4) Performance. Run NetworkManager from build [2] and setup a large number of profiles (551 profiles and 515 devices, mostly unrealized). This setup is already at the edge of what NetworkManager currently can handle. Of course, that is a different issue. Here we just check how long plain `nmcli` takes on the system. ``` do_cleanup() { for UUID in $(nmcli -g NAME,UUID connection show | sed -n 's/^xx-c-.*:\([^:]\+\)$/\1/p'); do nmcli connection delete uuid "$UUID" done for DEVICE in $(nmcli -g DEVICE device status | grep '^xx-i-'); do nmcli device delete "$DEVICE" done } do_setup() { do_cleanup for i in {1..30}; do nmcli connection add type bond autoconnect no con-name xx-c-bond-$i ifname xx-i-bond-$i ipv4.method disabled ipv6.method ignore for j in $(seq $i 30); do nmcli connection add type vlan autoconnect no con-name xx-c-vlan-$i-$j vlan.id $j ifname xx-i-vlan-$i-$j vlan.parent xx-i-bond-$i ipv4.method disabled ipv6.method ignore done done systemctl restart NetworkManager.service sleep 5 } do_test() { perf stat -r 50 -B nmcli 1>/dev/null } do_test ``` [1] Performance counter stats for 'nmcli' (50 runs): 456.33 msec task-clock:u # 1.093 CPUs utilized ( +- 0.44% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,900 page-faults:u # 0.013 M/sec ( +- 0.02% ) 1,408,675,453 cycles:u # 3.087 GHz ( +- 0.48% ) 1,594,741,060 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 368,744,018 branches:u # 808.061 M/sec ( +- 0.02% ) 4,566,058 branch-misses:u # 1.24% of all branches ( +- 0.76% ) 0.41761 +- 0.00282 seconds time elapsed ( +- 0.68% ) [2] Performance counter stats for 'nmcli' (50 runs): 477.99 msec task-clock:u # 1.088 CPUs utilized ( +- 0.36% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,948 page-faults:u # 0.012 M/sec ( +- 0.03% ) 1,471,133,482 cycles:u # 3.078 GHz ( +- 0.36% ) 1,655,275,369 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 382,595,152 branches:u # 800.433 M/sec ( +- 0.02% ) 4,746,070 branch-misses:u # 1.24% of all branches ( +- 0.49% ) 0.43923 +- 0.00242 seconds time elapsed ( +- 0.55% ) [3] Performance counter stats for 'nmcli' (50 runs): 352.36 msec task-clock:u # 1.027 CPUs utilized ( +- 0.32% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 4,790 page-faults:u # 0.014 M/sec ( +- 0.26% ) 1,092,341,186 cycles:u # 3.100 GHz ( +- 0.26% ) 1,209,045,283 instructions:u # 1.11 insn per cycle ( +- 0.02% ) 281,708,462 branches:u # 799.499 M/sec ( +- 0.01% ) 3,101,031 branch-misses:u # 1.10% of all branches ( +- 0.61% ) 0.34296 +- 0.00120 seconds time elapsed ( +- 0.35% ) --- N5) same setup as N4), but run `PAGER= /bin/time -v nmcli`: [1] Command being timed: "nmcli" User time (seconds): 0.42 System time (seconds): 0.04 Percent of CPU this job got: 107% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.43 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34456 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6128 Voluntary context switches: 1298 Involuntary context switches: 1106 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [2] Command being timed: "nmcli" User time (seconds): 0.44 System time (seconds): 0.04 Percent of CPU this job got: 108% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.44 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34452 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6169 Voluntary context switches: 1849 Involuntary context switches: 142 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [3] Command being timed: "nmcli" User time (seconds): 0.32 System time (seconds): 0.02 Percent of CPU this job got: 102% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.34 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 29196 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 5059 Voluntary context switches: 919 Involuntary context switches: 685 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 --- N6) same setup as N4), but run `nmcli monitor` and look at `ps aux` for the RSS size. USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND [1] me 1492900 21.0 0.2 461348 33248 pts/10 Sl+ 15:02 0:00 nmcli monitor [2] me 1490721 5.0 0.2 461496 33548 pts/10 Sl+ 15:00 0:00 nmcli monitor [3] me 1495801 16.5 0.1 459476 28692 pts/10 Sl+ 15:04 0:00 nmcli monitor
2019-10-30 11:42:58 +01:00
static void
_notify_event_state_changed (NMClient *client,
NMClientNotifyEventWithPtr *notify_event)
{
libnm: refactor caching of D-Bus objects in NMClient No longer use GDBusObjectMangaerClient and gdbus-codegen generated classes for the NMClient cache. Instead, use GDBusConnection directly and a custom implementation (NMLDBusObject) for caching D-Bus' ObjectManager data. CHANGES ------- - This is a complete rework. I think the previous implementation was difficult to understand. There were unfixed bugs and nobody understood the code well enough to fix them. Maybe somebody out there understood the code, but I certainly did not. At least nobody provided patches to fix those issues. I do believe that this implementation is more straightforward and easier to understand. It removes a lot of layers of code. Whether this claim of simplicity is true, each reader must decide for himself/herself. Note that it is still fairly complex. - There was a lingering performance issue with large number of D-Bus objects. The patch tries hard that the implementation scales well. Of course, when we cache N objects that have N-to-M references to other, we still are fundamentally O(N*M) for runtime and memory consumption (with M being the number of references between objects). But each part should behave efficiently and well. - Play well with GMainContext. libnm code (NMClient) is generally not thread safe. However, it should work to use multiple instances in parallel, as long as each access to a NMClient is through the caller's GMainContext. This follows glib's style and effectively allows to use NMClient in a multi threaded scenario. This implies to stick to a main context upon construction and ensure that callbacks are only invoked when iterating that context. Also, NMClient itself shall never iterate the caller's context. This also means, libnm must never use g_idle_add() or g_timeout_add(), as those enqueue sources in the g_main_context_default() context. - Get ordering of messages right. All events are consistently enqueued in a GMainContext and processed strictly in order. For example, previously "nm-object.c" tried to combine signals and emit them on an idle handler. That is wrong, signals must be emitted in the right order and when they happen. Note that when using GInitable's synchronous initialization to initialize the NMClient instance, NMClient internally still operates fully asynchronously. In that case NMClient has an internal main context. - NMClient takes over most of the functionality. When using D-Bus' ObjectManager interface, one needs to handle basically the entire state of the D-Bus interface. That cannot be separated well into distinct parts, and even if you try, you just end up having closely related code in different source files. Spreading related code does not make it easier to understand, on the contrary. That means, NMClient is inherently complex as it contains most of the logic. I think that is not avoidable, but it's not as bad as it sounds. - NMClient processes D-Bus messages and state changes in separate steps. First NMClient unpacks the message (e.g. _dbus_handle_properties_changed()) and keeps track of the changed data. Then we update the GObject instances (_dbus_handle_obj_changed_dbus()) without emitting any signals yet. Finally, we emit all signals and notifications that were collected (_dbus_handle_changes_commit()). Note that for example during the initial GetManagedObjects() reply, NMClient receive a large amount of state at once. But we first apply all the changes to our GObject instances before emitting any signals. The result is that signals are always emitted in a moment when the cache is consistent. The unavoidable downside is that when you receive a property changed signal, possibly many other properties changed already and more signals are about to be emitted. - NMDeviceWifi no longer modifies the content of the cache from client side during poke_wireless_devices_with_rf_status(). The content of the cache should be determined by D-Bus alone and follow what NetworkManager service exposes. Local modifications should be avoided. - This aims to bring no API/ABI change, though it does of course bring various subtle changes in behavior. Those should be all for the better, but the goal is not to break any existing clients. This does change internal (albeit externally visible) API, like dropping NM_OBJECT_DBUS_OBJECT_MANAGER property and NMObject no longer implementing GInitableIface and GAsyncInitableIface. - Some uses of gdbus-codegen classes remain in NMVpnPluginOld, NMVpnServicePlugin and NMSecretAgentOld. These are independent of NMClient/NMObject and should be reworked separately. - While we no longer use generated classes from gdbus-codegen, we don't need more glue code than before. Also before we constructed NMPropertiesInfo and a had large amount of code to propagate properties from NMDBus* to NMObject. That got completely reworked, but did not fundamentally change. You still need about the same effort to create the NMLDBusMetaIface. Not using generated bindings did not make anything worse (which tells about the usefulness of generated code, at least in the way it was used). - NMLDBusMetaIface and other meta data is static and immutable. This avoids copying them around. Also, macros like NML_DBUS_META_PROPERTY_INIT_U() have compile time checks to ensure the property types matches. It's pretty hard to misuse them because it won't compile. - The meta data now explicitly encodes the expected D-Bus types and makes sure never to accept wrong data. That would only matter when the server (accidentally or intentionally) exposes unexpected types on D-Bus. I don't think that was previously ensured in all cases. For example, demarshal_generic() only cared about the GObject property type, it didn't know the expected D-Bus type. - Previously GDBusObjectManager would sometimes emit warnings (g_log()). Those probably indicated real bugs. In any case, it prevented us from running CI with G_DEBUG=fatal-warnings, because there would be just too many unrelated crashes. Now we log debug messages that can be enabled with "LIBNM_CLIENT_DEBUG=trace". Some of these messages can also be turned into g_warning()/g_critical() by setting LIBNM_CLIENT_DEBUG=warning,error. Together with G_DEBUG=fatal-warnings, this turns them into assertions. Note that such "assertion failures" might also happen because of a server bug (or change). Thus these are not common assertions that indicate a bug in libnm and are thus not armed unless explicitly requested. In our CI we should now always run with LIBNM_CLIENT_DEBUG=warning,error and G_DEBUG=fatal-warnings and to catch bugs. Note that currently NetworkManager has bugs in this regard, so enabling this will result in assertion failures. That should be fixed first. - Note that this changes the order in which we emit "notify:devices" and "device-added" signals. I think it makes the most sense to emit first "device-removed", then "notify:devices", and finally "device-added" signals. This changes behavior for commit 52ae28f6e5bf ('libnm: queue added/removed signals and suppress uninitialized notifications'), but I don't think that users should actually rely on the order. Still, the new order makes the most sense to me. - In NetworkManager, profiles can be invisible to the user by setting "connection.permissions". Such profiles would be hidden by NMClient's nm_client_get_connections() and their "connection-added"/"connection-removed" signals. Note that NMActiveConnection's nm_active_connection_get_connection() and NMDevice's nm_device_get_available_connections() still exposes such hidden NMRemoteConnection instances. This behavior was preserved. NUMBERS ------- I compared 3 versions of libnm. [1] 962297f9085d, current tip of nm-1-20 branch [2] 4fad8c7c642e, current master, immediate parent of this patch [3] this patch All tests were done on Fedora 31, x86_64, gcc 9.2.1-1.fc31. The libraries were build with $ ./contrib/fedora/rpm/build_clean.sh -g -w test -W debug Note that RPM build already stripped the library. --- N1) File size of libnm.so.0.1.0 in bytes. There currently seems to be a issue on Fedora 31 generating wrong ELF notes. Usually, libnm is smaller but in these tests it had large (and bogus) ELF notes. Anyway, the point is to show the relative sizes, so it doesn't matter). [1] 4075552 (102.7%) [2] 3969624 (100.0%) [3] 3705208 ( 93.3%) --- N2) `size /usr/lib64/libnm.so.0.1.0`: text data bss dec hex filename [1] 1314569 (102.0%) 69980 ( 94.8%) 10632 ( 80.4%) 1395181 (101.4%) 1549ed /usr/lib64/libnm.so.0.1.0 [2] 1288410 (100.0%) 73796 (100.0%) 13224 (100.0%) 1375430 (100.0%) 14fcc6 /usr/lib64/libnm.so.0.1.0 [3] 1229066 ( 95.4%) 65248 ( 88.4%) 13400 (101.3%) 1307714 ( 95.1%) 13f442 /usr/lib64/libnm.so.0.1.0 --- N3) Performance test with test-client.py. With checkout of [2], run ``` prepare_checkout() { rm -rf /tmp/nm-test && \ git checkout -B test 4fad8c7c642e && \ git clean -fdx && \ ./autogen.sh --prefix=/tmp/nm-test && \ make -j 5 install && \ make -j 5 check-local-clients-tests-test-client } prepare_test() { NM_TEST_REGENERATE=1 NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v } do_test() { for i in {1..10}; do NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v || return -1 done echo "done!" } prepare_checkout prepare_test time do_test ``` [1] real 2m14.497s (101.3%) user 5m26.651s (100.3%) sys 1m40.453s (101.4%) [2] real 2m12.800s (100.0%) user 5m25.619s (100.0%) sys 1m39.065s (100.0%) [3] real 1m54.915s ( 86.5%) user 4m18.585s ( 79.4%) sys 1m32.066s ( 92.9%) --- N4) Performance. Run NetworkManager from build [2] and setup a large number of profiles (551 profiles and 515 devices, mostly unrealized). This setup is already at the edge of what NetworkManager currently can handle. Of course, that is a different issue. Here we just check how long plain `nmcli` takes on the system. ``` do_cleanup() { for UUID in $(nmcli -g NAME,UUID connection show | sed -n 's/^xx-c-.*:\([^:]\+\)$/\1/p'); do nmcli connection delete uuid "$UUID" done for DEVICE in $(nmcli -g DEVICE device status | grep '^xx-i-'); do nmcli device delete "$DEVICE" done } do_setup() { do_cleanup for i in {1..30}; do nmcli connection add type bond autoconnect no con-name xx-c-bond-$i ifname xx-i-bond-$i ipv4.method disabled ipv6.method ignore for j in $(seq $i 30); do nmcli connection add type vlan autoconnect no con-name xx-c-vlan-$i-$j vlan.id $j ifname xx-i-vlan-$i-$j vlan.parent xx-i-bond-$i ipv4.method disabled ipv6.method ignore done done systemctl restart NetworkManager.service sleep 5 } do_test() { perf stat -r 50 -B nmcli 1>/dev/null } do_test ``` [1] Performance counter stats for 'nmcli' (50 runs): 456.33 msec task-clock:u # 1.093 CPUs utilized ( +- 0.44% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,900 page-faults:u # 0.013 M/sec ( +- 0.02% ) 1,408,675,453 cycles:u # 3.087 GHz ( +- 0.48% ) 1,594,741,060 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 368,744,018 branches:u # 808.061 M/sec ( +- 0.02% ) 4,566,058 branch-misses:u # 1.24% of all branches ( +- 0.76% ) 0.41761 +- 0.00282 seconds time elapsed ( +- 0.68% ) [2] Performance counter stats for 'nmcli' (50 runs): 477.99 msec task-clock:u # 1.088 CPUs utilized ( +- 0.36% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,948 page-faults:u # 0.012 M/sec ( +- 0.03% ) 1,471,133,482 cycles:u # 3.078 GHz ( +- 0.36% ) 1,655,275,369 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 382,595,152 branches:u # 800.433 M/sec ( +- 0.02% ) 4,746,070 branch-misses:u # 1.24% of all branches ( +- 0.49% ) 0.43923 +- 0.00242 seconds time elapsed ( +- 0.55% ) [3] Performance counter stats for 'nmcli' (50 runs): 352.36 msec task-clock:u # 1.027 CPUs utilized ( +- 0.32% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 4,790 page-faults:u # 0.014 M/sec ( +- 0.26% ) 1,092,341,186 cycles:u # 3.100 GHz ( +- 0.26% ) 1,209,045,283 instructions:u # 1.11 insn per cycle ( +- 0.02% ) 281,708,462 branches:u # 799.499 M/sec ( +- 0.01% ) 3,101,031 branch-misses:u # 1.10% of all branches ( +- 0.61% ) 0.34296 +- 0.00120 seconds time elapsed ( +- 0.35% ) --- N5) same setup as N4), but run `PAGER= /bin/time -v nmcli`: [1] Command being timed: "nmcli" User time (seconds): 0.42 System time (seconds): 0.04 Percent of CPU this job got: 107% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.43 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34456 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6128 Voluntary context switches: 1298 Involuntary context switches: 1106 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [2] Command being timed: "nmcli" User time (seconds): 0.44 System time (seconds): 0.04 Percent of CPU this job got: 108% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.44 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34452 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6169 Voluntary context switches: 1849 Involuntary context switches: 142 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [3] Command being timed: "nmcli" User time (seconds): 0.32 System time (seconds): 0.02 Percent of CPU this job got: 102% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.34 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 29196 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 5059 Voluntary context switches: 919 Involuntary context switches: 685 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 --- N6) same setup as N4), but run `nmcli monitor` and look at `ps aux` for the RSS size. USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND [1] me 1492900 21.0 0.2 461348 33248 pts/10 Sl+ 15:02 0:00 nmcli monitor [2] me 1490721 5.0 0.2 461496 33548 pts/10 Sl+ 15:00 0:00 nmcli monitor [3] me 1495801 16.5 0.1 459476 28692 pts/10 Sl+ 15:04 0:00 nmcli monitor
2019-10-30 11:42:58 +01:00
gs_unref_object NMDevice *self = notify_event->user_data;
NMDevicePrivate *priv = NM_DEVICE_GET_PRIVATE (self);
NML_NMCLIENT_LOG_T (client,
libnm: refactor caching of D-Bus objects in NMClient No longer use GDBusObjectMangaerClient and gdbus-codegen generated classes for the NMClient cache. Instead, use GDBusConnection directly and a custom implementation (NMLDBusObject) for caching D-Bus' ObjectManager data. CHANGES ------- - This is a complete rework. I think the previous implementation was difficult to understand. There were unfixed bugs and nobody understood the code well enough to fix them. Maybe somebody out there understood the code, but I certainly did not. At least nobody provided patches to fix those issues. I do believe that this implementation is more straightforward and easier to understand. It removes a lot of layers of code. Whether this claim of simplicity is true, each reader must decide for himself/herself. Note that it is still fairly complex. - There was a lingering performance issue with large number of D-Bus objects. The patch tries hard that the implementation scales well. Of course, when we cache N objects that have N-to-M references to other, we still are fundamentally O(N*M) for runtime and memory consumption (with M being the number of references between objects). But each part should behave efficiently and well. - Play well with GMainContext. libnm code (NMClient) is generally not thread safe. However, it should work to use multiple instances in parallel, as long as each access to a NMClient is through the caller's GMainContext. This follows glib's style and effectively allows to use NMClient in a multi threaded scenario. This implies to stick to a main context upon construction and ensure that callbacks are only invoked when iterating that context. Also, NMClient itself shall never iterate the caller's context. This also means, libnm must never use g_idle_add() or g_timeout_add(), as those enqueue sources in the g_main_context_default() context. - Get ordering of messages right. All events are consistently enqueued in a GMainContext and processed strictly in order. For example, previously "nm-object.c" tried to combine signals and emit them on an idle handler. That is wrong, signals must be emitted in the right order and when they happen. Note that when using GInitable's synchronous initialization to initialize the NMClient instance, NMClient internally still operates fully asynchronously. In that case NMClient has an internal main context. - NMClient takes over most of the functionality. When using D-Bus' ObjectManager interface, one needs to handle basically the entire state of the D-Bus interface. That cannot be separated well into distinct parts, and even if you try, you just end up having closely related code in different source files. Spreading related code does not make it easier to understand, on the contrary. That means, NMClient is inherently complex as it contains most of the logic. I think that is not avoidable, but it's not as bad as it sounds. - NMClient processes D-Bus messages and state changes in separate steps. First NMClient unpacks the message (e.g. _dbus_handle_properties_changed()) and keeps track of the changed data. Then we update the GObject instances (_dbus_handle_obj_changed_dbus()) without emitting any signals yet. Finally, we emit all signals and notifications that were collected (_dbus_handle_changes_commit()). Note that for example during the initial GetManagedObjects() reply, NMClient receive a large amount of state at once. But we first apply all the changes to our GObject instances before emitting any signals. The result is that signals are always emitted in a moment when the cache is consistent. The unavoidable downside is that when you receive a property changed signal, possibly many other properties changed already and more signals are about to be emitted. - NMDeviceWifi no longer modifies the content of the cache from client side during poke_wireless_devices_with_rf_status(). The content of the cache should be determined by D-Bus alone and follow what NetworkManager service exposes. Local modifications should be avoided. - This aims to bring no API/ABI change, though it does of course bring various subtle changes in behavior. Those should be all for the better, but the goal is not to break any existing clients. This does change internal (albeit externally visible) API, like dropping NM_OBJECT_DBUS_OBJECT_MANAGER property and NMObject no longer implementing GInitableIface and GAsyncInitableIface. - Some uses of gdbus-codegen classes remain in NMVpnPluginOld, NMVpnServicePlugin and NMSecretAgentOld. These are independent of NMClient/NMObject and should be reworked separately. - While we no longer use generated classes from gdbus-codegen, we don't need more glue code than before. Also before we constructed NMPropertiesInfo and a had large amount of code to propagate properties from NMDBus* to NMObject. That got completely reworked, but did not fundamentally change. You still need about the same effort to create the NMLDBusMetaIface. Not using generated bindings did not make anything worse (which tells about the usefulness of generated code, at least in the way it was used). - NMLDBusMetaIface and other meta data is static and immutable. This avoids copying them around. Also, macros like NML_DBUS_META_PROPERTY_INIT_U() have compile time checks to ensure the property types matches. It's pretty hard to misuse them because it won't compile. - The meta data now explicitly encodes the expected D-Bus types and makes sure never to accept wrong data. That would only matter when the server (accidentally or intentionally) exposes unexpected types on D-Bus. I don't think that was previously ensured in all cases. For example, demarshal_generic() only cared about the GObject property type, it didn't know the expected D-Bus type. - Previously GDBusObjectManager would sometimes emit warnings (g_log()). Those probably indicated real bugs. In any case, it prevented us from running CI with G_DEBUG=fatal-warnings, because there would be just too many unrelated crashes. Now we log debug messages that can be enabled with "LIBNM_CLIENT_DEBUG=trace". Some of these messages can also be turned into g_warning()/g_critical() by setting LIBNM_CLIENT_DEBUG=warning,error. Together with G_DEBUG=fatal-warnings, this turns them into assertions. Note that such "assertion failures" might also happen because of a server bug (or change). Thus these are not common assertions that indicate a bug in libnm and are thus not armed unless explicitly requested. In our CI we should now always run with LIBNM_CLIENT_DEBUG=warning,error and G_DEBUG=fatal-warnings and to catch bugs. Note that currently NetworkManager has bugs in this regard, so enabling this will result in assertion failures. That should be fixed first. - Note that this changes the order in which we emit "notify:devices" and "device-added" signals. I think it makes the most sense to emit first "device-removed", then "notify:devices", and finally "device-added" signals. This changes behavior for commit 52ae28f6e5bf ('libnm: queue added/removed signals and suppress uninitialized notifications'), but I don't think that users should actually rely on the order. Still, the new order makes the most sense to me. - In NetworkManager, profiles can be invisible to the user by setting "connection.permissions". Such profiles would be hidden by NMClient's nm_client_get_connections() and their "connection-added"/"connection-removed" signals. Note that NMActiveConnection's nm_active_connection_get_connection() and NMDevice's nm_device_get_available_connections() still exposes such hidden NMRemoteConnection instances. This behavior was preserved. NUMBERS ------- I compared 3 versions of libnm. [1] 962297f9085d, current tip of nm-1-20 branch [2] 4fad8c7c642e, current master, immediate parent of this patch [3] this patch All tests were done on Fedora 31, x86_64, gcc 9.2.1-1.fc31. The libraries were build with $ ./contrib/fedora/rpm/build_clean.sh -g -w test -W debug Note that RPM build already stripped the library. --- N1) File size of libnm.so.0.1.0 in bytes. There currently seems to be a issue on Fedora 31 generating wrong ELF notes. Usually, libnm is smaller but in these tests it had large (and bogus) ELF notes. Anyway, the point is to show the relative sizes, so it doesn't matter). [1] 4075552 (102.7%) [2] 3969624 (100.0%) [3] 3705208 ( 93.3%) --- N2) `size /usr/lib64/libnm.so.0.1.0`: text data bss dec hex filename [1] 1314569 (102.0%) 69980 ( 94.8%) 10632 ( 80.4%) 1395181 (101.4%) 1549ed /usr/lib64/libnm.so.0.1.0 [2] 1288410 (100.0%) 73796 (100.0%) 13224 (100.0%) 1375430 (100.0%) 14fcc6 /usr/lib64/libnm.so.0.1.0 [3] 1229066 ( 95.4%) 65248 ( 88.4%) 13400 (101.3%) 1307714 ( 95.1%) 13f442 /usr/lib64/libnm.so.0.1.0 --- N3) Performance test with test-client.py. With checkout of [2], run ``` prepare_checkout() { rm -rf /tmp/nm-test && \ git checkout -B test 4fad8c7c642e && \ git clean -fdx && \ ./autogen.sh --prefix=/tmp/nm-test && \ make -j 5 install && \ make -j 5 check-local-clients-tests-test-client } prepare_test() { NM_TEST_REGENERATE=1 NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v } do_test() { for i in {1..10}; do NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v || return -1 done echo "done!" } prepare_checkout prepare_test time do_test ``` [1] real 2m14.497s (101.3%) user 5m26.651s (100.3%) sys 1m40.453s (101.4%) [2] real 2m12.800s (100.0%) user 5m25.619s (100.0%) sys 1m39.065s (100.0%) [3] real 1m54.915s ( 86.5%) user 4m18.585s ( 79.4%) sys 1m32.066s ( 92.9%) --- N4) Performance. Run NetworkManager from build [2] and setup a large number of profiles (551 profiles and 515 devices, mostly unrealized). This setup is already at the edge of what NetworkManager currently can handle. Of course, that is a different issue. Here we just check how long plain `nmcli` takes on the system. ``` do_cleanup() { for UUID in $(nmcli -g NAME,UUID connection show | sed -n 's/^xx-c-.*:\([^:]\+\)$/\1/p'); do nmcli connection delete uuid "$UUID" done for DEVICE in $(nmcli -g DEVICE device status | grep '^xx-i-'); do nmcli device delete "$DEVICE" done } do_setup() { do_cleanup for i in {1..30}; do nmcli connection add type bond autoconnect no con-name xx-c-bond-$i ifname xx-i-bond-$i ipv4.method disabled ipv6.method ignore for j in $(seq $i 30); do nmcli connection add type vlan autoconnect no con-name xx-c-vlan-$i-$j vlan.id $j ifname xx-i-vlan-$i-$j vlan.parent xx-i-bond-$i ipv4.method disabled ipv6.method ignore done done systemctl restart NetworkManager.service sleep 5 } do_test() { perf stat -r 50 -B nmcli 1>/dev/null } do_test ``` [1] Performance counter stats for 'nmcli' (50 runs): 456.33 msec task-clock:u # 1.093 CPUs utilized ( +- 0.44% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,900 page-faults:u # 0.013 M/sec ( +- 0.02% ) 1,408,675,453 cycles:u # 3.087 GHz ( +- 0.48% ) 1,594,741,060 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 368,744,018 branches:u # 808.061 M/sec ( +- 0.02% ) 4,566,058 branch-misses:u # 1.24% of all branches ( +- 0.76% ) 0.41761 +- 0.00282 seconds time elapsed ( +- 0.68% ) [2] Performance counter stats for 'nmcli' (50 runs): 477.99 msec task-clock:u # 1.088 CPUs utilized ( +- 0.36% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,948 page-faults:u # 0.012 M/sec ( +- 0.03% ) 1,471,133,482 cycles:u # 3.078 GHz ( +- 0.36% ) 1,655,275,369 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 382,595,152 branches:u # 800.433 M/sec ( +- 0.02% ) 4,746,070 branch-misses:u # 1.24% of all branches ( +- 0.49% ) 0.43923 +- 0.00242 seconds time elapsed ( +- 0.55% ) [3] Performance counter stats for 'nmcli' (50 runs): 352.36 msec task-clock:u # 1.027 CPUs utilized ( +- 0.32% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 4,790 page-faults:u # 0.014 M/sec ( +- 0.26% ) 1,092,341,186 cycles:u # 3.100 GHz ( +- 0.26% ) 1,209,045,283 instructions:u # 1.11 insn per cycle ( +- 0.02% ) 281,708,462 branches:u # 799.499 M/sec ( +- 0.01% ) 3,101,031 branch-misses:u # 1.10% of all branches ( +- 0.61% ) 0.34296 +- 0.00120 seconds time elapsed ( +- 0.35% ) --- N5) same setup as N4), but run `PAGER= /bin/time -v nmcli`: [1] Command being timed: "nmcli" User time (seconds): 0.42 System time (seconds): 0.04 Percent of CPU this job got: 107% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.43 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34456 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6128 Voluntary context switches: 1298 Involuntary context switches: 1106 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [2] Command being timed: "nmcli" User time (seconds): 0.44 System time (seconds): 0.04 Percent of CPU this job got: 108% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.44 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34452 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6169 Voluntary context switches: 1849 Involuntary context switches: 142 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [3] Command being timed: "nmcli" User time (seconds): 0.32 System time (seconds): 0.02 Percent of CPU this job got: 102% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.34 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 29196 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 5059 Voluntary context switches: 919 Involuntary context switches: 685 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 --- N6) same setup as N4), but run `nmcli monitor` and look at `ps aux` for the RSS size. USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND [1] me 1492900 21.0 0.2 461348 33248 pts/10 Sl+ 15:02 0:00 nmcli monitor [2] me 1490721 5.0 0.2 461496 33548 pts/10 Sl+ 15:00 0:00 nmcli monitor [3] me 1495801 16.5 0.1 459476 28692 pts/10 Sl+ 15:04 0:00 nmcli monitor
2019-10-30 11:42:58 +01:00
"[%s] emit Device's StateChanged signal %u -> %u, reason: %u",
_nm_object_get_path (self),
(guint) priv->old_state,
(guint) priv->state,
(guint) priv->state_reason);
g_signal_emit (self,
signals[STATE_CHANGED],
0,
(guint) priv->state,
(guint) priv->old_state,
(guint) priv->state_reason);
}
static NMLDBusNotifyUpdatePropFlags
_notify_update_prop_state_reason (NMClient *client,
NMLDBusObject *dbobj,
const NMLDBusMetaIface *meta_iface,
guint dbus_property_idx,
GVariant *value)
{
NMDevice *self = NM_DEVICE (dbobj->nmobj);
NMDevicePrivate *priv = NM_DEVICE_GET_PRIVATE (self);
guint32 new_state = NM_DEVICE_STATE_UNKNOWN;
guint32 reason = NM_DEVICE_STATE_REASON_NONE;
libnm: refactor caching of D-Bus objects in NMClient No longer use GDBusObjectMangaerClient and gdbus-codegen generated classes for the NMClient cache. Instead, use GDBusConnection directly and a custom implementation (NMLDBusObject) for caching D-Bus' ObjectManager data. CHANGES ------- - This is a complete rework. I think the previous implementation was difficult to understand. There were unfixed bugs and nobody understood the code well enough to fix them. Maybe somebody out there understood the code, but I certainly did not. At least nobody provided patches to fix those issues. I do believe that this implementation is more straightforward and easier to understand. It removes a lot of layers of code. Whether this claim of simplicity is true, each reader must decide for himself/herself. Note that it is still fairly complex. - There was a lingering performance issue with large number of D-Bus objects. The patch tries hard that the implementation scales well. Of course, when we cache N objects that have N-to-M references to other, we still are fundamentally O(N*M) for runtime and memory consumption (with M being the number of references between objects). But each part should behave efficiently and well. - Play well with GMainContext. libnm code (NMClient) is generally not thread safe. However, it should work to use multiple instances in parallel, as long as each access to a NMClient is through the caller's GMainContext. This follows glib's style and effectively allows to use NMClient in a multi threaded scenario. This implies to stick to a main context upon construction and ensure that callbacks are only invoked when iterating that context. Also, NMClient itself shall never iterate the caller's context. This also means, libnm must never use g_idle_add() or g_timeout_add(), as those enqueue sources in the g_main_context_default() context. - Get ordering of messages right. All events are consistently enqueued in a GMainContext and processed strictly in order. For example, previously "nm-object.c" tried to combine signals and emit them on an idle handler. That is wrong, signals must be emitted in the right order and when they happen. Note that when using GInitable's synchronous initialization to initialize the NMClient instance, NMClient internally still operates fully asynchronously. In that case NMClient has an internal main context. - NMClient takes over most of the functionality. When using D-Bus' ObjectManager interface, one needs to handle basically the entire state of the D-Bus interface. That cannot be separated well into distinct parts, and even if you try, you just end up having closely related code in different source files. Spreading related code does not make it easier to understand, on the contrary. That means, NMClient is inherently complex as it contains most of the logic. I think that is not avoidable, but it's not as bad as it sounds. - NMClient processes D-Bus messages and state changes in separate steps. First NMClient unpacks the message (e.g. _dbus_handle_properties_changed()) and keeps track of the changed data. Then we update the GObject instances (_dbus_handle_obj_changed_dbus()) without emitting any signals yet. Finally, we emit all signals and notifications that were collected (_dbus_handle_changes_commit()). Note that for example during the initial GetManagedObjects() reply, NMClient receive a large amount of state at once. But we first apply all the changes to our GObject instances before emitting any signals. The result is that signals are always emitted in a moment when the cache is consistent. The unavoidable downside is that when you receive a property changed signal, possibly many other properties changed already and more signals are about to be emitted. - NMDeviceWifi no longer modifies the content of the cache from client side during poke_wireless_devices_with_rf_status(). The content of the cache should be determined by D-Bus alone and follow what NetworkManager service exposes. Local modifications should be avoided. - This aims to bring no API/ABI change, though it does of course bring various subtle changes in behavior. Those should be all for the better, but the goal is not to break any existing clients. This does change internal (albeit externally visible) API, like dropping NM_OBJECT_DBUS_OBJECT_MANAGER property and NMObject no longer implementing GInitableIface and GAsyncInitableIface. - Some uses of gdbus-codegen classes remain in NMVpnPluginOld, NMVpnServicePlugin and NMSecretAgentOld. These are independent of NMClient/NMObject and should be reworked separately. - While we no longer use generated classes from gdbus-codegen, we don't need more glue code than before. Also before we constructed NMPropertiesInfo and a had large amount of code to propagate properties from NMDBus* to NMObject. That got completely reworked, but did not fundamentally change. You still need about the same effort to create the NMLDBusMetaIface. Not using generated bindings did not make anything worse (which tells about the usefulness of generated code, at least in the way it was used). - NMLDBusMetaIface and other meta data is static and immutable. This avoids copying them around. Also, macros like NML_DBUS_META_PROPERTY_INIT_U() have compile time checks to ensure the property types matches. It's pretty hard to misuse them because it won't compile. - The meta data now explicitly encodes the expected D-Bus types and makes sure never to accept wrong data. That would only matter when the server (accidentally or intentionally) exposes unexpected types on D-Bus. I don't think that was previously ensured in all cases. For example, demarshal_generic() only cared about the GObject property type, it didn't know the expected D-Bus type. - Previously GDBusObjectManager would sometimes emit warnings (g_log()). Those probably indicated real bugs. In any case, it prevented us from running CI with G_DEBUG=fatal-warnings, because there would be just too many unrelated crashes. Now we log debug messages that can be enabled with "LIBNM_CLIENT_DEBUG=trace". Some of these messages can also be turned into g_warning()/g_critical() by setting LIBNM_CLIENT_DEBUG=warning,error. Together with G_DEBUG=fatal-warnings, this turns them into assertions. Note that such "assertion failures" might also happen because of a server bug (or change). Thus these are not common assertions that indicate a bug in libnm and are thus not armed unless explicitly requested. In our CI we should now always run with LIBNM_CLIENT_DEBUG=warning,error and G_DEBUG=fatal-warnings and to catch bugs. Note that currently NetworkManager has bugs in this regard, so enabling this will result in assertion failures. That should be fixed first. - Note that this changes the order in which we emit "notify:devices" and "device-added" signals. I think it makes the most sense to emit first "device-removed", then "notify:devices", and finally "device-added" signals. This changes behavior for commit 52ae28f6e5bf ('libnm: queue added/removed signals and suppress uninitialized notifications'), but I don't think that users should actually rely on the order. Still, the new order makes the most sense to me. - In NetworkManager, profiles can be invisible to the user by setting "connection.permissions". Such profiles would be hidden by NMClient's nm_client_get_connections() and their "connection-added"/"connection-removed" signals. Note that NMActiveConnection's nm_active_connection_get_connection() and NMDevice's nm_device_get_available_connections() still exposes such hidden NMRemoteConnection instances. This behavior was preserved. NUMBERS ------- I compared 3 versions of libnm. [1] 962297f9085d, current tip of nm-1-20 branch [2] 4fad8c7c642e, current master, immediate parent of this patch [3] this patch All tests were done on Fedora 31, x86_64, gcc 9.2.1-1.fc31. The libraries were build with $ ./contrib/fedora/rpm/build_clean.sh -g -w test -W debug Note that RPM build already stripped the library. --- N1) File size of libnm.so.0.1.0 in bytes. There currently seems to be a issue on Fedora 31 generating wrong ELF notes. Usually, libnm is smaller but in these tests it had large (and bogus) ELF notes. Anyway, the point is to show the relative sizes, so it doesn't matter). [1] 4075552 (102.7%) [2] 3969624 (100.0%) [3] 3705208 ( 93.3%) --- N2) `size /usr/lib64/libnm.so.0.1.0`: text data bss dec hex filename [1] 1314569 (102.0%) 69980 ( 94.8%) 10632 ( 80.4%) 1395181 (101.4%) 1549ed /usr/lib64/libnm.so.0.1.0 [2] 1288410 (100.0%) 73796 (100.0%) 13224 (100.0%) 1375430 (100.0%) 14fcc6 /usr/lib64/libnm.so.0.1.0 [3] 1229066 ( 95.4%) 65248 ( 88.4%) 13400 (101.3%) 1307714 ( 95.1%) 13f442 /usr/lib64/libnm.so.0.1.0 --- N3) Performance test with test-client.py. With checkout of [2], run ``` prepare_checkout() { rm -rf /tmp/nm-test && \ git checkout -B test 4fad8c7c642e && \ git clean -fdx && \ ./autogen.sh --prefix=/tmp/nm-test && \ make -j 5 install && \ make -j 5 check-local-clients-tests-test-client } prepare_test() { NM_TEST_REGENERATE=1 NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v } do_test() { for i in {1..10}; do NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v || return -1 done echo "done!" } prepare_checkout prepare_test time do_test ``` [1] real 2m14.497s (101.3%) user 5m26.651s (100.3%) sys 1m40.453s (101.4%) [2] real 2m12.800s (100.0%) user 5m25.619s (100.0%) sys 1m39.065s (100.0%) [3] real 1m54.915s ( 86.5%) user 4m18.585s ( 79.4%) sys 1m32.066s ( 92.9%) --- N4) Performance. Run NetworkManager from build [2] and setup a large number of profiles (551 profiles and 515 devices, mostly unrealized). This setup is already at the edge of what NetworkManager currently can handle. Of course, that is a different issue. Here we just check how long plain `nmcli` takes on the system. ``` do_cleanup() { for UUID in $(nmcli -g NAME,UUID connection show | sed -n 's/^xx-c-.*:\([^:]\+\)$/\1/p'); do nmcli connection delete uuid "$UUID" done for DEVICE in $(nmcli -g DEVICE device status | grep '^xx-i-'); do nmcli device delete "$DEVICE" done } do_setup() { do_cleanup for i in {1..30}; do nmcli connection add type bond autoconnect no con-name xx-c-bond-$i ifname xx-i-bond-$i ipv4.method disabled ipv6.method ignore for j in $(seq $i 30); do nmcli connection add type vlan autoconnect no con-name xx-c-vlan-$i-$j vlan.id $j ifname xx-i-vlan-$i-$j vlan.parent xx-i-bond-$i ipv4.method disabled ipv6.method ignore done done systemctl restart NetworkManager.service sleep 5 } do_test() { perf stat -r 50 -B nmcli 1>/dev/null } do_test ``` [1] Performance counter stats for 'nmcli' (50 runs): 456.33 msec task-clock:u # 1.093 CPUs utilized ( +- 0.44% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,900 page-faults:u # 0.013 M/sec ( +- 0.02% ) 1,408,675,453 cycles:u # 3.087 GHz ( +- 0.48% ) 1,594,741,060 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 368,744,018 branches:u # 808.061 M/sec ( +- 0.02% ) 4,566,058 branch-misses:u # 1.24% of all branches ( +- 0.76% ) 0.41761 +- 0.00282 seconds time elapsed ( +- 0.68% ) [2] Performance counter stats for 'nmcli' (50 runs): 477.99 msec task-clock:u # 1.088 CPUs utilized ( +- 0.36% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,948 page-faults:u # 0.012 M/sec ( +- 0.03% ) 1,471,133,482 cycles:u # 3.078 GHz ( +- 0.36% ) 1,655,275,369 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 382,595,152 branches:u # 800.433 M/sec ( +- 0.02% ) 4,746,070 branch-misses:u # 1.24% of all branches ( +- 0.49% ) 0.43923 +- 0.00242 seconds time elapsed ( +- 0.55% ) [3] Performance counter stats for 'nmcli' (50 runs): 352.36 msec task-clock:u # 1.027 CPUs utilized ( +- 0.32% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 4,790 page-faults:u # 0.014 M/sec ( +- 0.26% ) 1,092,341,186 cycles:u # 3.100 GHz ( +- 0.26% ) 1,209,045,283 instructions:u # 1.11 insn per cycle ( +- 0.02% ) 281,708,462 branches:u # 799.499 M/sec ( +- 0.01% ) 3,101,031 branch-misses:u # 1.10% of all branches ( +- 0.61% ) 0.34296 +- 0.00120 seconds time elapsed ( +- 0.35% ) --- N5) same setup as N4), but run `PAGER= /bin/time -v nmcli`: [1] Command being timed: "nmcli" User time (seconds): 0.42 System time (seconds): 0.04 Percent of CPU this job got: 107% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.43 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34456 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6128 Voluntary context switches: 1298 Involuntary context switches: 1106 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [2] Command being timed: "nmcli" User time (seconds): 0.44 System time (seconds): 0.04 Percent of CPU this job got: 108% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.44 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34452 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6169 Voluntary context switches: 1849 Involuntary context switches: 142 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [3] Command being timed: "nmcli" User time (seconds): 0.32 System time (seconds): 0.02 Percent of CPU this job got: 102% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.34 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 29196 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 5059 Voluntary context switches: 919 Involuntary context switches: 685 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 --- N6) same setup as N4), but run `nmcli monitor` and look at `ps aux` for the RSS size. USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND [1] me 1492900 21.0 0.2 461348 33248 pts/10 Sl+ 15:02 0:00 nmcli monitor [2] me 1490721 5.0 0.2 461496 33548 pts/10 Sl+ 15:00 0:00 nmcli monitor [3] me 1495801 16.5 0.1 459476 28692 pts/10 Sl+ 15:04 0:00 nmcli monitor
2019-10-30 11:42:58 +01:00
/* We ignore the "State" property and the "StateChanged" signal of the device.
* This information is redundant to the "StateReason" property, and we rely
* on that one alone. In the best case, the information is identical. If it
* would not be, then we stick to the information from "StateReason" property. */
libnm: refactor caching of D-Bus objects in NMClient No longer use GDBusObjectMangaerClient and gdbus-codegen generated classes for the NMClient cache. Instead, use GDBusConnection directly and a custom implementation (NMLDBusObject) for caching D-Bus' ObjectManager data. CHANGES ------- - This is a complete rework. I think the previous implementation was difficult to understand. There were unfixed bugs and nobody understood the code well enough to fix them. Maybe somebody out there understood the code, but I certainly did not. At least nobody provided patches to fix those issues. I do believe that this implementation is more straightforward and easier to understand. It removes a lot of layers of code. Whether this claim of simplicity is true, each reader must decide for himself/herself. Note that it is still fairly complex. - There was a lingering performance issue with large number of D-Bus objects. The patch tries hard that the implementation scales well. Of course, when we cache N objects that have N-to-M references to other, we still are fundamentally O(N*M) for runtime and memory consumption (with M being the number of references between objects). But each part should behave efficiently and well. - Play well with GMainContext. libnm code (NMClient) is generally not thread safe. However, it should work to use multiple instances in parallel, as long as each access to a NMClient is through the caller's GMainContext. This follows glib's style and effectively allows to use NMClient in a multi threaded scenario. This implies to stick to a main context upon construction and ensure that callbacks are only invoked when iterating that context. Also, NMClient itself shall never iterate the caller's context. This also means, libnm must never use g_idle_add() or g_timeout_add(), as those enqueue sources in the g_main_context_default() context. - Get ordering of messages right. All events are consistently enqueued in a GMainContext and processed strictly in order. For example, previously "nm-object.c" tried to combine signals and emit them on an idle handler. That is wrong, signals must be emitted in the right order and when they happen. Note that when using GInitable's synchronous initialization to initialize the NMClient instance, NMClient internally still operates fully asynchronously. In that case NMClient has an internal main context. - NMClient takes over most of the functionality. When using D-Bus' ObjectManager interface, one needs to handle basically the entire state of the D-Bus interface. That cannot be separated well into distinct parts, and even if you try, you just end up having closely related code in different source files. Spreading related code does not make it easier to understand, on the contrary. That means, NMClient is inherently complex as it contains most of the logic. I think that is not avoidable, but it's not as bad as it sounds. - NMClient processes D-Bus messages and state changes in separate steps. First NMClient unpacks the message (e.g. _dbus_handle_properties_changed()) and keeps track of the changed data. Then we update the GObject instances (_dbus_handle_obj_changed_dbus()) without emitting any signals yet. Finally, we emit all signals and notifications that were collected (_dbus_handle_changes_commit()). Note that for example during the initial GetManagedObjects() reply, NMClient receive a large amount of state at once. But we first apply all the changes to our GObject instances before emitting any signals. The result is that signals are always emitted in a moment when the cache is consistent. The unavoidable downside is that when you receive a property changed signal, possibly many other properties changed already and more signals are about to be emitted. - NMDeviceWifi no longer modifies the content of the cache from client side during poke_wireless_devices_with_rf_status(). The content of the cache should be determined by D-Bus alone and follow what NetworkManager service exposes. Local modifications should be avoided. - This aims to bring no API/ABI change, though it does of course bring various subtle changes in behavior. Those should be all for the better, but the goal is not to break any existing clients. This does change internal (albeit externally visible) API, like dropping NM_OBJECT_DBUS_OBJECT_MANAGER property and NMObject no longer implementing GInitableIface and GAsyncInitableIface. - Some uses of gdbus-codegen classes remain in NMVpnPluginOld, NMVpnServicePlugin and NMSecretAgentOld. These are independent of NMClient/NMObject and should be reworked separately. - While we no longer use generated classes from gdbus-codegen, we don't need more glue code than before. Also before we constructed NMPropertiesInfo and a had large amount of code to propagate properties from NMDBus* to NMObject. That got completely reworked, but did not fundamentally change. You still need about the same effort to create the NMLDBusMetaIface. Not using generated bindings did not make anything worse (which tells about the usefulness of generated code, at least in the way it was used). - NMLDBusMetaIface and other meta data is static and immutable. This avoids copying them around. Also, macros like NML_DBUS_META_PROPERTY_INIT_U() have compile time checks to ensure the property types matches. It's pretty hard to misuse them because it won't compile. - The meta data now explicitly encodes the expected D-Bus types and makes sure never to accept wrong data. That would only matter when the server (accidentally or intentionally) exposes unexpected types on D-Bus. I don't think that was previously ensured in all cases. For example, demarshal_generic() only cared about the GObject property type, it didn't know the expected D-Bus type. - Previously GDBusObjectManager would sometimes emit warnings (g_log()). Those probably indicated real bugs. In any case, it prevented us from running CI with G_DEBUG=fatal-warnings, because there would be just too many unrelated crashes. Now we log debug messages that can be enabled with "LIBNM_CLIENT_DEBUG=trace". Some of these messages can also be turned into g_warning()/g_critical() by setting LIBNM_CLIENT_DEBUG=warning,error. Together with G_DEBUG=fatal-warnings, this turns them into assertions. Note that such "assertion failures" might also happen because of a server bug (or change). Thus these are not common assertions that indicate a bug in libnm and are thus not armed unless explicitly requested. In our CI we should now always run with LIBNM_CLIENT_DEBUG=warning,error and G_DEBUG=fatal-warnings and to catch bugs. Note that currently NetworkManager has bugs in this regard, so enabling this will result in assertion failures. That should be fixed first. - Note that this changes the order in which we emit "notify:devices" and "device-added" signals. I think it makes the most sense to emit first "device-removed", then "notify:devices", and finally "device-added" signals. This changes behavior for commit 52ae28f6e5bf ('libnm: queue added/removed signals and suppress uninitialized notifications'), but I don't think that users should actually rely on the order. Still, the new order makes the most sense to me. - In NetworkManager, profiles can be invisible to the user by setting "connection.permissions". Such profiles would be hidden by NMClient's nm_client_get_connections() and their "connection-added"/"connection-removed" signals. Note that NMActiveConnection's nm_active_connection_get_connection() and NMDevice's nm_device_get_available_connections() still exposes such hidden NMRemoteConnection instances. This behavior was preserved. NUMBERS ------- I compared 3 versions of libnm. [1] 962297f9085d, current tip of nm-1-20 branch [2] 4fad8c7c642e, current master, immediate parent of this patch [3] this patch All tests were done on Fedora 31, x86_64, gcc 9.2.1-1.fc31. The libraries were build with $ ./contrib/fedora/rpm/build_clean.sh -g -w test -W debug Note that RPM build already stripped the library. --- N1) File size of libnm.so.0.1.0 in bytes. There currently seems to be a issue on Fedora 31 generating wrong ELF notes. Usually, libnm is smaller but in these tests it had large (and bogus) ELF notes. Anyway, the point is to show the relative sizes, so it doesn't matter). [1] 4075552 (102.7%) [2] 3969624 (100.0%) [3] 3705208 ( 93.3%) --- N2) `size /usr/lib64/libnm.so.0.1.0`: text data bss dec hex filename [1] 1314569 (102.0%) 69980 ( 94.8%) 10632 ( 80.4%) 1395181 (101.4%) 1549ed /usr/lib64/libnm.so.0.1.0 [2] 1288410 (100.0%) 73796 (100.0%) 13224 (100.0%) 1375430 (100.0%) 14fcc6 /usr/lib64/libnm.so.0.1.0 [3] 1229066 ( 95.4%) 65248 ( 88.4%) 13400 (101.3%) 1307714 ( 95.1%) 13f442 /usr/lib64/libnm.so.0.1.0 --- N3) Performance test with test-client.py. With checkout of [2], run ``` prepare_checkout() { rm -rf /tmp/nm-test && \ git checkout -B test 4fad8c7c642e && \ git clean -fdx && \ ./autogen.sh --prefix=/tmp/nm-test && \ make -j 5 install && \ make -j 5 check-local-clients-tests-test-client } prepare_test() { NM_TEST_REGENERATE=1 NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v } do_test() { for i in {1..10}; do NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v || return -1 done echo "done!" } prepare_checkout prepare_test time do_test ``` [1] real 2m14.497s (101.3%) user 5m26.651s (100.3%) sys 1m40.453s (101.4%) [2] real 2m12.800s (100.0%) user 5m25.619s (100.0%) sys 1m39.065s (100.0%) [3] real 1m54.915s ( 86.5%) user 4m18.585s ( 79.4%) sys 1m32.066s ( 92.9%) --- N4) Performance. Run NetworkManager from build [2] and setup a large number of profiles (551 profiles and 515 devices, mostly unrealized). This setup is already at the edge of what NetworkManager currently can handle. Of course, that is a different issue. Here we just check how long plain `nmcli` takes on the system. ``` do_cleanup() { for UUID in $(nmcli -g NAME,UUID connection show | sed -n 's/^xx-c-.*:\([^:]\+\)$/\1/p'); do nmcli connection delete uuid "$UUID" done for DEVICE in $(nmcli -g DEVICE device status | grep '^xx-i-'); do nmcli device delete "$DEVICE" done } do_setup() { do_cleanup for i in {1..30}; do nmcli connection add type bond autoconnect no con-name xx-c-bond-$i ifname xx-i-bond-$i ipv4.method disabled ipv6.method ignore for j in $(seq $i 30); do nmcli connection add type vlan autoconnect no con-name xx-c-vlan-$i-$j vlan.id $j ifname xx-i-vlan-$i-$j vlan.parent xx-i-bond-$i ipv4.method disabled ipv6.method ignore done done systemctl restart NetworkManager.service sleep 5 } do_test() { perf stat -r 50 -B nmcli 1>/dev/null } do_test ``` [1] Performance counter stats for 'nmcli' (50 runs): 456.33 msec task-clock:u # 1.093 CPUs utilized ( +- 0.44% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,900 page-faults:u # 0.013 M/sec ( +- 0.02% ) 1,408,675,453 cycles:u # 3.087 GHz ( +- 0.48% ) 1,594,741,060 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 368,744,018 branches:u # 808.061 M/sec ( +- 0.02% ) 4,566,058 branch-misses:u # 1.24% of all branches ( +- 0.76% ) 0.41761 +- 0.00282 seconds time elapsed ( +- 0.68% ) [2] Performance counter stats for 'nmcli' (50 runs): 477.99 msec task-clock:u # 1.088 CPUs utilized ( +- 0.36% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,948 page-faults:u # 0.012 M/sec ( +- 0.03% ) 1,471,133,482 cycles:u # 3.078 GHz ( +- 0.36% ) 1,655,275,369 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 382,595,152 branches:u # 800.433 M/sec ( +- 0.02% ) 4,746,070 branch-misses:u # 1.24% of all branches ( +- 0.49% ) 0.43923 +- 0.00242 seconds time elapsed ( +- 0.55% ) [3] Performance counter stats for 'nmcli' (50 runs): 352.36 msec task-clock:u # 1.027 CPUs utilized ( +- 0.32% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 4,790 page-faults:u # 0.014 M/sec ( +- 0.26% ) 1,092,341,186 cycles:u # 3.100 GHz ( +- 0.26% ) 1,209,045,283 instructions:u # 1.11 insn per cycle ( +- 0.02% ) 281,708,462 branches:u # 799.499 M/sec ( +- 0.01% ) 3,101,031 branch-misses:u # 1.10% of all branches ( +- 0.61% ) 0.34296 +- 0.00120 seconds time elapsed ( +- 0.35% ) --- N5) same setup as N4), but run `PAGER= /bin/time -v nmcli`: [1] Command being timed: "nmcli" User time (seconds): 0.42 System time (seconds): 0.04 Percent of CPU this job got: 107% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.43 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34456 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6128 Voluntary context switches: 1298 Involuntary context switches: 1106 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [2] Command being timed: "nmcli" User time (seconds): 0.44 System time (seconds): 0.04 Percent of CPU this job got: 108% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.44 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34452 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6169 Voluntary context switches: 1849 Involuntary context switches: 142 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [3] Command being timed: "nmcli" User time (seconds): 0.32 System time (seconds): 0.02 Percent of CPU this job got: 102% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.34 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 29196 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 5059 Voluntary context switches: 919 Involuntary context switches: 685 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 --- N6) same setup as N4), but run `nmcli monitor` and look at `ps aux` for the RSS size. USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND [1] me 1492900 21.0 0.2 461348 33248 pts/10 Sl+ 15:02 0:00 nmcli monitor [2] me 1490721 5.0 0.2 461496 33548 pts/10 Sl+ 15:00 0:00 nmcli monitor [3] me 1495801 16.5 0.1 459476 28692 pts/10 Sl+ 15:04 0:00 nmcli monitor
2019-10-30 11:42:58 +01:00
if (value)
g_variant_get (value, "(uu)", &new_state, &reason);
libnm: refactor caching of D-Bus objects in NMClient No longer use GDBusObjectMangaerClient and gdbus-codegen generated classes for the NMClient cache. Instead, use GDBusConnection directly and a custom implementation (NMLDBusObject) for caching D-Bus' ObjectManager data. CHANGES ------- - This is a complete rework. I think the previous implementation was difficult to understand. There were unfixed bugs and nobody understood the code well enough to fix them. Maybe somebody out there understood the code, but I certainly did not. At least nobody provided patches to fix those issues. I do believe that this implementation is more straightforward and easier to understand. It removes a lot of layers of code. Whether this claim of simplicity is true, each reader must decide for himself/herself. Note that it is still fairly complex. - There was a lingering performance issue with large number of D-Bus objects. The patch tries hard that the implementation scales well. Of course, when we cache N objects that have N-to-M references to other, we still are fundamentally O(N*M) for runtime and memory consumption (with M being the number of references between objects). But each part should behave efficiently and well. - Play well with GMainContext. libnm code (NMClient) is generally not thread safe. However, it should work to use multiple instances in parallel, as long as each access to a NMClient is through the caller's GMainContext. This follows glib's style and effectively allows to use NMClient in a multi threaded scenario. This implies to stick to a main context upon construction and ensure that callbacks are only invoked when iterating that context. Also, NMClient itself shall never iterate the caller's context. This also means, libnm must never use g_idle_add() or g_timeout_add(), as those enqueue sources in the g_main_context_default() context. - Get ordering of messages right. All events are consistently enqueued in a GMainContext and processed strictly in order. For example, previously "nm-object.c" tried to combine signals and emit them on an idle handler. That is wrong, signals must be emitted in the right order and when they happen. Note that when using GInitable's synchronous initialization to initialize the NMClient instance, NMClient internally still operates fully asynchronously. In that case NMClient has an internal main context. - NMClient takes over most of the functionality. When using D-Bus' ObjectManager interface, one needs to handle basically the entire state of the D-Bus interface. That cannot be separated well into distinct parts, and even if you try, you just end up having closely related code in different source files. Spreading related code does not make it easier to understand, on the contrary. That means, NMClient is inherently complex as it contains most of the logic. I think that is not avoidable, but it's not as bad as it sounds. - NMClient processes D-Bus messages and state changes in separate steps. First NMClient unpacks the message (e.g. _dbus_handle_properties_changed()) and keeps track of the changed data. Then we update the GObject instances (_dbus_handle_obj_changed_dbus()) without emitting any signals yet. Finally, we emit all signals and notifications that were collected (_dbus_handle_changes_commit()). Note that for example during the initial GetManagedObjects() reply, NMClient receive a large amount of state at once. But we first apply all the changes to our GObject instances before emitting any signals. The result is that signals are always emitted in a moment when the cache is consistent. The unavoidable downside is that when you receive a property changed signal, possibly many other properties changed already and more signals are about to be emitted. - NMDeviceWifi no longer modifies the content of the cache from client side during poke_wireless_devices_with_rf_status(). The content of the cache should be determined by D-Bus alone and follow what NetworkManager service exposes. Local modifications should be avoided. - This aims to bring no API/ABI change, though it does of course bring various subtle changes in behavior. Those should be all for the better, but the goal is not to break any existing clients. This does change internal (albeit externally visible) API, like dropping NM_OBJECT_DBUS_OBJECT_MANAGER property and NMObject no longer implementing GInitableIface and GAsyncInitableIface. - Some uses of gdbus-codegen classes remain in NMVpnPluginOld, NMVpnServicePlugin and NMSecretAgentOld. These are independent of NMClient/NMObject and should be reworked separately. - While we no longer use generated classes from gdbus-codegen, we don't need more glue code than before. Also before we constructed NMPropertiesInfo and a had large amount of code to propagate properties from NMDBus* to NMObject. That got completely reworked, but did not fundamentally change. You still need about the same effort to create the NMLDBusMetaIface. Not using generated bindings did not make anything worse (which tells about the usefulness of generated code, at least in the way it was used). - NMLDBusMetaIface and other meta data is static and immutable. This avoids copying them around. Also, macros like NML_DBUS_META_PROPERTY_INIT_U() have compile time checks to ensure the property types matches. It's pretty hard to misuse them because it won't compile. - The meta data now explicitly encodes the expected D-Bus types and makes sure never to accept wrong data. That would only matter when the server (accidentally or intentionally) exposes unexpected types on D-Bus. I don't think that was previously ensured in all cases. For example, demarshal_generic() only cared about the GObject property type, it didn't know the expected D-Bus type. - Previously GDBusObjectManager would sometimes emit warnings (g_log()). Those probably indicated real bugs. In any case, it prevented us from running CI with G_DEBUG=fatal-warnings, because there would be just too many unrelated crashes. Now we log debug messages that can be enabled with "LIBNM_CLIENT_DEBUG=trace". Some of these messages can also be turned into g_warning()/g_critical() by setting LIBNM_CLIENT_DEBUG=warning,error. Together with G_DEBUG=fatal-warnings, this turns them into assertions. Note that such "assertion failures" might also happen because of a server bug (or change). Thus these are not common assertions that indicate a bug in libnm and are thus not armed unless explicitly requested. In our CI we should now always run with LIBNM_CLIENT_DEBUG=warning,error and G_DEBUG=fatal-warnings and to catch bugs. Note that currently NetworkManager has bugs in this regard, so enabling this will result in assertion failures. That should be fixed first. - Note that this changes the order in which we emit "notify:devices" and "device-added" signals. I think it makes the most sense to emit first "device-removed", then "notify:devices", and finally "device-added" signals. This changes behavior for commit 52ae28f6e5bf ('libnm: queue added/removed signals and suppress uninitialized notifications'), but I don't think that users should actually rely on the order. Still, the new order makes the most sense to me. - In NetworkManager, profiles can be invisible to the user by setting "connection.permissions". Such profiles would be hidden by NMClient's nm_client_get_connections() and their "connection-added"/"connection-removed" signals. Note that NMActiveConnection's nm_active_connection_get_connection() and NMDevice's nm_device_get_available_connections() still exposes such hidden NMRemoteConnection instances. This behavior was preserved. NUMBERS ------- I compared 3 versions of libnm. [1] 962297f9085d, current tip of nm-1-20 branch [2] 4fad8c7c642e, current master, immediate parent of this patch [3] this patch All tests were done on Fedora 31, x86_64, gcc 9.2.1-1.fc31. The libraries were build with $ ./contrib/fedora/rpm/build_clean.sh -g -w test -W debug Note that RPM build already stripped the library. --- N1) File size of libnm.so.0.1.0 in bytes. There currently seems to be a issue on Fedora 31 generating wrong ELF notes. Usually, libnm is smaller but in these tests it had large (and bogus) ELF notes. Anyway, the point is to show the relative sizes, so it doesn't matter). [1] 4075552 (102.7%) [2] 3969624 (100.0%) [3] 3705208 ( 93.3%) --- N2) `size /usr/lib64/libnm.so.0.1.0`: text data bss dec hex filename [1] 1314569 (102.0%) 69980 ( 94.8%) 10632 ( 80.4%) 1395181 (101.4%) 1549ed /usr/lib64/libnm.so.0.1.0 [2] 1288410 (100.0%) 73796 (100.0%) 13224 (100.0%) 1375430 (100.0%) 14fcc6 /usr/lib64/libnm.so.0.1.0 [3] 1229066 ( 95.4%) 65248 ( 88.4%) 13400 (101.3%) 1307714 ( 95.1%) 13f442 /usr/lib64/libnm.so.0.1.0 --- N3) Performance test with test-client.py. With checkout of [2], run ``` prepare_checkout() { rm -rf /tmp/nm-test && \ git checkout -B test 4fad8c7c642e && \ git clean -fdx && \ ./autogen.sh --prefix=/tmp/nm-test && \ make -j 5 install && \ make -j 5 check-local-clients-tests-test-client } prepare_test() { NM_TEST_REGENERATE=1 NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v } do_test() { for i in {1..10}; do NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v || return -1 done echo "done!" } prepare_checkout prepare_test time do_test ``` [1] real 2m14.497s (101.3%) user 5m26.651s (100.3%) sys 1m40.453s (101.4%) [2] real 2m12.800s (100.0%) user 5m25.619s (100.0%) sys 1m39.065s (100.0%) [3] real 1m54.915s ( 86.5%) user 4m18.585s ( 79.4%) sys 1m32.066s ( 92.9%) --- N4) Performance. Run NetworkManager from build [2] and setup a large number of profiles (551 profiles and 515 devices, mostly unrealized). This setup is already at the edge of what NetworkManager currently can handle. Of course, that is a different issue. Here we just check how long plain `nmcli` takes on the system. ``` do_cleanup() { for UUID in $(nmcli -g NAME,UUID connection show | sed -n 's/^xx-c-.*:\([^:]\+\)$/\1/p'); do nmcli connection delete uuid "$UUID" done for DEVICE in $(nmcli -g DEVICE device status | grep '^xx-i-'); do nmcli device delete "$DEVICE" done } do_setup() { do_cleanup for i in {1..30}; do nmcli connection add type bond autoconnect no con-name xx-c-bond-$i ifname xx-i-bond-$i ipv4.method disabled ipv6.method ignore for j in $(seq $i 30); do nmcli connection add type vlan autoconnect no con-name xx-c-vlan-$i-$j vlan.id $j ifname xx-i-vlan-$i-$j vlan.parent xx-i-bond-$i ipv4.method disabled ipv6.method ignore done done systemctl restart NetworkManager.service sleep 5 } do_test() { perf stat -r 50 -B nmcli 1>/dev/null } do_test ``` [1] Performance counter stats for 'nmcli' (50 runs): 456.33 msec task-clock:u # 1.093 CPUs utilized ( +- 0.44% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,900 page-faults:u # 0.013 M/sec ( +- 0.02% ) 1,408,675,453 cycles:u # 3.087 GHz ( +- 0.48% ) 1,594,741,060 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 368,744,018 branches:u # 808.061 M/sec ( +- 0.02% ) 4,566,058 branch-misses:u # 1.24% of all branches ( +- 0.76% ) 0.41761 +- 0.00282 seconds time elapsed ( +- 0.68% ) [2] Performance counter stats for 'nmcli' (50 runs): 477.99 msec task-clock:u # 1.088 CPUs utilized ( +- 0.36% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,948 page-faults:u # 0.012 M/sec ( +- 0.03% ) 1,471,133,482 cycles:u # 3.078 GHz ( +- 0.36% ) 1,655,275,369 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 382,595,152 branches:u # 800.433 M/sec ( +- 0.02% ) 4,746,070 branch-misses:u # 1.24% of all branches ( +- 0.49% ) 0.43923 +- 0.00242 seconds time elapsed ( +- 0.55% ) [3] Performance counter stats for 'nmcli' (50 runs): 352.36 msec task-clock:u # 1.027 CPUs utilized ( +- 0.32% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 4,790 page-faults:u # 0.014 M/sec ( +- 0.26% ) 1,092,341,186 cycles:u # 3.100 GHz ( +- 0.26% ) 1,209,045,283 instructions:u # 1.11 insn per cycle ( +- 0.02% ) 281,708,462 branches:u # 799.499 M/sec ( +- 0.01% ) 3,101,031 branch-misses:u # 1.10% of all branches ( +- 0.61% ) 0.34296 +- 0.00120 seconds time elapsed ( +- 0.35% ) --- N5) same setup as N4), but run `PAGER= /bin/time -v nmcli`: [1] Command being timed: "nmcli" User time (seconds): 0.42 System time (seconds): 0.04 Percent of CPU this job got: 107% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.43 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34456 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6128 Voluntary context switches: 1298 Involuntary context switches: 1106 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [2] Command being timed: "nmcli" User time (seconds): 0.44 System time (seconds): 0.04 Percent of CPU this job got: 108% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.44 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34452 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6169 Voluntary context switches: 1849 Involuntary context switches: 142 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [3] Command being timed: "nmcli" User time (seconds): 0.32 System time (seconds): 0.02 Percent of CPU this job got: 102% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.34 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 29196 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 5059 Voluntary context switches: 919 Involuntary context switches: 685 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 --- N6) same setup as N4), but run `nmcli monitor` and look at `ps aux` for the RSS size. USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND [1] me 1492900 21.0 0.2 461348 33248 pts/10 Sl+ 15:02 0:00 nmcli monitor [2] me 1490721 5.0 0.2 461496 33548 pts/10 Sl+ 15:00 0:00 nmcli monitor [3] me 1495801 16.5 0.1 459476 28692 pts/10 Sl+ 15:04 0:00 nmcli monitor
2019-10-30 11:42:58 +01:00
if ( priv->state == new_state
&& priv->state_reason == reason) {
/* no changes. */
return NML_DBUS_NOTIFY_UPDATE_PROP_FLAGS_NONE;
}
libnm: refactor caching of D-Bus objects in NMClient No longer use GDBusObjectMangaerClient and gdbus-codegen generated classes for the NMClient cache. Instead, use GDBusConnection directly and a custom implementation (NMLDBusObject) for caching D-Bus' ObjectManager data. CHANGES ------- - This is a complete rework. I think the previous implementation was difficult to understand. There were unfixed bugs and nobody understood the code well enough to fix them. Maybe somebody out there understood the code, but I certainly did not. At least nobody provided patches to fix those issues. I do believe that this implementation is more straightforward and easier to understand. It removes a lot of layers of code. Whether this claim of simplicity is true, each reader must decide for himself/herself. Note that it is still fairly complex. - There was a lingering performance issue with large number of D-Bus objects. The patch tries hard that the implementation scales well. Of course, when we cache N objects that have N-to-M references to other, we still are fundamentally O(N*M) for runtime and memory consumption (with M being the number of references between objects). But each part should behave efficiently and well. - Play well with GMainContext. libnm code (NMClient) is generally not thread safe. However, it should work to use multiple instances in parallel, as long as each access to a NMClient is through the caller's GMainContext. This follows glib's style and effectively allows to use NMClient in a multi threaded scenario. This implies to stick to a main context upon construction and ensure that callbacks are only invoked when iterating that context. Also, NMClient itself shall never iterate the caller's context. This also means, libnm must never use g_idle_add() or g_timeout_add(), as those enqueue sources in the g_main_context_default() context. - Get ordering of messages right. All events are consistently enqueued in a GMainContext and processed strictly in order. For example, previously "nm-object.c" tried to combine signals and emit them on an idle handler. That is wrong, signals must be emitted in the right order and when they happen. Note that when using GInitable's synchronous initialization to initialize the NMClient instance, NMClient internally still operates fully asynchronously. In that case NMClient has an internal main context. - NMClient takes over most of the functionality. When using D-Bus' ObjectManager interface, one needs to handle basically the entire state of the D-Bus interface. That cannot be separated well into distinct parts, and even if you try, you just end up having closely related code in different source files. Spreading related code does not make it easier to understand, on the contrary. That means, NMClient is inherently complex as it contains most of the logic. I think that is not avoidable, but it's not as bad as it sounds. - NMClient processes D-Bus messages and state changes in separate steps. First NMClient unpacks the message (e.g. _dbus_handle_properties_changed()) and keeps track of the changed data. Then we update the GObject instances (_dbus_handle_obj_changed_dbus()) without emitting any signals yet. Finally, we emit all signals and notifications that were collected (_dbus_handle_changes_commit()). Note that for example during the initial GetManagedObjects() reply, NMClient receive a large amount of state at once. But we first apply all the changes to our GObject instances before emitting any signals. The result is that signals are always emitted in a moment when the cache is consistent. The unavoidable downside is that when you receive a property changed signal, possibly many other properties changed already and more signals are about to be emitted. - NMDeviceWifi no longer modifies the content of the cache from client side during poke_wireless_devices_with_rf_status(). The content of the cache should be determined by D-Bus alone and follow what NetworkManager service exposes. Local modifications should be avoided. - This aims to bring no API/ABI change, though it does of course bring various subtle changes in behavior. Those should be all for the better, but the goal is not to break any existing clients. This does change internal (albeit externally visible) API, like dropping NM_OBJECT_DBUS_OBJECT_MANAGER property and NMObject no longer implementing GInitableIface and GAsyncInitableIface. - Some uses of gdbus-codegen classes remain in NMVpnPluginOld, NMVpnServicePlugin and NMSecretAgentOld. These are independent of NMClient/NMObject and should be reworked separately. - While we no longer use generated classes from gdbus-codegen, we don't need more glue code than before. Also before we constructed NMPropertiesInfo and a had large amount of code to propagate properties from NMDBus* to NMObject. That got completely reworked, but did not fundamentally change. You still need about the same effort to create the NMLDBusMetaIface. Not using generated bindings did not make anything worse (which tells about the usefulness of generated code, at least in the way it was used). - NMLDBusMetaIface and other meta data is static and immutable. This avoids copying them around. Also, macros like NML_DBUS_META_PROPERTY_INIT_U() have compile time checks to ensure the property types matches. It's pretty hard to misuse them because it won't compile. - The meta data now explicitly encodes the expected D-Bus types and makes sure never to accept wrong data. That would only matter when the server (accidentally or intentionally) exposes unexpected types on D-Bus. I don't think that was previously ensured in all cases. For example, demarshal_generic() only cared about the GObject property type, it didn't know the expected D-Bus type. - Previously GDBusObjectManager would sometimes emit warnings (g_log()). Those probably indicated real bugs. In any case, it prevented us from running CI with G_DEBUG=fatal-warnings, because there would be just too many unrelated crashes. Now we log debug messages that can be enabled with "LIBNM_CLIENT_DEBUG=trace". Some of these messages can also be turned into g_warning()/g_critical() by setting LIBNM_CLIENT_DEBUG=warning,error. Together with G_DEBUG=fatal-warnings, this turns them into assertions. Note that such "assertion failures" might also happen because of a server bug (or change). Thus these are not common assertions that indicate a bug in libnm and are thus not armed unless explicitly requested. In our CI we should now always run with LIBNM_CLIENT_DEBUG=warning,error and G_DEBUG=fatal-warnings and to catch bugs. Note that currently NetworkManager has bugs in this regard, so enabling this will result in assertion failures. That should be fixed first. - Note that this changes the order in which we emit "notify:devices" and "device-added" signals. I think it makes the most sense to emit first "device-removed", then "notify:devices", and finally "device-added" signals. This changes behavior for commit 52ae28f6e5bf ('libnm: queue added/removed signals and suppress uninitialized notifications'), but I don't think that users should actually rely on the order. Still, the new order makes the most sense to me. - In NetworkManager, profiles can be invisible to the user by setting "connection.permissions". Such profiles would be hidden by NMClient's nm_client_get_connections() and their "connection-added"/"connection-removed" signals. Note that NMActiveConnection's nm_active_connection_get_connection() and NMDevice's nm_device_get_available_connections() still exposes such hidden NMRemoteConnection instances. This behavior was preserved. NUMBERS ------- I compared 3 versions of libnm. [1] 962297f9085d, current tip of nm-1-20 branch [2] 4fad8c7c642e, current master, immediate parent of this patch [3] this patch All tests were done on Fedora 31, x86_64, gcc 9.2.1-1.fc31. The libraries were build with $ ./contrib/fedora/rpm/build_clean.sh -g -w test -W debug Note that RPM build already stripped the library. --- N1) File size of libnm.so.0.1.0 in bytes. There currently seems to be a issue on Fedora 31 generating wrong ELF notes. Usually, libnm is smaller but in these tests it had large (and bogus) ELF notes. Anyway, the point is to show the relative sizes, so it doesn't matter). [1] 4075552 (102.7%) [2] 3969624 (100.0%) [3] 3705208 ( 93.3%) --- N2) `size /usr/lib64/libnm.so.0.1.0`: text data bss dec hex filename [1] 1314569 (102.0%) 69980 ( 94.8%) 10632 ( 80.4%) 1395181 (101.4%) 1549ed /usr/lib64/libnm.so.0.1.0 [2] 1288410 (100.0%) 73796 (100.0%) 13224 (100.0%) 1375430 (100.0%) 14fcc6 /usr/lib64/libnm.so.0.1.0 [3] 1229066 ( 95.4%) 65248 ( 88.4%) 13400 (101.3%) 1307714 ( 95.1%) 13f442 /usr/lib64/libnm.so.0.1.0 --- N3) Performance test with test-client.py. With checkout of [2], run ``` prepare_checkout() { rm -rf /tmp/nm-test && \ git checkout -B test 4fad8c7c642e && \ git clean -fdx && \ ./autogen.sh --prefix=/tmp/nm-test && \ make -j 5 install && \ make -j 5 check-local-clients-tests-test-client } prepare_test() { NM_TEST_REGENERATE=1 NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v } do_test() { for i in {1..10}; do NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v || return -1 done echo "done!" } prepare_checkout prepare_test time do_test ``` [1] real 2m14.497s (101.3%) user 5m26.651s (100.3%) sys 1m40.453s (101.4%) [2] real 2m12.800s (100.0%) user 5m25.619s (100.0%) sys 1m39.065s (100.0%) [3] real 1m54.915s ( 86.5%) user 4m18.585s ( 79.4%) sys 1m32.066s ( 92.9%) --- N4) Performance. Run NetworkManager from build [2] and setup a large number of profiles (551 profiles and 515 devices, mostly unrealized). This setup is already at the edge of what NetworkManager currently can handle. Of course, that is a different issue. Here we just check how long plain `nmcli` takes on the system. ``` do_cleanup() { for UUID in $(nmcli -g NAME,UUID connection show | sed -n 's/^xx-c-.*:\([^:]\+\)$/\1/p'); do nmcli connection delete uuid "$UUID" done for DEVICE in $(nmcli -g DEVICE device status | grep '^xx-i-'); do nmcli device delete "$DEVICE" done } do_setup() { do_cleanup for i in {1..30}; do nmcli connection add type bond autoconnect no con-name xx-c-bond-$i ifname xx-i-bond-$i ipv4.method disabled ipv6.method ignore for j in $(seq $i 30); do nmcli connection add type vlan autoconnect no con-name xx-c-vlan-$i-$j vlan.id $j ifname xx-i-vlan-$i-$j vlan.parent xx-i-bond-$i ipv4.method disabled ipv6.method ignore done done systemctl restart NetworkManager.service sleep 5 } do_test() { perf stat -r 50 -B nmcli 1>/dev/null } do_test ``` [1] Performance counter stats for 'nmcli' (50 runs): 456.33 msec task-clock:u # 1.093 CPUs utilized ( +- 0.44% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,900 page-faults:u # 0.013 M/sec ( +- 0.02% ) 1,408,675,453 cycles:u # 3.087 GHz ( +- 0.48% ) 1,594,741,060 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 368,744,018 branches:u # 808.061 M/sec ( +- 0.02% ) 4,566,058 branch-misses:u # 1.24% of all branches ( +- 0.76% ) 0.41761 +- 0.00282 seconds time elapsed ( +- 0.68% ) [2] Performance counter stats for 'nmcli' (50 runs): 477.99 msec task-clock:u # 1.088 CPUs utilized ( +- 0.36% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,948 page-faults:u # 0.012 M/sec ( +- 0.03% ) 1,471,133,482 cycles:u # 3.078 GHz ( +- 0.36% ) 1,655,275,369 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 382,595,152 branches:u # 800.433 M/sec ( +- 0.02% ) 4,746,070 branch-misses:u # 1.24% of all branches ( +- 0.49% ) 0.43923 +- 0.00242 seconds time elapsed ( +- 0.55% ) [3] Performance counter stats for 'nmcli' (50 runs): 352.36 msec task-clock:u # 1.027 CPUs utilized ( +- 0.32% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 4,790 page-faults:u # 0.014 M/sec ( +- 0.26% ) 1,092,341,186 cycles:u # 3.100 GHz ( +- 0.26% ) 1,209,045,283 instructions:u # 1.11 insn per cycle ( +- 0.02% ) 281,708,462 branches:u # 799.499 M/sec ( +- 0.01% ) 3,101,031 branch-misses:u # 1.10% of all branches ( +- 0.61% ) 0.34296 +- 0.00120 seconds time elapsed ( +- 0.35% ) --- N5) same setup as N4), but run `PAGER= /bin/time -v nmcli`: [1] Command being timed: "nmcli" User time (seconds): 0.42 System time (seconds): 0.04 Percent of CPU this job got: 107% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.43 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34456 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6128 Voluntary context switches: 1298 Involuntary context switches: 1106 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [2] Command being timed: "nmcli" User time (seconds): 0.44 System time (seconds): 0.04 Percent of CPU this job got: 108% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.44 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34452 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6169 Voluntary context switches: 1849 Involuntary context switches: 142 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [3] Command being timed: "nmcli" User time (seconds): 0.32 System time (seconds): 0.02 Percent of CPU this job got: 102% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.34 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 29196 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 5059 Voluntary context switches: 919 Involuntary context switches: 685 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 --- N6) same setup as N4), but run `nmcli monitor` and look at `ps aux` for the RSS size. USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND [1] me 1492900 21.0 0.2 461348 33248 pts/10 Sl+ 15:02 0:00 nmcli monitor [2] me 1490721 5.0 0.2 461496 33548 pts/10 Sl+ 15:00 0:00 nmcli monitor [3] me 1495801 16.5 0.1 459476 28692 pts/10 Sl+ 15:04 0:00 nmcli monitor
2019-10-30 11:42:58 +01:00
if (priv->state != new_state) {
priv->old_state = priv->state;
priv->state = new_state;
_nm_client_queue_notify_object (client,
self,
obj_properties[PROP_STATE]);
}
libnm: refactor caching of D-Bus objects in NMClient No longer use GDBusObjectMangaerClient and gdbus-codegen generated classes for the NMClient cache. Instead, use GDBusConnection directly and a custom implementation (NMLDBusObject) for caching D-Bus' ObjectManager data. CHANGES ------- - This is a complete rework. I think the previous implementation was difficult to understand. There were unfixed bugs and nobody understood the code well enough to fix them. Maybe somebody out there understood the code, but I certainly did not. At least nobody provided patches to fix those issues. I do believe that this implementation is more straightforward and easier to understand. It removes a lot of layers of code. Whether this claim of simplicity is true, each reader must decide for himself/herself. Note that it is still fairly complex. - There was a lingering performance issue with large number of D-Bus objects. The patch tries hard that the implementation scales well. Of course, when we cache N objects that have N-to-M references to other, we still are fundamentally O(N*M) for runtime and memory consumption (with M being the number of references between objects). But each part should behave efficiently and well. - Play well with GMainContext. libnm code (NMClient) is generally not thread safe. However, it should work to use multiple instances in parallel, as long as each access to a NMClient is through the caller's GMainContext. This follows glib's style and effectively allows to use NMClient in a multi threaded scenario. This implies to stick to a main context upon construction and ensure that callbacks are only invoked when iterating that context. Also, NMClient itself shall never iterate the caller's context. This also means, libnm must never use g_idle_add() or g_timeout_add(), as those enqueue sources in the g_main_context_default() context. - Get ordering of messages right. All events are consistently enqueued in a GMainContext and processed strictly in order. For example, previously "nm-object.c" tried to combine signals and emit them on an idle handler. That is wrong, signals must be emitted in the right order and when they happen. Note that when using GInitable's synchronous initialization to initialize the NMClient instance, NMClient internally still operates fully asynchronously. In that case NMClient has an internal main context. - NMClient takes over most of the functionality. When using D-Bus' ObjectManager interface, one needs to handle basically the entire state of the D-Bus interface. That cannot be separated well into distinct parts, and even if you try, you just end up having closely related code in different source files. Spreading related code does not make it easier to understand, on the contrary. That means, NMClient is inherently complex as it contains most of the logic. I think that is not avoidable, but it's not as bad as it sounds. - NMClient processes D-Bus messages and state changes in separate steps. First NMClient unpacks the message (e.g. _dbus_handle_properties_changed()) and keeps track of the changed data. Then we update the GObject instances (_dbus_handle_obj_changed_dbus()) without emitting any signals yet. Finally, we emit all signals and notifications that were collected (_dbus_handle_changes_commit()). Note that for example during the initial GetManagedObjects() reply, NMClient receive a large amount of state at once. But we first apply all the changes to our GObject instances before emitting any signals. The result is that signals are always emitted in a moment when the cache is consistent. The unavoidable downside is that when you receive a property changed signal, possibly many other properties changed already and more signals are about to be emitted. - NMDeviceWifi no longer modifies the content of the cache from client side during poke_wireless_devices_with_rf_status(). The content of the cache should be determined by D-Bus alone and follow what NetworkManager service exposes. Local modifications should be avoided. - This aims to bring no API/ABI change, though it does of course bring various subtle changes in behavior. Those should be all for the better, but the goal is not to break any existing clients. This does change internal (albeit externally visible) API, like dropping NM_OBJECT_DBUS_OBJECT_MANAGER property and NMObject no longer implementing GInitableIface and GAsyncInitableIface. - Some uses of gdbus-codegen classes remain in NMVpnPluginOld, NMVpnServicePlugin and NMSecretAgentOld. These are independent of NMClient/NMObject and should be reworked separately. - While we no longer use generated classes from gdbus-codegen, we don't need more glue code than before. Also before we constructed NMPropertiesInfo and a had large amount of code to propagate properties from NMDBus* to NMObject. That got completely reworked, but did not fundamentally change. You still need about the same effort to create the NMLDBusMetaIface. Not using generated bindings did not make anything worse (which tells about the usefulness of generated code, at least in the way it was used). - NMLDBusMetaIface and other meta data is static and immutable. This avoids copying them around. Also, macros like NML_DBUS_META_PROPERTY_INIT_U() have compile time checks to ensure the property types matches. It's pretty hard to misuse them because it won't compile. - The meta data now explicitly encodes the expected D-Bus types and makes sure never to accept wrong data. That would only matter when the server (accidentally or intentionally) exposes unexpected types on D-Bus. I don't think that was previously ensured in all cases. For example, demarshal_generic() only cared about the GObject property type, it didn't know the expected D-Bus type. - Previously GDBusObjectManager would sometimes emit warnings (g_log()). Those probably indicated real bugs. In any case, it prevented us from running CI with G_DEBUG=fatal-warnings, because there would be just too many unrelated crashes. Now we log debug messages that can be enabled with "LIBNM_CLIENT_DEBUG=trace". Some of these messages can also be turned into g_warning()/g_critical() by setting LIBNM_CLIENT_DEBUG=warning,error. Together with G_DEBUG=fatal-warnings, this turns them into assertions. Note that such "assertion failures" might also happen because of a server bug (or change). Thus these are not common assertions that indicate a bug in libnm and are thus not armed unless explicitly requested. In our CI we should now always run with LIBNM_CLIENT_DEBUG=warning,error and G_DEBUG=fatal-warnings and to catch bugs. Note that currently NetworkManager has bugs in this regard, so enabling this will result in assertion failures. That should be fixed first. - Note that this changes the order in which we emit "notify:devices" and "device-added" signals. I think it makes the most sense to emit first "device-removed", then "notify:devices", and finally "device-added" signals. This changes behavior for commit 52ae28f6e5bf ('libnm: queue added/removed signals and suppress uninitialized notifications'), but I don't think that users should actually rely on the order. Still, the new order makes the most sense to me. - In NetworkManager, profiles can be invisible to the user by setting "connection.permissions". Such profiles would be hidden by NMClient's nm_client_get_connections() and their "connection-added"/"connection-removed" signals. Note that NMActiveConnection's nm_active_connection_get_connection() and NMDevice's nm_device_get_available_connections() still exposes such hidden NMRemoteConnection instances. This behavior was preserved. NUMBERS ------- I compared 3 versions of libnm. [1] 962297f9085d, current tip of nm-1-20 branch [2] 4fad8c7c642e, current master, immediate parent of this patch [3] this patch All tests were done on Fedora 31, x86_64, gcc 9.2.1-1.fc31. The libraries were build with $ ./contrib/fedora/rpm/build_clean.sh -g -w test -W debug Note that RPM build already stripped the library. --- N1) File size of libnm.so.0.1.0 in bytes. There currently seems to be a issue on Fedora 31 generating wrong ELF notes. Usually, libnm is smaller but in these tests it had large (and bogus) ELF notes. Anyway, the point is to show the relative sizes, so it doesn't matter). [1] 4075552 (102.7%) [2] 3969624 (100.0%) [3] 3705208 ( 93.3%) --- N2) `size /usr/lib64/libnm.so.0.1.0`: text data bss dec hex filename [1] 1314569 (102.0%) 69980 ( 94.8%) 10632 ( 80.4%) 1395181 (101.4%) 1549ed /usr/lib64/libnm.so.0.1.0 [2] 1288410 (100.0%) 73796 (100.0%) 13224 (100.0%) 1375430 (100.0%) 14fcc6 /usr/lib64/libnm.so.0.1.0 [3] 1229066 ( 95.4%) 65248 ( 88.4%) 13400 (101.3%) 1307714 ( 95.1%) 13f442 /usr/lib64/libnm.so.0.1.0 --- N3) Performance test with test-client.py. With checkout of [2], run ``` prepare_checkout() { rm -rf /tmp/nm-test && \ git checkout -B test 4fad8c7c642e && \ git clean -fdx && \ ./autogen.sh --prefix=/tmp/nm-test && \ make -j 5 install && \ make -j 5 check-local-clients-tests-test-client } prepare_test() { NM_TEST_REGENERATE=1 NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v } do_test() { for i in {1..10}; do NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v || return -1 done echo "done!" } prepare_checkout prepare_test time do_test ``` [1] real 2m14.497s (101.3%) user 5m26.651s (100.3%) sys 1m40.453s (101.4%) [2] real 2m12.800s (100.0%) user 5m25.619s (100.0%) sys 1m39.065s (100.0%) [3] real 1m54.915s ( 86.5%) user 4m18.585s ( 79.4%) sys 1m32.066s ( 92.9%) --- N4) Performance. Run NetworkManager from build [2] and setup a large number of profiles (551 profiles and 515 devices, mostly unrealized). This setup is already at the edge of what NetworkManager currently can handle. Of course, that is a different issue. Here we just check how long plain `nmcli` takes on the system. ``` do_cleanup() { for UUID in $(nmcli -g NAME,UUID connection show | sed -n 's/^xx-c-.*:\([^:]\+\)$/\1/p'); do nmcli connection delete uuid "$UUID" done for DEVICE in $(nmcli -g DEVICE device status | grep '^xx-i-'); do nmcli device delete "$DEVICE" done } do_setup() { do_cleanup for i in {1..30}; do nmcli connection add type bond autoconnect no con-name xx-c-bond-$i ifname xx-i-bond-$i ipv4.method disabled ipv6.method ignore for j in $(seq $i 30); do nmcli connection add type vlan autoconnect no con-name xx-c-vlan-$i-$j vlan.id $j ifname xx-i-vlan-$i-$j vlan.parent xx-i-bond-$i ipv4.method disabled ipv6.method ignore done done systemctl restart NetworkManager.service sleep 5 } do_test() { perf stat -r 50 -B nmcli 1>/dev/null } do_test ``` [1] Performance counter stats for 'nmcli' (50 runs): 456.33 msec task-clock:u # 1.093 CPUs utilized ( +- 0.44% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,900 page-faults:u # 0.013 M/sec ( +- 0.02% ) 1,408,675,453 cycles:u # 3.087 GHz ( +- 0.48% ) 1,594,741,060 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 368,744,018 branches:u # 808.061 M/sec ( +- 0.02% ) 4,566,058 branch-misses:u # 1.24% of all branches ( +- 0.76% ) 0.41761 +- 0.00282 seconds time elapsed ( +- 0.68% ) [2] Performance counter stats for 'nmcli' (50 runs): 477.99 msec task-clock:u # 1.088 CPUs utilized ( +- 0.36% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,948 page-faults:u # 0.012 M/sec ( +- 0.03% ) 1,471,133,482 cycles:u # 3.078 GHz ( +- 0.36% ) 1,655,275,369 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 382,595,152 branches:u # 800.433 M/sec ( +- 0.02% ) 4,746,070 branch-misses:u # 1.24% of all branches ( +- 0.49% ) 0.43923 +- 0.00242 seconds time elapsed ( +- 0.55% ) [3] Performance counter stats for 'nmcli' (50 runs): 352.36 msec task-clock:u # 1.027 CPUs utilized ( +- 0.32% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 4,790 page-faults:u # 0.014 M/sec ( +- 0.26% ) 1,092,341,186 cycles:u # 3.100 GHz ( +- 0.26% ) 1,209,045,283 instructions:u # 1.11 insn per cycle ( +- 0.02% ) 281,708,462 branches:u # 799.499 M/sec ( +- 0.01% ) 3,101,031 branch-misses:u # 1.10% of all branches ( +- 0.61% ) 0.34296 +- 0.00120 seconds time elapsed ( +- 0.35% ) --- N5) same setup as N4), but run `PAGER= /bin/time -v nmcli`: [1] Command being timed: "nmcli" User time (seconds): 0.42 System time (seconds): 0.04 Percent of CPU this job got: 107% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.43 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34456 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6128 Voluntary context switches: 1298 Involuntary context switches: 1106 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [2] Command being timed: "nmcli" User time (seconds): 0.44 System time (seconds): 0.04 Percent of CPU this job got: 108% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.44 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34452 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6169 Voluntary context switches: 1849 Involuntary context switches: 142 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [3] Command being timed: "nmcli" User time (seconds): 0.32 System time (seconds): 0.02 Percent of CPU this job got: 102% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.34 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 29196 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 5059 Voluntary context switches: 919 Involuntary context switches: 685 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 --- N6) same setup as N4), but run `nmcli monitor` and look at `ps aux` for the RSS size. USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND [1] me 1492900 21.0 0.2 461348 33248 pts/10 Sl+ 15:02 0:00 nmcli monitor [2] me 1490721 5.0 0.2 461496 33548 pts/10 Sl+ 15:00 0:00 nmcli monitor [3] me 1495801 16.5 0.1 459476 28692 pts/10 Sl+ 15:04 0:00 nmcli monitor
2019-10-30 11:42:58 +01:00
if (priv->state_reason != reason) {
priv->state_reason = reason;
_nm_client_queue_notify_object (client,
self,
obj_properties[PROP_STATE_REASON]);
}
libnm: refactor caching of D-Bus objects in NMClient No longer use GDBusObjectMangaerClient and gdbus-codegen generated classes for the NMClient cache. Instead, use GDBusConnection directly and a custom implementation (NMLDBusObject) for caching D-Bus' ObjectManager data. CHANGES ------- - This is a complete rework. I think the previous implementation was difficult to understand. There were unfixed bugs and nobody understood the code well enough to fix them. Maybe somebody out there understood the code, but I certainly did not. At least nobody provided patches to fix those issues. I do believe that this implementation is more straightforward and easier to understand. It removes a lot of layers of code. Whether this claim of simplicity is true, each reader must decide for himself/herself. Note that it is still fairly complex. - There was a lingering performance issue with large number of D-Bus objects. The patch tries hard that the implementation scales well. Of course, when we cache N objects that have N-to-M references to other, we still are fundamentally O(N*M) for runtime and memory consumption (with M being the number of references between objects). But each part should behave efficiently and well. - Play well with GMainContext. libnm code (NMClient) is generally not thread safe. However, it should work to use multiple instances in parallel, as long as each access to a NMClient is through the caller's GMainContext. This follows glib's style and effectively allows to use NMClient in a multi threaded scenario. This implies to stick to a main context upon construction and ensure that callbacks are only invoked when iterating that context. Also, NMClient itself shall never iterate the caller's context. This also means, libnm must never use g_idle_add() or g_timeout_add(), as those enqueue sources in the g_main_context_default() context. - Get ordering of messages right. All events are consistently enqueued in a GMainContext and processed strictly in order. For example, previously "nm-object.c" tried to combine signals and emit them on an idle handler. That is wrong, signals must be emitted in the right order and when they happen. Note that when using GInitable's synchronous initialization to initialize the NMClient instance, NMClient internally still operates fully asynchronously. In that case NMClient has an internal main context. - NMClient takes over most of the functionality. When using D-Bus' ObjectManager interface, one needs to handle basically the entire state of the D-Bus interface. That cannot be separated well into distinct parts, and even if you try, you just end up having closely related code in different source files. Spreading related code does not make it easier to understand, on the contrary. That means, NMClient is inherently complex as it contains most of the logic. I think that is not avoidable, but it's not as bad as it sounds. - NMClient processes D-Bus messages and state changes in separate steps. First NMClient unpacks the message (e.g. _dbus_handle_properties_changed()) and keeps track of the changed data. Then we update the GObject instances (_dbus_handle_obj_changed_dbus()) without emitting any signals yet. Finally, we emit all signals and notifications that were collected (_dbus_handle_changes_commit()). Note that for example during the initial GetManagedObjects() reply, NMClient receive a large amount of state at once. But we first apply all the changes to our GObject instances before emitting any signals. The result is that signals are always emitted in a moment when the cache is consistent. The unavoidable downside is that when you receive a property changed signal, possibly many other properties changed already and more signals are about to be emitted. - NMDeviceWifi no longer modifies the content of the cache from client side during poke_wireless_devices_with_rf_status(). The content of the cache should be determined by D-Bus alone and follow what NetworkManager service exposes. Local modifications should be avoided. - This aims to bring no API/ABI change, though it does of course bring various subtle changes in behavior. Those should be all for the better, but the goal is not to break any existing clients. This does change internal (albeit externally visible) API, like dropping NM_OBJECT_DBUS_OBJECT_MANAGER property and NMObject no longer implementing GInitableIface and GAsyncInitableIface. - Some uses of gdbus-codegen classes remain in NMVpnPluginOld, NMVpnServicePlugin and NMSecretAgentOld. These are independent of NMClient/NMObject and should be reworked separately. - While we no longer use generated classes from gdbus-codegen, we don't need more glue code than before. Also before we constructed NMPropertiesInfo and a had large amount of code to propagate properties from NMDBus* to NMObject. That got completely reworked, but did not fundamentally change. You still need about the same effort to create the NMLDBusMetaIface. Not using generated bindings did not make anything worse (which tells about the usefulness of generated code, at least in the way it was used). - NMLDBusMetaIface and other meta data is static and immutable. This avoids copying them around. Also, macros like NML_DBUS_META_PROPERTY_INIT_U() have compile time checks to ensure the property types matches. It's pretty hard to misuse them because it won't compile. - The meta data now explicitly encodes the expected D-Bus types and makes sure never to accept wrong data. That would only matter when the server (accidentally or intentionally) exposes unexpected types on D-Bus. I don't think that was previously ensured in all cases. For example, demarshal_generic() only cared about the GObject property type, it didn't know the expected D-Bus type. - Previously GDBusObjectManager would sometimes emit warnings (g_log()). Those probably indicated real bugs. In any case, it prevented us from running CI with G_DEBUG=fatal-warnings, because there would be just too many unrelated crashes. Now we log debug messages that can be enabled with "LIBNM_CLIENT_DEBUG=trace". Some of these messages can also be turned into g_warning()/g_critical() by setting LIBNM_CLIENT_DEBUG=warning,error. Together with G_DEBUG=fatal-warnings, this turns them into assertions. Note that such "assertion failures" might also happen because of a server bug (or change). Thus these are not common assertions that indicate a bug in libnm and are thus not armed unless explicitly requested. In our CI we should now always run with LIBNM_CLIENT_DEBUG=warning,error and G_DEBUG=fatal-warnings and to catch bugs. Note that currently NetworkManager has bugs in this regard, so enabling this will result in assertion failures. That should be fixed first. - Note that this changes the order in which we emit "notify:devices" and "device-added" signals. I think it makes the most sense to emit first "device-removed", then "notify:devices", and finally "device-added" signals. This changes behavior for commit 52ae28f6e5bf ('libnm: queue added/removed signals and suppress uninitialized notifications'), but I don't think that users should actually rely on the order. Still, the new order makes the most sense to me. - In NetworkManager, profiles can be invisible to the user by setting "connection.permissions". Such profiles would be hidden by NMClient's nm_client_get_connections() and their "connection-added"/"connection-removed" signals. Note that NMActiveConnection's nm_active_connection_get_connection() and NMDevice's nm_device_get_available_connections() still exposes such hidden NMRemoteConnection instances. This behavior was preserved. NUMBERS ------- I compared 3 versions of libnm. [1] 962297f9085d, current tip of nm-1-20 branch [2] 4fad8c7c642e, current master, immediate parent of this patch [3] this patch All tests were done on Fedora 31, x86_64, gcc 9.2.1-1.fc31. The libraries were build with $ ./contrib/fedora/rpm/build_clean.sh -g -w test -W debug Note that RPM build already stripped the library. --- N1) File size of libnm.so.0.1.0 in bytes. There currently seems to be a issue on Fedora 31 generating wrong ELF notes. Usually, libnm is smaller but in these tests it had large (and bogus) ELF notes. Anyway, the point is to show the relative sizes, so it doesn't matter). [1] 4075552 (102.7%) [2] 3969624 (100.0%) [3] 3705208 ( 93.3%) --- N2) `size /usr/lib64/libnm.so.0.1.0`: text data bss dec hex filename [1] 1314569 (102.0%) 69980 ( 94.8%) 10632 ( 80.4%) 1395181 (101.4%) 1549ed /usr/lib64/libnm.so.0.1.0 [2] 1288410 (100.0%) 73796 (100.0%) 13224 (100.0%) 1375430 (100.0%) 14fcc6 /usr/lib64/libnm.so.0.1.0 [3] 1229066 ( 95.4%) 65248 ( 88.4%) 13400 (101.3%) 1307714 ( 95.1%) 13f442 /usr/lib64/libnm.so.0.1.0 --- N3) Performance test with test-client.py. With checkout of [2], run ``` prepare_checkout() { rm -rf /tmp/nm-test && \ git checkout -B test 4fad8c7c642e && \ git clean -fdx && \ ./autogen.sh --prefix=/tmp/nm-test && \ make -j 5 install && \ make -j 5 check-local-clients-tests-test-client } prepare_test() { NM_TEST_REGENERATE=1 NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v } do_test() { for i in {1..10}; do NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v || return -1 done echo "done!" } prepare_checkout prepare_test time do_test ``` [1] real 2m14.497s (101.3%) user 5m26.651s (100.3%) sys 1m40.453s (101.4%) [2] real 2m12.800s (100.0%) user 5m25.619s (100.0%) sys 1m39.065s (100.0%) [3] real 1m54.915s ( 86.5%) user 4m18.585s ( 79.4%) sys 1m32.066s ( 92.9%) --- N4) Performance. Run NetworkManager from build [2] and setup a large number of profiles (551 profiles and 515 devices, mostly unrealized). This setup is already at the edge of what NetworkManager currently can handle. Of course, that is a different issue. Here we just check how long plain `nmcli` takes on the system. ``` do_cleanup() { for UUID in $(nmcli -g NAME,UUID connection show | sed -n 's/^xx-c-.*:\([^:]\+\)$/\1/p'); do nmcli connection delete uuid "$UUID" done for DEVICE in $(nmcli -g DEVICE device status | grep '^xx-i-'); do nmcli device delete "$DEVICE" done } do_setup() { do_cleanup for i in {1..30}; do nmcli connection add type bond autoconnect no con-name xx-c-bond-$i ifname xx-i-bond-$i ipv4.method disabled ipv6.method ignore for j in $(seq $i 30); do nmcli connection add type vlan autoconnect no con-name xx-c-vlan-$i-$j vlan.id $j ifname xx-i-vlan-$i-$j vlan.parent xx-i-bond-$i ipv4.method disabled ipv6.method ignore done done systemctl restart NetworkManager.service sleep 5 } do_test() { perf stat -r 50 -B nmcli 1>/dev/null } do_test ``` [1] Performance counter stats for 'nmcli' (50 runs): 456.33 msec task-clock:u # 1.093 CPUs utilized ( +- 0.44% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,900 page-faults:u # 0.013 M/sec ( +- 0.02% ) 1,408,675,453 cycles:u # 3.087 GHz ( +- 0.48% ) 1,594,741,060 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 368,744,018 branches:u # 808.061 M/sec ( +- 0.02% ) 4,566,058 branch-misses:u # 1.24% of all branches ( +- 0.76% ) 0.41761 +- 0.00282 seconds time elapsed ( +- 0.68% ) [2] Performance counter stats for 'nmcli' (50 runs): 477.99 msec task-clock:u # 1.088 CPUs utilized ( +- 0.36% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,948 page-faults:u # 0.012 M/sec ( +- 0.03% ) 1,471,133,482 cycles:u # 3.078 GHz ( +- 0.36% ) 1,655,275,369 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 382,595,152 branches:u # 800.433 M/sec ( +- 0.02% ) 4,746,070 branch-misses:u # 1.24% of all branches ( +- 0.49% ) 0.43923 +- 0.00242 seconds time elapsed ( +- 0.55% ) [3] Performance counter stats for 'nmcli' (50 runs): 352.36 msec task-clock:u # 1.027 CPUs utilized ( +- 0.32% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 4,790 page-faults:u # 0.014 M/sec ( +- 0.26% ) 1,092,341,186 cycles:u # 3.100 GHz ( +- 0.26% ) 1,209,045,283 instructions:u # 1.11 insn per cycle ( +- 0.02% ) 281,708,462 branches:u # 799.499 M/sec ( +- 0.01% ) 3,101,031 branch-misses:u # 1.10% of all branches ( +- 0.61% ) 0.34296 +- 0.00120 seconds time elapsed ( +- 0.35% ) --- N5) same setup as N4), but run `PAGER= /bin/time -v nmcli`: [1] Command being timed: "nmcli" User time (seconds): 0.42 System time (seconds): 0.04 Percent of CPU this job got: 107% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.43 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34456 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6128 Voluntary context switches: 1298 Involuntary context switches: 1106 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [2] Command being timed: "nmcli" User time (seconds): 0.44 System time (seconds): 0.04 Percent of CPU this job got: 108% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.44 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34452 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6169 Voluntary context switches: 1849 Involuntary context switches: 142 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [3] Command being timed: "nmcli" User time (seconds): 0.32 System time (seconds): 0.02 Percent of CPU this job got: 102% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.34 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 29196 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 5059 Voluntary context switches: 919 Involuntary context switches: 685 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 --- N6) same setup as N4), but run `nmcli monitor` and look at `ps aux` for the RSS size. USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND [1] me 1492900 21.0 0.2 461348 33248 pts/10 Sl+ 15:02 0:00 nmcli monitor [2] me 1490721 5.0 0.2 461496 33548 pts/10 Sl+ 15:00 0:00 nmcli monitor [3] me 1495801 16.5 0.1 459476 28692 pts/10 Sl+ 15:04 0:00 nmcli monitor
2019-10-30 11:42:58 +01:00
_nm_client_notify_event_queue_with_ptr (client,
NM_CLIENT_NOTIFY_EVENT_PRIO_GPROP + 1,
_notify_event_state_changed,
g_object_ref (self));
libnm: refactor caching of D-Bus objects in NMClient No longer use GDBusObjectMangaerClient and gdbus-codegen generated classes for the NMClient cache. Instead, use GDBusConnection directly and a custom implementation (NMLDBusObject) for caching D-Bus' ObjectManager data. CHANGES ------- - This is a complete rework. I think the previous implementation was difficult to understand. There were unfixed bugs and nobody understood the code well enough to fix them. Maybe somebody out there understood the code, but I certainly did not. At least nobody provided patches to fix those issues. I do believe that this implementation is more straightforward and easier to understand. It removes a lot of layers of code. Whether this claim of simplicity is true, each reader must decide for himself/herself. Note that it is still fairly complex. - There was a lingering performance issue with large number of D-Bus objects. The patch tries hard that the implementation scales well. Of course, when we cache N objects that have N-to-M references to other, we still are fundamentally O(N*M) for runtime and memory consumption (with M being the number of references between objects). But each part should behave efficiently and well. - Play well with GMainContext. libnm code (NMClient) is generally not thread safe. However, it should work to use multiple instances in parallel, as long as each access to a NMClient is through the caller's GMainContext. This follows glib's style and effectively allows to use NMClient in a multi threaded scenario. This implies to stick to a main context upon construction and ensure that callbacks are only invoked when iterating that context. Also, NMClient itself shall never iterate the caller's context. This also means, libnm must never use g_idle_add() or g_timeout_add(), as those enqueue sources in the g_main_context_default() context. - Get ordering of messages right. All events are consistently enqueued in a GMainContext and processed strictly in order. For example, previously "nm-object.c" tried to combine signals and emit them on an idle handler. That is wrong, signals must be emitted in the right order and when they happen. Note that when using GInitable's synchronous initialization to initialize the NMClient instance, NMClient internally still operates fully asynchronously. In that case NMClient has an internal main context. - NMClient takes over most of the functionality. When using D-Bus' ObjectManager interface, one needs to handle basically the entire state of the D-Bus interface. That cannot be separated well into distinct parts, and even if you try, you just end up having closely related code in different source files. Spreading related code does not make it easier to understand, on the contrary. That means, NMClient is inherently complex as it contains most of the logic. I think that is not avoidable, but it's not as bad as it sounds. - NMClient processes D-Bus messages and state changes in separate steps. First NMClient unpacks the message (e.g. _dbus_handle_properties_changed()) and keeps track of the changed data. Then we update the GObject instances (_dbus_handle_obj_changed_dbus()) without emitting any signals yet. Finally, we emit all signals and notifications that were collected (_dbus_handle_changes_commit()). Note that for example during the initial GetManagedObjects() reply, NMClient receive a large amount of state at once. But we first apply all the changes to our GObject instances before emitting any signals. The result is that signals are always emitted in a moment when the cache is consistent. The unavoidable downside is that when you receive a property changed signal, possibly many other properties changed already and more signals are about to be emitted. - NMDeviceWifi no longer modifies the content of the cache from client side during poke_wireless_devices_with_rf_status(). The content of the cache should be determined by D-Bus alone and follow what NetworkManager service exposes. Local modifications should be avoided. - This aims to bring no API/ABI change, though it does of course bring various subtle changes in behavior. Those should be all for the better, but the goal is not to break any existing clients. This does change internal (albeit externally visible) API, like dropping NM_OBJECT_DBUS_OBJECT_MANAGER property and NMObject no longer implementing GInitableIface and GAsyncInitableIface. - Some uses of gdbus-codegen classes remain in NMVpnPluginOld, NMVpnServicePlugin and NMSecretAgentOld. These are independent of NMClient/NMObject and should be reworked separately. - While we no longer use generated classes from gdbus-codegen, we don't need more glue code than before. Also before we constructed NMPropertiesInfo and a had large amount of code to propagate properties from NMDBus* to NMObject. That got completely reworked, but did not fundamentally change. You still need about the same effort to create the NMLDBusMetaIface. Not using generated bindings did not make anything worse (which tells about the usefulness of generated code, at least in the way it was used). - NMLDBusMetaIface and other meta data is static and immutable. This avoids copying them around. Also, macros like NML_DBUS_META_PROPERTY_INIT_U() have compile time checks to ensure the property types matches. It's pretty hard to misuse them because it won't compile. - The meta data now explicitly encodes the expected D-Bus types and makes sure never to accept wrong data. That would only matter when the server (accidentally or intentionally) exposes unexpected types on D-Bus. I don't think that was previously ensured in all cases. For example, demarshal_generic() only cared about the GObject property type, it didn't know the expected D-Bus type. - Previously GDBusObjectManager would sometimes emit warnings (g_log()). Those probably indicated real bugs. In any case, it prevented us from running CI with G_DEBUG=fatal-warnings, because there would be just too many unrelated crashes. Now we log debug messages that can be enabled with "LIBNM_CLIENT_DEBUG=trace". Some of these messages can also be turned into g_warning()/g_critical() by setting LIBNM_CLIENT_DEBUG=warning,error. Together with G_DEBUG=fatal-warnings, this turns them into assertions. Note that such "assertion failures" might also happen because of a server bug (or change). Thus these are not common assertions that indicate a bug in libnm and are thus not armed unless explicitly requested. In our CI we should now always run with LIBNM_CLIENT_DEBUG=warning,error and G_DEBUG=fatal-warnings and to catch bugs. Note that currently NetworkManager has bugs in this regard, so enabling this will result in assertion failures. That should be fixed first. - Note that this changes the order in which we emit "notify:devices" and "device-added" signals. I think it makes the most sense to emit first "device-removed", then "notify:devices", and finally "device-added" signals. This changes behavior for commit 52ae28f6e5bf ('libnm: queue added/removed signals and suppress uninitialized notifications'), but I don't think that users should actually rely on the order. Still, the new order makes the most sense to me. - In NetworkManager, profiles can be invisible to the user by setting "connection.permissions". Such profiles would be hidden by NMClient's nm_client_get_connections() and their "connection-added"/"connection-removed" signals. Note that NMActiveConnection's nm_active_connection_get_connection() and NMDevice's nm_device_get_available_connections() still exposes such hidden NMRemoteConnection instances. This behavior was preserved. NUMBERS ------- I compared 3 versions of libnm. [1] 962297f9085d, current tip of nm-1-20 branch [2] 4fad8c7c642e, current master, immediate parent of this patch [3] this patch All tests were done on Fedora 31, x86_64, gcc 9.2.1-1.fc31. The libraries were build with $ ./contrib/fedora/rpm/build_clean.sh -g -w test -W debug Note that RPM build already stripped the library. --- N1) File size of libnm.so.0.1.0 in bytes. There currently seems to be a issue on Fedora 31 generating wrong ELF notes. Usually, libnm is smaller but in these tests it had large (and bogus) ELF notes. Anyway, the point is to show the relative sizes, so it doesn't matter). [1] 4075552 (102.7%) [2] 3969624 (100.0%) [3] 3705208 ( 93.3%) --- N2) `size /usr/lib64/libnm.so.0.1.0`: text data bss dec hex filename [1] 1314569 (102.0%) 69980 ( 94.8%) 10632 ( 80.4%) 1395181 (101.4%) 1549ed /usr/lib64/libnm.so.0.1.0 [2] 1288410 (100.0%) 73796 (100.0%) 13224 (100.0%) 1375430 (100.0%) 14fcc6 /usr/lib64/libnm.so.0.1.0 [3] 1229066 ( 95.4%) 65248 ( 88.4%) 13400 (101.3%) 1307714 ( 95.1%) 13f442 /usr/lib64/libnm.so.0.1.0 --- N3) Performance test with test-client.py. With checkout of [2], run ``` prepare_checkout() { rm -rf /tmp/nm-test && \ git checkout -B test 4fad8c7c642e && \ git clean -fdx && \ ./autogen.sh --prefix=/tmp/nm-test && \ make -j 5 install && \ make -j 5 check-local-clients-tests-test-client } prepare_test() { NM_TEST_REGENERATE=1 NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v } do_test() { for i in {1..10}; do NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v || return -1 done echo "done!" } prepare_checkout prepare_test time do_test ``` [1] real 2m14.497s (101.3%) user 5m26.651s (100.3%) sys 1m40.453s (101.4%) [2] real 2m12.800s (100.0%) user 5m25.619s (100.0%) sys 1m39.065s (100.0%) [3] real 1m54.915s ( 86.5%) user 4m18.585s ( 79.4%) sys 1m32.066s ( 92.9%) --- N4) Performance. Run NetworkManager from build [2] and setup a large number of profiles (551 profiles and 515 devices, mostly unrealized). This setup is already at the edge of what NetworkManager currently can handle. Of course, that is a different issue. Here we just check how long plain `nmcli` takes on the system. ``` do_cleanup() { for UUID in $(nmcli -g NAME,UUID connection show | sed -n 's/^xx-c-.*:\([^:]\+\)$/\1/p'); do nmcli connection delete uuid "$UUID" done for DEVICE in $(nmcli -g DEVICE device status | grep '^xx-i-'); do nmcli device delete "$DEVICE" done } do_setup() { do_cleanup for i in {1..30}; do nmcli connection add type bond autoconnect no con-name xx-c-bond-$i ifname xx-i-bond-$i ipv4.method disabled ipv6.method ignore for j in $(seq $i 30); do nmcli connection add type vlan autoconnect no con-name xx-c-vlan-$i-$j vlan.id $j ifname xx-i-vlan-$i-$j vlan.parent xx-i-bond-$i ipv4.method disabled ipv6.method ignore done done systemctl restart NetworkManager.service sleep 5 } do_test() { perf stat -r 50 -B nmcli 1>/dev/null } do_test ``` [1] Performance counter stats for 'nmcli' (50 runs): 456.33 msec task-clock:u # 1.093 CPUs utilized ( +- 0.44% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,900 page-faults:u # 0.013 M/sec ( +- 0.02% ) 1,408,675,453 cycles:u # 3.087 GHz ( +- 0.48% ) 1,594,741,060 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 368,744,018 branches:u # 808.061 M/sec ( +- 0.02% ) 4,566,058 branch-misses:u # 1.24% of all branches ( +- 0.76% ) 0.41761 +- 0.00282 seconds time elapsed ( +- 0.68% ) [2] Performance counter stats for 'nmcli' (50 runs): 477.99 msec task-clock:u # 1.088 CPUs utilized ( +- 0.36% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,948 page-faults:u # 0.012 M/sec ( +- 0.03% ) 1,471,133,482 cycles:u # 3.078 GHz ( +- 0.36% ) 1,655,275,369 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 382,595,152 branches:u # 800.433 M/sec ( +- 0.02% ) 4,746,070 branch-misses:u # 1.24% of all branches ( +- 0.49% ) 0.43923 +- 0.00242 seconds time elapsed ( +- 0.55% ) [3] Performance counter stats for 'nmcli' (50 runs): 352.36 msec task-clock:u # 1.027 CPUs utilized ( +- 0.32% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 4,790 page-faults:u # 0.014 M/sec ( +- 0.26% ) 1,092,341,186 cycles:u # 3.100 GHz ( +- 0.26% ) 1,209,045,283 instructions:u # 1.11 insn per cycle ( +- 0.02% ) 281,708,462 branches:u # 799.499 M/sec ( +- 0.01% ) 3,101,031 branch-misses:u # 1.10% of all branches ( +- 0.61% ) 0.34296 +- 0.00120 seconds time elapsed ( +- 0.35% ) --- N5) same setup as N4), but run `PAGER= /bin/time -v nmcli`: [1] Command being timed: "nmcli" User time (seconds): 0.42 System time (seconds): 0.04 Percent of CPU this job got: 107% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.43 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34456 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6128 Voluntary context switches: 1298 Involuntary context switches: 1106 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [2] Command being timed: "nmcli" User time (seconds): 0.44 System time (seconds): 0.04 Percent of CPU this job got: 108% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.44 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34452 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6169 Voluntary context switches: 1849 Involuntary context switches: 142 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [3] Command being timed: "nmcli" User time (seconds): 0.32 System time (seconds): 0.02 Percent of CPU this job got: 102% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.34 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 29196 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 5059 Voluntary context switches: 919 Involuntary context switches: 685 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 --- N6) same setup as N4), but run `nmcli monitor` and look at `ps aux` for the RSS size. USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND [1] me 1492900 21.0 0.2 461348 33248 pts/10 Sl+ 15:02 0:00 nmcli monitor [2] me 1490721 5.0 0.2 461496 33548 pts/10 Sl+ 15:00 0:00 nmcli monitor [3] me 1495801 16.5 0.1 459476 28692 pts/10 Sl+ 15:04 0:00 nmcli monitor
2019-10-30 11:42:58 +01:00
return NML_DBUS_NOTIFY_UPDATE_PROP_FLAGS_NONE;
}
libnm: refactor caching of D-Bus objects in NMClient No longer use GDBusObjectMangaerClient and gdbus-codegen generated classes for the NMClient cache. Instead, use GDBusConnection directly and a custom implementation (NMLDBusObject) for caching D-Bus' ObjectManager data. CHANGES ------- - This is a complete rework. I think the previous implementation was difficult to understand. There were unfixed bugs and nobody understood the code well enough to fix them. Maybe somebody out there understood the code, but I certainly did not. At least nobody provided patches to fix those issues. I do believe that this implementation is more straightforward and easier to understand. It removes a lot of layers of code. Whether this claim of simplicity is true, each reader must decide for himself/herself. Note that it is still fairly complex. - There was a lingering performance issue with large number of D-Bus objects. The patch tries hard that the implementation scales well. Of course, when we cache N objects that have N-to-M references to other, we still are fundamentally O(N*M) for runtime and memory consumption (with M being the number of references between objects). But each part should behave efficiently and well. - Play well with GMainContext. libnm code (NMClient) is generally not thread safe. However, it should work to use multiple instances in parallel, as long as each access to a NMClient is through the caller's GMainContext. This follows glib's style and effectively allows to use NMClient in a multi threaded scenario. This implies to stick to a main context upon construction and ensure that callbacks are only invoked when iterating that context. Also, NMClient itself shall never iterate the caller's context. This also means, libnm must never use g_idle_add() or g_timeout_add(), as those enqueue sources in the g_main_context_default() context. - Get ordering of messages right. All events are consistently enqueued in a GMainContext and processed strictly in order. For example, previously "nm-object.c" tried to combine signals and emit them on an idle handler. That is wrong, signals must be emitted in the right order and when they happen. Note that when using GInitable's synchronous initialization to initialize the NMClient instance, NMClient internally still operates fully asynchronously. In that case NMClient has an internal main context. - NMClient takes over most of the functionality. When using D-Bus' ObjectManager interface, one needs to handle basically the entire state of the D-Bus interface. That cannot be separated well into distinct parts, and even if you try, you just end up having closely related code in different source files. Spreading related code does not make it easier to understand, on the contrary. That means, NMClient is inherently complex as it contains most of the logic. I think that is not avoidable, but it's not as bad as it sounds. - NMClient processes D-Bus messages and state changes in separate steps. First NMClient unpacks the message (e.g. _dbus_handle_properties_changed()) and keeps track of the changed data. Then we update the GObject instances (_dbus_handle_obj_changed_dbus()) without emitting any signals yet. Finally, we emit all signals and notifications that were collected (_dbus_handle_changes_commit()). Note that for example during the initial GetManagedObjects() reply, NMClient receive a large amount of state at once. But we first apply all the changes to our GObject instances before emitting any signals. The result is that signals are always emitted in a moment when the cache is consistent. The unavoidable downside is that when you receive a property changed signal, possibly many other properties changed already and more signals are about to be emitted. - NMDeviceWifi no longer modifies the content of the cache from client side during poke_wireless_devices_with_rf_status(). The content of the cache should be determined by D-Bus alone and follow what NetworkManager service exposes. Local modifications should be avoided. - This aims to bring no API/ABI change, though it does of course bring various subtle changes in behavior. Those should be all for the better, but the goal is not to break any existing clients. This does change internal (albeit externally visible) API, like dropping NM_OBJECT_DBUS_OBJECT_MANAGER property and NMObject no longer implementing GInitableIface and GAsyncInitableIface. - Some uses of gdbus-codegen classes remain in NMVpnPluginOld, NMVpnServicePlugin and NMSecretAgentOld. These are independent of NMClient/NMObject and should be reworked separately. - While we no longer use generated classes from gdbus-codegen, we don't need more glue code than before. Also before we constructed NMPropertiesInfo and a had large amount of code to propagate properties from NMDBus* to NMObject. That got completely reworked, but did not fundamentally change. You still need about the same effort to create the NMLDBusMetaIface. Not using generated bindings did not make anything worse (which tells about the usefulness of generated code, at least in the way it was used). - NMLDBusMetaIface and other meta data is static and immutable. This avoids copying them around. Also, macros like NML_DBUS_META_PROPERTY_INIT_U() have compile time checks to ensure the property types matches. It's pretty hard to misuse them because it won't compile. - The meta data now explicitly encodes the expected D-Bus types and makes sure never to accept wrong data. That would only matter when the server (accidentally or intentionally) exposes unexpected types on D-Bus. I don't think that was previously ensured in all cases. For example, demarshal_generic() only cared about the GObject property type, it didn't know the expected D-Bus type. - Previously GDBusObjectManager would sometimes emit warnings (g_log()). Those probably indicated real bugs. In any case, it prevented us from running CI with G_DEBUG=fatal-warnings, because there would be just too many unrelated crashes. Now we log debug messages that can be enabled with "LIBNM_CLIENT_DEBUG=trace". Some of these messages can also be turned into g_warning()/g_critical() by setting LIBNM_CLIENT_DEBUG=warning,error. Together with G_DEBUG=fatal-warnings, this turns them into assertions. Note that such "assertion failures" might also happen because of a server bug (or change). Thus these are not common assertions that indicate a bug in libnm and are thus not armed unless explicitly requested. In our CI we should now always run with LIBNM_CLIENT_DEBUG=warning,error and G_DEBUG=fatal-warnings and to catch bugs. Note that currently NetworkManager has bugs in this regard, so enabling this will result in assertion failures. That should be fixed first. - Note that this changes the order in which we emit "notify:devices" and "device-added" signals. I think it makes the most sense to emit first "device-removed", then "notify:devices", and finally "device-added" signals. This changes behavior for commit 52ae28f6e5bf ('libnm: queue added/removed signals and suppress uninitialized notifications'), but I don't think that users should actually rely on the order. Still, the new order makes the most sense to me. - In NetworkManager, profiles can be invisible to the user by setting "connection.permissions". Such profiles would be hidden by NMClient's nm_client_get_connections() and their "connection-added"/"connection-removed" signals. Note that NMActiveConnection's nm_active_connection_get_connection() and NMDevice's nm_device_get_available_connections() still exposes such hidden NMRemoteConnection instances. This behavior was preserved. NUMBERS ------- I compared 3 versions of libnm. [1] 962297f9085d, current tip of nm-1-20 branch [2] 4fad8c7c642e, current master, immediate parent of this patch [3] this patch All tests were done on Fedora 31, x86_64, gcc 9.2.1-1.fc31. The libraries were build with $ ./contrib/fedora/rpm/build_clean.sh -g -w test -W debug Note that RPM build already stripped the library. --- N1) File size of libnm.so.0.1.0 in bytes. There currently seems to be a issue on Fedora 31 generating wrong ELF notes. Usually, libnm is smaller but in these tests it had large (and bogus) ELF notes. Anyway, the point is to show the relative sizes, so it doesn't matter). [1] 4075552 (102.7%) [2] 3969624 (100.0%) [3] 3705208 ( 93.3%) --- N2) `size /usr/lib64/libnm.so.0.1.0`: text data bss dec hex filename [1] 1314569 (102.0%) 69980 ( 94.8%) 10632 ( 80.4%) 1395181 (101.4%) 1549ed /usr/lib64/libnm.so.0.1.0 [2] 1288410 (100.0%) 73796 (100.0%) 13224 (100.0%) 1375430 (100.0%) 14fcc6 /usr/lib64/libnm.so.0.1.0 [3] 1229066 ( 95.4%) 65248 ( 88.4%) 13400 (101.3%) 1307714 ( 95.1%) 13f442 /usr/lib64/libnm.so.0.1.0 --- N3) Performance test with test-client.py. With checkout of [2], run ``` prepare_checkout() { rm -rf /tmp/nm-test && \ git checkout -B test 4fad8c7c642e && \ git clean -fdx && \ ./autogen.sh --prefix=/tmp/nm-test && \ make -j 5 install && \ make -j 5 check-local-clients-tests-test-client } prepare_test() { NM_TEST_REGENERATE=1 NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v } do_test() { for i in {1..10}; do NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v || return -1 done echo "done!" } prepare_checkout prepare_test time do_test ``` [1] real 2m14.497s (101.3%) user 5m26.651s (100.3%) sys 1m40.453s (101.4%) [2] real 2m12.800s (100.0%) user 5m25.619s (100.0%) sys 1m39.065s (100.0%) [3] real 1m54.915s ( 86.5%) user 4m18.585s ( 79.4%) sys 1m32.066s ( 92.9%) --- N4) Performance. Run NetworkManager from build [2] and setup a large number of profiles (551 profiles and 515 devices, mostly unrealized). This setup is already at the edge of what NetworkManager currently can handle. Of course, that is a different issue. Here we just check how long plain `nmcli` takes on the system. ``` do_cleanup() { for UUID in $(nmcli -g NAME,UUID connection show | sed -n 's/^xx-c-.*:\([^:]\+\)$/\1/p'); do nmcli connection delete uuid "$UUID" done for DEVICE in $(nmcli -g DEVICE device status | grep '^xx-i-'); do nmcli device delete "$DEVICE" done } do_setup() { do_cleanup for i in {1..30}; do nmcli connection add type bond autoconnect no con-name xx-c-bond-$i ifname xx-i-bond-$i ipv4.method disabled ipv6.method ignore for j in $(seq $i 30); do nmcli connection add type vlan autoconnect no con-name xx-c-vlan-$i-$j vlan.id $j ifname xx-i-vlan-$i-$j vlan.parent xx-i-bond-$i ipv4.method disabled ipv6.method ignore done done systemctl restart NetworkManager.service sleep 5 } do_test() { perf stat -r 50 -B nmcli 1>/dev/null } do_test ``` [1] Performance counter stats for 'nmcli' (50 runs): 456.33 msec task-clock:u # 1.093 CPUs utilized ( +- 0.44% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,900 page-faults:u # 0.013 M/sec ( +- 0.02% ) 1,408,675,453 cycles:u # 3.087 GHz ( +- 0.48% ) 1,594,741,060 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 368,744,018 branches:u # 808.061 M/sec ( +- 0.02% ) 4,566,058 branch-misses:u # 1.24% of all branches ( +- 0.76% ) 0.41761 +- 0.00282 seconds time elapsed ( +- 0.68% ) [2] Performance counter stats for 'nmcli' (50 runs): 477.99 msec task-clock:u # 1.088 CPUs utilized ( +- 0.36% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,948 page-faults:u # 0.012 M/sec ( +- 0.03% ) 1,471,133,482 cycles:u # 3.078 GHz ( +- 0.36% ) 1,655,275,369 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 382,595,152 branches:u # 800.433 M/sec ( +- 0.02% ) 4,746,070 branch-misses:u # 1.24% of all branches ( +- 0.49% ) 0.43923 +- 0.00242 seconds time elapsed ( +- 0.55% ) [3] Performance counter stats for 'nmcli' (50 runs): 352.36 msec task-clock:u # 1.027 CPUs utilized ( +- 0.32% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 4,790 page-faults:u # 0.014 M/sec ( +- 0.26% ) 1,092,341,186 cycles:u # 3.100 GHz ( +- 0.26% ) 1,209,045,283 instructions:u # 1.11 insn per cycle ( +- 0.02% ) 281,708,462 branches:u # 799.499 M/sec ( +- 0.01% ) 3,101,031 branch-misses:u # 1.10% of all branches ( +- 0.61% ) 0.34296 +- 0.00120 seconds time elapsed ( +- 0.35% ) --- N5) same setup as N4), but run `PAGER= /bin/time -v nmcli`: [1] Command being timed: "nmcli" User time (seconds): 0.42 System time (seconds): 0.04 Percent of CPU this job got: 107% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.43 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34456 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6128 Voluntary context switches: 1298 Involuntary context switches: 1106 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [2] Command being timed: "nmcli" User time (seconds): 0.44 System time (seconds): 0.04 Percent of CPU this job got: 108% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.44 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34452 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6169 Voluntary context switches: 1849 Involuntary context switches: 142 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [3] Command being timed: "nmcli" User time (seconds): 0.32 System time (seconds): 0.02 Percent of CPU this job got: 102% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.34 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 29196 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 5059 Voluntary context switches: 919 Involuntary context switches: 685 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 --- N6) same setup as N4), but run `nmcli monitor` and look at `ps aux` for the RSS size. USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND [1] me 1492900 21.0 0.2 461348 33248 pts/10 Sl+ 15:02 0:00 nmcli monitor [2] me 1490721 5.0 0.2 461496 33548 pts/10 Sl+ 15:00 0:00 nmcli monitor [3] me 1495801 16.5 0.1 459476 28692 pts/10 Sl+ 15:04 0:00 nmcli monitor
2019-10-30 11:42:58 +01:00
static NMLDBusNotifyUpdatePropFlags
_notify_update_prop_lldp_neighbors (NMClient *client,
NMLDBusObject *dbobj,
const NMLDBusMetaIface *meta_iface,
guint dbus_property_idx,
GVariant *value)
{
libnm: refactor caching of D-Bus objects in NMClient No longer use GDBusObjectMangaerClient and gdbus-codegen generated classes for the NMClient cache. Instead, use GDBusConnection directly and a custom implementation (NMLDBusObject) for caching D-Bus' ObjectManager data. CHANGES ------- - This is a complete rework. I think the previous implementation was difficult to understand. There were unfixed bugs and nobody understood the code well enough to fix them. Maybe somebody out there understood the code, but I certainly did not. At least nobody provided patches to fix those issues. I do believe that this implementation is more straightforward and easier to understand. It removes a lot of layers of code. Whether this claim of simplicity is true, each reader must decide for himself/herself. Note that it is still fairly complex. - There was a lingering performance issue with large number of D-Bus objects. The patch tries hard that the implementation scales well. Of course, when we cache N objects that have N-to-M references to other, we still are fundamentally O(N*M) for runtime and memory consumption (with M being the number of references between objects). But each part should behave efficiently and well. - Play well with GMainContext. libnm code (NMClient) is generally not thread safe. However, it should work to use multiple instances in parallel, as long as each access to a NMClient is through the caller's GMainContext. This follows glib's style and effectively allows to use NMClient in a multi threaded scenario. This implies to stick to a main context upon construction and ensure that callbacks are only invoked when iterating that context. Also, NMClient itself shall never iterate the caller's context. This also means, libnm must never use g_idle_add() or g_timeout_add(), as those enqueue sources in the g_main_context_default() context. - Get ordering of messages right. All events are consistently enqueued in a GMainContext and processed strictly in order. For example, previously "nm-object.c" tried to combine signals and emit them on an idle handler. That is wrong, signals must be emitted in the right order and when they happen. Note that when using GInitable's synchronous initialization to initialize the NMClient instance, NMClient internally still operates fully asynchronously. In that case NMClient has an internal main context. - NMClient takes over most of the functionality. When using D-Bus' ObjectManager interface, one needs to handle basically the entire state of the D-Bus interface. That cannot be separated well into distinct parts, and even if you try, you just end up having closely related code in different source files. Spreading related code does not make it easier to understand, on the contrary. That means, NMClient is inherently complex as it contains most of the logic. I think that is not avoidable, but it's not as bad as it sounds. - NMClient processes D-Bus messages and state changes in separate steps. First NMClient unpacks the message (e.g. _dbus_handle_properties_changed()) and keeps track of the changed data. Then we update the GObject instances (_dbus_handle_obj_changed_dbus()) without emitting any signals yet. Finally, we emit all signals and notifications that were collected (_dbus_handle_changes_commit()). Note that for example during the initial GetManagedObjects() reply, NMClient receive a large amount of state at once. But we first apply all the changes to our GObject instances before emitting any signals. The result is that signals are always emitted in a moment when the cache is consistent. The unavoidable downside is that when you receive a property changed signal, possibly many other properties changed already and more signals are about to be emitted. - NMDeviceWifi no longer modifies the content of the cache from client side during poke_wireless_devices_with_rf_status(). The content of the cache should be determined by D-Bus alone and follow what NetworkManager service exposes. Local modifications should be avoided. - This aims to bring no API/ABI change, though it does of course bring various subtle changes in behavior. Those should be all for the better, but the goal is not to break any existing clients. This does change internal (albeit externally visible) API, like dropping NM_OBJECT_DBUS_OBJECT_MANAGER property and NMObject no longer implementing GInitableIface and GAsyncInitableIface. - Some uses of gdbus-codegen classes remain in NMVpnPluginOld, NMVpnServicePlugin and NMSecretAgentOld. These are independent of NMClient/NMObject and should be reworked separately. - While we no longer use generated classes from gdbus-codegen, we don't need more glue code than before. Also before we constructed NMPropertiesInfo and a had large amount of code to propagate properties from NMDBus* to NMObject. That got completely reworked, but did not fundamentally change. You still need about the same effort to create the NMLDBusMetaIface. Not using generated bindings did not make anything worse (which tells about the usefulness of generated code, at least in the way it was used). - NMLDBusMetaIface and other meta data is static and immutable. This avoids copying them around. Also, macros like NML_DBUS_META_PROPERTY_INIT_U() have compile time checks to ensure the property types matches. It's pretty hard to misuse them because it won't compile. - The meta data now explicitly encodes the expected D-Bus types and makes sure never to accept wrong data. That would only matter when the server (accidentally or intentionally) exposes unexpected types on D-Bus. I don't think that was previously ensured in all cases. For example, demarshal_generic() only cared about the GObject property type, it didn't know the expected D-Bus type. - Previously GDBusObjectManager would sometimes emit warnings (g_log()). Those probably indicated real bugs. In any case, it prevented us from running CI with G_DEBUG=fatal-warnings, because there would be just too many unrelated crashes. Now we log debug messages that can be enabled with "LIBNM_CLIENT_DEBUG=trace". Some of these messages can also be turned into g_warning()/g_critical() by setting LIBNM_CLIENT_DEBUG=warning,error. Together with G_DEBUG=fatal-warnings, this turns them into assertions. Note that such "assertion failures" might also happen because of a server bug (or change). Thus these are not common assertions that indicate a bug in libnm and are thus not armed unless explicitly requested. In our CI we should now always run with LIBNM_CLIENT_DEBUG=warning,error and G_DEBUG=fatal-warnings and to catch bugs. Note that currently NetworkManager has bugs in this regard, so enabling this will result in assertion failures. That should be fixed first. - Note that this changes the order in which we emit "notify:devices" and "device-added" signals. I think it makes the most sense to emit first "device-removed", then "notify:devices", and finally "device-added" signals. This changes behavior for commit 52ae28f6e5bf ('libnm: queue added/removed signals and suppress uninitialized notifications'), but I don't think that users should actually rely on the order. Still, the new order makes the most sense to me. - In NetworkManager, profiles can be invisible to the user by setting "connection.permissions". Such profiles would be hidden by NMClient's nm_client_get_connections() and their "connection-added"/"connection-removed" signals. Note that NMActiveConnection's nm_active_connection_get_connection() and NMDevice's nm_device_get_available_connections() still exposes such hidden NMRemoteConnection instances. This behavior was preserved. NUMBERS ------- I compared 3 versions of libnm. [1] 962297f9085d, current tip of nm-1-20 branch [2] 4fad8c7c642e, current master, immediate parent of this patch [3] this patch All tests were done on Fedora 31, x86_64, gcc 9.2.1-1.fc31. The libraries were build with $ ./contrib/fedora/rpm/build_clean.sh -g -w test -W debug Note that RPM build already stripped the library. --- N1) File size of libnm.so.0.1.0 in bytes. There currently seems to be a issue on Fedora 31 generating wrong ELF notes. Usually, libnm is smaller but in these tests it had large (and bogus) ELF notes. Anyway, the point is to show the relative sizes, so it doesn't matter). [1] 4075552 (102.7%) [2] 3969624 (100.0%) [3] 3705208 ( 93.3%) --- N2) `size /usr/lib64/libnm.so.0.1.0`: text data bss dec hex filename [1] 1314569 (102.0%) 69980 ( 94.8%) 10632 ( 80.4%) 1395181 (101.4%) 1549ed /usr/lib64/libnm.so.0.1.0 [2] 1288410 (100.0%) 73796 (100.0%) 13224 (100.0%) 1375430 (100.0%) 14fcc6 /usr/lib64/libnm.so.0.1.0 [3] 1229066 ( 95.4%) 65248 ( 88.4%) 13400 (101.3%) 1307714 ( 95.1%) 13f442 /usr/lib64/libnm.so.0.1.0 --- N3) Performance test with test-client.py. With checkout of [2], run ``` prepare_checkout() { rm -rf /tmp/nm-test && \ git checkout -B test 4fad8c7c642e && \ git clean -fdx && \ ./autogen.sh --prefix=/tmp/nm-test && \ make -j 5 install && \ make -j 5 check-local-clients-tests-test-client } prepare_test() { NM_TEST_REGENERATE=1 NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v } do_test() { for i in {1..10}; do NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v || return -1 done echo "done!" } prepare_checkout prepare_test time do_test ``` [1] real 2m14.497s (101.3%) user 5m26.651s (100.3%) sys 1m40.453s (101.4%) [2] real 2m12.800s (100.0%) user 5m25.619s (100.0%) sys 1m39.065s (100.0%) [3] real 1m54.915s ( 86.5%) user 4m18.585s ( 79.4%) sys 1m32.066s ( 92.9%) --- N4) Performance. Run NetworkManager from build [2] and setup a large number of profiles (551 profiles and 515 devices, mostly unrealized). This setup is already at the edge of what NetworkManager currently can handle. Of course, that is a different issue. Here we just check how long plain `nmcli` takes on the system. ``` do_cleanup() { for UUID in $(nmcli -g NAME,UUID connection show | sed -n 's/^xx-c-.*:\([^:]\+\)$/\1/p'); do nmcli connection delete uuid "$UUID" done for DEVICE in $(nmcli -g DEVICE device status | grep '^xx-i-'); do nmcli device delete "$DEVICE" done } do_setup() { do_cleanup for i in {1..30}; do nmcli connection add type bond autoconnect no con-name xx-c-bond-$i ifname xx-i-bond-$i ipv4.method disabled ipv6.method ignore for j in $(seq $i 30); do nmcli connection add type vlan autoconnect no con-name xx-c-vlan-$i-$j vlan.id $j ifname xx-i-vlan-$i-$j vlan.parent xx-i-bond-$i ipv4.method disabled ipv6.method ignore done done systemctl restart NetworkManager.service sleep 5 } do_test() { perf stat -r 50 -B nmcli 1>/dev/null } do_test ``` [1] Performance counter stats for 'nmcli' (50 runs): 456.33 msec task-clock:u # 1.093 CPUs utilized ( +- 0.44% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,900 page-faults:u # 0.013 M/sec ( +- 0.02% ) 1,408,675,453 cycles:u # 3.087 GHz ( +- 0.48% ) 1,594,741,060 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 368,744,018 branches:u # 808.061 M/sec ( +- 0.02% ) 4,566,058 branch-misses:u # 1.24% of all branches ( +- 0.76% ) 0.41761 +- 0.00282 seconds time elapsed ( +- 0.68% ) [2] Performance counter stats for 'nmcli' (50 runs): 477.99 msec task-clock:u # 1.088 CPUs utilized ( +- 0.36% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,948 page-faults:u # 0.012 M/sec ( +- 0.03% ) 1,471,133,482 cycles:u # 3.078 GHz ( +- 0.36% ) 1,655,275,369 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 382,595,152 branches:u # 800.433 M/sec ( +- 0.02% ) 4,746,070 branch-misses:u # 1.24% of all branches ( +- 0.49% ) 0.43923 +- 0.00242 seconds time elapsed ( +- 0.55% ) [3] Performance counter stats for 'nmcli' (50 runs): 352.36 msec task-clock:u # 1.027 CPUs utilized ( +- 0.32% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 4,790 page-faults:u # 0.014 M/sec ( +- 0.26% ) 1,092,341,186 cycles:u # 3.100 GHz ( +- 0.26% ) 1,209,045,283 instructions:u # 1.11 insn per cycle ( +- 0.02% ) 281,708,462 branches:u # 799.499 M/sec ( +- 0.01% ) 3,101,031 branch-misses:u # 1.10% of all branches ( +- 0.61% ) 0.34296 +- 0.00120 seconds time elapsed ( +- 0.35% ) --- N5) same setup as N4), but run `PAGER= /bin/time -v nmcli`: [1] Command being timed: "nmcli" User time (seconds): 0.42 System time (seconds): 0.04 Percent of CPU this job got: 107% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.43 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34456 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6128 Voluntary context switches: 1298 Involuntary context switches: 1106 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [2] Command being timed: "nmcli" User time (seconds): 0.44 System time (seconds): 0.04 Percent of CPU this job got: 108% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.44 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34452 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6169 Voluntary context switches: 1849 Involuntary context switches: 142 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [3] Command being timed: "nmcli" User time (seconds): 0.32 System time (seconds): 0.02 Percent of CPU this job got: 102% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.34 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 29196 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 5059 Voluntary context switches: 919 Involuntary context switches: 685 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 --- N6) same setup as N4), but run `nmcli monitor` and look at `ps aux` for the RSS size. USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND [1] me 1492900 21.0 0.2 461348 33248 pts/10 Sl+ 15:02 0:00 nmcli monitor [2] me 1490721 5.0 0.2 461496 33548 pts/10 Sl+ 15:00 0:00 nmcli monitor [3] me 1495801 16.5 0.1 459476 28692 pts/10 Sl+ 15:04 0:00 nmcli monitor
2019-10-30 11:42:58 +01:00
NMDevice *self = NM_DEVICE (dbobj->nmobj);
NMDevicePrivate *priv = NM_DEVICE_GET_PRIVATE (self);
libnm: refactor caching of D-Bus objects in NMClient No longer use GDBusObjectMangaerClient and gdbus-codegen generated classes for the NMClient cache. Instead, use GDBusConnection directly and a custom implementation (NMLDBusObject) for caching D-Bus' ObjectManager data. CHANGES ------- - This is a complete rework. I think the previous implementation was difficult to understand. There were unfixed bugs and nobody understood the code well enough to fix them. Maybe somebody out there understood the code, but I certainly did not. At least nobody provided patches to fix those issues. I do believe that this implementation is more straightforward and easier to understand. It removes a lot of layers of code. Whether this claim of simplicity is true, each reader must decide for himself/herself. Note that it is still fairly complex. - There was a lingering performance issue with large number of D-Bus objects. The patch tries hard that the implementation scales well. Of course, when we cache N objects that have N-to-M references to other, we still are fundamentally O(N*M) for runtime and memory consumption (with M being the number of references between objects). But each part should behave efficiently and well. - Play well with GMainContext. libnm code (NMClient) is generally not thread safe. However, it should work to use multiple instances in parallel, as long as each access to a NMClient is through the caller's GMainContext. This follows glib's style and effectively allows to use NMClient in a multi threaded scenario. This implies to stick to a main context upon construction and ensure that callbacks are only invoked when iterating that context. Also, NMClient itself shall never iterate the caller's context. This also means, libnm must never use g_idle_add() or g_timeout_add(), as those enqueue sources in the g_main_context_default() context. - Get ordering of messages right. All events are consistently enqueued in a GMainContext and processed strictly in order. For example, previously "nm-object.c" tried to combine signals and emit them on an idle handler. That is wrong, signals must be emitted in the right order and when they happen. Note that when using GInitable's synchronous initialization to initialize the NMClient instance, NMClient internally still operates fully asynchronously. In that case NMClient has an internal main context. - NMClient takes over most of the functionality. When using D-Bus' ObjectManager interface, one needs to handle basically the entire state of the D-Bus interface. That cannot be separated well into distinct parts, and even if you try, you just end up having closely related code in different source files. Spreading related code does not make it easier to understand, on the contrary. That means, NMClient is inherently complex as it contains most of the logic. I think that is not avoidable, but it's not as bad as it sounds. - NMClient processes D-Bus messages and state changes in separate steps. First NMClient unpacks the message (e.g. _dbus_handle_properties_changed()) and keeps track of the changed data. Then we update the GObject instances (_dbus_handle_obj_changed_dbus()) without emitting any signals yet. Finally, we emit all signals and notifications that were collected (_dbus_handle_changes_commit()). Note that for example during the initial GetManagedObjects() reply, NMClient receive a large amount of state at once. But we first apply all the changes to our GObject instances before emitting any signals. The result is that signals are always emitted in a moment when the cache is consistent. The unavoidable downside is that when you receive a property changed signal, possibly many other properties changed already and more signals are about to be emitted. - NMDeviceWifi no longer modifies the content of the cache from client side during poke_wireless_devices_with_rf_status(). The content of the cache should be determined by D-Bus alone and follow what NetworkManager service exposes. Local modifications should be avoided. - This aims to bring no API/ABI change, though it does of course bring various subtle changes in behavior. Those should be all for the better, but the goal is not to break any existing clients. This does change internal (albeit externally visible) API, like dropping NM_OBJECT_DBUS_OBJECT_MANAGER property and NMObject no longer implementing GInitableIface and GAsyncInitableIface. - Some uses of gdbus-codegen classes remain in NMVpnPluginOld, NMVpnServicePlugin and NMSecretAgentOld. These are independent of NMClient/NMObject and should be reworked separately. - While we no longer use generated classes from gdbus-codegen, we don't need more glue code than before. Also before we constructed NMPropertiesInfo and a had large amount of code to propagate properties from NMDBus* to NMObject. That got completely reworked, but did not fundamentally change. You still need about the same effort to create the NMLDBusMetaIface. Not using generated bindings did not make anything worse (which tells about the usefulness of generated code, at least in the way it was used). - NMLDBusMetaIface and other meta data is static and immutable. This avoids copying them around. Also, macros like NML_DBUS_META_PROPERTY_INIT_U() have compile time checks to ensure the property types matches. It's pretty hard to misuse them because it won't compile. - The meta data now explicitly encodes the expected D-Bus types and makes sure never to accept wrong data. That would only matter when the server (accidentally or intentionally) exposes unexpected types on D-Bus. I don't think that was previously ensured in all cases. For example, demarshal_generic() only cared about the GObject property type, it didn't know the expected D-Bus type. - Previously GDBusObjectManager would sometimes emit warnings (g_log()). Those probably indicated real bugs. In any case, it prevented us from running CI with G_DEBUG=fatal-warnings, because there would be just too many unrelated crashes. Now we log debug messages that can be enabled with "LIBNM_CLIENT_DEBUG=trace". Some of these messages can also be turned into g_warning()/g_critical() by setting LIBNM_CLIENT_DEBUG=warning,error. Together with G_DEBUG=fatal-warnings, this turns them into assertions. Note that such "assertion failures" might also happen because of a server bug (or change). Thus these are not common assertions that indicate a bug in libnm and are thus not armed unless explicitly requested. In our CI we should now always run with LIBNM_CLIENT_DEBUG=warning,error and G_DEBUG=fatal-warnings and to catch bugs. Note that currently NetworkManager has bugs in this regard, so enabling this will result in assertion failures. That should be fixed first. - Note that this changes the order in which we emit "notify:devices" and "device-added" signals. I think it makes the most sense to emit first "device-removed", then "notify:devices", and finally "device-added" signals. This changes behavior for commit 52ae28f6e5bf ('libnm: queue added/removed signals and suppress uninitialized notifications'), but I don't think that users should actually rely on the order. Still, the new order makes the most sense to me. - In NetworkManager, profiles can be invisible to the user by setting "connection.permissions". Such profiles would be hidden by NMClient's nm_client_get_connections() and their "connection-added"/"connection-removed" signals. Note that NMActiveConnection's nm_active_connection_get_connection() and NMDevice's nm_device_get_available_connections() still exposes such hidden NMRemoteConnection instances. This behavior was preserved. NUMBERS ------- I compared 3 versions of libnm. [1] 962297f9085d, current tip of nm-1-20 branch [2] 4fad8c7c642e, current master, immediate parent of this patch [3] this patch All tests were done on Fedora 31, x86_64, gcc 9.2.1-1.fc31. The libraries were build with $ ./contrib/fedora/rpm/build_clean.sh -g -w test -W debug Note that RPM build already stripped the library. --- N1) File size of libnm.so.0.1.0 in bytes. There currently seems to be a issue on Fedora 31 generating wrong ELF notes. Usually, libnm is smaller but in these tests it had large (and bogus) ELF notes. Anyway, the point is to show the relative sizes, so it doesn't matter). [1] 4075552 (102.7%) [2] 3969624 (100.0%) [3] 3705208 ( 93.3%) --- N2) `size /usr/lib64/libnm.so.0.1.0`: text data bss dec hex filename [1] 1314569 (102.0%) 69980 ( 94.8%) 10632 ( 80.4%) 1395181 (101.4%) 1549ed /usr/lib64/libnm.so.0.1.0 [2] 1288410 (100.0%) 73796 (100.0%) 13224 (100.0%) 1375430 (100.0%) 14fcc6 /usr/lib64/libnm.so.0.1.0 [3] 1229066 ( 95.4%) 65248 ( 88.4%) 13400 (101.3%) 1307714 ( 95.1%) 13f442 /usr/lib64/libnm.so.0.1.0 --- N3) Performance test with test-client.py. With checkout of [2], run ``` prepare_checkout() { rm -rf /tmp/nm-test && \ git checkout -B test 4fad8c7c642e && \ git clean -fdx && \ ./autogen.sh --prefix=/tmp/nm-test && \ make -j 5 install && \ make -j 5 check-local-clients-tests-test-client } prepare_test() { NM_TEST_REGENERATE=1 NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v } do_test() { for i in {1..10}; do NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v || return -1 done echo "done!" } prepare_checkout prepare_test time do_test ``` [1] real 2m14.497s (101.3%) user 5m26.651s (100.3%) sys 1m40.453s (101.4%) [2] real 2m12.800s (100.0%) user 5m25.619s (100.0%) sys 1m39.065s (100.0%) [3] real 1m54.915s ( 86.5%) user 4m18.585s ( 79.4%) sys 1m32.066s ( 92.9%) --- N4) Performance. Run NetworkManager from build [2] and setup a large number of profiles (551 profiles and 515 devices, mostly unrealized). This setup is already at the edge of what NetworkManager currently can handle. Of course, that is a different issue. Here we just check how long plain `nmcli` takes on the system. ``` do_cleanup() { for UUID in $(nmcli -g NAME,UUID connection show | sed -n 's/^xx-c-.*:\([^:]\+\)$/\1/p'); do nmcli connection delete uuid "$UUID" done for DEVICE in $(nmcli -g DEVICE device status | grep '^xx-i-'); do nmcli device delete "$DEVICE" done } do_setup() { do_cleanup for i in {1..30}; do nmcli connection add type bond autoconnect no con-name xx-c-bond-$i ifname xx-i-bond-$i ipv4.method disabled ipv6.method ignore for j in $(seq $i 30); do nmcli connection add type vlan autoconnect no con-name xx-c-vlan-$i-$j vlan.id $j ifname xx-i-vlan-$i-$j vlan.parent xx-i-bond-$i ipv4.method disabled ipv6.method ignore done done systemctl restart NetworkManager.service sleep 5 } do_test() { perf stat -r 50 -B nmcli 1>/dev/null } do_test ``` [1] Performance counter stats for 'nmcli' (50 runs): 456.33 msec task-clock:u # 1.093 CPUs utilized ( +- 0.44% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,900 page-faults:u # 0.013 M/sec ( +- 0.02% ) 1,408,675,453 cycles:u # 3.087 GHz ( +- 0.48% ) 1,594,741,060 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 368,744,018 branches:u # 808.061 M/sec ( +- 0.02% ) 4,566,058 branch-misses:u # 1.24% of all branches ( +- 0.76% ) 0.41761 +- 0.00282 seconds time elapsed ( +- 0.68% ) [2] Performance counter stats for 'nmcli' (50 runs): 477.99 msec task-clock:u # 1.088 CPUs utilized ( +- 0.36% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,948 page-faults:u # 0.012 M/sec ( +- 0.03% ) 1,471,133,482 cycles:u # 3.078 GHz ( +- 0.36% ) 1,655,275,369 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 382,595,152 branches:u # 800.433 M/sec ( +- 0.02% ) 4,746,070 branch-misses:u # 1.24% of all branches ( +- 0.49% ) 0.43923 +- 0.00242 seconds time elapsed ( +- 0.55% ) [3] Performance counter stats for 'nmcli' (50 runs): 352.36 msec task-clock:u # 1.027 CPUs utilized ( +- 0.32% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 4,790 page-faults:u # 0.014 M/sec ( +- 0.26% ) 1,092,341,186 cycles:u # 3.100 GHz ( +- 0.26% ) 1,209,045,283 instructions:u # 1.11 insn per cycle ( +- 0.02% ) 281,708,462 branches:u # 799.499 M/sec ( +- 0.01% ) 3,101,031 branch-misses:u # 1.10% of all branches ( +- 0.61% ) 0.34296 +- 0.00120 seconds time elapsed ( +- 0.35% ) --- N5) same setup as N4), but run `PAGER= /bin/time -v nmcli`: [1] Command being timed: "nmcli" User time (seconds): 0.42 System time (seconds): 0.04 Percent of CPU this job got: 107% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.43 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34456 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6128 Voluntary context switches: 1298 Involuntary context switches: 1106 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [2] Command being timed: "nmcli" User time (seconds): 0.44 System time (seconds): 0.04 Percent of CPU this job got: 108% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.44 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34452 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6169 Voluntary context switches: 1849 Involuntary context switches: 142 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [3] Command being timed: "nmcli" User time (seconds): 0.32 System time (seconds): 0.02 Percent of CPU this job got: 102% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.34 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 29196 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 5059 Voluntary context switches: 919 Involuntary context switches: 685 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 --- N6) same setup as N4), but run `nmcli monitor` and look at `ps aux` for the RSS size. USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND [1] me 1492900 21.0 0.2 461348 33248 pts/10 Sl+ 15:02 0:00 nmcli monitor [2] me 1490721 5.0 0.2 461496 33548 pts/10 Sl+ 15:00 0:00 nmcli monitor [3] me 1495801 16.5 0.1 459476 28692 pts/10 Sl+ 15:04 0:00 nmcli monitor
2019-10-30 11:42:58 +01:00
gs_unref_ptrarray GPtrArray *old = NULL;
gs_unref_ptrarray GPtrArray *new = NULL;
GVariantIter *attrs_iter;
GVariantIter iter;
new = g_ptr_array_new_with_free_func ((GDestroyNotify) nm_lldp_neighbor_unref);
if (value) {
g_variant_iter_init (&iter, value);
while (g_variant_iter_next (&iter, "a{sv}", &attrs_iter)) {
GVariant *attr_variant;
const char *attr_name;
NMLldpNeighbor *neigh;
neigh = nm_lldp_neighbor_new ();
while (g_variant_iter_next (attrs_iter, "{&sv}", &attr_name, &attr_variant))
g_hash_table_insert (neigh->attrs, g_strdup (attr_name), attr_variant);
g_ptr_array_add (new, neigh);
g_variant_iter_free (attrs_iter);
}
}
libnm: refactor caching of D-Bus objects in NMClient No longer use GDBusObjectMangaerClient and gdbus-codegen generated classes for the NMClient cache. Instead, use GDBusConnection directly and a custom implementation (NMLDBusObject) for caching D-Bus' ObjectManager data. CHANGES ------- - This is a complete rework. I think the previous implementation was difficult to understand. There were unfixed bugs and nobody understood the code well enough to fix them. Maybe somebody out there understood the code, but I certainly did not. At least nobody provided patches to fix those issues. I do believe that this implementation is more straightforward and easier to understand. It removes a lot of layers of code. Whether this claim of simplicity is true, each reader must decide for himself/herself. Note that it is still fairly complex. - There was a lingering performance issue with large number of D-Bus objects. The patch tries hard that the implementation scales well. Of course, when we cache N objects that have N-to-M references to other, we still are fundamentally O(N*M) for runtime and memory consumption (with M being the number of references between objects). But each part should behave efficiently and well. - Play well with GMainContext. libnm code (NMClient) is generally not thread safe. However, it should work to use multiple instances in parallel, as long as each access to a NMClient is through the caller's GMainContext. This follows glib's style and effectively allows to use NMClient in a multi threaded scenario. This implies to stick to a main context upon construction and ensure that callbacks are only invoked when iterating that context. Also, NMClient itself shall never iterate the caller's context. This also means, libnm must never use g_idle_add() or g_timeout_add(), as those enqueue sources in the g_main_context_default() context. - Get ordering of messages right. All events are consistently enqueued in a GMainContext and processed strictly in order. For example, previously "nm-object.c" tried to combine signals and emit them on an idle handler. That is wrong, signals must be emitted in the right order and when they happen. Note that when using GInitable's synchronous initialization to initialize the NMClient instance, NMClient internally still operates fully asynchronously. In that case NMClient has an internal main context. - NMClient takes over most of the functionality. When using D-Bus' ObjectManager interface, one needs to handle basically the entire state of the D-Bus interface. That cannot be separated well into distinct parts, and even if you try, you just end up having closely related code in different source files. Spreading related code does not make it easier to understand, on the contrary. That means, NMClient is inherently complex as it contains most of the logic. I think that is not avoidable, but it's not as bad as it sounds. - NMClient processes D-Bus messages and state changes in separate steps. First NMClient unpacks the message (e.g. _dbus_handle_properties_changed()) and keeps track of the changed data. Then we update the GObject instances (_dbus_handle_obj_changed_dbus()) without emitting any signals yet. Finally, we emit all signals and notifications that were collected (_dbus_handle_changes_commit()). Note that for example during the initial GetManagedObjects() reply, NMClient receive a large amount of state at once. But we first apply all the changes to our GObject instances before emitting any signals. The result is that signals are always emitted in a moment when the cache is consistent. The unavoidable downside is that when you receive a property changed signal, possibly many other properties changed already and more signals are about to be emitted. - NMDeviceWifi no longer modifies the content of the cache from client side during poke_wireless_devices_with_rf_status(). The content of the cache should be determined by D-Bus alone and follow what NetworkManager service exposes. Local modifications should be avoided. - This aims to bring no API/ABI change, though it does of course bring various subtle changes in behavior. Those should be all for the better, but the goal is not to break any existing clients. This does change internal (albeit externally visible) API, like dropping NM_OBJECT_DBUS_OBJECT_MANAGER property and NMObject no longer implementing GInitableIface and GAsyncInitableIface. - Some uses of gdbus-codegen classes remain in NMVpnPluginOld, NMVpnServicePlugin and NMSecretAgentOld. These are independent of NMClient/NMObject and should be reworked separately. - While we no longer use generated classes from gdbus-codegen, we don't need more glue code than before. Also before we constructed NMPropertiesInfo and a had large amount of code to propagate properties from NMDBus* to NMObject. That got completely reworked, but did not fundamentally change. You still need about the same effort to create the NMLDBusMetaIface. Not using generated bindings did not make anything worse (which tells about the usefulness of generated code, at least in the way it was used). - NMLDBusMetaIface and other meta data is static and immutable. This avoids copying them around. Also, macros like NML_DBUS_META_PROPERTY_INIT_U() have compile time checks to ensure the property types matches. It's pretty hard to misuse them because it won't compile. - The meta data now explicitly encodes the expected D-Bus types and makes sure never to accept wrong data. That would only matter when the server (accidentally or intentionally) exposes unexpected types on D-Bus. I don't think that was previously ensured in all cases. For example, demarshal_generic() only cared about the GObject property type, it didn't know the expected D-Bus type. - Previously GDBusObjectManager would sometimes emit warnings (g_log()). Those probably indicated real bugs. In any case, it prevented us from running CI with G_DEBUG=fatal-warnings, because there would be just too many unrelated crashes. Now we log debug messages that can be enabled with "LIBNM_CLIENT_DEBUG=trace". Some of these messages can also be turned into g_warning()/g_critical() by setting LIBNM_CLIENT_DEBUG=warning,error. Together with G_DEBUG=fatal-warnings, this turns them into assertions. Note that such "assertion failures" might also happen because of a server bug (or change). Thus these are not common assertions that indicate a bug in libnm and are thus not armed unless explicitly requested. In our CI we should now always run with LIBNM_CLIENT_DEBUG=warning,error and G_DEBUG=fatal-warnings and to catch bugs. Note that currently NetworkManager has bugs in this regard, so enabling this will result in assertion failures. That should be fixed first. - Note that this changes the order in which we emit "notify:devices" and "device-added" signals. I think it makes the most sense to emit first "device-removed", then "notify:devices", and finally "device-added" signals. This changes behavior for commit 52ae28f6e5bf ('libnm: queue added/removed signals and suppress uninitialized notifications'), but I don't think that users should actually rely on the order. Still, the new order makes the most sense to me. - In NetworkManager, profiles can be invisible to the user by setting "connection.permissions". Such profiles would be hidden by NMClient's nm_client_get_connections() and their "connection-added"/"connection-removed" signals. Note that NMActiveConnection's nm_active_connection_get_connection() and NMDevice's nm_device_get_available_connections() still exposes such hidden NMRemoteConnection instances. This behavior was preserved. NUMBERS ------- I compared 3 versions of libnm. [1] 962297f9085d, current tip of nm-1-20 branch [2] 4fad8c7c642e, current master, immediate parent of this patch [3] this patch All tests were done on Fedora 31, x86_64, gcc 9.2.1-1.fc31. The libraries were build with $ ./contrib/fedora/rpm/build_clean.sh -g -w test -W debug Note that RPM build already stripped the library. --- N1) File size of libnm.so.0.1.0 in bytes. There currently seems to be a issue on Fedora 31 generating wrong ELF notes. Usually, libnm is smaller but in these tests it had large (and bogus) ELF notes. Anyway, the point is to show the relative sizes, so it doesn't matter). [1] 4075552 (102.7%) [2] 3969624 (100.0%) [3] 3705208 ( 93.3%) --- N2) `size /usr/lib64/libnm.so.0.1.0`: text data bss dec hex filename [1] 1314569 (102.0%) 69980 ( 94.8%) 10632 ( 80.4%) 1395181 (101.4%) 1549ed /usr/lib64/libnm.so.0.1.0 [2] 1288410 (100.0%) 73796 (100.0%) 13224 (100.0%) 1375430 (100.0%) 14fcc6 /usr/lib64/libnm.so.0.1.0 [3] 1229066 ( 95.4%) 65248 ( 88.4%) 13400 (101.3%) 1307714 ( 95.1%) 13f442 /usr/lib64/libnm.so.0.1.0 --- N3) Performance test with test-client.py. With checkout of [2], run ``` prepare_checkout() { rm -rf /tmp/nm-test && \ git checkout -B test 4fad8c7c642e && \ git clean -fdx && \ ./autogen.sh --prefix=/tmp/nm-test && \ make -j 5 install && \ make -j 5 check-local-clients-tests-test-client } prepare_test() { NM_TEST_REGENERATE=1 NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v } do_test() { for i in {1..10}; do NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v || return -1 done echo "done!" } prepare_checkout prepare_test time do_test ``` [1] real 2m14.497s (101.3%) user 5m26.651s (100.3%) sys 1m40.453s (101.4%) [2] real 2m12.800s (100.0%) user 5m25.619s (100.0%) sys 1m39.065s (100.0%) [3] real 1m54.915s ( 86.5%) user 4m18.585s ( 79.4%) sys 1m32.066s ( 92.9%) --- N4) Performance. Run NetworkManager from build [2] and setup a large number of profiles (551 profiles and 515 devices, mostly unrealized). This setup is already at the edge of what NetworkManager currently can handle. Of course, that is a different issue. Here we just check how long plain `nmcli` takes on the system. ``` do_cleanup() { for UUID in $(nmcli -g NAME,UUID connection show | sed -n 's/^xx-c-.*:\([^:]\+\)$/\1/p'); do nmcli connection delete uuid "$UUID" done for DEVICE in $(nmcli -g DEVICE device status | grep '^xx-i-'); do nmcli device delete "$DEVICE" done } do_setup() { do_cleanup for i in {1..30}; do nmcli connection add type bond autoconnect no con-name xx-c-bond-$i ifname xx-i-bond-$i ipv4.method disabled ipv6.method ignore for j in $(seq $i 30); do nmcli connection add type vlan autoconnect no con-name xx-c-vlan-$i-$j vlan.id $j ifname xx-i-vlan-$i-$j vlan.parent xx-i-bond-$i ipv4.method disabled ipv6.method ignore done done systemctl restart NetworkManager.service sleep 5 } do_test() { perf stat -r 50 -B nmcli 1>/dev/null } do_test ``` [1] Performance counter stats for 'nmcli' (50 runs): 456.33 msec task-clock:u # 1.093 CPUs utilized ( +- 0.44% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,900 page-faults:u # 0.013 M/sec ( +- 0.02% ) 1,408,675,453 cycles:u # 3.087 GHz ( +- 0.48% ) 1,594,741,060 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 368,744,018 branches:u # 808.061 M/sec ( +- 0.02% ) 4,566,058 branch-misses:u # 1.24% of all branches ( +- 0.76% ) 0.41761 +- 0.00282 seconds time elapsed ( +- 0.68% ) [2] Performance counter stats for 'nmcli' (50 runs): 477.99 msec task-clock:u # 1.088 CPUs utilized ( +- 0.36% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,948 page-faults:u # 0.012 M/sec ( +- 0.03% ) 1,471,133,482 cycles:u # 3.078 GHz ( +- 0.36% ) 1,655,275,369 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 382,595,152 branches:u # 800.433 M/sec ( +- 0.02% ) 4,746,070 branch-misses:u # 1.24% of all branches ( +- 0.49% ) 0.43923 +- 0.00242 seconds time elapsed ( +- 0.55% ) [3] Performance counter stats for 'nmcli' (50 runs): 352.36 msec task-clock:u # 1.027 CPUs utilized ( +- 0.32% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 4,790 page-faults:u # 0.014 M/sec ( +- 0.26% ) 1,092,341,186 cycles:u # 3.100 GHz ( +- 0.26% ) 1,209,045,283 instructions:u # 1.11 insn per cycle ( +- 0.02% ) 281,708,462 branches:u # 799.499 M/sec ( +- 0.01% ) 3,101,031 branch-misses:u # 1.10% of all branches ( +- 0.61% ) 0.34296 +- 0.00120 seconds time elapsed ( +- 0.35% ) --- N5) same setup as N4), but run `PAGER= /bin/time -v nmcli`: [1] Command being timed: "nmcli" User time (seconds): 0.42 System time (seconds): 0.04 Percent of CPU this job got: 107% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.43 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34456 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6128 Voluntary context switches: 1298 Involuntary context switches: 1106 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [2] Command being timed: "nmcli" User time (seconds): 0.44 System time (seconds): 0.04 Percent of CPU this job got: 108% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.44 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34452 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6169 Voluntary context switches: 1849 Involuntary context switches: 142 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [3] Command being timed: "nmcli" User time (seconds): 0.32 System time (seconds): 0.02 Percent of CPU this job got: 102% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.34 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 29196 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 5059 Voluntary context switches: 919 Involuntary context switches: 685 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 --- N6) same setup as N4), but run `nmcli monitor` and look at `ps aux` for the RSS size. USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND [1] me 1492900 21.0 0.2 461348 33248 pts/10 Sl+ 15:02 0:00 nmcli monitor [2] me 1490721 5.0 0.2 461496 33548 pts/10 Sl+ 15:00 0:00 nmcli monitor [3] me 1495801 16.5 0.1 459476 28692 pts/10 Sl+ 15:04 0:00 nmcli monitor
2019-10-30 11:42:58 +01:00
old = g_steal_pointer (&priv->lldp_neighbors);
priv->lldp_neighbors = g_steal_pointer (&new);
return NML_DBUS_NOTIFY_UPDATE_PROP_FLAGS_NOTIFY;
}
libnm: refactor caching of D-Bus objects in NMClient No longer use GDBusObjectMangaerClient and gdbus-codegen generated classes for the NMClient cache. Instead, use GDBusConnection directly and a custom implementation (NMLDBusObject) for caching D-Bus' ObjectManager data. CHANGES ------- - This is a complete rework. I think the previous implementation was difficult to understand. There were unfixed bugs and nobody understood the code well enough to fix them. Maybe somebody out there understood the code, but I certainly did not. At least nobody provided patches to fix those issues. I do believe that this implementation is more straightforward and easier to understand. It removes a lot of layers of code. Whether this claim of simplicity is true, each reader must decide for himself/herself. Note that it is still fairly complex. - There was a lingering performance issue with large number of D-Bus objects. The patch tries hard that the implementation scales well. Of course, when we cache N objects that have N-to-M references to other, we still are fundamentally O(N*M) for runtime and memory consumption (with M being the number of references between objects). But each part should behave efficiently and well. - Play well with GMainContext. libnm code (NMClient) is generally not thread safe. However, it should work to use multiple instances in parallel, as long as each access to a NMClient is through the caller's GMainContext. This follows glib's style and effectively allows to use NMClient in a multi threaded scenario. This implies to stick to a main context upon construction and ensure that callbacks are only invoked when iterating that context. Also, NMClient itself shall never iterate the caller's context. This also means, libnm must never use g_idle_add() or g_timeout_add(), as those enqueue sources in the g_main_context_default() context. - Get ordering of messages right. All events are consistently enqueued in a GMainContext and processed strictly in order. For example, previously "nm-object.c" tried to combine signals and emit them on an idle handler. That is wrong, signals must be emitted in the right order and when they happen. Note that when using GInitable's synchronous initialization to initialize the NMClient instance, NMClient internally still operates fully asynchronously. In that case NMClient has an internal main context. - NMClient takes over most of the functionality. When using D-Bus' ObjectManager interface, one needs to handle basically the entire state of the D-Bus interface. That cannot be separated well into distinct parts, and even if you try, you just end up having closely related code in different source files. Spreading related code does not make it easier to understand, on the contrary. That means, NMClient is inherently complex as it contains most of the logic. I think that is not avoidable, but it's not as bad as it sounds. - NMClient processes D-Bus messages and state changes in separate steps. First NMClient unpacks the message (e.g. _dbus_handle_properties_changed()) and keeps track of the changed data. Then we update the GObject instances (_dbus_handle_obj_changed_dbus()) without emitting any signals yet. Finally, we emit all signals and notifications that were collected (_dbus_handle_changes_commit()). Note that for example during the initial GetManagedObjects() reply, NMClient receive a large amount of state at once. But we first apply all the changes to our GObject instances before emitting any signals. The result is that signals are always emitted in a moment when the cache is consistent. The unavoidable downside is that when you receive a property changed signal, possibly many other properties changed already and more signals are about to be emitted. - NMDeviceWifi no longer modifies the content of the cache from client side during poke_wireless_devices_with_rf_status(). The content of the cache should be determined by D-Bus alone and follow what NetworkManager service exposes. Local modifications should be avoided. - This aims to bring no API/ABI change, though it does of course bring various subtle changes in behavior. Those should be all for the better, but the goal is not to break any existing clients. This does change internal (albeit externally visible) API, like dropping NM_OBJECT_DBUS_OBJECT_MANAGER property and NMObject no longer implementing GInitableIface and GAsyncInitableIface. - Some uses of gdbus-codegen classes remain in NMVpnPluginOld, NMVpnServicePlugin and NMSecretAgentOld. These are independent of NMClient/NMObject and should be reworked separately. - While we no longer use generated classes from gdbus-codegen, we don't need more glue code than before. Also before we constructed NMPropertiesInfo and a had large amount of code to propagate properties from NMDBus* to NMObject. That got completely reworked, but did not fundamentally change. You still need about the same effort to create the NMLDBusMetaIface. Not using generated bindings did not make anything worse (which tells about the usefulness of generated code, at least in the way it was used). - NMLDBusMetaIface and other meta data is static and immutable. This avoids copying them around. Also, macros like NML_DBUS_META_PROPERTY_INIT_U() have compile time checks to ensure the property types matches. It's pretty hard to misuse them because it won't compile. - The meta data now explicitly encodes the expected D-Bus types and makes sure never to accept wrong data. That would only matter when the server (accidentally or intentionally) exposes unexpected types on D-Bus. I don't think that was previously ensured in all cases. For example, demarshal_generic() only cared about the GObject property type, it didn't know the expected D-Bus type. - Previously GDBusObjectManager would sometimes emit warnings (g_log()). Those probably indicated real bugs. In any case, it prevented us from running CI with G_DEBUG=fatal-warnings, because there would be just too many unrelated crashes. Now we log debug messages that can be enabled with "LIBNM_CLIENT_DEBUG=trace". Some of these messages can also be turned into g_warning()/g_critical() by setting LIBNM_CLIENT_DEBUG=warning,error. Together with G_DEBUG=fatal-warnings, this turns them into assertions. Note that such "assertion failures" might also happen because of a server bug (or change). Thus these are not common assertions that indicate a bug in libnm and are thus not armed unless explicitly requested. In our CI we should now always run with LIBNM_CLIENT_DEBUG=warning,error and G_DEBUG=fatal-warnings and to catch bugs. Note that currently NetworkManager has bugs in this regard, so enabling this will result in assertion failures. That should be fixed first. - Note that this changes the order in which we emit "notify:devices" and "device-added" signals. I think it makes the most sense to emit first "device-removed", then "notify:devices", and finally "device-added" signals. This changes behavior for commit 52ae28f6e5bf ('libnm: queue added/removed signals and suppress uninitialized notifications'), but I don't think that users should actually rely on the order. Still, the new order makes the most sense to me. - In NetworkManager, profiles can be invisible to the user by setting "connection.permissions". Such profiles would be hidden by NMClient's nm_client_get_connections() and their "connection-added"/"connection-removed" signals. Note that NMActiveConnection's nm_active_connection_get_connection() and NMDevice's nm_device_get_available_connections() still exposes such hidden NMRemoteConnection instances. This behavior was preserved. NUMBERS ------- I compared 3 versions of libnm. [1] 962297f9085d, current tip of nm-1-20 branch [2] 4fad8c7c642e, current master, immediate parent of this patch [3] this patch All tests were done on Fedora 31, x86_64, gcc 9.2.1-1.fc31. The libraries were build with $ ./contrib/fedora/rpm/build_clean.sh -g -w test -W debug Note that RPM build already stripped the library. --- N1) File size of libnm.so.0.1.0 in bytes. There currently seems to be a issue on Fedora 31 generating wrong ELF notes. Usually, libnm is smaller but in these tests it had large (and bogus) ELF notes. Anyway, the point is to show the relative sizes, so it doesn't matter). [1] 4075552 (102.7%) [2] 3969624 (100.0%) [3] 3705208 ( 93.3%) --- N2) `size /usr/lib64/libnm.so.0.1.0`: text data bss dec hex filename [1] 1314569 (102.0%) 69980 ( 94.8%) 10632 ( 80.4%) 1395181 (101.4%) 1549ed /usr/lib64/libnm.so.0.1.0 [2] 1288410 (100.0%) 73796 (100.0%) 13224 (100.0%) 1375430 (100.0%) 14fcc6 /usr/lib64/libnm.so.0.1.0 [3] 1229066 ( 95.4%) 65248 ( 88.4%) 13400 (101.3%) 1307714 ( 95.1%) 13f442 /usr/lib64/libnm.so.0.1.0 --- N3) Performance test with test-client.py. With checkout of [2], run ``` prepare_checkout() { rm -rf /tmp/nm-test && \ git checkout -B test 4fad8c7c642e && \ git clean -fdx && \ ./autogen.sh --prefix=/tmp/nm-test && \ make -j 5 install && \ make -j 5 check-local-clients-tests-test-client } prepare_test() { NM_TEST_REGENERATE=1 NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v } do_test() { for i in {1..10}; do NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v || return -1 done echo "done!" } prepare_checkout prepare_test time do_test ``` [1] real 2m14.497s (101.3%) user 5m26.651s (100.3%) sys 1m40.453s (101.4%) [2] real 2m12.800s (100.0%) user 5m25.619s (100.0%) sys 1m39.065s (100.0%) [3] real 1m54.915s ( 86.5%) user 4m18.585s ( 79.4%) sys 1m32.066s ( 92.9%) --- N4) Performance. Run NetworkManager from build [2] and setup a large number of profiles (551 profiles and 515 devices, mostly unrealized). This setup is already at the edge of what NetworkManager currently can handle. Of course, that is a different issue. Here we just check how long plain `nmcli` takes on the system. ``` do_cleanup() { for UUID in $(nmcli -g NAME,UUID connection show | sed -n 's/^xx-c-.*:\([^:]\+\)$/\1/p'); do nmcli connection delete uuid "$UUID" done for DEVICE in $(nmcli -g DEVICE device status | grep '^xx-i-'); do nmcli device delete "$DEVICE" done } do_setup() { do_cleanup for i in {1..30}; do nmcli connection add type bond autoconnect no con-name xx-c-bond-$i ifname xx-i-bond-$i ipv4.method disabled ipv6.method ignore for j in $(seq $i 30); do nmcli connection add type vlan autoconnect no con-name xx-c-vlan-$i-$j vlan.id $j ifname xx-i-vlan-$i-$j vlan.parent xx-i-bond-$i ipv4.method disabled ipv6.method ignore done done systemctl restart NetworkManager.service sleep 5 } do_test() { perf stat -r 50 -B nmcli 1>/dev/null } do_test ``` [1] Performance counter stats for 'nmcli' (50 runs): 456.33 msec task-clock:u # 1.093 CPUs utilized ( +- 0.44% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,900 page-faults:u # 0.013 M/sec ( +- 0.02% ) 1,408,675,453 cycles:u # 3.087 GHz ( +- 0.48% ) 1,594,741,060 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 368,744,018 branches:u # 808.061 M/sec ( +- 0.02% ) 4,566,058 branch-misses:u # 1.24% of all branches ( +- 0.76% ) 0.41761 +- 0.00282 seconds time elapsed ( +- 0.68% ) [2] Performance counter stats for 'nmcli' (50 runs): 477.99 msec task-clock:u # 1.088 CPUs utilized ( +- 0.36% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,948 page-faults:u # 0.012 M/sec ( +- 0.03% ) 1,471,133,482 cycles:u # 3.078 GHz ( +- 0.36% ) 1,655,275,369 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 382,595,152 branches:u # 800.433 M/sec ( +- 0.02% ) 4,746,070 branch-misses:u # 1.24% of all branches ( +- 0.49% ) 0.43923 +- 0.00242 seconds time elapsed ( +- 0.55% ) [3] Performance counter stats for 'nmcli' (50 runs): 352.36 msec task-clock:u # 1.027 CPUs utilized ( +- 0.32% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 4,790 page-faults:u # 0.014 M/sec ( +- 0.26% ) 1,092,341,186 cycles:u # 3.100 GHz ( +- 0.26% ) 1,209,045,283 instructions:u # 1.11 insn per cycle ( +- 0.02% ) 281,708,462 branches:u # 799.499 M/sec ( +- 0.01% ) 3,101,031 branch-misses:u # 1.10% of all branches ( +- 0.61% ) 0.34296 +- 0.00120 seconds time elapsed ( +- 0.35% ) --- N5) same setup as N4), but run `PAGER= /bin/time -v nmcli`: [1] Command being timed: "nmcli" User time (seconds): 0.42 System time (seconds): 0.04 Percent of CPU this job got: 107% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.43 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34456 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6128 Voluntary context switches: 1298 Involuntary context switches: 1106 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [2] Command being timed: "nmcli" User time (seconds): 0.44 System time (seconds): 0.04 Percent of CPU this job got: 108% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.44 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34452 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6169 Voluntary context switches: 1849 Involuntary context switches: 142 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [3] Command being timed: "nmcli" User time (seconds): 0.32 System time (seconds): 0.02 Percent of CPU this job got: 102% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.34 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 29196 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 5059 Voluntary context switches: 919 Involuntary context switches: 685 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 --- N6) same setup as N4), but run `nmcli monitor` and look at `ps aux` for the RSS size. USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND [1] me 1492900 21.0 0.2 461348 33248 pts/10 Sl+ 15:02 0:00 nmcli monitor [2] me 1490721 5.0 0.2 461496 33548 pts/10 Sl+ 15:00 0:00 nmcli monitor [3] me 1495801 16.5 0.1 459476 28692 pts/10 Sl+ 15:04 0:00 nmcli monitor
2019-10-30 11:42:58 +01:00
/*****************************************************************************/
static NMDeviceType
coerce_type (NMDeviceType type)
{
switch (type) {
case NM_DEVICE_TYPE_ETHERNET:
case NM_DEVICE_TYPE_WIFI:
case NM_DEVICE_TYPE_BT:
case NM_DEVICE_TYPE_OLPC_MESH:
case NM_DEVICE_TYPE_OVS_INTERFACE:
case NM_DEVICE_TYPE_OVS_PORT:
case NM_DEVICE_TYPE_OVS_BRIDGE:
case NM_DEVICE_TYPE_WIMAX:
case NM_DEVICE_TYPE_MODEM:
case NM_DEVICE_TYPE_INFINIBAND:
case NM_DEVICE_TYPE_BOND:
case NM_DEVICE_TYPE_TEAM:
case NM_DEVICE_TYPE_BRIDGE:
case NM_DEVICE_TYPE_VLAN:
case NM_DEVICE_TYPE_ADSL:
case NM_DEVICE_TYPE_MACSEC:
case NM_DEVICE_TYPE_MACVLAN:
case NM_DEVICE_TYPE_VXLAN:
case NM_DEVICE_TYPE_IP_TUNNEL:
case NM_DEVICE_TYPE_TUN:
case NM_DEVICE_TYPE_VETH:
case NM_DEVICE_TYPE_GENERIC:
case NM_DEVICE_TYPE_UNUSED1:
case NM_DEVICE_TYPE_UNUSED2:
case NM_DEVICE_TYPE_UNKNOWN:
case NM_DEVICE_TYPE_DUMMY:
case NM_DEVICE_TYPE_PPP:
2018-03-09 16:26:25 +01:00
case NM_DEVICE_TYPE_WPAN:
2018-05-22 16:25:54 +02:00
case NM_DEVICE_TYPE_6LOWPAN:
case NM_DEVICE_TYPE_WIREGUARD:
case NM_DEVICE_TYPE_WIFI_P2P:
case NM_DEVICE_TYPE_VRF:
return type;
}
return NM_DEVICE_TYPE_UNKNOWN;
}
libnm: refactor caching of D-Bus objects in NMClient No longer use GDBusObjectMangaerClient and gdbus-codegen generated classes for the NMClient cache. Instead, use GDBusConnection directly and a custom implementation (NMLDBusObject) for caching D-Bus' ObjectManager data. CHANGES ------- - This is a complete rework. I think the previous implementation was difficult to understand. There were unfixed bugs and nobody understood the code well enough to fix them. Maybe somebody out there understood the code, but I certainly did not. At least nobody provided patches to fix those issues. I do believe that this implementation is more straightforward and easier to understand. It removes a lot of layers of code. Whether this claim of simplicity is true, each reader must decide for himself/herself. Note that it is still fairly complex. - There was a lingering performance issue with large number of D-Bus objects. The patch tries hard that the implementation scales well. Of course, when we cache N objects that have N-to-M references to other, we still are fundamentally O(N*M) for runtime and memory consumption (with M being the number of references between objects). But each part should behave efficiently and well. - Play well with GMainContext. libnm code (NMClient) is generally not thread safe. However, it should work to use multiple instances in parallel, as long as each access to a NMClient is through the caller's GMainContext. This follows glib's style and effectively allows to use NMClient in a multi threaded scenario. This implies to stick to a main context upon construction and ensure that callbacks are only invoked when iterating that context. Also, NMClient itself shall never iterate the caller's context. This also means, libnm must never use g_idle_add() or g_timeout_add(), as those enqueue sources in the g_main_context_default() context. - Get ordering of messages right. All events are consistently enqueued in a GMainContext and processed strictly in order. For example, previously "nm-object.c" tried to combine signals and emit them on an idle handler. That is wrong, signals must be emitted in the right order and when they happen. Note that when using GInitable's synchronous initialization to initialize the NMClient instance, NMClient internally still operates fully asynchronously. In that case NMClient has an internal main context. - NMClient takes over most of the functionality. When using D-Bus' ObjectManager interface, one needs to handle basically the entire state of the D-Bus interface. That cannot be separated well into distinct parts, and even if you try, you just end up having closely related code in different source files. Spreading related code does not make it easier to understand, on the contrary. That means, NMClient is inherently complex as it contains most of the logic. I think that is not avoidable, but it's not as bad as it sounds. - NMClient processes D-Bus messages and state changes in separate steps. First NMClient unpacks the message (e.g. _dbus_handle_properties_changed()) and keeps track of the changed data. Then we update the GObject instances (_dbus_handle_obj_changed_dbus()) without emitting any signals yet. Finally, we emit all signals and notifications that were collected (_dbus_handle_changes_commit()). Note that for example during the initial GetManagedObjects() reply, NMClient receive a large amount of state at once. But we first apply all the changes to our GObject instances before emitting any signals. The result is that signals are always emitted in a moment when the cache is consistent. The unavoidable downside is that when you receive a property changed signal, possibly many other properties changed already and more signals are about to be emitted. - NMDeviceWifi no longer modifies the content of the cache from client side during poke_wireless_devices_with_rf_status(). The content of the cache should be determined by D-Bus alone and follow what NetworkManager service exposes. Local modifications should be avoided. - This aims to bring no API/ABI change, though it does of course bring various subtle changes in behavior. Those should be all for the better, but the goal is not to break any existing clients. This does change internal (albeit externally visible) API, like dropping NM_OBJECT_DBUS_OBJECT_MANAGER property and NMObject no longer implementing GInitableIface and GAsyncInitableIface. - Some uses of gdbus-codegen classes remain in NMVpnPluginOld, NMVpnServicePlugin and NMSecretAgentOld. These are independent of NMClient/NMObject and should be reworked separately. - While we no longer use generated classes from gdbus-codegen, we don't need more glue code than before. Also before we constructed NMPropertiesInfo and a had large amount of code to propagate properties from NMDBus* to NMObject. That got completely reworked, but did not fundamentally change. You still need about the same effort to create the NMLDBusMetaIface. Not using generated bindings did not make anything worse (which tells about the usefulness of generated code, at least in the way it was used). - NMLDBusMetaIface and other meta data is static and immutable. This avoids copying them around. Also, macros like NML_DBUS_META_PROPERTY_INIT_U() have compile time checks to ensure the property types matches. It's pretty hard to misuse them because it won't compile. - The meta data now explicitly encodes the expected D-Bus types and makes sure never to accept wrong data. That would only matter when the server (accidentally or intentionally) exposes unexpected types on D-Bus. I don't think that was previously ensured in all cases. For example, demarshal_generic() only cared about the GObject property type, it didn't know the expected D-Bus type. - Previously GDBusObjectManager would sometimes emit warnings (g_log()). Those probably indicated real bugs. In any case, it prevented us from running CI with G_DEBUG=fatal-warnings, because there would be just too many unrelated crashes. Now we log debug messages that can be enabled with "LIBNM_CLIENT_DEBUG=trace". Some of these messages can also be turned into g_warning()/g_critical() by setting LIBNM_CLIENT_DEBUG=warning,error. Together with G_DEBUG=fatal-warnings, this turns them into assertions. Note that such "assertion failures" might also happen because of a server bug (or change). Thus these are not common assertions that indicate a bug in libnm and are thus not armed unless explicitly requested. In our CI we should now always run with LIBNM_CLIENT_DEBUG=warning,error and G_DEBUG=fatal-warnings and to catch bugs. Note that currently NetworkManager has bugs in this regard, so enabling this will result in assertion failures. That should be fixed first. - Note that this changes the order in which we emit "notify:devices" and "device-added" signals. I think it makes the most sense to emit first "device-removed", then "notify:devices", and finally "device-added" signals. This changes behavior for commit 52ae28f6e5bf ('libnm: queue added/removed signals and suppress uninitialized notifications'), but I don't think that users should actually rely on the order. Still, the new order makes the most sense to me. - In NetworkManager, profiles can be invisible to the user by setting "connection.permissions". Such profiles would be hidden by NMClient's nm_client_get_connections() and their "connection-added"/"connection-removed" signals. Note that NMActiveConnection's nm_active_connection_get_connection() and NMDevice's nm_device_get_available_connections() still exposes such hidden NMRemoteConnection instances. This behavior was preserved. NUMBERS ------- I compared 3 versions of libnm. [1] 962297f9085d, current tip of nm-1-20 branch [2] 4fad8c7c642e, current master, immediate parent of this patch [3] this patch All tests were done on Fedora 31, x86_64, gcc 9.2.1-1.fc31. The libraries were build with $ ./contrib/fedora/rpm/build_clean.sh -g -w test -W debug Note that RPM build already stripped the library. --- N1) File size of libnm.so.0.1.0 in bytes. There currently seems to be a issue on Fedora 31 generating wrong ELF notes. Usually, libnm is smaller but in these tests it had large (and bogus) ELF notes. Anyway, the point is to show the relative sizes, so it doesn't matter). [1] 4075552 (102.7%) [2] 3969624 (100.0%) [3] 3705208 ( 93.3%) --- N2) `size /usr/lib64/libnm.so.0.1.0`: text data bss dec hex filename [1] 1314569 (102.0%) 69980 ( 94.8%) 10632 ( 80.4%) 1395181 (101.4%) 1549ed /usr/lib64/libnm.so.0.1.0 [2] 1288410 (100.0%) 73796 (100.0%) 13224 (100.0%) 1375430 (100.0%) 14fcc6 /usr/lib64/libnm.so.0.1.0 [3] 1229066 ( 95.4%) 65248 ( 88.4%) 13400 (101.3%) 1307714 ( 95.1%) 13f442 /usr/lib64/libnm.so.0.1.0 --- N3) Performance test with test-client.py. With checkout of [2], run ``` prepare_checkout() { rm -rf /tmp/nm-test && \ git checkout -B test 4fad8c7c642e && \ git clean -fdx && \ ./autogen.sh --prefix=/tmp/nm-test && \ make -j 5 install && \ make -j 5 check-local-clients-tests-test-client } prepare_test() { NM_TEST_REGENERATE=1 NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v } do_test() { for i in {1..10}; do NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v || return -1 done echo "done!" } prepare_checkout prepare_test time do_test ``` [1] real 2m14.497s (101.3%) user 5m26.651s (100.3%) sys 1m40.453s (101.4%) [2] real 2m12.800s (100.0%) user 5m25.619s (100.0%) sys 1m39.065s (100.0%) [3] real 1m54.915s ( 86.5%) user 4m18.585s ( 79.4%) sys 1m32.066s ( 92.9%) --- N4) Performance. Run NetworkManager from build [2] and setup a large number of profiles (551 profiles and 515 devices, mostly unrealized). This setup is already at the edge of what NetworkManager currently can handle. Of course, that is a different issue. Here we just check how long plain `nmcli` takes on the system. ``` do_cleanup() { for UUID in $(nmcli -g NAME,UUID connection show | sed -n 's/^xx-c-.*:\([^:]\+\)$/\1/p'); do nmcli connection delete uuid "$UUID" done for DEVICE in $(nmcli -g DEVICE device status | grep '^xx-i-'); do nmcli device delete "$DEVICE" done } do_setup() { do_cleanup for i in {1..30}; do nmcli connection add type bond autoconnect no con-name xx-c-bond-$i ifname xx-i-bond-$i ipv4.method disabled ipv6.method ignore for j in $(seq $i 30); do nmcli connection add type vlan autoconnect no con-name xx-c-vlan-$i-$j vlan.id $j ifname xx-i-vlan-$i-$j vlan.parent xx-i-bond-$i ipv4.method disabled ipv6.method ignore done done systemctl restart NetworkManager.service sleep 5 } do_test() { perf stat -r 50 -B nmcli 1>/dev/null } do_test ``` [1] Performance counter stats for 'nmcli' (50 runs): 456.33 msec task-clock:u # 1.093 CPUs utilized ( +- 0.44% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,900 page-faults:u # 0.013 M/sec ( +- 0.02% ) 1,408,675,453 cycles:u # 3.087 GHz ( +- 0.48% ) 1,594,741,060 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 368,744,018 branches:u # 808.061 M/sec ( +- 0.02% ) 4,566,058 branch-misses:u # 1.24% of all branches ( +- 0.76% ) 0.41761 +- 0.00282 seconds time elapsed ( +- 0.68% ) [2] Performance counter stats for 'nmcli' (50 runs): 477.99 msec task-clock:u # 1.088 CPUs utilized ( +- 0.36% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,948 page-faults:u # 0.012 M/sec ( +- 0.03% ) 1,471,133,482 cycles:u # 3.078 GHz ( +- 0.36% ) 1,655,275,369 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 382,595,152 branches:u # 800.433 M/sec ( +- 0.02% ) 4,746,070 branch-misses:u # 1.24% of all branches ( +- 0.49% ) 0.43923 +- 0.00242 seconds time elapsed ( +- 0.55% ) [3] Performance counter stats for 'nmcli' (50 runs): 352.36 msec task-clock:u # 1.027 CPUs utilized ( +- 0.32% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 4,790 page-faults:u # 0.014 M/sec ( +- 0.26% ) 1,092,341,186 cycles:u # 3.100 GHz ( +- 0.26% ) 1,209,045,283 instructions:u # 1.11 insn per cycle ( +- 0.02% ) 281,708,462 branches:u # 799.499 M/sec ( +- 0.01% ) 3,101,031 branch-misses:u # 1.10% of all branches ( +- 0.61% ) 0.34296 +- 0.00120 seconds time elapsed ( +- 0.35% ) --- N5) same setup as N4), but run `PAGER= /bin/time -v nmcli`: [1] Command being timed: "nmcli" User time (seconds): 0.42 System time (seconds): 0.04 Percent of CPU this job got: 107% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.43 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34456 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6128 Voluntary context switches: 1298 Involuntary context switches: 1106 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [2] Command being timed: "nmcli" User time (seconds): 0.44 System time (seconds): 0.04 Percent of CPU this job got: 108% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.44 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34452 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6169 Voluntary context switches: 1849 Involuntary context switches: 142 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [3] Command being timed: "nmcli" User time (seconds): 0.32 System time (seconds): 0.02 Percent of CPU this job got: 102% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.34 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 29196 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 5059 Voluntary context switches: 919 Involuntary context switches: 685 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 --- N6) same setup as N4), but run `nmcli monitor` and look at `ps aux` for the RSS size. USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND [1] me 1492900 21.0 0.2 461348 33248 pts/10 Sl+ 15:02 0:00 nmcli monitor [2] me 1490721 5.0 0.2 461496 33548 pts/10 Sl+ 15:00 0:00 nmcli monitor [3] me 1495801 16.5 0.1 459476 28692 pts/10 Sl+ 15:04 0:00 nmcli monitor
2019-10-30 11:42:58 +01:00
/*****************************************************************************/
static void
libnm: refactor caching of D-Bus objects in NMClient No longer use GDBusObjectMangaerClient and gdbus-codegen generated classes for the NMClient cache. Instead, use GDBusConnection directly and a custom implementation (NMLDBusObject) for caching D-Bus' ObjectManager data. CHANGES ------- - This is a complete rework. I think the previous implementation was difficult to understand. There were unfixed bugs and nobody understood the code well enough to fix them. Maybe somebody out there understood the code, but I certainly did not. At least nobody provided patches to fix those issues. I do believe that this implementation is more straightforward and easier to understand. It removes a lot of layers of code. Whether this claim of simplicity is true, each reader must decide for himself/herself. Note that it is still fairly complex. - There was a lingering performance issue with large number of D-Bus objects. The patch tries hard that the implementation scales well. Of course, when we cache N objects that have N-to-M references to other, we still are fundamentally O(N*M) for runtime and memory consumption (with M being the number of references between objects). But each part should behave efficiently and well. - Play well with GMainContext. libnm code (NMClient) is generally not thread safe. However, it should work to use multiple instances in parallel, as long as each access to a NMClient is through the caller's GMainContext. This follows glib's style and effectively allows to use NMClient in a multi threaded scenario. This implies to stick to a main context upon construction and ensure that callbacks are only invoked when iterating that context. Also, NMClient itself shall never iterate the caller's context. This also means, libnm must never use g_idle_add() or g_timeout_add(), as those enqueue sources in the g_main_context_default() context. - Get ordering of messages right. All events are consistently enqueued in a GMainContext and processed strictly in order. For example, previously "nm-object.c" tried to combine signals and emit them on an idle handler. That is wrong, signals must be emitted in the right order and when they happen. Note that when using GInitable's synchronous initialization to initialize the NMClient instance, NMClient internally still operates fully asynchronously. In that case NMClient has an internal main context. - NMClient takes over most of the functionality. When using D-Bus' ObjectManager interface, one needs to handle basically the entire state of the D-Bus interface. That cannot be separated well into distinct parts, and even if you try, you just end up having closely related code in different source files. Spreading related code does not make it easier to understand, on the contrary. That means, NMClient is inherently complex as it contains most of the logic. I think that is not avoidable, but it's not as bad as it sounds. - NMClient processes D-Bus messages and state changes in separate steps. First NMClient unpacks the message (e.g. _dbus_handle_properties_changed()) and keeps track of the changed data. Then we update the GObject instances (_dbus_handle_obj_changed_dbus()) without emitting any signals yet. Finally, we emit all signals and notifications that were collected (_dbus_handle_changes_commit()). Note that for example during the initial GetManagedObjects() reply, NMClient receive a large amount of state at once. But we first apply all the changes to our GObject instances before emitting any signals. The result is that signals are always emitted in a moment when the cache is consistent. The unavoidable downside is that when you receive a property changed signal, possibly many other properties changed already and more signals are about to be emitted. - NMDeviceWifi no longer modifies the content of the cache from client side during poke_wireless_devices_with_rf_status(). The content of the cache should be determined by D-Bus alone and follow what NetworkManager service exposes. Local modifications should be avoided. - This aims to bring no API/ABI change, though it does of course bring various subtle changes in behavior. Those should be all for the better, but the goal is not to break any existing clients. This does change internal (albeit externally visible) API, like dropping NM_OBJECT_DBUS_OBJECT_MANAGER property and NMObject no longer implementing GInitableIface and GAsyncInitableIface. - Some uses of gdbus-codegen classes remain in NMVpnPluginOld, NMVpnServicePlugin and NMSecretAgentOld. These are independent of NMClient/NMObject and should be reworked separately. - While we no longer use generated classes from gdbus-codegen, we don't need more glue code than before. Also before we constructed NMPropertiesInfo and a had large amount of code to propagate properties from NMDBus* to NMObject. That got completely reworked, but did not fundamentally change. You still need about the same effort to create the NMLDBusMetaIface. Not using generated bindings did not make anything worse (which tells about the usefulness of generated code, at least in the way it was used). - NMLDBusMetaIface and other meta data is static and immutable. This avoids copying them around. Also, macros like NML_DBUS_META_PROPERTY_INIT_U() have compile time checks to ensure the property types matches. It's pretty hard to misuse them because it won't compile. - The meta data now explicitly encodes the expected D-Bus types and makes sure never to accept wrong data. That would only matter when the server (accidentally or intentionally) exposes unexpected types on D-Bus. I don't think that was previously ensured in all cases. For example, demarshal_generic() only cared about the GObject property type, it didn't know the expected D-Bus type. - Previously GDBusObjectManager would sometimes emit warnings (g_log()). Those probably indicated real bugs. In any case, it prevented us from running CI with G_DEBUG=fatal-warnings, because there would be just too many unrelated crashes. Now we log debug messages that can be enabled with "LIBNM_CLIENT_DEBUG=trace". Some of these messages can also be turned into g_warning()/g_critical() by setting LIBNM_CLIENT_DEBUG=warning,error. Together with G_DEBUG=fatal-warnings, this turns them into assertions. Note that such "assertion failures" might also happen because of a server bug (or change). Thus these are not common assertions that indicate a bug in libnm and are thus not armed unless explicitly requested. In our CI we should now always run with LIBNM_CLIENT_DEBUG=warning,error and G_DEBUG=fatal-warnings and to catch bugs. Note that currently NetworkManager has bugs in this regard, so enabling this will result in assertion failures. That should be fixed first. - Note that this changes the order in which we emit "notify:devices" and "device-added" signals. I think it makes the most sense to emit first "device-removed", then "notify:devices", and finally "device-added" signals. This changes behavior for commit 52ae28f6e5bf ('libnm: queue added/removed signals and suppress uninitialized notifications'), but I don't think that users should actually rely on the order. Still, the new order makes the most sense to me. - In NetworkManager, profiles can be invisible to the user by setting "connection.permissions". Such profiles would be hidden by NMClient's nm_client_get_connections() and their "connection-added"/"connection-removed" signals. Note that NMActiveConnection's nm_active_connection_get_connection() and NMDevice's nm_device_get_available_connections() still exposes such hidden NMRemoteConnection instances. This behavior was preserved. NUMBERS ------- I compared 3 versions of libnm. [1] 962297f9085d, current tip of nm-1-20 branch [2] 4fad8c7c642e, current master, immediate parent of this patch [3] this patch All tests were done on Fedora 31, x86_64, gcc 9.2.1-1.fc31. The libraries were build with $ ./contrib/fedora/rpm/build_clean.sh -g -w test -W debug Note that RPM build already stripped the library. --- N1) File size of libnm.so.0.1.0 in bytes. There currently seems to be a issue on Fedora 31 generating wrong ELF notes. Usually, libnm is smaller but in these tests it had large (and bogus) ELF notes. Anyway, the point is to show the relative sizes, so it doesn't matter). [1] 4075552 (102.7%) [2] 3969624 (100.0%) [3] 3705208 ( 93.3%) --- N2) `size /usr/lib64/libnm.so.0.1.0`: text data bss dec hex filename [1] 1314569 (102.0%) 69980 ( 94.8%) 10632 ( 80.4%) 1395181 (101.4%) 1549ed /usr/lib64/libnm.so.0.1.0 [2] 1288410 (100.0%) 73796 (100.0%) 13224 (100.0%) 1375430 (100.0%) 14fcc6 /usr/lib64/libnm.so.0.1.0 [3] 1229066 ( 95.4%) 65248 ( 88.4%) 13400 (101.3%) 1307714 ( 95.1%) 13f442 /usr/lib64/libnm.so.0.1.0 --- N3) Performance test with test-client.py. With checkout of [2], run ``` prepare_checkout() { rm -rf /tmp/nm-test && \ git checkout -B test 4fad8c7c642e && \ git clean -fdx && \ ./autogen.sh --prefix=/tmp/nm-test && \ make -j 5 install && \ make -j 5 check-local-clients-tests-test-client } prepare_test() { NM_TEST_REGENERATE=1 NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v } do_test() { for i in {1..10}; do NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v || return -1 done echo "done!" } prepare_checkout prepare_test time do_test ``` [1] real 2m14.497s (101.3%) user 5m26.651s (100.3%) sys 1m40.453s (101.4%) [2] real 2m12.800s (100.0%) user 5m25.619s (100.0%) sys 1m39.065s (100.0%) [3] real 1m54.915s ( 86.5%) user 4m18.585s ( 79.4%) sys 1m32.066s ( 92.9%) --- N4) Performance. Run NetworkManager from build [2] and setup a large number of profiles (551 profiles and 515 devices, mostly unrealized). This setup is already at the edge of what NetworkManager currently can handle. Of course, that is a different issue. Here we just check how long plain `nmcli` takes on the system. ``` do_cleanup() { for UUID in $(nmcli -g NAME,UUID connection show | sed -n 's/^xx-c-.*:\([^:]\+\)$/\1/p'); do nmcli connection delete uuid "$UUID" done for DEVICE in $(nmcli -g DEVICE device status | grep '^xx-i-'); do nmcli device delete "$DEVICE" done } do_setup() { do_cleanup for i in {1..30}; do nmcli connection add type bond autoconnect no con-name xx-c-bond-$i ifname xx-i-bond-$i ipv4.method disabled ipv6.method ignore for j in $(seq $i 30); do nmcli connection add type vlan autoconnect no con-name xx-c-vlan-$i-$j vlan.id $j ifname xx-i-vlan-$i-$j vlan.parent xx-i-bond-$i ipv4.method disabled ipv6.method ignore done done systemctl restart NetworkManager.service sleep 5 } do_test() { perf stat -r 50 -B nmcli 1>/dev/null } do_test ``` [1] Performance counter stats for 'nmcli' (50 runs): 456.33 msec task-clock:u # 1.093 CPUs utilized ( +- 0.44% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,900 page-faults:u # 0.013 M/sec ( +- 0.02% ) 1,408,675,453 cycles:u # 3.087 GHz ( +- 0.48% ) 1,594,741,060 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 368,744,018 branches:u # 808.061 M/sec ( +- 0.02% ) 4,566,058 branch-misses:u # 1.24% of all branches ( +- 0.76% ) 0.41761 +- 0.00282 seconds time elapsed ( +- 0.68% ) [2] Performance counter stats for 'nmcli' (50 runs): 477.99 msec task-clock:u # 1.088 CPUs utilized ( +- 0.36% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,948 page-faults:u # 0.012 M/sec ( +- 0.03% ) 1,471,133,482 cycles:u # 3.078 GHz ( +- 0.36% ) 1,655,275,369 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 382,595,152 branches:u # 800.433 M/sec ( +- 0.02% ) 4,746,070 branch-misses:u # 1.24% of all branches ( +- 0.49% ) 0.43923 +- 0.00242 seconds time elapsed ( +- 0.55% ) [3] Performance counter stats for 'nmcli' (50 runs): 352.36 msec task-clock:u # 1.027 CPUs utilized ( +- 0.32% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 4,790 page-faults:u # 0.014 M/sec ( +- 0.26% ) 1,092,341,186 cycles:u # 3.100 GHz ( +- 0.26% ) 1,209,045,283 instructions:u # 1.11 insn per cycle ( +- 0.02% ) 281,708,462 branches:u # 799.499 M/sec ( +- 0.01% ) 3,101,031 branch-misses:u # 1.10% of all branches ( +- 0.61% ) 0.34296 +- 0.00120 seconds time elapsed ( +- 0.35% ) --- N5) same setup as N4), but run `PAGER= /bin/time -v nmcli`: [1] Command being timed: "nmcli" User time (seconds): 0.42 System time (seconds): 0.04 Percent of CPU this job got: 107% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.43 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34456 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6128 Voluntary context switches: 1298 Involuntary context switches: 1106 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [2] Command being timed: "nmcli" User time (seconds): 0.44 System time (seconds): 0.04 Percent of CPU this job got: 108% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.44 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34452 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6169 Voluntary context switches: 1849 Involuntary context switches: 142 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [3] Command being timed: "nmcli" User time (seconds): 0.32 System time (seconds): 0.02 Percent of CPU this job got: 102% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.34 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 29196 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 5059 Voluntary context switches: 919 Involuntary context switches: 685 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 --- N6) same setup as N4), but run `nmcli monitor` and look at `ps aux` for the RSS size. USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND [1] me 1492900 21.0 0.2 461348 33248 pts/10 Sl+ 15:02 0:00 nmcli monitor [2] me 1490721 5.0 0.2 461496 33548 pts/10 Sl+ 15:00 0:00 nmcli monitor [3] me 1495801 16.5 0.1 459476 28692 pts/10 Sl+ 15:04 0:00 nmcli monitor
2019-10-30 11:42:58 +01:00
register_client (NMObject *nmobj,
NMClient *client,
NMLDBusObject *dbobj)
{
libnm: refactor caching of D-Bus objects in NMClient No longer use GDBusObjectMangaerClient and gdbus-codegen generated classes for the NMClient cache. Instead, use GDBusConnection directly and a custom implementation (NMLDBusObject) for caching D-Bus' ObjectManager data. CHANGES ------- - This is a complete rework. I think the previous implementation was difficult to understand. There were unfixed bugs and nobody understood the code well enough to fix them. Maybe somebody out there understood the code, but I certainly did not. At least nobody provided patches to fix those issues. I do believe that this implementation is more straightforward and easier to understand. It removes a lot of layers of code. Whether this claim of simplicity is true, each reader must decide for himself/herself. Note that it is still fairly complex. - There was a lingering performance issue with large number of D-Bus objects. The patch tries hard that the implementation scales well. Of course, when we cache N objects that have N-to-M references to other, we still are fundamentally O(N*M) for runtime and memory consumption (with M being the number of references between objects). But each part should behave efficiently and well. - Play well with GMainContext. libnm code (NMClient) is generally not thread safe. However, it should work to use multiple instances in parallel, as long as each access to a NMClient is through the caller's GMainContext. This follows glib's style and effectively allows to use NMClient in a multi threaded scenario. This implies to stick to a main context upon construction and ensure that callbacks are only invoked when iterating that context. Also, NMClient itself shall never iterate the caller's context. This also means, libnm must never use g_idle_add() or g_timeout_add(), as those enqueue sources in the g_main_context_default() context. - Get ordering of messages right. All events are consistently enqueued in a GMainContext and processed strictly in order. For example, previously "nm-object.c" tried to combine signals and emit them on an idle handler. That is wrong, signals must be emitted in the right order and when they happen. Note that when using GInitable's synchronous initialization to initialize the NMClient instance, NMClient internally still operates fully asynchronously. In that case NMClient has an internal main context. - NMClient takes over most of the functionality. When using D-Bus' ObjectManager interface, one needs to handle basically the entire state of the D-Bus interface. That cannot be separated well into distinct parts, and even if you try, you just end up having closely related code in different source files. Spreading related code does not make it easier to understand, on the contrary. That means, NMClient is inherently complex as it contains most of the logic. I think that is not avoidable, but it's not as bad as it sounds. - NMClient processes D-Bus messages and state changes in separate steps. First NMClient unpacks the message (e.g. _dbus_handle_properties_changed()) and keeps track of the changed data. Then we update the GObject instances (_dbus_handle_obj_changed_dbus()) without emitting any signals yet. Finally, we emit all signals and notifications that were collected (_dbus_handle_changes_commit()). Note that for example during the initial GetManagedObjects() reply, NMClient receive a large amount of state at once. But we first apply all the changes to our GObject instances before emitting any signals. The result is that signals are always emitted in a moment when the cache is consistent. The unavoidable downside is that when you receive a property changed signal, possibly many other properties changed already and more signals are about to be emitted. - NMDeviceWifi no longer modifies the content of the cache from client side during poke_wireless_devices_with_rf_status(). The content of the cache should be determined by D-Bus alone and follow what NetworkManager service exposes. Local modifications should be avoided. - This aims to bring no API/ABI change, though it does of course bring various subtle changes in behavior. Those should be all for the better, but the goal is not to break any existing clients. This does change internal (albeit externally visible) API, like dropping NM_OBJECT_DBUS_OBJECT_MANAGER property and NMObject no longer implementing GInitableIface and GAsyncInitableIface. - Some uses of gdbus-codegen classes remain in NMVpnPluginOld, NMVpnServicePlugin and NMSecretAgentOld. These are independent of NMClient/NMObject and should be reworked separately. - While we no longer use generated classes from gdbus-codegen, we don't need more glue code than before. Also before we constructed NMPropertiesInfo and a had large amount of code to propagate properties from NMDBus* to NMObject. That got completely reworked, but did not fundamentally change. You still need about the same effort to create the NMLDBusMetaIface. Not using generated bindings did not make anything worse (which tells about the usefulness of generated code, at least in the way it was used). - NMLDBusMetaIface and other meta data is static and immutable. This avoids copying them around. Also, macros like NML_DBUS_META_PROPERTY_INIT_U() have compile time checks to ensure the property types matches. It's pretty hard to misuse them because it won't compile. - The meta data now explicitly encodes the expected D-Bus types and makes sure never to accept wrong data. That would only matter when the server (accidentally or intentionally) exposes unexpected types on D-Bus. I don't think that was previously ensured in all cases. For example, demarshal_generic() only cared about the GObject property type, it didn't know the expected D-Bus type. - Previously GDBusObjectManager would sometimes emit warnings (g_log()). Those probably indicated real bugs. In any case, it prevented us from running CI with G_DEBUG=fatal-warnings, because there would be just too many unrelated crashes. Now we log debug messages that can be enabled with "LIBNM_CLIENT_DEBUG=trace". Some of these messages can also be turned into g_warning()/g_critical() by setting LIBNM_CLIENT_DEBUG=warning,error. Together with G_DEBUG=fatal-warnings, this turns them into assertions. Note that such "assertion failures" might also happen because of a server bug (or change). Thus these are not common assertions that indicate a bug in libnm and are thus not armed unless explicitly requested. In our CI we should now always run with LIBNM_CLIENT_DEBUG=warning,error and G_DEBUG=fatal-warnings and to catch bugs. Note that currently NetworkManager has bugs in this regard, so enabling this will result in assertion failures. That should be fixed first. - Note that this changes the order in which we emit "notify:devices" and "device-added" signals. I think it makes the most sense to emit first "device-removed", then "notify:devices", and finally "device-added" signals. This changes behavior for commit 52ae28f6e5bf ('libnm: queue added/removed signals and suppress uninitialized notifications'), but I don't think that users should actually rely on the order. Still, the new order makes the most sense to me. - In NetworkManager, profiles can be invisible to the user by setting "connection.permissions". Such profiles would be hidden by NMClient's nm_client_get_connections() and their "connection-added"/"connection-removed" signals. Note that NMActiveConnection's nm_active_connection_get_connection() and NMDevice's nm_device_get_available_connections() still exposes such hidden NMRemoteConnection instances. This behavior was preserved. NUMBERS ------- I compared 3 versions of libnm. [1] 962297f9085d, current tip of nm-1-20 branch [2] 4fad8c7c642e, current master, immediate parent of this patch [3] this patch All tests were done on Fedora 31, x86_64, gcc 9.2.1-1.fc31. The libraries were build with $ ./contrib/fedora/rpm/build_clean.sh -g -w test -W debug Note that RPM build already stripped the library. --- N1) File size of libnm.so.0.1.0 in bytes. There currently seems to be a issue on Fedora 31 generating wrong ELF notes. Usually, libnm is smaller but in these tests it had large (and bogus) ELF notes. Anyway, the point is to show the relative sizes, so it doesn't matter). [1] 4075552 (102.7%) [2] 3969624 (100.0%) [3] 3705208 ( 93.3%) --- N2) `size /usr/lib64/libnm.so.0.1.0`: text data bss dec hex filename [1] 1314569 (102.0%) 69980 ( 94.8%) 10632 ( 80.4%) 1395181 (101.4%) 1549ed /usr/lib64/libnm.so.0.1.0 [2] 1288410 (100.0%) 73796 (100.0%) 13224 (100.0%) 1375430 (100.0%) 14fcc6 /usr/lib64/libnm.so.0.1.0 [3] 1229066 ( 95.4%) 65248 ( 88.4%) 13400 (101.3%) 1307714 ( 95.1%) 13f442 /usr/lib64/libnm.so.0.1.0 --- N3) Performance test with test-client.py. With checkout of [2], run ``` prepare_checkout() { rm -rf /tmp/nm-test && \ git checkout -B test 4fad8c7c642e && \ git clean -fdx && \ ./autogen.sh --prefix=/tmp/nm-test && \ make -j 5 install && \ make -j 5 check-local-clients-tests-test-client } prepare_test() { NM_TEST_REGENERATE=1 NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v } do_test() { for i in {1..10}; do NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v || return -1 done echo "done!" } prepare_checkout prepare_test time do_test ``` [1] real 2m14.497s (101.3%) user 5m26.651s (100.3%) sys 1m40.453s (101.4%) [2] real 2m12.800s (100.0%) user 5m25.619s (100.0%) sys 1m39.065s (100.0%) [3] real 1m54.915s ( 86.5%) user 4m18.585s ( 79.4%) sys 1m32.066s ( 92.9%) --- N4) Performance. Run NetworkManager from build [2] and setup a large number of profiles (551 profiles and 515 devices, mostly unrealized). This setup is already at the edge of what NetworkManager currently can handle. Of course, that is a different issue. Here we just check how long plain `nmcli` takes on the system. ``` do_cleanup() { for UUID in $(nmcli -g NAME,UUID connection show | sed -n 's/^xx-c-.*:\([^:]\+\)$/\1/p'); do nmcli connection delete uuid "$UUID" done for DEVICE in $(nmcli -g DEVICE device status | grep '^xx-i-'); do nmcli device delete "$DEVICE" done } do_setup() { do_cleanup for i in {1..30}; do nmcli connection add type bond autoconnect no con-name xx-c-bond-$i ifname xx-i-bond-$i ipv4.method disabled ipv6.method ignore for j in $(seq $i 30); do nmcli connection add type vlan autoconnect no con-name xx-c-vlan-$i-$j vlan.id $j ifname xx-i-vlan-$i-$j vlan.parent xx-i-bond-$i ipv4.method disabled ipv6.method ignore done done systemctl restart NetworkManager.service sleep 5 } do_test() { perf stat -r 50 -B nmcli 1>/dev/null } do_test ``` [1] Performance counter stats for 'nmcli' (50 runs): 456.33 msec task-clock:u # 1.093 CPUs utilized ( +- 0.44% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,900 page-faults:u # 0.013 M/sec ( +- 0.02% ) 1,408,675,453 cycles:u # 3.087 GHz ( +- 0.48% ) 1,594,741,060 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 368,744,018 branches:u # 808.061 M/sec ( +- 0.02% ) 4,566,058 branch-misses:u # 1.24% of all branches ( +- 0.76% ) 0.41761 +- 0.00282 seconds time elapsed ( +- 0.68% ) [2] Performance counter stats for 'nmcli' (50 runs): 477.99 msec task-clock:u # 1.088 CPUs utilized ( +- 0.36% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,948 page-faults:u # 0.012 M/sec ( +- 0.03% ) 1,471,133,482 cycles:u # 3.078 GHz ( +- 0.36% ) 1,655,275,369 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 382,595,152 branches:u # 800.433 M/sec ( +- 0.02% ) 4,746,070 branch-misses:u # 1.24% of all branches ( +- 0.49% ) 0.43923 +- 0.00242 seconds time elapsed ( +- 0.55% ) [3] Performance counter stats for 'nmcli' (50 runs): 352.36 msec task-clock:u # 1.027 CPUs utilized ( +- 0.32% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 4,790 page-faults:u # 0.014 M/sec ( +- 0.26% ) 1,092,341,186 cycles:u # 3.100 GHz ( +- 0.26% ) 1,209,045,283 instructions:u # 1.11 insn per cycle ( +- 0.02% ) 281,708,462 branches:u # 799.499 M/sec ( +- 0.01% ) 3,101,031 branch-misses:u # 1.10% of all branches ( +- 0.61% ) 0.34296 +- 0.00120 seconds time elapsed ( +- 0.35% ) --- N5) same setup as N4), but run `PAGER= /bin/time -v nmcli`: [1] Command being timed: "nmcli" User time (seconds): 0.42 System time (seconds): 0.04 Percent of CPU this job got: 107% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.43 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34456 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6128 Voluntary context switches: 1298 Involuntary context switches: 1106 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [2] Command being timed: "nmcli" User time (seconds): 0.44 System time (seconds): 0.04 Percent of CPU this job got: 108% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.44 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34452 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6169 Voluntary context switches: 1849 Involuntary context switches: 142 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [3] Command being timed: "nmcli" User time (seconds): 0.32 System time (seconds): 0.02 Percent of CPU this job got: 102% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.34 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 29196 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 5059 Voluntary context switches: 919 Involuntary context switches: 685 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 --- N6) same setup as N4), but run `nmcli monitor` and look at `ps aux` for the RSS size. USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND [1] me 1492900 21.0 0.2 461348 33248 pts/10 Sl+ 15:02 0:00 nmcli monitor [2] me 1490721 5.0 0.2 461496 33548 pts/10 Sl+ 15:00 0:00 nmcli monitor [3] me 1495801 16.5 0.1 459476 28692 pts/10 Sl+ 15:04 0:00 nmcli monitor
2019-10-30 11:42:58 +01:00
NMDevicePrivate *priv = NM_DEVICE_GET_PRIVATE (nmobj);
libnm: refactor caching of D-Bus objects in NMClient No longer use GDBusObjectMangaerClient and gdbus-codegen generated classes for the NMClient cache. Instead, use GDBusConnection directly and a custom implementation (NMLDBusObject) for caching D-Bus' ObjectManager data. CHANGES ------- - This is a complete rework. I think the previous implementation was difficult to understand. There were unfixed bugs and nobody understood the code well enough to fix them. Maybe somebody out there understood the code, but I certainly did not. At least nobody provided patches to fix those issues. I do believe that this implementation is more straightforward and easier to understand. It removes a lot of layers of code. Whether this claim of simplicity is true, each reader must decide for himself/herself. Note that it is still fairly complex. - There was a lingering performance issue with large number of D-Bus objects. The patch tries hard that the implementation scales well. Of course, when we cache N objects that have N-to-M references to other, we still are fundamentally O(N*M) for runtime and memory consumption (with M being the number of references between objects). But each part should behave efficiently and well. - Play well with GMainContext. libnm code (NMClient) is generally not thread safe. However, it should work to use multiple instances in parallel, as long as each access to a NMClient is through the caller's GMainContext. This follows glib's style and effectively allows to use NMClient in a multi threaded scenario. This implies to stick to a main context upon construction and ensure that callbacks are only invoked when iterating that context. Also, NMClient itself shall never iterate the caller's context. This also means, libnm must never use g_idle_add() or g_timeout_add(), as those enqueue sources in the g_main_context_default() context. - Get ordering of messages right. All events are consistently enqueued in a GMainContext and processed strictly in order. For example, previously "nm-object.c" tried to combine signals and emit them on an idle handler. That is wrong, signals must be emitted in the right order and when they happen. Note that when using GInitable's synchronous initialization to initialize the NMClient instance, NMClient internally still operates fully asynchronously. In that case NMClient has an internal main context. - NMClient takes over most of the functionality. When using D-Bus' ObjectManager interface, one needs to handle basically the entire state of the D-Bus interface. That cannot be separated well into distinct parts, and even if you try, you just end up having closely related code in different source files. Spreading related code does not make it easier to understand, on the contrary. That means, NMClient is inherently complex as it contains most of the logic. I think that is not avoidable, but it's not as bad as it sounds. - NMClient processes D-Bus messages and state changes in separate steps. First NMClient unpacks the message (e.g. _dbus_handle_properties_changed()) and keeps track of the changed data. Then we update the GObject instances (_dbus_handle_obj_changed_dbus()) without emitting any signals yet. Finally, we emit all signals and notifications that were collected (_dbus_handle_changes_commit()). Note that for example during the initial GetManagedObjects() reply, NMClient receive a large amount of state at once. But we first apply all the changes to our GObject instances before emitting any signals. The result is that signals are always emitted in a moment when the cache is consistent. The unavoidable downside is that when you receive a property changed signal, possibly many other properties changed already and more signals are about to be emitted. - NMDeviceWifi no longer modifies the content of the cache from client side during poke_wireless_devices_with_rf_status(). The content of the cache should be determined by D-Bus alone and follow what NetworkManager service exposes. Local modifications should be avoided. - This aims to bring no API/ABI change, though it does of course bring various subtle changes in behavior. Those should be all for the better, but the goal is not to break any existing clients. This does change internal (albeit externally visible) API, like dropping NM_OBJECT_DBUS_OBJECT_MANAGER property and NMObject no longer implementing GInitableIface and GAsyncInitableIface. - Some uses of gdbus-codegen classes remain in NMVpnPluginOld, NMVpnServicePlugin and NMSecretAgentOld. These are independent of NMClient/NMObject and should be reworked separately. - While we no longer use generated classes from gdbus-codegen, we don't need more glue code than before. Also before we constructed NMPropertiesInfo and a had large amount of code to propagate properties from NMDBus* to NMObject. That got completely reworked, but did not fundamentally change. You still need about the same effort to create the NMLDBusMetaIface. Not using generated bindings did not make anything worse (which tells about the usefulness of generated code, at least in the way it was used). - NMLDBusMetaIface and other meta data is static and immutable. This avoids copying them around. Also, macros like NML_DBUS_META_PROPERTY_INIT_U() have compile time checks to ensure the property types matches. It's pretty hard to misuse them because it won't compile. - The meta data now explicitly encodes the expected D-Bus types and makes sure never to accept wrong data. That would only matter when the server (accidentally or intentionally) exposes unexpected types on D-Bus. I don't think that was previously ensured in all cases. For example, demarshal_generic() only cared about the GObject property type, it didn't know the expected D-Bus type. - Previously GDBusObjectManager would sometimes emit warnings (g_log()). Those probably indicated real bugs. In any case, it prevented us from running CI with G_DEBUG=fatal-warnings, because there would be just too many unrelated crashes. Now we log debug messages that can be enabled with "LIBNM_CLIENT_DEBUG=trace". Some of these messages can also be turned into g_warning()/g_critical() by setting LIBNM_CLIENT_DEBUG=warning,error. Together with G_DEBUG=fatal-warnings, this turns them into assertions. Note that such "assertion failures" might also happen because of a server bug (or change). Thus these are not common assertions that indicate a bug in libnm and are thus not armed unless explicitly requested. In our CI we should now always run with LIBNM_CLIENT_DEBUG=warning,error and G_DEBUG=fatal-warnings and to catch bugs. Note that currently NetworkManager has bugs in this regard, so enabling this will result in assertion failures. That should be fixed first. - Note that this changes the order in which we emit "notify:devices" and "device-added" signals. I think it makes the most sense to emit first "device-removed", then "notify:devices", and finally "device-added" signals. This changes behavior for commit 52ae28f6e5bf ('libnm: queue added/removed signals and suppress uninitialized notifications'), but I don't think that users should actually rely on the order. Still, the new order makes the most sense to me. - In NetworkManager, profiles can be invisible to the user by setting "connection.permissions". Such profiles would be hidden by NMClient's nm_client_get_connections() and their "connection-added"/"connection-removed" signals. Note that NMActiveConnection's nm_active_connection_get_connection() and NMDevice's nm_device_get_available_connections() still exposes such hidden NMRemoteConnection instances. This behavior was preserved. NUMBERS ------- I compared 3 versions of libnm. [1] 962297f9085d, current tip of nm-1-20 branch [2] 4fad8c7c642e, current master, immediate parent of this patch [3] this patch All tests were done on Fedora 31, x86_64, gcc 9.2.1-1.fc31. The libraries were build with $ ./contrib/fedora/rpm/build_clean.sh -g -w test -W debug Note that RPM build already stripped the library. --- N1) File size of libnm.so.0.1.0 in bytes. There currently seems to be a issue on Fedora 31 generating wrong ELF notes. Usually, libnm is smaller but in these tests it had large (and bogus) ELF notes. Anyway, the point is to show the relative sizes, so it doesn't matter). [1] 4075552 (102.7%) [2] 3969624 (100.0%) [3] 3705208 ( 93.3%) --- N2) `size /usr/lib64/libnm.so.0.1.0`: text data bss dec hex filename [1] 1314569 (102.0%) 69980 ( 94.8%) 10632 ( 80.4%) 1395181 (101.4%) 1549ed /usr/lib64/libnm.so.0.1.0 [2] 1288410 (100.0%) 73796 (100.0%) 13224 (100.0%) 1375430 (100.0%) 14fcc6 /usr/lib64/libnm.so.0.1.0 [3] 1229066 ( 95.4%) 65248 ( 88.4%) 13400 (101.3%) 1307714 ( 95.1%) 13f442 /usr/lib64/libnm.so.0.1.0 --- N3) Performance test with test-client.py. With checkout of [2], run ``` prepare_checkout() { rm -rf /tmp/nm-test && \ git checkout -B test 4fad8c7c642e && \ git clean -fdx && \ ./autogen.sh --prefix=/tmp/nm-test && \ make -j 5 install && \ make -j 5 check-local-clients-tests-test-client } prepare_test() { NM_TEST_REGENERATE=1 NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v } do_test() { for i in {1..10}; do NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v || return -1 done echo "done!" } prepare_checkout prepare_test time do_test ``` [1] real 2m14.497s (101.3%) user 5m26.651s (100.3%) sys 1m40.453s (101.4%) [2] real 2m12.800s (100.0%) user 5m25.619s (100.0%) sys 1m39.065s (100.0%) [3] real 1m54.915s ( 86.5%) user 4m18.585s ( 79.4%) sys 1m32.066s ( 92.9%) --- N4) Performance. Run NetworkManager from build [2] and setup a large number of profiles (551 profiles and 515 devices, mostly unrealized). This setup is already at the edge of what NetworkManager currently can handle. Of course, that is a different issue. Here we just check how long plain `nmcli` takes on the system. ``` do_cleanup() { for UUID in $(nmcli -g NAME,UUID connection show | sed -n 's/^xx-c-.*:\([^:]\+\)$/\1/p'); do nmcli connection delete uuid "$UUID" done for DEVICE in $(nmcli -g DEVICE device status | grep '^xx-i-'); do nmcli device delete "$DEVICE" done } do_setup() { do_cleanup for i in {1..30}; do nmcli connection add type bond autoconnect no con-name xx-c-bond-$i ifname xx-i-bond-$i ipv4.method disabled ipv6.method ignore for j in $(seq $i 30); do nmcli connection add type vlan autoconnect no con-name xx-c-vlan-$i-$j vlan.id $j ifname xx-i-vlan-$i-$j vlan.parent xx-i-bond-$i ipv4.method disabled ipv6.method ignore done done systemctl restart NetworkManager.service sleep 5 } do_test() { perf stat -r 50 -B nmcli 1>/dev/null } do_test ``` [1] Performance counter stats for 'nmcli' (50 runs): 456.33 msec task-clock:u # 1.093 CPUs utilized ( +- 0.44% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,900 page-faults:u # 0.013 M/sec ( +- 0.02% ) 1,408,675,453 cycles:u # 3.087 GHz ( +- 0.48% ) 1,594,741,060 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 368,744,018 branches:u # 808.061 M/sec ( +- 0.02% ) 4,566,058 branch-misses:u # 1.24% of all branches ( +- 0.76% ) 0.41761 +- 0.00282 seconds time elapsed ( +- 0.68% ) [2] Performance counter stats for 'nmcli' (50 runs): 477.99 msec task-clock:u # 1.088 CPUs utilized ( +- 0.36% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,948 page-faults:u # 0.012 M/sec ( +- 0.03% ) 1,471,133,482 cycles:u # 3.078 GHz ( +- 0.36% ) 1,655,275,369 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 382,595,152 branches:u # 800.433 M/sec ( +- 0.02% ) 4,746,070 branch-misses:u # 1.24% of all branches ( +- 0.49% ) 0.43923 +- 0.00242 seconds time elapsed ( +- 0.55% ) [3] Performance counter stats for 'nmcli' (50 runs): 352.36 msec task-clock:u # 1.027 CPUs utilized ( +- 0.32% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 4,790 page-faults:u # 0.014 M/sec ( +- 0.26% ) 1,092,341,186 cycles:u # 3.100 GHz ( +- 0.26% ) 1,209,045,283 instructions:u # 1.11 insn per cycle ( +- 0.02% ) 281,708,462 branches:u # 799.499 M/sec ( +- 0.01% ) 3,101,031 branch-misses:u # 1.10% of all branches ( +- 0.61% ) 0.34296 +- 0.00120 seconds time elapsed ( +- 0.35% ) --- N5) same setup as N4), but run `PAGER= /bin/time -v nmcli`: [1] Command being timed: "nmcli" User time (seconds): 0.42 System time (seconds): 0.04 Percent of CPU this job got: 107% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.43 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34456 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6128 Voluntary context switches: 1298 Involuntary context switches: 1106 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [2] Command being timed: "nmcli" User time (seconds): 0.44 System time (seconds): 0.04 Percent of CPU this job got: 108% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.44 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34452 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6169 Voluntary context switches: 1849 Involuntary context switches: 142 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [3] Command being timed: "nmcli" User time (seconds): 0.32 System time (seconds): 0.02 Percent of CPU this job got: 102% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.34 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 29196 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 5059 Voluntary context switches: 919 Involuntary context switches: 685 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 --- N6) same setup as N4), but run `nmcli monitor` and look at `ps aux` for the RSS size. USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND [1] me 1492900 21.0 0.2 461348 33248 pts/10 Sl+ 15:02 0:00 nmcli monitor [2] me 1490721 5.0 0.2 461496 33548 pts/10 Sl+ 15:00 0:00 nmcli monitor [3] me 1495801 16.5 0.1 459476 28692 pts/10 Sl+ 15:04 0:00 nmcli monitor
2019-10-30 11:42:58 +01:00
priv->udev = _nm_client_get_udev (client);
if (priv->udev)
udev_ref (priv->udev);
libnm: refactor caching of D-Bus objects in NMClient No longer use GDBusObjectMangaerClient and gdbus-codegen generated classes for the NMClient cache. Instead, use GDBusConnection directly and a custom implementation (NMLDBusObject) for caching D-Bus' ObjectManager data. CHANGES ------- - This is a complete rework. I think the previous implementation was difficult to understand. There were unfixed bugs and nobody understood the code well enough to fix them. Maybe somebody out there understood the code, but I certainly did not. At least nobody provided patches to fix those issues. I do believe that this implementation is more straightforward and easier to understand. It removes a lot of layers of code. Whether this claim of simplicity is true, each reader must decide for himself/herself. Note that it is still fairly complex. - There was a lingering performance issue with large number of D-Bus objects. The patch tries hard that the implementation scales well. Of course, when we cache N objects that have N-to-M references to other, we still are fundamentally O(N*M) for runtime and memory consumption (with M being the number of references between objects). But each part should behave efficiently and well. - Play well with GMainContext. libnm code (NMClient) is generally not thread safe. However, it should work to use multiple instances in parallel, as long as each access to a NMClient is through the caller's GMainContext. This follows glib's style and effectively allows to use NMClient in a multi threaded scenario. This implies to stick to a main context upon construction and ensure that callbacks are only invoked when iterating that context. Also, NMClient itself shall never iterate the caller's context. This also means, libnm must never use g_idle_add() or g_timeout_add(), as those enqueue sources in the g_main_context_default() context. - Get ordering of messages right. All events are consistently enqueued in a GMainContext and processed strictly in order. For example, previously "nm-object.c" tried to combine signals and emit them on an idle handler. That is wrong, signals must be emitted in the right order and when they happen. Note that when using GInitable's synchronous initialization to initialize the NMClient instance, NMClient internally still operates fully asynchronously. In that case NMClient has an internal main context. - NMClient takes over most of the functionality. When using D-Bus' ObjectManager interface, one needs to handle basically the entire state of the D-Bus interface. That cannot be separated well into distinct parts, and even if you try, you just end up having closely related code in different source files. Spreading related code does not make it easier to understand, on the contrary. That means, NMClient is inherently complex as it contains most of the logic. I think that is not avoidable, but it's not as bad as it sounds. - NMClient processes D-Bus messages and state changes in separate steps. First NMClient unpacks the message (e.g. _dbus_handle_properties_changed()) and keeps track of the changed data. Then we update the GObject instances (_dbus_handle_obj_changed_dbus()) without emitting any signals yet. Finally, we emit all signals and notifications that were collected (_dbus_handle_changes_commit()). Note that for example during the initial GetManagedObjects() reply, NMClient receive a large amount of state at once. But we first apply all the changes to our GObject instances before emitting any signals. The result is that signals are always emitted in a moment when the cache is consistent. The unavoidable downside is that when you receive a property changed signal, possibly many other properties changed already and more signals are about to be emitted. - NMDeviceWifi no longer modifies the content of the cache from client side during poke_wireless_devices_with_rf_status(). The content of the cache should be determined by D-Bus alone and follow what NetworkManager service exposes. Local modifications should be avoided. - This aims to bring no API/ABI change, though it does of course bring various subtle changes in behavior. Those should be all for the better, but the goal is not to break any existing clients. This does change internal (albeit externally visible) API, like dropping NM_OBJECT_DBUS_OBJECT_MANAGER property and NMObject no longer implementing GInitableIface and GAsyncInitableIface. - Some uses of gdbus-codegen classes remain in NMVpnPluginOld, NMVpnServicePlugin and NMSecretAgentOld. These are independent of NMClient/NMObject and should be reworked separately. - While we no longer use generated classes from gdbus-codegen, we don't need more glue code than before. Also before we constructed NMPropertiesInfo and a had large amount of code to propagate properties from NMDBus* to NMObject. That got completely reworked, but did not fundamentally change. You still need about the same effort to create the NMLDBusMetaIface. Not using generated bindings did not make anything worse (which tells about the usefulness of generated code, at least in the way it was used). - NMLDBusMetaIface and other meta data is static and immutable. This avoids copying them around. Also, macros like NML_DBUS_META_PROPERTY_INIT_U() have compile time checks to ensure the property types matches. It's pretty hard to misuse them because it won't compile. - The meta data now explicitly encodes the expected D-Bus types and makes sure never to accept wrong data. That would only matter when the server (accidentally or intentionally) exposes unexpected types on D-Bus. I don't think that was previously ensured in all cases. For example, demarshal_generic() only cared about the GObject property type, it didn't know the expected D-Bus type. - Previously GDBusObjectManager would sometimes emit warnings (g_log()). Those probably indicated real bugs. In any case, it prevented us from running CI with G_DEBUG=fatal-warnings, because there would be just too many unrelated crashes. Now we log debug messages that can be enabled with "LIBNM_CLIENT_DEBUG=trace". Some of these messages can also be turned into g_warning()/g_critical() by setting LIBNM_CLIENT_DEBUG=warning,error. Together with G_DEBUG=fatal-warnings, this turns them into assertions. Note that such "assertion failures" might also happen because of a server bug (or change). Thus these are not common assertions that indicate a bug in libnm and are thus not armed unless explicitly requested. In our CI we should now always run with LIBNM_CLIENT_DEBUG=warning,error and G_DEBUG=fatal-warnings and to catch bugs. Note that currently NetworkManager has bugs in this regard, so enabling this will result in assertion failures. That should be fixed first. - Note that this changes the order in which we emit "notify:devices" and "device-added" signals. I think it makes the most sense to emit first "device-removed", then "notify:devices", and finally "device-added" signals. This changes behavior for commit 52ae28f6e5bf ('libnm: queue added/removed signals and suppress uninitialized notifications'), but I don't think that users should actually rely on the order. Still, the new order makes the most sense to me. - In NetworkManager, profiles can be invisible to the user by setting "connection.permissions". Such profiles would be hidden by NMClient's nm_client_get_connections() and their "connection-added"/"connection-removed" signals. Note that NMActiveConnection's nm_active_connection_get_connection() and NMDevice's nm_device_get_available_connections() still exposes such hidden NMRemoteConnection instances. This behavior was preserved. NUMBERS ------- I compared 3 versions of libnm. [1] 962297f9085d, current tip of nm-1-20 branch [2] 4fad8c7c642e, current master, immediate parent of this patch [3] this patch All tests were done on Fedora 31, x86_64, gcc 9.2.1-1.fc31. The libraries were build with $ ./contrib/fedora/rpm/build_clean.sh -g -w test -W debug Note that RPM build already stripped the library. --- N1) File size of libnm.so.0.1.0 in bytes. There currently seems to be a issue on Fedora 31 generating wrong ELF notes. Usually, libnm is smaller but in these tests it had large (and bogus) ELF notes. Anyway, the point is to show the relative sizes, so it doesn't matter). [1] 4075552 (102.7%) [2] 3969624 (100.0%) [3] 3705208 ( 93.3%) --- N2) `size /usr/lib64/libnm.so.0.1.0`: text data bss dec hex filename [1] 1314569 (102.0%) 69980 ( 94.8%) 10632 ( 80.4%) 1395181 (101.4%) 1549ed /usr/lib64/libnm.so.0.1.0 [2] 1288410 (100.0%) 73796 (100.0%) 13224 (100.0%) 1375430 (100.0%) 14fcc6 /usr/lib64/libnm.so.0.1.0 [3] 1229066 ( 95.4%) 65248 ( 88.4%) 13400 (101.3%) 1307714 ( 95.1%) 13f442 /usr/lib64/libnm.so.0.1.0 --- N3) Performance test with test-client.py. With checkout of [2], run ``` prepare_checkout() { rm -rf /tmp/nm-test && \ git checkout -B test 4fad8c7c642e && \ git clean -fdx && \ ./autogen.sh --prefix=/tmp/nm-test && \ make -j 5 install && \ make -j 5 check-local-clients-tests-test-client } prepare_test() { NM_TEST_REGENERATE=1 NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v } do_test() { for i in {1..10}; do NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v || return -1 done echo "done!" } prepare_checkout prepare_test time do_test ``` [1] real 2m14.497s (101.3%) user 5m26.651s (100.3%) sys 1m40.453s (101.4%) [2] real 2m12.800s (100.0%) user 5m25.619s (100.0%) sys 1m39.065s (100.0%) [3] real 1m54.915s ( 86.5%) user 4m18.585s ( 79.4%) sys 1m32.066s ( 92.9%) --- N4) Performance. Run NetworkManager from build [2] and setup a large number of profiles (551 profiles and 515 devices, mostly unrealized). This setup is already at the edge of what NetworkManager currently can handle. Of course, that is a different issue. Here we just check how long plain `nmcli` takes on the system. ``` do_cleanup() { for UUID in $(nmcli -g NAME,UUID connection show | sed -n 's/^xx-c-.*:\([^:]\+\)$/\1/p'); do nmcli connection delete uuid "$UUID" done for DEVICE in $(nmcli -g DEVICE device status | grep '^xx-i-'); do nmcli device delete "$DEVICE" done } do_setup() { do_cleanup for i in {1..30}; do nmcli connection add type bond autoconnect no con-name xx-c-bond-$i ifname xx-i-bond-$i ipv4.method disabled ipv6.method ignore for j in $(seq $i 30); do nmcli connection add type vlan autoconnect no con-name xx-c-vlan-$i-$j vlan.id $j ifname xx-i-vlan-$i-$j vlan.parent xx-i-bond-$i ipv4.method disabled ipv6.method ignore done done systemctl restart NetworkManager.service sleep 5 } do_test() { perf stat -r 50 -B nmcli 1>/dev/null } do_test ``` [1] Performance counter stats for 'nmcli' (50 runs): 456.33 msec task-clock:u # 1.093 CPUs utilized ( +- 0.44% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,900 page-faults:u # 0.013 M/sec ( +- 0.02% ) 1,408,675,453 cycles:u # 3.087 GHz ( +- 0.48% ) 1,594,741,060 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 368,744,018 branches:u # 808.061 M/sec ( +- 0.02% ) 4,566,058 branch-misses:u # 1.24% of all branches ( +- 0.76% ) 0.41761 +- 0.00282 seconds time elapsed ( +- 0.68% ) [2] Performance counter stats for 'nmcli' (50 runs): 477.99 msec task-clock:u # 1.088 CPUs utilized ( +- 0.36% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,948 page-faults:u # 0.012 M/sec ( +- 0.03% ) 1,471,133,482 cycles:u # 3.078 GHz ( +- 0.36% ) 1,655,275,369 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 382,595,152 branches:u # 800.433 M/sec ( +- 0.02% ) 4,746,070 branch-misses:u # 1.24% of all branches ( +- 0.49% ) 0.43923 +- 0.00242 seconds time elapsed ( +- 0.55% ) [3] Performance counter stats for 'nmcli' (50 runs): 352.36 msec task-clock:u # 1.027 CPUs utilized ( +- 0.32% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 4,790 page-faults:u # 0.014 M/sec ( +- 0.26% ) 1,092,341,186 cycles:u # 3.100 GHz ( +- 0.26% ) 1,209,045,283 instructions:u # 1.11 insn per cycle ( +- 0.02% ) 281,708,462 branches:u # 799.499 M/sec ( +- 0.01% ) 3,101,031 branch-misses:u # 1.10% of all branches ( +- 0.61% ) 0.34296 +- 0.00120 seconds time elapsed ( +- 0.35% ) --- N5) same setup as N4), but run `PAGER= /bin/time -v nmcli`: [1] Command being timed: "nmcli" User time (seconds): 0.42 System time (seconds): 0.04 Percent of CPU this job got: 107% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.43 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34456 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6128 Voluntary context switches: 1298 Involuntary context switches: 1106 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [2] Command being timed: "nmcli" User time (seconds): 0.44 System time (seconds): 0.04 Percent of CPU this job got: 108% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.44 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34452 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6169 Voluntary context switches: 1849 Involuntary context switches: 142 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [3] Command being timed: "nmcli" User time (seconds): 0.32 System time (seconds): 0.02 Percent of CPU this job got: 102% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.34 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 29196 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 5059 Voluntary context switches: 919 Involuntary context switches: 685 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 --- N6) same setup as N4), but run `nmcli monitor` and look at `ps aux` for the RSS size. USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND [1] me 1492900 21.0 0.2 461348 33248 pts/10 Sl+ 15:02 0:00 nmcli monitor [2] me 1490721 5.0 0.2 461496 33548 pts/10 Sl+ 15:00 0:00 nmcli monitor [3] me 1495801 16.5 0.1 459476 28692 pts/10 Sl+ 15:04 0:00 nmcli monitor
2019-10-30 11:42:58 +01:00
NM_OBJECT_CLASS (nm_device_parent_class)->register_client (nmobj, client, dbobj);
}
libnm: refactor caching of D-Bus objects in NMClient No longer use GDBusObjectMangaerClient and gdbus-codegen generated classes for the NMClient cache. Instead, use GDBusConnection directly and a custom implementation (NMLDBusObject) for caching D-Bus' ObjectManager data. CHANGES ------- - This is a complete rework. I think the previous implementation was difficult to understand. There were unfixed bugs and nobody understood the code well enough to fix them. Maybe somebody out there understood the code, but I certainly did not. At least nobody provided patches to fix those issues. I do believe that this implementation is more straightforward and easier to understand. It removes a lot of layers of code. Whether this claim of simplicity is true, each reader must decide for himself/herself. Note that it is still fairly complex. - There was a lingering performance issue with large number of D-Bus objects. The patch tries hard that the implementation scales well. Of course, when we cache N objects that have N-to-M references to other, we still are fundamentally O(N*M) for runtime and memory consumption (with M being the number of references between objects). But each part should behave efficiently and well. - Play well with GMainContext. libnm code (NMClient) is generally not thread safe. However, it should work to use multiple instances in parallel, as long as each access to a NMClient is through the caller's GMainContext. This follows glib's style and effectively allows to use NMClient in a multi threaded scenario. This implies to stick to a main context upon construction and ensure that callbacks are only invoked when iterating that context. Also, NMClient itself shall never iterate the caller's context. This also means, libnm must never use g_idle_add() or g_timeout_add(), as those enqueue sources in the g_main_context_default() context. - Get ordering of messages right. All events are consistently enqueued in a GMainContext and processed strictly in order. For example, previously "nm-object.c" tried to combine signals and emit them on an idle handler. That is wrong, signals must be emitted in the right order and when they happen. Note that when using GInitable's synchronous initialization to initialize the NMClient instance, NMClient internally still operates fully asynchronously. In that case NMClient has an internal main context. - NMClient takes over most of the functionality. When using D-Bus' ObjectManager interface, one needs to handle basically the entire state of the D-Bus interface. That cannot be separated well into distinct parts, and even if you try, you just end up having closely related code in different source files. Spreading related code does not make it easier to understand, on the contrary. That means, NMClient is inherently complex as it contains most of the logic. I think that is not avoidable, but it's not as bad as it sounds. - NMClient processes D-Bus messages and state changes in separate steps. First NMClient unpacks the message (e.g. _dbus_handle_properties_changed()) and keeps track of the changed data. Then we update the GObject instances (_dbus_handle_obj_changed_dbus()) without emitting any signals yet. Finally, we emit all signals and notifications that were collected (_dbus_handle_changes_commit()). Note that for example during the initial GetManagedObjects() reply, NMClient receive a large amount of state at once. But we first apply all the changes to our GObject instances before emitting any signals. The result is that signals are always emitted in a moment when the cache is consistent. The unavoidable downside is that when you receive a property changed signal, possibly many other properties changed already and more signals are about to be emitted. - NMDeviceWifi no longer modifies the content of the cache from client side during poke_wireless_devices_with_rf_status(). The content of the cache should be determined by D-Bus alone and follow what NetworkManager service exposes. Local modifications should be avoided. - This aims to bring no API/ABI change, though it does of course bring various subtle changes in behavior. Those should be all for the better, but the goal is not to break any existing clients. This does change internal (albeit externally visible) API, like dropping NM_OBJECT_DBUS_OBJECT_MANAGER property and NMObject no longer implementing GInitableIface and GAsyncInitableIface. - Some uses of gdbus-codegen classes remain in NMVpnPluginOld, NMVpnServicePlugin and NMSecretAgentOld. These are independent of NMClient/NMObject and should be reworked separately. - While we no longer use generated classes from gdbus-codegen, we don't need more glue code than before. Also before we constructed NMPropertiesInfo and a had large amount of code to propagate properties from NMDBus* to NMObject. That got completely reworked, but did not fundamentally change. You still need about the same effort to create the NMLDBusMetaIface. Not using generated bindings did not make anything worse (which tells about the usefulness of generated code, at least in the way it was used). - NMLDBusMetaIface and other meta data is static and immutable. This avoids copying them around. Also, macros like NML_DBUS_META_PROPERTY_INIT_U() have compile time checks to ensure the property types matches. It's pretty hard to misuse them because it won't compile. - The meta data now explicitly encodes the expected D-Bus types and makes sure never to accept wrong data. That would only matter when the server (accidentally or intentionally) exposes unexpected types on D-Bus. I don't think that was previously ensured in all cases. For example, demarshal_generic() only cared about the GObject property type, it didn't know the expected D-Bus type. - Previously GDBusObjectManager would sometimes emit warnings (g_log()). Those probably indicated real bugs. In any case, it prevented us from running CI with G_DEBUG=fatal-warnings, because there would be just too many unrelated crashes. Now we log debug messages that can be enabled with "LIBNM_CLIENT_DEBUG=trace". Some of these messages can also be turned into g_warning()/g_critical() by setting LIBNM_CLIENT_DEBUG=warning,error. Together with G_DEBUG=fatal-warnings, this turns them into assertions. Note that such "assertion failures" might also happen because of a server bug (or change). Thus these are not common assertions that indicate a bug in libnm and are thus not armed unless explicitly requested. In our CI we should now always run with LIBNM_CLIENT_DEBUG=warning,error and G_DEBUG=fatal-warnings and to catch bugs. Note that currently NetworkManager has bugs in this regard, so enabling this will result in assertion failures. That should be fixed first. - Note that this changes the order in which we emit "notify:devices" and "device-added" signals. I think it makes the most sense to emit first "device-removed", then "notify:devices", and finally "device-added" signals. This changes behavior for commit 52ae28f6e5bf ('libnm: queue added/removed signals and suppress uninitialized notifications'), but I don't think that users should actually rely on the order. Still, the new order makes the most sense to me. - In NetworkManager, profiles can be invisible to the user by setting "connection.permissions". Such profiles would be hidden by NMClient's nm_client_get_connections() and their "connection-added"/"connection-removed" signals. Note that NMActiveConnection's nm_active_connection_get_connection() and NMDevice's nm_device_get_available_connections() still exposes such hidden NMRemoteConnection instances. This behavior was preserved. NUMBERS ------- I compared 3 versions of libnm. [1] 962297f9085d, current tip of nm-1-20 branch [2] 4fad8c7c642e, current master, immediate parent of this patch [3] this patch All tests were done on Fedora 31, x86_64, gcc 9.2.1-1.fc31. The libraries were build with $ ./contrib/fedora/rpm/build_clean.sh -g -w test -W debug Note that RPM build already stripped the library. --- N1) File size of libnm.so.0.1.0 in bytes. There currently seems to be a issue on Fedora 31 generating wrong ELF notes. Usually, libnm is smaller but in these tests it had large (and bogus) ELF notes. Anyway, the point is to show the relative sizes, so it doesn't matter). [1] 4075552 (102.7%) [2] 3969624 (100.0%) [3] 3705208 ( 93.3%) --- N2) `size /usr/lib64/libnm.so.0.1.0`: text data bss dec hex filename [1] 1314569 (102.0%) 69980 ( 94.8%) 10632 ( 80.4%) 1395181 (101.4%) 1549ed /usr/lib64/libnm.so.0.1.0 [2] 1288410 (100.0%) 73796 (100.0%) 13224 (100.0%) 1375430 (100.0%) 14fcc6 /usr/lib64/libnm.so.0.1.0 [3] 1229066 ( 95.4%) 65248 ( 88.4%) 13400 (101.3%) 1307714 ( 95.1%) 13f442 /usr/lib64/libnm.so.0.1.0 --- N3) Performance test with test-client.py. With checkout of [2], run ``` prepare_checkout() { rm -rf /tmp/nm-test && \ git checkout -B test 4fad8c7c642e && \ git clean -fdx && \ ./autogen.sh --prefix=/tmp/nm-test && \ make -j 5 install && \ make -j 5 check-local-clients-tests-test-client } prepare_test() { NM_TEST_REGENERATE=1 NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v } do_test() { for i in {1..10}; do NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v || return -1 done echo "done!" } prepare_checkout prepare_test time do_test ``` [1] real 2m14.497s (101.3%) user 5m26.651s (100.3%) sys 1m40.453s (101.4%) [2] real 2m12.800s (100.0%) user 5m25.619s (100.0%) sys 1m39.065s (100.0%) [3] real 1m54.915s ( 86.5%) user 4m18.585s ( 79.4%) sys 1m32.066s ( 92.9%) --- N4) Performance. Run NetworkManager from build [2] and setup a large number of profiles (551 profiles and 515 devices, mostly unrealized). This setup is already at the edge of what NetworkManager currently can handle. Of course, that is a different issue. Here we just check how long plain `nmcli` takes on the system. ``` do_cleanup() { for UUID in $(nmcli -g NAME,UUID connection show | sed -n 's/^xx-c-.*:\([^:]\+\)$/\1/p'); do nmcli connection delete uuid "$UUID" done for DEVICE in $(nmcli -g DEVICE device status | grep '^xx-i-'); do nmcli device delete "$DEVICE" done } do_setup() { do_cleanup for i in {1..30}; do nmcli connection add type bond autoconnect no con-name xx-c-bond-$i ifname xx-i-bond-$i ipv4.method disabled ipv6.method ignore for j in $(seq $i 30); do nmcli connection add type vlan autoconnect no con-name xx-c-vlan-$i-$j vlan.id $j ifname xx-i-vlan-$i-$j vlan.parent xx-i-bond-$i ipv4.method disabled ipv6.method ignore done done systemctl restart NetworkManager.service sleep 5 } do_test() { perf stat -r 50 -B nmcli 1>/dev/null } do_test ``` [1] Performance counter stats for 'nmcli' (50 runs): 456.33 msec task-clock:u # 1.093 CPUs utilized ( +- 0.44% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,900 page-faults:u # 0.013 M/sec ( +- 0.02% ) 1,408,675,453 cycles:u # 3.087 GHz ( +- 0.48% ) 1,594,741,060 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 368,744,018 branches:u # 808.061 M/sec ( +- 0.02% ) 4,566,058 branch-misses:u # 1.24% of all branches ( +- 0.76% ) 0.41761 +- 0.00282 seconds time elapsed ( +- 0.68% ) [2] Performance counter stats for 'nmcli' (50 runs): 477.99 msec task-clock:u # 1.088 CPUs utilized ( +- 0.36% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,948 page-faults:u # 0.012 M/sec ( +- 0.03% ) 1,471,133,482 cycles:u # 3.078 GHz ( +- 0.36% ) 1,655,275,369 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 382,595,152 branches:u # 800.433 M/sec ( +- 0.02% ) 4,746,070 branch-misses:u # 1.24% of all branches ( +- 0.49% ) 0.43923 +- 0.00242 seconds time elapsed ( +- 0.55% ) [3] Performance counter stats for 'nmcli' (50 runs): 352.36 msec task-clock:u # 1.027 CPUs utilized ( +- 0.32% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 4,790 page-faults:u # 0.014 M/sec ( +- 0.26% ) 1,092,341,186 cycles:u # 3.100 GHz ( +- 0.26% ) 1,209,045,283 instructions:u # 1.11 insn per cycle ( +- 0.02% ) 281,708,462 branches:u # 799.499 M/sec ( +- 0.01% ) 3,101,031 branch-misses:u # 1.10% of all branches ( +- 0.61% ) 0.34296 +- 0.00120 seconds time elapsed ( +- 0.35% ) --- N5) same setup as N4), but run `PAGER= /bin/time -v nmcli`: [1] Command being timed: "nmcli" User time (seconds): 0.42 System time (seconds): 0.04 Percent of CPU this job got: 107% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.43 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34456 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6128 Voluntary context switches: 1298 Involuntary context switches: 1106 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [2] Command being timed: "nmcli" User time (seconds): 0.44 System time (seconds): 0.04 Percent of CPU this job got: 108% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.44 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34452 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6169 Voluntary context switches: 1849 Involuntary context switches: 142 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [3] Command being timed: "nmcli" User time (seconds): 0.32 System time (seconds): 0.02 Percent of CPU this job got: 102% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.34 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 29196 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 5059 Voluntary context switches: 919 Involuntary context switches: 685 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 --- N6) same setup as N4), but run `nmcli monitor` and look at `ps aux` for the RSS size. USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND [1] me 1492900 21.0 0.2 461348 33248 pts/10 Sl+ 15:02 0:00 nmcli monitor [2] me 1490721 5.0 0.2 461496 33548 pts/10 Sl+ 15:00 0:00 nmcli monitor [3] me 1495801 16.5 0.1 459476 28692 pts/10 Sl+ 15:04 0:00 nmcli monitor
2019-10-30 11:42:58 +01:00
/*****************************************************************************/
static void
finalize (GObject *object)
{
NMDevicePrivate *priv = NM_DEVICE_GET_PRIVATE (object);
nm_clear_pointer (&priv->lldp_neighbors, g_ptr_array_unref);
libnm: refactor caching of D-Bus objects in NMClient No longer use GDBusObjectMangaerClient and gdbus-codegen generated classes for the NMClient cache. Instead, use GDBusConnection directly and a custom implementation (NMLDBusObject) for caching D-Bus' ObjectManager data. CHANGES ------- - This is a complete rework. I think the previous implementation was difficult to understand. There were unfixed bugs and nobody understood the code well enough to fix them. Maybe somebody out there understood the code, but I certainly did not. At least nobody provided patches to fix those issues. I do believe that this implementation is more straightforward and easier to understand. It removes a lot of layers of code. Whether this claim of simplicity is true, each reader must decide for himself/herself. Note that it is still fairly complex. - There was a lingering performance issue with large number of D-Bus objects. The patch tries hard that the implementation scales well. Of course, when we cache N objects that have N-to-M references to other, we still are fundamentally O(N*M) for runtime and memory consumption (with M being the number of references between objects). But each part should behave efficiently and well. - Play well with GMainContext. libnm code (NMClient) is generally not thread safe. However, it should work to use multiple instances in parallel, as long as each access to a NMClient is through the caller's GMainContext. This follows glib's style and effectively allows to use NMClient in a multi threaded scenario. This implies to stick to a main context upon construction and ensure that callbacks are only invoked when iterating that context. Also, NMClient itself shall never iterate the caller's context. This also means, libnm must never use g_idle_add() or g_timeout_add(), as those enqueue sources in the g_main_context_default() context. - Get ordering of messages right. All events are consistently enqueued in a GMainContext and processed strictly in order. For example, previously "nm-object.c" tried to combine signals and emit them on an idle handler. That is wrong, signals must be emitted in the right order and when they happen. Note that when using GInitable's synchronous initialization to initialize the NMClient instance, NMClient internally still operates fully asynchronously. In that case NMClient has an internal main context. - NMClient takes over most of the functionality. When using D-Bus' ObjectManager interface, one needs to handle basically the entire state of the D-Bus interface. That cannot be separated well into distinct parts, and even if you try, you just end up having closely related code in different source files. Spreading related code does not make it easier to understand, on the contrary. That means, NMClient is inherently complex as it contains most of the logic. I think that is not avoidable, but it's not as bad as it sounds. - NMClient processes D-Bus messages and state changes in separate steps. First NMClient unpacks the message (e.g. _dbus_handle_properties_changed()) and keeps track of the changed data. Then we update the GObject instances (_dbus_handle_obj_changed_dbus()) without emitting any signals yet. Finally, we emit all signals and notifications that were collected (_dbus_handle_changes_commit()). Note that for example during the initial GetManagedObjects() reply, NMClient receive a large amount of state at once. But we first apply all the changes to our GObject instances before emitting any signals. The result is that signals are always emitted in a moment when the cache is consistent. The unavoidable downside is that when you receive a property changed signal, possibly many other properties changed already and more signals are about to be emitted. - NMDeviceWifi no longer modifies the content of the cache from client side during poke_wireless_devices_with_rf_status(). The content of the cache should be determined by D-Bus alone and follow what NetworkManager service exposes. Local modifications should be avoided. - This aims to bring no API/ABI change, though it does of course bring various subtle changes in behavior. Those should be all for the better, but the goal is not to break any existing clients. This does change internal (albeit externally visible) API, like dropping NM_OBJECT_DBUS_OBJECT_MANAGER property and NMObject no longer implementing GInitableIface and GAsyncInitableIface. - Some uses of gdbus-codegen classes remain in NMVpnPluginOld, NMVpnServicePlugin and NMSecretAgentOld. These are independent of NMClient/NMObject and should be reworked separately. - While we no longer use generated classes from gdbus-codegen, we don't need more glue code than before. Also before we constructed NMPropertiesInfo and a had large amount of code to propagate properties from NMDBus* to NMObject. That got completely reworked, but did not fundamentally change. You still need about the same effort to create the NMLDBusMetaIface. Not using generated bindings did not make anything worse (which tells about the usefulness of generated code, at least in the way it was used). - NMLDBusMetaIface and other meta data is static and immutable. This avoids copying them around. Also, macros like NML_DBUS_META_PROPERTY_INIT_U() have compile time checks to ensure the property types matches. It's pretty hard to misuse them because it won't compile. - The meta data now explicitly encodes the expected D-Bus types and makes sure never to accept wrong data. That would only matter when the server (accidentally or intentionally) exposes unexpected types on D-Bus. I don't think that was previously ensured in all cases. For example, demarshal_generic() only cared about the GObject property type, it didn't know the expected D-Bus type. - Previously GDBusObjectManager would sometimes emit warnings (g_log()). Those probably indicated real bugs. In any case, it prevented us from running CI with G_DEBUG=fatal-warnings, because there would be just too many unrelated crashes. Now we log debug messages that can be enabled with "LIBNM_CLIENT_DEBUG=trace". Some of these messages can also be turned into g_warning()/g_critical() by setting LIBNM_CLIENT_DEBUG=warning,error. Together with G_DEBUG=fatal-warnings, this turns them into assertions. Note that such "assertion failures" might also happen because of a server bug (or change). Thus these are not common assertions that indicate a bug in libnm and are thus not armed unless explicitly requested. In our CI we should now always run with LIBNM_CLIENT_DEBUG=warning,error and G_DEBUG=fatal-warnings and to catch bugs. Note that currently NetworkManager has bugs in this regard, so enabling this will result in assertion failures. That should be fixed first. - Note that this changes the order in which we emit "notify:devices" and "device-added" signals. I think it makes the most sense to emit first "device-removed", then "notify:devices", and finally "device-added" signals. This changes behavior for commit 52ae28f6e5bf ('libnm: queue added/removed signals and suppress uninitialized notifications'), but I don't think that users should actually rely on the order. Still, the new order makes the most sense to me. - In NetworkManager, profiles can be invisible to the user by setting "connection.permissions". Such profiles would be hidden by NMClient's nm_client_get_connections() and their "connection-added"/"connection-removed" signals. Note that NMActiveConnection's nm_active_connection_get_connection() and NMDevice's nm_device_get_available_connections() still exposes such hidden NMRemoteConnection instances. This behavior was preserved. NUMBERS ------- I compared 3 versions of libnm. [1] 962297f9085d, current tip of nm-1-20 branch [2] 4fad8c7c642e, current master, immediate parent of this patch [3] this patch All tests were done on Fedora 31, x86_64, gcc 9.2.1-1.fc31. The libraries were build with $ ./contrib/fedora/rpm/build_clean.sh -g -w test -W debug Note that RPM build already stripped the library. --- N1) File size of libnm.so.0.1.0 in bytes. There currently seems to be a issue on Fedora 31 generating wrong ELF notes. Usually, libnm is smaller but in these tests it had large (and bogus) ELF notes. Anyway, the point is to show the relative sizes, so it doesn't matter). [1] 4075552 (102.7%) [2] 3969624 (100.0%) [3] 3705208 ( 93.3%) --- N2) `size /usr/lib64/libnm.so.0.1.0`: text data bss dec hex filename [1] 1314569 (102.0%) 69980 ( 94.8%) 10632 ( 80.4%) 1395181 (101.4%) 1549ed /usr/lib64/libnm.so.0.1.0 [2] 1288410 (100.0%) 73796 (100.0%) 13224 (100.0%) 1375430 (100.0%) 14fcc6 /usr/lib64/libnm.so.0.1.0 [3] 1229066 ( 95.4%) 65248 ( 88.4%) 13400 (101.3%) 1307714 ( 95.1%) 13f442 /usr/lib64/libnm.so.0.1.0 --- N3) Performance test with test-client.py. With checkout of [2], run ``` prepare_checkout() { rm -rf /tmp/nm-test && \ git checkout -B test 4fad8c7c642e && \ git clean -fdx && \ ./autogen.sh --prefix=/tmp/nm-test && \ make -j 5 install && \ make -j 5 check-local-clients-tests-test-client } prepare_test() { NM_TEST_REGENERATE=1 NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v } do_test() { for i in {1..10}; do NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v || return -1 done echo "done!" } prepare_checkout prepare_test time do_test ``` [1] real 2m14.497s (101.3%) user 5m26.651s (100.3%) sys 1m40.453s (101.4%) [2] real 2m12.800s (100.0%) user 5m25.619s (100.0%) sys 1m39.065s (100.0%) [3] real 1m54.915s ( 86.5%) user 4m18.585s ( 79.4%) sys 1m32.066s ( 92.9%) --- N4) Performance. Run NetworkManager from build [2] and setup a large number of profiles (551 profiles and 515 devices, mostly unrealized). This setup is already at the edge of what NetworkManager currently can handle. Of course, that is a different issue. Here we just check how long plain `nmcli` takes on the system. ``` do_cleanup() { for UUID in $(nmcli -g NAME,UUID connection show | sed -n 's/^xx-c-.*:\([^:]\+\)$/\1/p'); do nmcli connection delete uuid "$UUID" done for DEVICE in $(nmcli -g DEVICE device status | grep '^xx-i-'); do nmcli device delete "$DEVICE" done } do_setup() { do_cleanup for i in {1..30}; do nmcli connection add type bond autoconnect no con-name xx-c-bond-$i ifname xx-i-bond-$i ipv4.method disabled ipv6.method ignore for j in $(seq $i 30); do nmcli connection add type vlan autoconnect no con-name xx-c-vlan-$i-$j vlan.id $j ifname xx-i-vlan-$i-$j vlan.parent xx-i-bond-$i ipv4.method disabled ipv6.method ignore done done systemctl restart NetworkManager.service sleep 5 } do_test() { perf stat -r 50 -B nmcli 1>/dev/null } do_test ``` [1] Performance counter stats for 'nmcli' (50 runs): 456.33 msec task-clock:u # 1.093 CPUs utilized ( +- 0.44% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,900 page-faults:u # 0.013 M/sec ( +- 0.02% ) 1,408,675,453 cycles:u # 3.087 GHz ( +- 0.48% ) 1,594,741,060 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 368,744,018 branches:u # 808.061 M/sec ( +- 0.02% ) 4,566,058 branch-misses:u # 1.24% of all branches ( +- 0.76% ) 0.41761 +- 0.00282 seconds time elapsed ( +- 0.68% ) [2] Performance counter stats for 'nmcli' (50 runs): 477.99 msec task-clock:u # 1.088 CPUs utilized ( +- 0.36% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,948 page-faults:u # 0.012 M/sec ( +- 0.03% ) 1,471,133,482 cycles:u # 3.078 GHz ( +- 0.36% ) 1,655,275,369 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 382,595,152 branches:u # 800.433 M/sec ( +- 0.02% ) 4,746,070 branch-misses:u # 1.24% of all branches ( +- 0.49% ) 0.43923 +- 0.00242 seconds time elapsed ( +- 0.55% ) [3] Performance counter stats for 'nmcli' (50 runs): 352.36 msec task-clock:u # 1.027 CPUs utilized ( +- 0.32% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 4,790 page-faults:u # 0.014 M/sec ( +- 0.26% ) 1,092,341,186 cycles:u # 3.100 GHz ( +- 0.26% ) 1,209,045,283 instructions:u # 1.11 insn per cycle ( +- 0.02% ) 281,708,462 branches:u # 799.499 M/sec ( +- 0.01% ) 3,101,031 branch-misses:u # 1.10% of all branches ( +- 0.61% ) 0.34296 +- 0.00120 seconds time elapsed ( +- 0.35% ) --- N5) same setup as N4), but run `PAGER= /bin/time -v nmcli`: [1] Command being timed: "nmcli" User time (seconds): 0.42 System time (seconds): 0.04 Percent of CPU this job got: 107% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.43 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34456 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6128 Voluntary context switches: 1298 Involuntary context switches: 1106 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [2] Command being timed: "nmcli" User time (seconds): 0.44 System time (seconds): 0.04 Percent of CPU this job got: 108% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.44 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34452 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6169 Voluntary context switches: 1849 Involuntary context switches: 142 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [3] Command being timed: "nmcli" User time (seconds): 0.32 System time (seconds): 0.02 Percent of CPU this job got: 102% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.34 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 29196 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 5059 Voluntary context switches: 919 Involuntary context switches: 685 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 --- N6) same setup as N4), but run `nmcli monitor` and look at `ps aux` for the RSS size. USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND [1] me 1492900 21.0 0.2 461348 33248 pts/10 Sl+ 15:02 0:00 nmcli monitor [2] me 1490721 5.0 0.2 461496 33548 pts/10 Sl+ 15:00 0:00 nmcli monitor [3] me 1495801 16.5 0.1 459476 28692 pts/10 Sl+ 15:04 0:00 nmcli monitor
2019-10-30 11:42:58 +01:00
g_free (priv->interface);
g_free (priv->ip_interface);
g_free (priv->udi);
g_free (priv->path);
g_free (priv->driver);
g_free (priv->driver_version);
g_free (priv->firmware_version);
g_free (priv->product);
g_free (priv->vendor);
g_free (priv->short_vendor);
g_free (priv->description);
g_free (priv->bus_name);
g_free (priv->type_description);
g_free (priv->physical_port_id);
g_free (priv->hw_address);
libnm: refactor caching of D-Bus objects in NMClient No longer use GDBusObjectMangaerClient and gdbus-codegen generated classes for the NMClient cache. Instead, use GDBusConnection directly and a custom implementation (NMLDBusObject) for caching D-Bus' ObjectManager data. CHANGES ------- - This is a complete rework. I think the previous implementation was difficult to understand. There were unfixed bugs and nobody understood the code well enough to fix them. Maybe somebody out there understood the code, but I certainly did not. At least nobody provided patches to fix those issues. I do believe that this implementation is more straightforward and easier to understand. It removes a lot of layers of code. Whether this claim of simplicity is true, each reader must decide for himself/herself. Note that it is still fairly complex. - There was a lingering performance issue with large number of D-Bus objects. The patch tries hard that the implementation scales well. Of course, when we cache N objects that have N-to-M references to other, we still are fundamentally O(N*M) for runtime and memory consumption (with M being the number of references between objects). But each part should behave efficiently and well. - Play well with GMainContext. libnm code (NMClient) is generally not thread safe. However, it should work to use multiple instances in parallel, as long as each access to a NMClient is through the caller's GMainContext. This follows glib's style and effectively allows to use NMClient in a multi threaded scenario. This implies to stick to a main context upon construction and ensure that callbacks are only invoked when iterating that context. Also, NMClient itself shall never iterate the caller's context. This also means, libnm must never use g_idle_add() or g_timeout_add(), as those enqueue sources in the g_main_context_default() context. - Get ordering of messages right. All events are consistently enqueued in a GMainContext and processed strictly in order. For example, previously "nm-object.c" tried to combine signals and emit them on an idle handler. That is wrong, signals must be emitted in the right order and when they happen. Note that when using GInitable's synchronous initialization to initialize the NMClient instance, NMClient internally still operates fully asynchronously. In that case NMClient has an internal main context. - NMClient takes over most of the functionality. When using D-Bus' ObjectManager interface, one needs to handle basically the entire state of the D-Bus interface. That cannot be separated well into distinct parts, and even if you try, you just end up having closely related code in different source files. Spreading related code does not make it easier to understand, on the contrary. That means, NMClient is inherently complex as it contains most of the logic. I think that is not avoidable, but it's not as bad as it sounds. - NMClient processes D-Bus messages and state changes in separate steps. First NMClient unpacks the message (e.g. _dbus_handle_properties_changed()) and keeps track of the changed data. Then we update the GObject instances (_dbus_handle_obj_changed_dbus()) without emitting any signals yet. Finally, we emit all signals and notifications that were collected (_dbus_handle_changes_commit()). Note that for example during the initial GetManagedObjects() reply, NMClient receive a large amount of state at once. But we first apply all the changes to our GObject instances before emitting any signals. The result is that signals are always emitted in a moment when the cache is consistent. The unavoidable downside is that when you receive a property changed signal, possibly many other properties changed already and more signals are about to be emitted. - NMDeviceWifi no longer modifies the content of the cache from client side during poke_wireless_devices_with_rf_status(). The content of the cache should be determined by D-Bus alone and follow what NetworkManager service exposes. Local modifications should be avoided. - This aims to bring no API/ABI change, though it does of course bring various subtle changes in behavior. Those should be all for the better, but the goal is not to break any existing clients. This does change internal (albeit externally visible) API, like dropping NM_OBJECT_DBUS_OBJECT_MANAGER property and NMObject no longer implementing GInitableIface and GAsyncInitableIface. - Some uses of gdbus-codegen classes remain in NMVpnPluginOld, NMVpnServicePlugin and NMSecretAgentOld. These are independent of NMClient/NMObject and should be reworked separately. - While we no longer use generated classes from gdbus-codegen, we don't need more glue code than before. Also before we constructed NMPropertiesInfo and a had large amount of code to propagate properties from NMDBus* to NMObject. That got completely reworked, but did not fundamentally change. You still need about the same effort to create the NMLDBusMetaIface. Not using generated bindings did not make anything worse (which tells about the usefulness of generated code, at least in the way it was used). - NMLDBusMetaIface and other meta data is static and immutable. This avoids copying them around. Also, macros like NML_DBUS_META_PROPERTY_INIT_U() have compile time checks to ensure the property types matches. It's pretty hard to misuse them because it won't compile. - The meta data now explicitly encodes the expected D-Bus types and makes sure never to accept wrong data. That would only matter when the server (accidentally or intentionally) exposes unexpected types on D-Bus. I don't think that was previously ensured in all cases. For example, demarshal_generic() only cared about the GObject property type, it didn't know the expected D-Bus type. - Previously GDBusObjectManager would sometimes emit warnings (g_log()). Those probably indicated real bugs. In any case, it prevented us from running CI with G_DEBUG=fatal-warnings, because there would be just too many unrelated crashes. Now we log debug messages that can be enabled with "LIBNM_CLIENT_DEBUG=trace". Some of these messages can also be turned into g_warning()/g_critical() by setting LIBNM_CLIENT_DEBUG=warning,error. Together with G_DEBUG=fatal-warnings, this turns them into assertions. Note that such "assertion failures" might also happen because of a server bug (or change). Thus these are not common assertions that indicate a bug in libnm and are thus not armed unless explicitly requested. In our CI we should now always run with LIBNM_CLIENT_DEBUG=warning,error and G_DEBUG=fatal-warnings and to catch bugs. Note that currently NetworkManager has bugs in this regard, so enabling this will result in assertion failures. That should be fixed first. - Note that this changes the order in which we emit "notify:devices" and "device-added" signals. I think it makes the most sense to emit first "device-removed", then "notify:devices", and finally "device-added" signals. This changes behavior for commit 52ae28f6e5bf ('libnm: queue added/removed signals and suppress uninitialized notifications'), but I don't think that users should actually rely on the order. Still, the new order makes the most sense to me. - In NetworkManager, profiles can be invisible to the user by setting "connection.permissions". Such profiles would be hidden by NMClient's nm_client_get_connections() and their "connection-added"/"connection-removed" signals. Note that NMActiveConnection's nm_active_connection_get_connection() and NMDevice's nm_device_get_available_connections() still exposes such hidden NMRemoteConnection instances. This behavior was preserved. NUMBERS ------- I compared 3 versions of libnm. [1] 962297f9085d, current tip of nm-1-20 branch [2] 4fad8c7c642e, current master, immediate parent of this patch [3] this patch All tests were done on Fedora 31, x86_64, gcc 9.2.1-1.fc31. The libraries were build with $ ./contrib/fedora/rpm/build_clean.sh -g -w test -W debug Note that RPM build already stripped the library. --- N1) File size of libnm.so.0.1.0 in bytes. There currently seems to be a issue on Fedora 31 generating wrong ELF notes. Usually, libnm is smaller but in these tests it had large (and bogus) ELF notes. Anyway, the point is to show the relative sizes, so it doesn't matter). [1] 4075552 (102.7%) [2] 3969624 (100.0%) [3] 3705208 ( 93.3%) --- N2) `size /usr/lib64/libnm.so.0.1.0`: text data bss dec hex filename [1] 1314569 (102.0%) 69980 ( 94.8%) 10632 ( 80.4%) 1395181 (101.4%) 1549ed /usr/lib64/libnm.so.0.1.0 [2] 1288410 (100.0%) 73796 (100.0%) 13224 (100.0%) 1375430 (100.0%) 14fcc6 /usr/lib64/libnm.so.0.1.0 [3] 1229066 ( 95.4%) 65248 ( 88.4%) 13400 (101.3%) 1307714 ( 95.1%) 13f442 /usr/lib64/libnm.so.0.1.0 --- N3) Performance test with test-client.py. With checkout of [2], run ``` prepare_checkout() { rm -rf /tmp/nm-test && \ git checkout -B test 4fad8c7c642e && \ git clean -fdx && \ ./autogen.sh --prefix=/tmp/nm-test && \ make -j 5 install && \ make -j 5 check-local-clients-tests-test-client } prepare_test() { NM_TEST_REGENERATE=1 NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v } do_test() { for i in {1..10}; do NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v || return -1 done echo "done!" } prepare_checkout prepare_test time do_test ``` [1] real 2m14.497s (101.3%) user 5m26.651s (100.3%) sys 1m40.453s (101.4%) [2] real 2m12.800s (100.0%) user 5m25.619s (100.0%) sys 1m39.065s (100.0%) [3] real 1m54.915s ( 86.5%) user 4m18.585s ( 79.4%) sys 1m32.066s ( 92.9%) --- N4) Performance. Run NetworkManager from build [2] and setup a large number of profiles (551 profiles and 515 devices, mostly unrealized). This setup is already at the edge of what NetworkManager currently can handle. Of course, that is a different issue. Here we just check how long plain `nmcli` takes on the system. ``` do_cleanup() { for UUID in $(nmcli -g NAME,UUID connection show | sed -n 's/^xx-c-.*:\([^:]\+\)$/\1/p'); do nmcli connection delete uuid "$UUID" done for DEVICE in $(nmcli -g DEVICE device status | grep '^xx-i-'); do nmcli device delete "$DEVICE" done } do_setup() { do_cleanup for i in {1..30}; do nmcli connection add type bond autoconnect no con-name xx-c-bond-$i ifname xx-i-bond-$i ipv4.method disabled ipv6.method ignore for j in $(seq $i 30); do nmcli connection add type vlan autoconnect no con-name xx-c-vlan-$i-$j vlan.id $j ifname xx-i-vlan-$i-$j vlan.parent xx-i-bond-$i ipv4.method disabled ipv6.method ignore done done systemctl restart NetworkManager.service sleep 5 } do_test() { perf stat -r 50 -B nmcli 1>/dev/null } do_test ``` [1] Performance counter stats for 'nmcli' (50 runs): 456.33 msec task-clock:u # 1.093 CPUs utilized ( +- 0.44% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,900 page-faults:u # 0.013 M/sec ( +- 0.02% ) 1,408,675,453 cycles:u # 3.087 GHz ( +- 0.48% ) 1,594,741,060 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 368,744,018 branches:u # 808.061 M/sec ( +- 0.02% ) 4,566,058 branch-misses:u # 1.24% of all branches ( +- 0.76% ) 0.41761 +- 0.00282 seconds time elapsed ( +- 0.68% ) [2] Performance counter stats for 'nmcli' (50 runs): 477.99 msec task-clock:u # 1.088 CPUs utilized ( +- 0.36% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,948 page-faults:u # 0.012 M/sec ( +- 0.03% ) 1,471,133,482 cycles:u # 3.078 GHz ( +- 0.36% ) 1,655,275,369 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 382,595,152 branches:u # 800.433 M/sec ( +- 0.02% ) 4,746,070 branch-misses:u # 1.24% of all branches ( +- 0.49% ) 0.43923 +- 0.00242 seconds time elapsed ( +- 0.55% ) [3] Performance counter stats for 'nmcli' (50 runs): 352.36 msec task-clock:u # 1.027 CPUs utilized ( +- 0.32% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 4,790 page-faults:u # 0.014 M/sec ( +- 0.26% ) 1,092,341,186 cycles:u # 3.100 GHz ( +- 0.26% ) 1,209,045,283 instructions:u # 1.11 insn per cycle ( +- 0.02% ) 281,708,462 branches:u # 799.499 M/sec ( +- 0.01% ) 3,101,031 branch-misses:u # 1.10% of all branches ( +- 0.61% ) 0.34296 +- 0.00120 seconds time elapsed ( +- 0.35% ) --- N5) same setup as N4), but run `PAGER= /bin/time -v nmcli`: [1] Command being timed: "nmcli" User time (seconds): 0.42 System time (seconds): 0.04 Percent of CPU this job got: 107% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.43 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34456 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6128 Voluntary context switches: 1298 Involuntary context switches: 1106 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [2] Command being timed: "nmcli" User time (seconds): 0.44 System time (seconds): 0.04 Percent of CPU this job got: 108% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.44 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34452 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6169 Voluntary context switches: 1849 Involuntary context switches: 142 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [3] Command being timed: "nmcli" User time (seconds): 0.32 System time (seconds): 0.02 Percent of CPU this job got: 102% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.34 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 29196 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 5059 Voluntary context switches: 919 Involuntary context switches: 685 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 --- N6) same setup as N4), but run `nmcli monitor` and look at `ps aux` for the RSS size. USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND [1] me 1492900 21.0 0.2 461348 33248 pts/10 Sl+ 15:02 0:00 nmcli monitor [2] me 1490721 5.0 0.2 461496 33548 pts/10 Sl+ 15:00 0:00 nmcli monitor [3] me 1495801 16.5 0.1 459476 28692 pts/10 Sl+ 15:04 0:00 nmcli monitor
2019-10-30 11:42:58 +01:00
nm_clear_pointer (&priv->udev, udev_unref);
G_OBJECT_CLASS (nm_device_parent_class)->finalize (object);
}
static void
get_property (GObject *object,
guint prop_id,
GValue *value,
GParamSpec *pspec)
{
NMDevice *device = NM_DEVICE (object);
switch (prop_id) {
case PROP_DEVICE_TYPE:
g_value_set_enum (value, nm_device_get_device_type (device));
break;
case PROP_UDI:
g_value_set_string (value, nm_device_get_udi (device));
break;
case PROP_PATH:
g_value_set_string (value, nm_device_get_path (device));
break;
case PROP_INTERFACE:
g_value_set_string (value, nm_device_get_iface (device));
break;
case PROP_IP_INTERFACE:
g_value_set_string (value, nm_device_get_ip_iface (device));
break;
case PROP_DRIVER:
g_value_set_string (value, nm_device_get_driver (device));
break;
case PROP_DRIVER_VERSION:
g_value_set_string (value, nm_device_get_driver_version (device));
break;
case PROP_FIRMWARE_VERSION:
g_value_set_string (value, nm_device_get_firmware_version (device));
break;
case PROP_CAPABILITIES:
g_value_set_flags (value, nm_device_get_capabilities (device));
break;
case PROP_REAL:
g_value_set_boolean (value, nm_device_is_real (device));
break;
case PROP_MANAGED:
g_value_set_boolean (value, nm_device_get_managed (device));
break;
case PROP_AUTOCONNECT:
g_value_set_boolean (value, nm_device_get_autoconnect (device));
break;
case PROP_FIRMWARE_MISSING:
g_value_set_boolean (value, nm_device_get_firmware_missing (device));
break;
case PROP_NM_PLUGIN_MISSING:
g_value_set_boolean (value, nm_device_get_nm_plugin_missing (device));
break;
case PROP_IP4_CONFIG:
g_value_set_object (value, nm_device_get_ip4_config (device));
break;
case PROP_DHCP4_CONFIG:
g_value_set_object (value, nm_device_get_dhcp4_config (device));
break;
case PROP_IP6_CONFIG:
g_value_set_object (value, nm_device_get_ip6_config (device));
break;
case PROP_DHCP6_CONFIG:
g_value_set_object (value, nm_device_get_dhcp6_config (device));
break;
case PROP_STATE:
g_value_set_enum (value, nm_device_get_state (device));
break;
case PROP_STATE_REASON:
g_value_set_uint (value, nm_device_get_state_reason (device));
break;
case PROP_ACTIVE_CONNECTION:
g_value_set_object (value, nm_device_get_active_connection (device));
break;
case PROP_AVAILABLE_CONNECTIONS:
g_value_take_boxed (value, _nm_utils_copy_object_array (nm_device_get_available_connections (device)));
break;
case PROP_PRODUCT:
g_value_set_string (value, nm_device_get_product (device));
break;
case PROP_VENDOR:
g_value_set_string (value, nm_device_get_vendor (device));
break;
case PROP_PHYSICAL_PORT_ID:
g_value_set_string (value, nm_device_get_physical_port_id (device));
break;
case PROP_MTU:
g_value_set_uint (value, nm_device_get_mtu (device));
break;
case PROP_METERED:
g_value_set_uint (value, nm_device_get_metered (device));
break;
case PROP_LLDP_NEIGHBORS:
g_value_set_boxed (value, nm_device_get_lldp_neighbors (device));
break;
case PROP_IP4_CONNECTIVITY:
g_value_set_enum (value, nm_device_get_connectivity (device, AF_INET));
break;
case PROP_IP6_CONNECTIVITY:
g_value_set_enum (value, nm_device_get_connectivity (device, AF_INET6));
break;
case PROP_INTERFACE_FLAGS:
g_value_set_uint (value, nm_device_get_interface_flags (device));
break;
case PROP_HW_ADDRESS:
g_value_set_string (value, nm_device_get_hw_address (device));
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
static void
set_property (GObject *object,
guint prop_id,
const GValue *value,
GParamSpec *pspec)
{
NMDevice *self = NM_DEVICE (object);
NMDevicePrivate *priv = NM_DEVICE_GET_PRIVATE (self);
gboolean b;
switch (prop_id) {
case PROP_AUTOCONNECT:
b = g_value_get_boolean (value);
if (priv->autoconnect != b)
nm_device_set_autoconnect (NM_DEVICE (object), b);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
libnm: refactor caching of D-Bus objects in NMClient No longer use GDBusObjectMangaerClient and gdbus-codegen generated classes for the NMClient cache. Instead, use GDBusConnection directly and a custom implementation (NMLDBusObject) for caching D-Bus' ObjectManager data. CHANGES ------- - This is a complete rework. I think the previous implementation was difficult to understand. There were unfixed bugs and nobody understood the code well enough to fix them. Maybe somebody out there understood the code, but I certainly did not. At least nobody provided patches to fix those issues. I do believe that this implementation is more straightforward and easier to understand. It removes a lot of layers of code. Whether this claim of simplicity is true, each reader must decide for himself/herself. Note that it is still fairly complex. - There was a lingering performance issue with large number of D-Bus objects. The patch tries hard that the implementation scales well. Of course, when we cache N objects that have N-to-M references to other, we still are fundamentally O(N*M) for runtime and memory consumption (with M being the number of references between objects). But each part should behave efficiently and well. - Play well with GMainContext. libnm code (NMClient) is generally not thread safe. However, it should work to use multiple instances in parallel, as long as each access to a NMClient is through the caller's GMainContext. This follows glib's style and effectively allows to use NMClient in a multi threaded scenario. This implies to stick to a main context upon construction and ensure that callbacks are only invoked when iterating that context. Also, NMClient itself shall never iterate the caller's context. This also means, libnm must never use g_idle_add() or g_timeout_add(), as those enqueue sources in the g_main_context_default() context. - Get ordering of messages right. All events are consistently enqueued in a GMainContext and processed strictly in order. For example, previously "nm-object.c" tried to combine signals and emit them on an idle handler. That is wrong, signals must be emitted in the right order and when they happen. Note that when using GInitable's synchronous initialization to initialize the NMClient instance, NMClient internally still operates fully asynchronously. In that case NMClient has an internal main context. - NMClient takes over most of the functionality. When using D-Bus' ObjectManager interface, one needs to handle basically the entire state of the D-Bus interface. That cannot be separated well into distinct parts, and even if you try, you just end up having closely related code in different source files. Spreading related code does not make it easier to understand, on the contrary. That means, NMClient is inherently complex as it contains most of the logic. I think that is not avoidable, but it's not as bad as it sounds. - NMClient processes D-Bus messages and state changes in separate steps. First NMClient unpacks the message (e.g. _dbus_handle_properties_changed()) and keeps track of the changed data. Then we update the GObject instances (_dbus_handle_obj_changed_dbus()) without emitting any signals yet. Finally, we emit all signals and notifications that were collected (_dbus_handle_changes_commit()). Note that for example during the initial GetManagedObjects() reply, NMClient receive a large amount of state at once. But we first apply all the changes to our GObject instances before emitting any signals. The result is that signals are always emitted in a moment when the cache is consistent. The unavoidable downside is that when you receive a property changed signal, possibly many other properties changed already and more signals are about to be emitted. - NMDeviceWifi no longer modifies the content of the cache from client side during poke_wireless_devices_with_rf_status(). The content of the cache should be determined by D-Bus alone and follow what NetworkManager service exposes. Local modifications should be avoided. - This aims to bring no API/ABI change, though it does of course bring various subtle changes in behavior. Those should be all for the better, but the goal is not to break any existing clients. This does change internal (albeit externally visible) API, like dropping NM_OBJECT_DBUS_OBJECT_MANAGER property and NMObject no longer implementing GInitableIface and GAsyncInitableIface. - Some uses of gdbus-codegen classes remain in NMVpnPluginOld, NMVpnServicePlugin and NMSecretAgentOld. These are independent of NMClient/NMObject and should be reworked separately. - While we no longer use generated classes from gdbus-codegen, we don't need more glue code than before. Also before we constructed NMPropertiesInfo and a had large amount of code to propagate properties from NMDBus* to NMObject. That got completely reworked, but did not fundamentally change. You still need about the same effort to create the NMLDBusMetaIface. Not using generated bindings did not make anything worse (which tells about the usefulness of generated code, at least in the way it was used). - NMLDBusMetaIface and other meta data is static and immutable. This avoids copying them around. Also, macros like NML_DBUS_META_PROPERTY_INIT_U() have compile time checks to ensure the property types matches. It's pretty hard to misuse them because it won't compile. - The meta data now explicitly encodes the expected D-Bus types and makes sure never to accept wrong data. That would only matter when the server (accidentally or intentionally) exposes unexpected types on D-Bus. I don't think that was previously ensured in all cases. For example, demarshal_generic() only cared about the GObject property type, it didn't know the expected D-Bus type. - Previously GDBusObjectManager would sometimes emit warnings (g_log()). Those probably indicated real bugs. In any case, it prevented us from running CI with G_DEBUG=fatal-warnings, because there would be just too many unrelated crashes. Now we log debug messages that can be enabled with "LIBNM_CLIENT_DEBUG=trace". Some of these messages can also be turned into g_warning()/g_critical() by setting LIBNM_CLIENT_DEBUG=warning,error. Together with G_DEBUG=fatal-warnings, this turns them into assertions. Note that such "assertion failures" might also happen because of a server bug (or change). Thus these are not common assertions that indicate a bug in libnm and are thus not armed unless explicitly requested. In our CI we should now always run with LIBNM_CLIENT_DEBUG=warning,error and G_DEBUG=fatal-warnings and to catch bugs. Note that currently NetworkManager has bugs in this regard, so enabling this will result in assertion failures. That should be fixed first. - Note that this changes the order in which we emit "notify:devices" and "device-added" signals. I think it makes the most sense to emit first "device-removed", then "notify:devices", and finally "device-added" signals. This changes behavior for commit 52ae28f6e5bf ('libnm: queue added/removed signals and suppress uninitialized notifications'), but I don't think that users should actually rely on the order. Still, the new order makes the most sense to me. - In NetworkManager, profiles can be invisible to the user by setting "connection.permissions". Such profiles would be hidden by NMClient's nm_client_get_connections() and their "connection-added"/"connection-removed" signals. Note that NMActiveConnection's nm_active_connection_get_connection() and NMDevice's nm_device_get_available_connections() still exposes such hidden NMRemoteConnection instances. This behavior was preserved. NUMBERS ------- I compared 3 versions of libnm. [1] 962297f9085d, current tip of nm-1-20 branch [2] 4fad8c7c642e, current master, immediate parent of this patch [3] this patch All tests were done on Fedora 31, x86_64, gcc 9.2.1-1.fc31. The libraries were build with $ ./contrib/fedora/rpm/build_clean.sh -g -w test -W debug Note that RPM build already stripped the library. --- N1) File size of libnm.so.0.1.0 in bytes. There currently seems to be a issue on Fedora 31 generating wrong ELF notes. Usually, libnm is smaller but in these tests it had large (and bogus) ELF notes. Anyway, the point is to show the relative sizes, so it doesn't matter). [1] 4075552 (102.7%) [2] 3969624 (100.0%) [3] 3705208 ( 93.3%) --- N2) `size /usr/lib64/libnm.so.0.1.0`: text data bss dec hex filename [1] 1314569 (102.0%) 69980 ( 94.8%) 10632 ( 80.4%) 1395181 (101.4%) 1549ed /usr/lib64/libnm.so.0.1.0 [2] 1288410 (100.0%) 73796 (100.0%) 13224 (100.0%) 1375430 (100.0%) 14fcc6 /usr/lib64/libnm.so.0.1.0 [3] 1229066 ( 95.4%) 65248 ( 88.4%) 13400 (101.3%) 1307714 ( 95.1%) 13f442 /usr/lib64/libnm.so.0.1.0 --- N3) Performance test with test-client.py. With checkout of [2], run ``` prepare_checkout() { rm -rf /tmp/nm-test && \ git checkout -B test 4fad8c7c642e && \ git clean -fdx && \ ./autogen.sh --prefix=/tmp/nm-test && \ make -j 5 install && \ make -j 5 check-local-clients-tests-test-client } prepare_test() { NM_TEST_REGENERATE=1 NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v } do_test() { for i in {1..10}; do NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v || return -1 done echo "done!" } prepare_checkout prepare_test time do_test ``` [1] real 2m14.497s (101.3%) user 5m26.651s (100.3%) sys 1m40.453s (101.4%) [2] real 2m12.800s (100.0%) user 5m25.619s (100.0%) sys 1m39.065s (100.0%) [3] real 1m54.915s ( 86.5%) user 4m18.585s ( 79.4%) sys 1m32.066s ( 92.9%) --- N4) Performance. Run NetworkManager from build [2] and setup a large number of profiles (551 profiles and 515 devices, mostly unrealized). This setup is already at the edge of what NetworkManager currently can handle. Of course, that is a different issue. Here we just check how long plain `nmcli` takes on the system. ``` do_cleanup() { for UUID in $(nmcli -g NAME,UUID connection show | sed -n 's/^xx-c-.*:\([^:]\+\)$/\1/p'); do nmcli connection delete uuid "$UUID" done for DEVICE in $(nmcli -g DEVICE device status | grep '^xx-i-'); do nmcli device delete "$DEVICE" done } do_setup() { do_cleanup for i in {1..30}; do nmcli connection add type bond autoconnect no con-name xx-c-bond-$i ifname xx-i-bond-$i ipv4.method disabled ipv6.method ignore for j in $(seq $i 30); do nmcli connection add type vlan autoconnect no con-name xx-c-vlan-$i-$j vlan.id $j ifname xx-i-vlan-$i-$j vlan.parent xx-i-bond-$i ipv4.method disabled ipv6.method ignore done done systemctl restart NetworkManager.service sleep 5 } do_test() { perf stat -r 50 -B nmcli 1>/dev/null } do_test ``` [1] Performance counter stats for 'nmcli' (50 runs): 456.33 msec task-clock:u # 1.093 CPUs utilized ( +- 0.44% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,900 page-faults:u # 0.013 M/sec ( +- 0.02% ) 1,408,675,453 cycles:u # 3.087 GHz ( +- 0.48% ) 1,594,741,060 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 368,744,018 branches:u # 808.061 M/sec ( +- 0.02% ) 4,566,058 branch-misses:u # 1.24% of all branches ( +- 0.76% ) 0.41761 +- 0.00282 seconds time elapsed ( +- 0.68% ) [2] Performance counter stats for 'nmcli' (50 runs): 477.99 msec task-clock:u # 1.088 CPUs utilized ( +- 0.36% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,948 page-faults:u # 0.012 M/sec ( +- 0.03% ) 1,471,133,482 cycles:u # 3.078 GHz ( +- 0.36% ) 1,655,275,369 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 382,595,152 branches:u # 800.433 M/sec ( +- 0.02% ) 4,746,070 branch-misses:u # 1.24% of all branches ( +- 0.49% ) 0.43923 +- 0.00242 seconds time elapsed ( +- 0.55% ) [3] Performance counter stats for 'nmcli' (50 runs): 352.36 msec task-clock:u # 1.027 CPUs utilized ( +- 0.32% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 4,790 page-faults:u # 0.014 M/sec ( +- 0.26% ) 1,092,341,186 cycles:u # 3.100 GHz ( +- 0.26% ) 1,209,045,283 instructions:u # 1.11 insn per cycle ( +- 0.02% ) 281,708,462 branches:u # 799.499 M/sec ( +- 0.01% ) 3,101,031 branch-misses:u # 1.10% of all branches ( +- 0.61% ) 0.34296 +- 0.00120 seconds time elapsed ( +- 0.35% ) --- N5) same setup as N4), but run `PAGER= /bin/time -v nmcli`: [1] Command being timed: "nmcli" User time (seconds): 0.42 System time (seconds): 0.04 Percent of CPU this job got: 107% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.43 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34456 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6128 Voluntary context switches: 1298 Involuntary context switches: 1106 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [2] Command being timed: "nmcli" User time (seconds): 0.44 System time (seconds): 0.04 Percent of CPU this job got: 108% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.44 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34452 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6169 Voluntary context switches: 1849 Involuntary context switches: 142 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [3] Command being timed: "nmcli" User time (seconds): 0.32 System time (seconds): 0.02 Percent of CPU this job got: 102% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.34 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 29196 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 5059 Voluntary context switches: 919 Involuntary context switches: 685 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 --- N6) same setup as N4), but run `nmcli monitor` and look at `ps aux` for the RSS size. USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND [1] me 1492900 21.0 0.2 461348 33248 pts/10 Sl+ 15:02 0:00 nmcli monitor [2] me 1490721 5.0 0.2 461496 33548 pts/10 Sl+ 15:00 0:00 nmcli monitor [3] me 1495801 16.5 0.1 459476 28692 pts/10 Sl+ 15:04 0:00 nmcli monitor
2019-10-30 11:42:58 +01:00
/* TODO: statistics interface not yet implemented. */
const NMLDBusMetaIface _nml_dbus_meta_iface_nm_device_statistics = NML_DBUS_META_IFACE_INIT (
NM_DBUS_INTERFACE_DEVICE_STATISTICS,
NULL,
NML_DBUS_META_INTERFACE_PRIO_NONE,
NML_DBUS_META_IFACE_DBUS_PROPERTIES (
NML_DBUS_META_PROPERTY_INIT_TODO ("RefreshRateMs", "u" ),
NML_DBUS_META_PROPERTY_INIT_TODO ("RxBytes", "t" ),
NML_DBUS_META_PROPERTY_INIT_TODO ("TxBytes", "t" ),
),
);
const NMLDBusMetaIface _nml_dbus_meta_iface_nm_device = NML_DBUS_META_IFACE_INIT_PROP (
NM_DBUS_INTERFACE_DEVICE,
nm_device_get_type,
NML_DBUS_META_INTERFACE_PRIO_PARENT_TYPE,
NML_DBUS_META_IFACE_DBUS_PROPERTIES (
NML_DBUS_META_PROPERTY_INIT_O_PROP ("ActiveConnection", PROP_ACTIVE_CONNECTION, NMDevicePrivate, property_o[PROPERTY_O_IDX_ACTIVE_CONNECTION], nm_active_connection_get_type, .is_always_ready = TRUE ),
NML_DBUS_META_PROPERTY_INIT_B ("Autoconnect", PROP_AUTOCONNECT, NMDevicePrivate, autoconnect ),
NML_DBUS_META_PROPERTY_INIT_AO_PROP ("AvailableConnections", PROP_AVAILABLE_CONNECTIONS, NMDevicePrivate, available_connections, nm_remote_connection_get_type, .is_always_ready = TRUE ),
NML_DBUS_META_PROPERTY_INIT_U ("Capabilities", PROP_CAPABILITIES, NMDevicePrivate, capabilities ),
NML_DBUS_META_PROPERTY_INIT_U ("DeviceType", PROP_DEVICE_TYPE, NMDevicePrivate, device_type ),
NML_DBUS_META_PROPERTY_INIT_O_PROP ("Dhcp4Config", PROP_DHCP4_CONFIG, NMDevicePrivate, property_o[PROPERTY_O_IDX_DHCP4_CONFIG], nm_dhcp4_config_get_type ),
NML_DBUS_META_PROPERTY_INIT_O_PROP ("Dhcp6Config", PROP_DHCP6_CONFIG, NMDevicePrivate, property_o[PROPERTY_O_IDX_DHCP6_CONFIG], nm_dhcp6_config_get_type ),
NML_DBUS_META_PROPERTY_INIT_S ("Driver", PROP_DRIVER, NMDevicePrivate, driver ),
NML_DBUS_META_PROPERTY_INIT_S ("DriverVersion", PROP_DRIVER_VERSION, NMDevicePrivate, driver_version ),
NML_DBUS_META_PROPERTY_INIT_B ("FirmwareMissing", PROP_FIRMWARE_MISSING, NMDevicePrivate, firmware_missing ),
NML_DBUS_META_PROPERTY_INIT_S ("FirmwareVersion", PROP_FIRMWARE_VERSION, NMDevicePrivate, firmware_version ),
NML_DBUS_META_PROPERTY_INIT_FCN ("HwAddress", 0, "s", _nm_device_notify_update_prop_hw_address ),
libnm: refactor caching of D-Bus objects in NMClient No longer use GDBusObjectMangaerClient and gdbus-codegen generated classes for the NMClient cache. Instead, use GDBusConnection directly and a custom implementation (NMLDBusObject) for caching D-Bus' ObjectManager data. CHANGES ------- - This is a complete rework. I think the previous implementation was difficult to understand. There were unfixed bugs and nobody understood the code well enough to fix them. Maybe somebody out there understood the code, but I certainly did not. At least nobody provided patches to fix those issues. I do believe that this implementation is more straightforward and easier to understand. It removes a lot of layers of code. Whether this claim of simplicity is true, each reader must decide for himself/herself. Note that it is still fairly complex. - There was a lingering performance issue with large number of D-Bus objects. The patch tries hard that the implementation scales well. Of course, when we cache N objects that have N-to-M references to other, we still are fundamentally O(N*M) for runtime and memory consumption (with M being the number of references between objects). But each part should behave efficiently and well. - Play well with GMainContext. libnm code (NMClient) is generally not thread safe. However, it should work to use multiple instances in parallel, as long as each access to a NMClient is through the caller's GMainContext. This follows glib's style and effectively allows to use NMClient in a multi threaded scenario. This implies to stick to a main context upon construction and ensure that callbacks are only invoked when iterating that context. Also, NMClient itself shall never iterate the caller's context. This also means, libnm must never use g_idle_add() or g_timeout_add(), as those enqueue sources in the g_main_context_default() context. - Get ordering of messages right. All events are consistently enqueued in a GMainContext and processed strictly in order. For example, previously "nm-object.c" tried to combine signals and emit them on an idle handler. That is wrong, signals must be emitted in the right order and when they happen. Note that when using GInitable's synchronous initialization to initialize the NMClient instance, NMClient internally still operates fully asynchronously. In that case NMClient has an internal main context. - NMClient takes over most of the functionality. When using D-Bus' ObjectManager interface, one needs to handle basically the entire state of the D-Bus interface. That cannot be separated well into distinct parts, and even if you try, you just end up having closely related code in different source files. Spreading related code does not make it easier to understand, on the contrary. That means, NMClient is inherently complex as it contains most of the logic. I think that is not avoidable, but it's not as bad as it sounds. - NMClient processes D-Bus messages and state changes in separate steps. First NMClient unpacks the message (e.g. _dbus_handle_properties_changed()) and keeps track of the changed data. Then we update the GObject instances (_dbus_handle_obj_changed_dbus()) without emitting any signals yet. Finally, we emit all signals and notifications that were collected (_dbus_handle_changes_commit()). Note that for example during the initial GetManagedObjects() reply, NMClient receive a large amount of state at once. But we first apply all the changes to our GObject instances before emitting any signals. The result is that signals are always emitted in a moment when the cache is consistent. The unavoidable downside is that when you receive a property changed signal, possibly many other properties changed already and more signals are about to be emitted. - NMDeviceWifi no longer modifies the content of the cache from client side during poke_wireless_devices_with_rf_status(). The content of the cache should be determined by D-Bus alone and follow what NetworkManager service exposes. Local modifications should be avoided. - This aims to bring no API/ABI change, though it does of course bring various subtle changes in behavior. Those should be all for the better, but the goal is not to break any existing clients. This does change internal (albeit externally visible) API, like dropping NM_OBJECT_DBUS_OBJECT_MANAGER property and NMObject no longer implementing GInitableIface and GAsyncInitableIface. - Some uses of gdbus-codegen classes remain in NMVpnPluginOld, NMVpnServicePlugin and NMSecretAgentOld. These are independent of NMClient/NMObject and should be reworked separately. - While we no longer use generated classes from gdbus-codegen, we don't need more glue code than before. Also before we constructed NMPropertiesInfo and a had large amount of code to propagate properties from NMDBus* to NMObject. That got completely reworked, but did not fundamentally change. You still need about the same effort to create the NMLDBusMetaIface. Not using generated bindings did not make anything worse (which tells about the usefulness of generated code, at least in the way it was used). - NMLDBusMetaIface and other meta data is static and immutable. This avoids copying them around. Also, macros like NML_DBUS_META_PROPERTY_INIT_U() have compile time checks to ensure the property types matches. It's pretty hard to misuse them because it won't compile. - The meta data now explicitly encodes the expected D-Bus types and makes sure never to accept wrong data. That would only matter when the server (accidentally or intentionally) exposes unexpected types on D-Bus. I don't think that was previously ensured in all cases. For example, demarshal_generic() only cared about the GObject property type, it didn't know the expected D-Bus type. - Previously GDBusObjectManager would sometimes emit warnings (g_log()). Those probably indicated real bugs. In any case, it prevented us from running CI with G_DEBUG=fatal-warnings, because there would be just too many unrelated crashes. Now we log debug messages that can be enabled with "LIBNM_CLIENT_DEBUG=trace". Some of these messages can also be turned into g_warning()/g_critical() by setting LIBNM_CLIENT_DEBUG=warning,error. Together with G_DEBUG=fatal-warnings, this turns them into assertions. Note that such "assertion failures" might also happen because of a server bug (or change). Thus these are not common assertions that indicate a bug in libnm and are thus not armed unless explicitly requested. In our CI we should now always run with LIBNM_CLIENT_DEBUG=warning,error and G_DEBUG=fatal-warnings and to catch bugs. Note that currently NetworkManager has bugs in this regard, so enabling this will result in assertion failures. That should be fixed first. - Note that this changes the order in which we emit "notify:devices" and "device-added" signals. I think it makes the most sense to emit first "device-removed", then "notify:devices", and finally "device-added" signals. This changes behavior for commit 52ae28f6e5bf ('libnm: queue added/removed signals and suppress uninitialized notifications'), but I don't think that users should actually rely on the order. Still, the new order makes the most sense to me. - In NetworkManager, profiles can be invisible to the user by setting "connection.permissions". Such profiles would be hidden by NMClient's nm_client_get_connections() and their "connection-added"/"connection-removed" signals. Note that NMActiveConnection's nm_active_connection_get_connection() and NMDevice's nm_device_get_available_connections() still exposes such hidden NMRemoteConnection instances. This behavior was preserved. NUMBERS ------- I compared 3 versions of libnm. [1] 962297f9085d, current tip of nm-1-20 branch [2] 4fad8c7c642e, current master, immediate parent of this patch [3] this patch All tests were done on Fedora 31, x86_64, gcc 9.2.1-1.fc31. The libraries were build with $ ./contrib/fedora/rpm/build_clean.sh -g -w test -W debug Note that RPM build already stripped the library. --- N1) File size of libnm.so.0.1.0 in bytes. There currently seems to be a issue on Fedora 31 generating wrong ELF notes. Usually, libnm is smaller but in these tests it had large (and bogus) ELF notes. Anyway, the point is to show the relative sizes, so it doesn't matter). [1] 4075552 (102.7%) [2] 3969624 (100.0%) [3] 3705208 ( 93.3%) --- N2) `size /usr/lib64/libnm.so.0.1.0`: text data bss dec hex filename [1] 1314569 (102.0%) 69980 ( 94.8%) 10632 ( 80.4%) 1395181 (101.4%) 1549ed /usr/lib64/libnm.so.0.1.0 [2] 1288410 (100.0%) 73796 (100.0%) 13224 (100.0%) 1375430 (100.0%) 14fcc6 /usr/lib64/libnm.so.0.1.0 [3] 1229066 ( 95.4%) 65248 ( 88.4%) 13400 (101.3%) 1307714 ( 95.1%) 13f442 /usr/lib64/libnm.so.0.1.0 --- N3) Performance test with test-client.py. With checkout of [2], run ``` prepare_checkout() { rm -rf /tmp/nm-test && \ git checkout -B test 4fad8c7c642e && \ git clean -fdx && \ ./autogen.sh --prefix=/tmp/nm-test && \ make -j 5 install && \ make -j 5 check-local-clients-tests-test-client } prepare_test() { NM_TEST_REGENERATE=1 NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v } do_test() { for i in {1..10}; do NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v || return -1 done echo "done!" } prepare_checkout prepare_test time do_test ``` [1] real 2m14.497s (101.3%) user 5m26.651s (100.3%) sys 1m40.453s (101.4%) [2] real 2m12.800s (100.0%) user 5m25.619s (100.0%) sys 1m39.065s (100.0%) [3] real 1m54.915s ( 86.5%) user 4m18.585s ( 79.4%) sys 1m32.066s ( 92.9%) --- N4) Performance. Run NetworkManager from build [2] and setup a large number of profiles (551 profiles and 515 devices, mostly unrealized). This setup is already at the edge of what NetworkManager currently can handle. Of course, that is a different issue. Here we just check how long plain `nmcli` takes on the system. ``` do_cleanup() { for UUID in $(nmcli -g NAME,UUID connection show | sed -n 's/^xx-c-.*:\([^:]\+\)$/\1/p'); do nmcli connection delete uuid "$UUID" done for DEVICE in $(nmcli -g DEVICE device status | grep '^xx-i-'); do nmcli device delete "$DEVICE" done } do_setup() { do_cleanup for i in {1..30}; do nmcli connection add type bond autoconnect no con-name xx-c-bond-$i ifname xx-i-bond-$i ipv4.method disabled ipv6.method ignore for j in $(seq $i 30); do nmcli connection add type vlan autoconnect no con-name xx-c-vlan-$i-$j vlan.id $j ifname xx-i-vlan-$i-$j vlan.parent xx-i-bond-$i ipv4.method disabled ipv6.method ignore done done systemctl restart NetworkManager.service sleep 5 } do_test() { perf stat -r 50 -B nmcli 1>/dev/null } do_test ``` [1] Performance counter stats for 'nmcli' (50 runs): 456.33 msec task-clock:u # 1.093 CPUs utilized ( +- 0.44% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,900 page-faults:u # 0.013 M/sec ( +- 0.02% ) 1,408,675,453 cycles:u # 3.087 GHz ( +- 0.48% ) 1,594,741,060 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 368,744,018 branches:u # 808.061 M/sec ( +- 0.02% ) 4,566,058 branch-misses:u # 1.24% of all branches ( +- 0.76% ) 0.41761 +- 0.00282 seconds time elapsed ( +- 0.68% ) [2] Performance counter stats for 'nmcli' (50 runs): 477.99 msec task-clock:u # 1.088 CPUs utilized ( +- 0.36% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,948 page-faults:u # 0.012 M/sec ( +- 0.03% ) 1,471,133,482 cycles:u # 3.078 GHz ( +- 0.36% ) 1,655,275,369 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 382,595,152 branches:u # 800.433 M/sec ( +- 0.02% ) 4,746,070 branch-misses:u # 1.24% of all branches ( +- 0.49% ) 0.43923 +- 0.00242 seconds time elapsed ( +- 0.55% ) [3] Performance counter stats for 'nmcli' (50 runs): 352.36 msec task-clock:u # 1.027 CPUs utilized ( +- 0.32% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 4,790 page-faults:u # 0.014 M/sec ( +- 0.26% ) 1,092,341,186 cycles:u # 3.100 GHz ( +- 0.26% ) 1,209,045,283 instructions:u # 1.11 insn per cycle ( +- 0.02% ) 281,708,462 branches:u # 799.499 M/sec ( +- 0.01% ) 3,101,031 branch-misses:u # 1.10% of all branches ( +- 0.61% ) 0.34296 +- 0.00120 seconds time elapsed ( +- 0.35% ) --- N5) same setup as N4), but run `PAGER= /bin/time -v nmcli`: [1] Command being timed: "nmcli" User time (seconds): 0.42 System time (seconds): 0.04 Percent of CPU this job got: 107% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.43 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34456 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6128 Voluntary context switches: 1298 Involuntary context switches: 1106 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [2] Command being timed: "nmcli" User time (seconds): 0.44 System time (seconds): 0.04 Percent of CPU this job got: 108% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.44 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34452 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6169 Voluntary context switches: 1849 Involuntary context switches: 142 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [3] Command being timed: "nmcli" User time (seconds): 0.32 System time (seconds): 0.02 Percent of CPU this job got: 102% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.34 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 29196 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 5059 Voluntary context switches: 919 Involuntary context switches: 685 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 --- N6) same setup as N4), but run `nmcli monitor` and look at `ps aux` for the RSS size. USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND [1] me 1492900 21.0 0.2 461348 33248 pts/10 Sl+ 15:02 0:00 nmcli monitor [2] me 1490721 5.0 0.2 461496 33548 pts/10 Sl+ 15:00 0:00 nmcli monitor [3] me 1495801 16.5 0.1 459476 28692 pts/10 Sl+ 15:04 0:00 nmcli monitor
2019-10-30 11:42:58 +01:00
NML_DBUS_META_PROPERTY_INIT_S ("Interface", PROP_INTERFACE, NMDevicePrivate, interface ),
NML_DBUS_META_PROPERTY_INIT_U ("InterfaceFlags", PROP_INTERFACE_FLAGS, NMDevicePrivate, interface_flags ),
NML_DBUS_META_PROPERTY_INIT_IGNORE ("Ip4Address", "u" ),
NML_DBUS_META_PROPERTY_INIT_O_PROP ("Ip4Config", PROP_IP4_CONFIG, NMDevicePrivate, property_o[PROPERTY_O_IDX_IP4_CONFIG], nm_ip4_config_get_type ),
NML_DBUS_META_PROPERTY_INIT_U ("Ip4Connectivity", PROP_IP4_CONNECTIVITY, NMDevicePrivate, ip4_connectivity ),
NML_DBUS_META_PROPERTY_INIT_O_PROP ("Ip6Config", PROP_IP6_CONFIG, NMDevicePrivate, property_o[PROPERTY_O_IDX_IP6_CONFIG], nm_ip6_config_get_type ),
NML_DBUS_META_PROPERTY_INIT_U ("Ip6Connectivity", PROP_IP6_CONNECTIVITY, NMDevicePrivate, ip6_connectivity ),
NML_DBUS_META_PROPERTY_INIT_S ("IpInterface", PROP_IP_INTERFACE, NMDevicePrivate, ip_interface ),
NML_DBUS_META_PROPERTY_INIT_FCN ("LldpNeighbors", PROP_LLDP_NEIGHBORS, "aa{sv}", _notify_update_prop_lldp_neighbors ),
NML_DBUS_META_PROPERTY_INIT_B ("Managed", PROP_MANAGED, NMDevicePrivate, managed ),
NML_DBUS_META_PROPERTY_INIT_U ("Metered", PROP_METERED, NMDevicePrivate, metered ),
NML_DBUS_META_PROPERTY_INIT_U ("Mtu", PROP_MTU, NMDevicePrivate, mtu ),
NML_DBUS_META_PROPERTY_INIT_B ("NmPluginMissing", PROP_NM_PLUGIN_MISSING, NMDevicePrivate, nm_plugin_missing ),
NML_DBUS_META_PROPERTY_INIT_S ("Path", PROP_PATH, NMDevicePrivate, path ),
libnm: refactor caching of D-Bus objects in NMClient No longer use GDBusObjectMangaerClient and gdbus-codegen generated classes for the NMClient cache. Instead, use GDBusConnection directly and a custom implementation (NMLDBusObject) for caching D-Bus' ObjectManager data. CHANGES ------- - This is a complete rework. I think the previous implementation was difficult to understand. There were unfixed bugs and nobody understood the code well enough to fix them. Maybe somebody out there understood the code, but I certainly did not. At least nobody provided patches to fix those issues. I do believe that this implementation is more straightforward and easier to understand. It removes a lot of layers of code. Whether this claim of simplicity is true, each reader must decide for himself/herself. Note that it is still fairly complex. - There was a lingering performance issue with large number of D-Bus objects. The patch tries hard that the implementation scales well. Of course, when we cache N objects that have N-to-M references to other, we still are fundamentally O(N*M) for runtime and memory consumption (with M being the number of references between objects). But each part should behave efficiently and well. - Play well with GMainContext. libnm code (NMClient) is generally not thread safe. However, it should work to use multiple instances in parallel, as long as each access to a NMClient is through the caller's GMainContext. This follows glib's style and effectively allows to use NMClient in a multi threaded scenario. This implies to stick to a main context upon construction and ensure that callbacks are only invoked when iterating that context. Also, NMClient itself shall never iterate the caller's context. This also means, libnm must never use g_idle_add() or g_timeout_add(), as those enqueue sources in the g_main_context_default() context. - Get ordering of messages right. All events are consistently enqueued in a GMainContext and processed strictly in order. For example, previously "nm-object.c" tried to combine signals and emit them on an idle handler. That is wrong, signals must be emitted in the right order and when they happen. Note that when using GInitable's synchronous initialization to initialize the NMClient instance, NMClient internally still operates fully asynchronously. In that case NMClient has an internal main context. - NMClient takes over most of the functionality. When using D-Bus' ObjectManager interface, one needs to handle basically the entire state of the D-Bus interface. That cannot be separated well into distinct parts, and even if you try, you just end up having closely related code in different source files. Spreading related code does not make it easier to understand, on the contrary. That means, NMClient is inherently complex as it contains most of the logic. I think that is not avoidable, but it's not as bad as it sounds. - NMClient processes D-Bus messages and state changes in separate steps. First NMClient unpacks the message (e.g. _dbus_handle_properties_changed()) and keeps track of the changed data. Then we update the GObject instances (_dbus_handle_obj_changed_dbus()) without emitting any signals yet. Finally, we emit all signals and notifications that were collected (_dbus_handle_changes_commit()). Note that for example during the initial GetManagedObjects() reply, NMClient receive a large amount of state at once. But we first apply all the changes to our GObject instances before emitting any signals. The result is that signals are always emitted in a moment when the cache is consistent. The unavoidable downside is that when you receive a property changed signal, possibly many other properties changed already and more signals are about to be emitted. - NMDeviceWifi no longer modifies the content of the cache from client side during poke_wireless_devices_with_rf_status(). The content of the cache should be determined by D-Bus alone and follow what NetworkManager service exposes. Local modifications should be avoided. - This aims to bring no API/ABI change, though it does of course bring various subtle changes in behavior. Those should be all for the better, but the goal is not to break any existing clients. This does change internal (albeit externally visible) API, like dropping NM_OBJECT_DBUS_OBJECT_MANAGER property and NMObject no longer implementing GInitableIface and GAsyncInitableIface. - Some uses of gdbus-codegen classes remain in NMVpnPluginOld, NMVpnServicePlugin and NMSecretAgentOld. These are independent of NMClient/NMObject and should be reworked separately. - While we no longer use generated classes from gdbus-codegen, we don't need more glue code than before. Also before we constructed NMPropertiesInfo and a had large amount of code to propagate properties from NMDBus* to NMObject. That got completely reworked, but did not fundamentally change. You still need about the same effort to create the NMLDBusMetaIface. Not using generated bindings did not make anything worse (which tells about the usefulness of generated code, at least in the way it was used). - NMLDBusMetaIface and other meta data is static and immutable. This avoids copying them around. Also, macros like NML_DBUS_META_PROPERTY_INIT_U() have compile time checks to ensure the property types matches. It's pretty hard to misuse them because it won't compile. - The meta data now explicitly encodes the expected D-Bus types and makes sure never to accept wrong data. That would only matter when the server (accidentally or intentionally) exposes unexpected types on D-Bus. I don't think that was previously ensured in all cases. For example, demarshal_generic() only cared about the GObject property type, it didn't know the expected D-Bus type. - Previously GDBusObjectManager would sometimes emit warnings (g_log()). Those probably indicated real bugs. In any case, it prevented us from running CI with G_DEBUG=fatal-warnings, because there would be just too many unrelated crashes. Now we log debug messages that can be enabled with "LIBNM_CLIENT_DEBUG=trace". Some of these messages can also be turned into g_warning()/g_critical() by setting LIBNM_CLIENT_DEBUG=warning,error. Together with G_DEBUG=fatal-warnings, this turns them into assertions. Note that such "assertion failures" might also happen because of a server bug (or change). Thus these are not common assertions that indicate a bug in libnm and are thus not armed unless explicitly requested. In our CI we should now always run with LIBNM_CLIENT_DEBUG=warning,error and G_DEBUG=fatal-warnings and to catch bugs. Note that currently NetworkManager has bugs in this regard, so enabling this will result in assertion failures. That should be fixed first. - Note that this changes the order in which we emit "notify:devices" and "device-added" signals. I think it makes the most sense to emit first "device-removed", then "notify:devices", and finally "device-added" signals. This changes behavior for commit 52ae28f6e5bf ('libnm: queue added/removed signals and suppress uninitialized notifications'), but I don't think that users should actually rely on the order. Still, the new order makes the most sense to me. - In NetworkManager, profiles can be invisible to the user by setting "connection.permissions". Such profiles would be hidden by NMClient's nm_client_get_connections() and their "connection-added"/"connection-removed" signals. Note that NMActiveConnection's nm_active_connection_get_connection() and NMDevice's nm_device_get_available_connections() still exposes such hidden NMRemoteConnection instances. This behavior was preserved. NUMBERS ------- I compared 3 versions of libnm. [1] 962297f9085d, current tip of nm-1-20 branch [2] 4fad8c7c642e, current master, immediate parent of this patch [3] this patch All tests were done on Fedora 31, x86_64, gcc 9.2.1-1.fc31. The libraries were build with $ ./contrib/fedora/rpm/build_clean.sh -g -w test -W debug Note that RPM build already stripped the library. --- N1) File size of libnm.so.0.1.0 in bytes. There currently seems to be a issue on Fedora 31 generating wrong ELF notes. Usually, libnm is smaller but in these tests it had large (and bogus) ELF notes. Anyway, the point is to show the relative sizes, so it doesn't matter). [1] 4075552 (102.7%) [2] 3969624 (100.0%) [3] 3705208 ( 93.3%) --- N2) `size /usr/lib64/libnm.so.0.1.0`: text data bss dec hex filename [1] 1314569 (102.0%) 69980 ( 94.8%) 10632 ( 80.4%) 1395181 (101.4%) 1549ed /usr/lib64/libnm.so.0.1.0 [2] 1288410 (100.0%) 73796 (100.0%) 13224 (100.0%) 1375430 (100.0%) 14fcc6 /usr/lib64/libnm.so.0.1.0 [3] 1229066 ( 95.4%) 65248 ( 88.4%) 13400 (101.3%) 1307714 ( 95.1%) 13f442 /usr/lib64/libnm.so.0.1.0 --- N3) Performance test with test-client.py. With checkout of [2], run ``` prepare_checkout() { rm -rf /tmp/nm-test && \ git checkout -B test 4fad8c7c642e && \ git clean -fdx && \ ./autogen.sh --prefix=/tmp/nm-test && \ make -j 5 install && \ make -j 5 check-local-clients-tests-test-client } prepare_test() { NM_TEST_REGENERATE=1 NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v } do_test() { for i in {1..10}; do NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v || return -1 done echo "done!" } prepare_checkout prepare_test time do_test ``` [1] real 2m14.497s (101.3%) user 5m26.651s (100.3%) sys 1m40.453s (101.4%) [2] real 2m12.800s (100.0%) user 5m25.619s (100.0%) sys 1m39.065s (100.0%) [3] real 1m54.915s ( 86.5%) user 4m18.585s ( 79.4%) sys 1m32.066s ( 92.9%) --- N4) Performance. Run NetworkManager from build [2] and setup a large number of profiles (551 profiles and 515 devices, mostly unrealized). This setup is already at the edge of what NetworkManager currently can handle. Of course, that is a different issue. Here we just check how long plain `nmcli` takes on the system. ``` do_cleanup() { for UUID in $(nmcli -g NAME,UUID connection show | sed -n 's/^xx-c-.*:\([^:]\+\)$/\1/p'); do nmcli connection delete uuid "$UUID" done for DEVICE in $(nmcli -g DEVICE device status | grep '^xx-i-'); do nmcli device delete "$DEVICE" done } do_setup() { do_cleanup for i in {1..30}; do nmcli connection add type bond autoconnect no con-name xx-c-bond-$i ifname xx-i-bond-$i ipv4.method disabled ipv6.method ignore for j in $(seq $i 30); do nmcli connection add type vlan autoconnect no con-name xx-c-vlan-$i-$j vlan.id $j ifname xx-i-vlan-$i-$j vlan.parent xx-i-bond-$i ipv4.method disabled ipv6.method ignore done done systemctl restart NetworkManager.service sleep 5 } do_test() { perf stat -r 50 -B nmcli 1>/dev/null } do_test ``` [1] Performance counter stats for 'nmcli' (50 runs): 456.33 msec task-clock:u # 1.093 CPUs utilized ( +- 0.44% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,900 page-faults:u # 0.013 M/sec ( +- 0.02% ) 1,408,675,453 cycles:u # 3.087 GHz ( +- 0.48% ) 1,594,741,060 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 368,744,018 branches:u # 808.061 M/sec ( +- 0.02% ) 4,566,058 branch-misses:u # 1.24% of all branches ( +- 0.76% ) 0.41761 +- 0.00282 seconds time elapsed ( +- 0.68% ) [2] Performance counter stats for 'nmcli' (50 runs): 477.99 msec task-clock:u # 1.088 CPUs utilized ( +- 0.36% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,948 page-faults:u # 0.012 M/sec ( +- 0.03% ) 1,471,133,482 cycles:u # 3.078 GHz ( +- 0.36% ) 1,655,275,369 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 382,595,152 branches:u # 800.433 M/sec ( +- 0.02% ) 4,746,070 branch-misses:u # 1.24% of all branches ( +- 0.49% ) 0.43923 +- 0.00242 seconds time elapsed ( +- 0.55% ) [3] Performance counter stats for 'nmcli' (50 runs): 352.36 msec task-clock:u # 1.027 CPUs utilized ( +- 0.32% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 4,790 page-faults:u # 0.014 M/sec ( +- 0.26% ) 1,092,341,186 cycles:u # 3.100 GHz ( +- 0.26% ) 1,209,045,283 instructions:u # 1.11 insn per cycle ( +- 0.02% ) 281,708,462 branches:u # 799.499 M/sec ( +- 0.01% ) 3,101,031 branch-misses:u # 1.10% of all branches ( +- 0.61% ) 0.34296 +- 0.00120 seconds time elapsed ( +- 0.35% ) --- N5) same setup as N4), but run `PAGER= /bin/time -v nmcli`: [1] Command being timed: "nmcli" User time (seconds): 0.42 System time (seconds): 0.04 Percent of CPU this job got: 107% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.43 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34456 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6128 Voluntary context switches: 1298 Involuntary context switches: 1106 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [2] Command being timed: "nmcli" User time (seconds): 0.44 System time (seconds): 0.04 Percent of CPU this job got: 108% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.44 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34452 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6169 Voluntary context switches: 1849 Involuntary context switches: 142 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [3] Command being timed: "nmcli" User time (seconds): 0.32 System time (seconds): 0.02 Percent of CPU this job got: 102% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.34 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 29196 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 5059 Voluntary context switches: 919 Involuntary context switches: 685 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 --- N6) same setup as N4), but run `nmcli monitor` and look at `ps aux` for the RSS size. USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND [1] me 1492900 21.0 0.2 461348 33248 pts/10 Sl+ 15:02 0:00 nmcli monitor [2] me 1490721 5.0 0.2 461496 33548 pts/10 Sl+ 15:00 0:00 nmcli monitor [3] me 1495801 16.5 0.1 459476 28692 pts/10 Sl+ 15:04 0:00 nmcli monitor
2019-10-30 11:42:58 +01:00
NML_DBUS_META_PROPERTY_INIT_S ("PhysicalPortId", PROP_PHYSICAL_PORT_ID, NMDevicePrivate, physical_port_id ),
NML_DBUS_META_PROPERTY_INIT_B ("Real", PROP_REAL, NMDevicePrivate, real ),
NML_DBUS_META_PROPERTY_INIT_IGNORE ("State", "u" ),
NML_DBUS_META_PROPERTY_INIT_FCN ("StateReason", PROP_STATE_REASON, "(uu)", _notify_update_prop_state_reason ),
NML_DBUS_META_PROPERTY_INIT_S ("Udi", PROP_UDI, NMDevicePrivate, udi ),
),
.base_struct_offset = G_STRUCT_OFFSET (NMDevice, _priv),
);
static void
libnm: refactor caching of D-Bus objects in NMClient No longer use GDBusObjectMangaerClient and gdbus-codegen generated classes for the NMClient cache. Instead, use GDBusConnection directly and a custom implementation (NMLDBusObject) for caching D-Bus' ObjectManager data. CHANGES ------- - This is a complete rework. I think the previous implementation was difficult to understand. There were unfixed bugs and nobody understood the code well enough to fix them. Maybe somebody out there understood the code, but I certainly did not. At least nobody provided patches to fix those issues. I do believe that this implementation is more straightforward and easier to understand. It removes a lot of layers of code. Whether this claim of simplicity is true, each reader must decide for himself/herself. Note that it is still fairly complex. - There was a lingering performance issue with large number of D-Bus objects. The patch tries hard that the implementation scales well. Of course, when we cache N objects that have N-to-M references to other, we still are fundamentally O(N*M) for runtime and memory consumption (with M being the number of references between objects). But each part should behave efficiently and well. - Play well with GMainContext. libnm code (NMClient) is generally not thread safe. However, it should work to use multiple instances in parallel, as long as each access to a NMClient is through the caller's GMainContext. This follows glib's style and effectively allows to use NMClient in a multi threaded scenario. This implies to stick to a main context upon construction and ensure that callbacks are only invoked when iterating that context. Also, NMClient itself shall never iterate the caller's context. This also means, libnm must never use g_idle_add() or g_timeout_add(), as those enqueue sources in the g_main_context_default() context. - Get ordering of messages right. All events are consistently enqueued in a GMainContext and processed strictly in order. For example, previously "nm-object.c" tried to combine signals and emit them on an idle handler. That is wrong, signals must be emitted in the right order and when they happen. Note that when using GInitable's synchronous initialization to initialize the NMClient instance, NMClient internally still operates fully asynchronously. In that case NMClient has an internal main context. - NMClient takes over most of the functionality. When using D-Bus' ObjectManager interface, one needs to handle basically the entire state of the D-Bus interface. That cannot be separated well into distinct parts, and even if you try, you just end up having closely related code in different source files. Spreading related code does not make it easier to understand, on the contrary. That means, NMClient is inherently complex as it contains most of the logic. I think that is not avoidable, but it's not as bad as it sounds. - NMClient processes D-Bus messages and state changes in separate steps. First NMClient unpacks the message (e.g. _dbus_handle_properties_changed()) and keeps track of the changed data. Then we update the GObject instances (_dbus_handle_obj_changed_dbus()) without emitting any signals yet. Finally, we emit all signals and notifications that were collected (_dbus_handle_changes_commit()). Note that for example during the initial GetManagedObjects() reply, NMClient receive a large amount of state at once. But we first apply all the changes to our GObject instances before emitting any signals. The result is that signals are always emitted in a moment when the cache is consistent. The unavoidable downside is that when you receive a property changed signal, possibly many other properties changed already and more signals are about to be emitted. - NMDeviceWifi no longer modifies the content of the cache from client side during poke_wireless_devices_with_rf_status(). The content of the cache should be determined by D-Bus alone and follow what NetworkManager service exposes. Local modifications should be avoided. - This aims to bring no API/ABI change, though it does of course bring various subtle changes in behavior. Those should be all for the better, but the goal is not to break any existing clients. This does change internal (albeit externally visible) API, like dropping NM_OBJECT_DBUS_OBJECT_MANAGER property and NMObject no longer implementing GInitableIface and GAsyncInitableIface. - Some uses of gdbus-codegen classes remain in NMVpnPluginOld, NMVpnServicePlugin and NMSecretAgentOld. These are independent of NMClient/NMObject and should be reworked separately. - While we no longer use generated classes from gdbus-codegen, we don't need more glue code than before. Also before we constructed NMPropertiesInfo and a had large amount of code to propagate properties from NMDBus* to NMObject. That got completely reworked, but did not fundamentally change. You still need about the same effort to create the NMLDBusMetaIface. Not using generated bindings did not make anything worse (which tells about the usefulness of generated code, at least in the way it was used). - NMLDBusMetaIface and other meta data is static and immutable. This avoids copying them around. Also, macros like NML_DBUS_META_PROPERTY_INIT_U() have compile time checks to ensure the property types matches. It's pretty hard to misuse them because it won't compile. - The meta data now explicitly encodes the expected D-Bus types and makes sure never to accept wrong data. That would only matter when the server (accidentally or intentionally) exposes unexpected types on D-Bus. I don't think that was previously ensured in all cases. For example, demarshal_generic() only cared about the GObject property type, it didn't know the expected D-Bus type. - Previously GDBusObjectManager would sometimes emit warnings (g_log()). Those probably indicated real bugs. In any case, it prevented us from running CI with G_DEBUG=fatal-warnings, because there would be just too many unrelated crashes. Now we log debug messages that can be enabled with "LIBNM_CLIENT_DEBUG=trace". Some of these messages can also be turned into g_warning()/g_critical() by setting LIBNM_CLIENT_DEBUG=warning,error. Together with G_DEBUG=fatal-warnings, this turns them into assertions. Note that such "assertion failures" might also happen because of a server bug (or change). Thus these are not common assertions that indicate a bug in libnm and are thus not armed unless explicitly requested. In our CI we should now always run with LIBNM_CLIENT_DEBUG=warning,error and G_DEBUG=fatal-warnings and to catch bugs. Note that currently NetworkManager has bugs in this regard, so enabling this will result in assertion failures. That should be fixed first. - Note that this changes the order in which we emit "notify:devices" and "device-added" signals. I think it makes the most sense to emit first "device-removed", then "notify:devices", and finally "device-added" signals. This changes behavior for commit 52ae28f6e5bf ('libnm: queue added/removed signals and suppress uninitialized notifications'), but I don't think that users should actually rely on the order. Still, the new order makes the most sense to me. - In NetworkManager, profiles can be invisible to the user by setting "connection.permissions". Such profiles would be hidden by NMClient's nm_client_get_connections() and their "connection-added"/"connection-removed" signals. Note that NMActiveConnection's nm_active_connection_get_connection() and NMDevice's nm_device_get_available_connections() still exposes such hidden NMRemoteConnection instances. This behavior was preserved. NUMBERS ------- I compared 3 versions of libnm. [1] 962297f9085d, current tip of nm-1-20 branch [2] 4fad8c7c642e, current master, immediate parent of this patch [3] this patch All tests were done on Fedora 31, x86_64, gcc 9.2.1-1.fc31. The libraries were build with $ ./contrib/fedora/rpm/build_clean.sh -g -w test -W debug Note that RPM build already stripped the library. --- N1) File size of libnm.so.0.1.0 in bytes. There currently seems to be a issue on Fedora 31 generating wrong ELF notes. Usually, libnm is smaller but in these tests it had large (and bogus) ELF notes. Anyway, the point is to show the relative sizes, so it doesn't matter). [1] 4075552 (102.7%) [2] 3969624 (100.0%) [3] 3705208 ( 93.3%) --- N2) `size /usr/lib64/libnm.so.0.1.0`: text data bss dec hex filename [1] 1314569 (102.0%) 69980 ( 94.8%) 10632 ( 80.4%) 1395181 (101.4%) 1549ed /usr/lib64/libnm.so.0.1.0 [2] 1288410 (100.0%) 73796 (100.0%) 13224 (100.0%) 1375430 (100.0%) 14fcc6 /usr/lib64/libnm.so.0.1.0 [3] 1229066 ( 95.4%) 65248 ( 88.4%) 13400 (101.3%) 1307714 ( 95.1%) 13f442 /usr/lib64/libnm.so.0.1.0 --- N3) Performance test with test-client.py. With checkout of [2], run ``` prepare_checkout() { rm -rf /tmp/nm-test && \ git checkout -B test 4fad8c7c642e && \ git clean -fdx && \ ./autogen.sh --prefix=/tmp/nm-test && \ make -j 5 install && \ make -j 5 check-local-clients-tests-test-client } prepare_test() { NM_TEST_REGENERATE=1 NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v } do_test() { for i in {1..10}; do NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v || return -1 done echo "done!" } prepare_checkout prepare_test time do_test ``` [1] real 2m14.497s (101.3%) user 5m26.651s (100.3%) sys 1m40.453s (101.4%) [2] real 2m12.800s (100.0%) user 5m25.619s (100.0%) sys 1m39.065s (100.0%) [3] real 1m54.915s ( 86.5%) user 4m18.585s ( 79.4%) sys 1m32.066s ( 92.9%) --- N4) Performance. Run NetworkManager from build [2] and setup a large number of profiles (551 profiles and 515 devices, mostly unrealized). This setup is already at the edge of what NetworkManager currently can handle. Of course, that is a different issue. Here we just check how long plain `nmcli` takes on the system. ``` do_cleanup() { for UUID in $(nmcli -g NAME,UUID connection show | sed -n 's/^xx-c-.*:\([^:]\+\)$/\1/p'); do nmcli connection delete uuid "$UUID" done for DEVICE in $(nmcli -g DEVICE device status | grep '^xx-i-'); do nmcli device delete "$DEVICE" done } do_setup() { do_cleanup for i in {1..30}; do nmcli connection add type bond autoconnect no con-name xx-c-bond-$i ifname xx-i-bond-$i ipv4.method disabled ipv6.method ignore for j in $(seq $i 30); do nmcli connection add type vlan autoconnect no con-name xx-c-vlan-$i-$j vlan.id $j ifname xx-i-vlan-$i-$j vlan.parent xx-i-bond-$i ipv4.method disabled ipv6.method ignore done done systemctl restart NetworkManager.service sleep 5 } do_test() { perf stat -r 50 -B nmcli 1>/dev/null } do_test ``` [1] Performance counter stats for 'nmcli' (50 runs): 456.33 msec task-clock:u # 1.093 CPUs utilized ( +- 0.44% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,900 page-faults:u # 0.013 M/sec ( +- 0.02% ) 1,408,675,453 cycles:u # 3.087 GHz ( +- 0.48% ) 1,594,741,060 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 368,744,018 branches:u # 808.061 M/sec ( +- 0.02% ) 4,566,058 branch-misses:u # 1.24% of all branches ( +- 0.76% ) 0.41761 +- 0.00282 seconds time elapsed ( +- 0.68% ) [2] Performance counter stats for 'nmcli' (50 runs): 477.99 msec task-clock:u # 1.088 CPUs utilized ( +- 0.36% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,948 page-faults:u # 0.012 M/sec ( +- 0.03% ) 1,471,133,482 cycles:u # 3.078 GHz ( +- 0.36% ) 1,655,275,369 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 382,595,152 branches:u # 800.433 M/sec ( +- 0.02% ) 4,746,070 branch-misses:u # 1.24% of all branches ( +- 0.49% ) 0.43923 +- 0.00242 seconds time elapsed ( +- 0.55% ) [3] Performance counter stats for 'nmcli' (50 runs): 352.36 msec task-clock:u # 1.027 CPUs utilized ( +- 0.32% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 4,790 page-faults:u # 0.014 M/sec ( +- 0.26% ) 1,092,341,186 cycles:u # 3.100 GHz ( +- 0.26% ) 1,209,045,283 instructions:u # 1.11 insn per cycle ( +- 0.02% ) 281,708,462 branches:u # 799.499 M/sec ( +- 0.01% ) 3,101,031 branch-misses:u # 1.10% of all branches ( +- 0.61% ) 0.34296 +- 0.00120 seconds time elapsed ( +- 0.35% ) --- N5) same setup as N4), but run `PAGER= /bin/time -v nmcli`: [1] Command being timed: "nmcli" User time (seconds): 0.42 System time (seconds): 0.04 Percent of CPU this job got: 107% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.43 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34456 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6128 Voluntary context switches: 1298 Involuntary context switches: 1106 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [2] Command being timed: "nmcli" User time (seconds): 0.44 System time (seconds): 0.04 Percent of CPU this job got: 108% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.44 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34452 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6169 Voluntary context switches: 1849 Involuntary context switches: 142 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [3] Command being timed: "nmcli" User time (seconds): 0.32 System time (seconds): 0.02 Percent of CPU this job got: 102% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.34 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 29196 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 5059 Voluntary context switches: 919 Involuntary context switches: 685 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 --- N6) same setup as N4), but run `nmcli monitor` and look at `ps aux` for the RSS size. USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND [1] me 1492900 21.0 0.2 461348 33248 pts/10 Sl+ 15:02 0:00 nmcli monitor [2] me 1490721 5.0 0.2 461496 33548 pts/10 Sl+ 15:00 0:00 nmcli monitor [3] me 1495801 16.5 0.1 459476 28692 pts/10 Sl+ 15:04 0:00 nmcli monitor
2019-10-30 11:42:58 +01:00
nm_device_class_init (NMDeviceClass *klass)
{
libnm: refactor caching of D-Bus objects in NMClient No longer use GDBusObjectMangaerClient and gdbus-codegen generated classes for the NMClient cache. Instead, use GDBusConnection directly and a custom implementation (NMLDBusObject) for caching D-Bus' ObjectManager data. CHANGES ------- - This is a complete rework. I think the previous implementation was difficult to understand. There were unfixed bugs and nobody understood the code well enough to fix them. Maybe somebody out there understood the code, but I certainly did not. At least nobody provided patches to fix those issues. I do believe that this implementation is more straightforward and easier to understand. It removes a lot of layers of code. Whether this claim of simplicity is true, each reader must decide for himself/herself. Note that it is still fairly complex. - There was a lingering performance issue with large number of D-Bus objects. The patch tries hard that the implementation scales well. Of course, when we cache N objects that have N-to-M references to other, we still are fundamentally O(N*M) for runtime and memory consumption (with M being the number of references between objects). But each part should behave efficiently and well. - Play well with GMainContext. libnm code (NMClient) is generally not thread safe. However, it should work to use multiple instances in parallel, as long as each access to a NMClient is through the caller's GMainContext. This follows glib's style and effectively allows to use NMClient in a multi threaded scenario. This implies to stick to a main context upon construction and ensure that callbacks are only invoked when iterating that context. Also, NMClient itself shall never iterate the caller's context. This also means, libnm must never use g_idle_add() or g_timeout_add(), as those enqueue sources in the g_main_context_default() context. - Get ordering of messages right. All events are consistently enqueued in a GMainContext and processed strictly in order. For example, previously "nm-object.c" tried to combine signals and emit them on an idle handler. That is wrong, signals must be emitted in the right order and when they happen. Note that when using GInitable's synchronous initialization to initialize the NMClient instance, NMClient internally still operates fully asynchronously. In that case NMClient has an internal main context. - NMClient takes over most of the functionality. When using D-Bus' ObjectManager interface, one needs to handle basically the entire state of the D-Bus interface. That cannot be separated well into distinct parts, and even if you try, you just end up having closely related code in different source files. Spreading related code does not make it easier to understand, on the contrary. That means, NMClient is inherently complex as it contains most of the logic. I think that is not avoidable, but it's not as bad as it sounds. - NMClient processes D-Bus messages and state changes in separate steps. First NMClient unpacks the message (e.g. _dbus_handle_properties_changed()) and keeps track of the changed data. Then we update the GObject instances (_dbus_handle_obj_changed_dbus()) without emitting any signals yet. Finally, we emit all signals and notifications that were collected (_dbus_handle_changes_commit()). Note that for example during the initial GetManagedObjects() reply, NMClient receive a large amount of state at once. But we first apply all the changes to our GObject instances before emitting any signals. The result is that signals are always emitted in a moment when the cache is consistent. The unavoidable downside is that when you receive a property changed signal, possibly many other properties changed already and more signals are about to be emitted. - NMDeviceWifi no longer modifies the content of the cache from client side during poke_wireless_devices_with_rf_status(). The content of the cache should be determined by D-Bus alone and follow what NetworkManager service exposes. Local modifications should be avoided. - This aims to bring no API/ABI change, though it does of course bring various subtle changes in behavior. Those should be all for the better, but the goal is not to break any existing clients. This does change internal (albeit externally visible) API, like dropping NM_OBJECT_DBUS_OBJECT_MANAGER property and NMObject no longer implementing GInitableIface and GAsyncInitableIface. - Some uses of gdbus-codegen classes remain in NMVpnPluginOld, NMVpnServicePlugin and NMSecretAgentOld. These are independent of NMClient/NMObject and should be reworked separately. - While we no longer use generated classes from gdbus-codegen, we don't need more glue code than before. Also before we constructed NMPropertiesInfo and a had large amount of code to propagate properties from NMDBus* to NMObject. That got completely reworked, but did not fundamentally change. You still need about the same effort to create the NMLDBusMetaIface. Not using generated bindings did not make anything worse (which tells about the usefulness of generated code, at least in the way it was used). - NMLDBusMetaIface and other meta data is static and immutable. This avoids copying them around. Also, macros like NML_DBUS_META_PROPERTY_INIT_U() have compile time checks to ensure the property types matches. It's pretty hard to misuse them because it won't compile. - The meta data now explicitly encodes the expected D-Bus types and makes sure never to accept wrong data. That would only matter when the server (accidentally or intentionally) exposes unexpected types on D-Bus. I don't think that was previously ensured in all cases. For example, demarshal_generic() only cared about the GObject property type, it didn't know the expected D-Bus type. - Previously GDBusObjectManager would sometimes emit warnings (g_log()). Those probably indicated real bugs. In any case, it prevented us from running CI with G_DEBUG=fatal-warnings, because there would be just too many unrelated crashes. Now we log debug messages that can be enabled with "LIBNM_CLIENT_DEBUG=trace". Some of these messages can also be turned into g_warning()/g_critical() by setting LIBNM_CLIENT_DEBUG=warning,error. Together with G_DEBUG=fatal-warnings, this turns them into assertions. Note that such "assertion failures" might also happen because of a server bug (or change). Thus these are not common assertions that indicate a bug in libnm and are thus not armed unless explicitly requested. In our CI we should now always run with LIBNM_CLIENT_DEBUG=warning,error and G_DEBUG=fatal-warnings and to catch bugs. Note that currently NetworkManager has bugs in this regard, so enabling this will result in assertion failures. That should be fixed first. - Note that this changes the order in which we emit "notify:devices" and "device-added" signals. I think it makes the most sense to emit first "device-removed", then "notify:devices", and finally "device-added" signals. This changes behavior for commit 52ae28f6e5bf ('libnm: queue added/removed signals and suppress uninitialized notifications'), but I don't think that users should actually rely on the order. Still, the new order makes the most sense to me. - In NetworkManager, profiles can be invisible to the user by setting "connection.permissions". Such profiles would be hidden by NMClient's nm_client_get_connections() and their "connection-added"/"connection-removed" signals. Note that NMActiveConnection's nm_active_connection_get_connection() and NMDevice's nm_device_get_available_connections() still exposes such hidden NMRemoteConnection instances. This behavior was preserved. NUMBERS ------- I compared 3 versions of libnm. [1] 962297f9085d, current tip of nm-1-20 branch [2] 4fad8c7c642e, current master, immediate parent of this patch [3] this patch All tests were done on Fedora 31, x86_64, gcc 9.2.1-1.fc31. The libraries were build with $ ./contrib/fedora/rpm/build_clean.sh -g -w test -W debug Note that RPM build already stripped the library. --- N1) File size of libnm.so.0.1.0 in bytes. There currently seems to be a issue on Fedora 31 generating wrong ELF notes. Usually, libnm is smaller but in these tests it had large (and bogus) ELF notes. Anyway, the point is to show the relative sizes, so it doesn't matter). [1] 4075552 (102.7%) [2] 3969624 (100.0%) [3] 3705208 ( 93.3%) --- N2) `size /usr/lib64/libnm.so.0.1.0`: text data bss dec hex filename [1] 1314569 (102.0%) 69980 ( 94.8%) 10632 ( 80.4%) 1395181 (101.4%) 1549ed /usr/lib64/libnm.so.0.1.0 [2] 1288410 (100.0%) 73796 (100.0%) 13224 (100.0%) 1375430 (100.0%) 14fcc6 /usr/lib64/libnm.so.0.1.0 [3] 1229066 ( 95.4%) 65248 ( 88.4%) 13400 (101.3%) 1307714 ( 95.1%) 13f442 /usr/lib64/libnm.so.0.1.0 --- N3) Performance test with test-client.py. With checkout of [2], run ``` prepare_checkout() { rm -rf /tmp/nm-test && \ git checkout -B test 4fad8c7c642e && \ git clean -fdx && \ ./autogen.sh --prefix=/tmp/nm-test && \ make -j 5 install && \ make -j 5 check-local-clients-tests-test-client } prepare_test() { NM_TEST_REGENERATE=1 NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v } do_test() { for i in {1..10}; do NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v || return -1 done echo "done!" } prepare_checkout prepare_test time do_test ``` [1] real 2m14.497s (101.3%) user 5m26.651s (100.3%) sys 1m40.453s (101.4%) [2] real 2m12.800s (100.0%) user 5m25.619s (100.0%) sys 1m39.065s (100.0%) [3] real 1m54.915s ( 86.5%) user 4m18.585s ( 79.4%) sys 1m32.066s ( 92.9%) --- N4) Performance. Run NetworkManager from build [2] and setup a large number of profiles (551 profiles and 515 devices, mostly unrealized). This setup is already at the edge of what NetworkManager currently can handle. Of course, that is a different issue. Here we just check how long plain `nmcli` takes on the system. ``` do_cleanup() { for UUID in $(nmcli -g NAME,UUID connection show | sed -n 's/^xx-c-.*:\([^:]\+\)$/\1/p'); do nmcli connection delete uuid "$UUID" done for DEVICE in $(nmcli -g DEVICE device status | grep '^xx-i-'); do nmcli device delete "$DEVICE" done } do_setup() { do_cleanup for i in {1..30}; do nmcli connection add type bond autoconnect no con-name xx-c-bond-$i ifname xx-i-bond-$i ipv4.method disabled ipv6.method ignore for j in $(seq $i 30); do nmcli connection add type vlan autoconnect no con-name xx-c-vlan-$i-$j vlan.id $j ifname xx-i-vlan-$i-$j vlan.parent xx-i-bond-$i ipv4.method disabled ipv6.method ignore done done systemctl restart NetworkManager.service sleep 5 } do_test() { perf stat -r 50 -B nmcli 1>/dev/null } do_test ``` [1] Performance counter stats for 'nmcli' (50 runs): 456.33 msec task-clock:u # 1.093 CPUs utilized ( +- 0.44% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,900 page-faults:u # 0.013 M/sec ( +- 0.02% ) 1,408,675,453 cycles:u # 3.087 GHz ( +- 0.48% ) 1,594,741,060 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 368,744,018 branches:u # 808.061 M/sec ( +- 0.02% ) 4,566,058 branch-misses:u # 1.24% of all branches ( +- 0.76% ) 0.41761 +- 0.00282 seconds time elapsed ( +- 0.68% ) [2] Performance counter stats for 'nmcli' (50 runs): 477.99 msec task-clock:u # 1.088 CPUs utilized ( +- 0.36% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,948 page-faults:u # 0.012 M/sec ( +- 0.03% ) 1,471,133,482 cycles:u # 3.078 GHz ( +- 0.36% ) 1,655,275,369 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 382,595,152 branches:u # 800.433 M/sec ( +- 0.02% ) 4,746,070 branch-misses:u # 1.24% of all branches ( +- 0.49% ) 0.43923 +- 0.00242 seconds time elapsed ( +- 0.55% ) [3] Performance counter stats for 'nmcli' (50 runs): 352.36 msec task-clock:u # 1.027 CPUs utilized ( +- 0.32% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 4,790 page-faults:u # 0.014 M/sec ( +- 0.26% ) 1,092,341,186 cycles:u # 3.100 GHz ( +- 0.26% ) 1,209,045,283 instructions:u # 1.11 insn per cycle ( +- 0.02% ) 281,708,462 branches:u # 799.499 M/sec ( +- 0.01% ) 3,101,031 branch-misses:u # 1.10% of all branches ( +- 0.61% ) 0.34296 +- 0.00120 seconds time elapsed ( +- 0.35% ) --- N5) same setup as N4), but run `PAGER= /bin/time -v nmcli`: [1] Command being timed: "nmcli" User time (seconds): 0.42 System time (seconds): 0.04 Percent of CPU this job got: 107% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.43 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34456 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6128 Voluntary context switches: 1298 Involuntary context switches: 1106 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [2] Command being timed: "nmcli" User time (seconds): 0.44 System time (seconds): 0.04 Percent of CPU this job got: 108% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.44 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34452 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6169 Voluntary context switches: 1849 Involuntary context switches: 142 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [3] Command being timed: "nmcli" User time (seconds): 0.32 System time (seconds): 0.02 Percent of CPU this job got: 102% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.34 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 29196 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 5059 Voluntary context switches: 919 Involuntary context switches: 685 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 --- N6) same setup as N4), but run `nmcli monitor` and look at `ps aux` for the RSS size. USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND [1] me 1492900 21.0 0.2 461348 33248 pts/10 Sl+ 15:02 0:00 nmcli monitor [2] me 1490721 5.0 0.2 461496 33548 pts/10 Sl+ 15:00 0:00 nmcli monitor [3] me 1495801 16.5 0.1 459476 28692 pts/10 Sl+ 15:04 0:00 nmcli monitor
2019-10-30 11:42:58 +01:00
GObjectClass *object_class = G_OBJECT_CLASS (klass);
NMObjectClass *nm_object_class = NM_OBJECT_CLASS (klass);
libnm: refactor caching of D-Bus objects in NMClient No longer use GDBusObjectMangaerClient and gdbus-codegen generated classes for the NMClient cache. Instead, use GDBusConnection directly and a custom implementation (NMLDBusObject) for caching D-Bus' ObjectManager data. CHANGES ------- - This is a complete rework. I think the previous implementation was difficult to understand. There were unfixed bugs and nobody understood the code well enough to fix them. Maybe somebody out there understood the code, but I certainly did not. At least nobody provided patches to fix those issues. I do believe that this implementation is more straightforward and easier to understand. It removes a lot of layers of code. Whether this claim of simplicity is true, each reader must decide for himself/herself. Note that it is still fairly complex. - There was a lingering performance issue with large number of D-Bus objects. The patch tries hard that the implementation scales well. Of course, when we cache N objects that have N-to-M references to other, we still are fundamentally O(N*M) for runtime and memory consumption (with M being the number of references between objects). But each part should behave efficiently and well. - Play well with GMainContext. libnm code (NMClient) is generally not thread safe. However, it should work to use multiple instances in parallel, as long as each access to a NMClient is through the caller's GMainContext. This follows glib's style and effectively allows to use NMClient in a multi threaded scenario. This implies to stick to a main context upon construction and ensure that callbacks are only invoked when iterating that context. Also, NMClient itself shall never iterate the caller's context. This also means, libnm must never use g_idle_add() or g_timeout_add(), as those enqueue sources in the g_main_context_default() context. - Get ordering of messages right. All events are consistently enqueued in a GMainContext and processed strictly in order. For example, previously "nm-object.c" tried to combine signals and emit them on an idle handler. That is wrong, signals must be emitted in the right order and when they happen. Note that when using GInitable's synchronous initialization to initialize the NMClient instance, NMClient internally still operates fully asynchronously. In that case NMClient has an internal main context. - NMClient takes over most of the functionality. When using D-Bus' ObjectManager interface, one needs to handle basically the entire state of the D-Bus interface. That cannot be separated well into distinct parts, and even if you try, you just end up having closely related code in different source files. Spreading related code does not make it easier to understand, on the contrary. That means, NMClient is inherently complex as it contains most of the logic. I think that is not avoidable, but it's not as bad as it sounds. - NMClient processes D-Bus messages and state changes in separate steps. First NMClient unpacks the message (e.g. _dbus_handle_properties_changed()) and keeps track of the changed data. Then we update the GObject instances (_dbus_handle_obj_changed_dbus()) without emitting any signals yet. Finally, we emit all signals and notifications that were collected (_dbus_handle_changes_commit()). Note that for example during the initial GetManagedObjects() reply, NMClient receive a large amount of state at once. But we first apply all the changes to our GObject instances before emitting any signals. The result is that signals are always emitted in a moment when the cache is consistent. The unavoidable downside is that when you receive a property changed signal, possibly many other properties changed already and more signals are about to be emitted. - NMDeviceWifi no longer modifies the content of the cache from client side during poke_wireless_devices_with_rf_status(). The content of the cache should be determined by D-Bus alone and follow what NetworkManager service exposes. Local modifications should be avoided. - This aims to bring no API/ABI change, though it does of course bring various subtle changes in behavior. Those should be all for the better, but the goal is not to break any existing clients. This does change internal (albeit externally visible) API, like dropping NM_OBJECT_DBUS_OBJECT_MANAGER property and NMObject no longer implementing GInitableIface and GAsyncInitableIface. - Some uses of gdbus-codegen classes remain in NMVpnPluginOld, NMVpnServicePlugin and NMSecretAgentOld. These are independent of NMClient/NMObject and should be reworked separately. - While we no longer use generated classes from gdbus-codegen, we don't need more glue code than before. Also before we constructed NMPropertiesInfo and a had large amount of code to propagate properties from NMDBus* to NMObject. That got completely reworked, but did not fundamentally change. You still need about the same effort to create the NMLDBusMetaIface. Not using generated bindings did not make anything worse (which tells about the usefulness of generated code, at least in the way it was used). - NMLDBusMetaIface and other meta data is static and immutable. This avoids copying them around. Also, macros like NML_DBUS_META_PROPERTY_INIT_U() have compile time checks to ensure the property types matches. It's pretty hard to misuse them because it won't compile. - The meta data now explicitly encodes the expected D-Bus types and makes sure never to accept wrong data. That would only matter when the server (accidentally or intentionally) exposes unexpected types on D-Bus. I don't think that was previously ensured in all cases. For example, demarshal_generic() only cared about the GObject property type, it didn't know the expected D-Bus type. - Previously GDBusObjectManager would sometimes emit warnings (g_log()). Those probably indicated real bugs. In any case, it prevented us from running CI with G_DEBUG=fatal-warnings, because there would be just too many unrelated crashes. Now we log debug messages that can be enabled with "LIBNM_CLIENT_DEBUG=trace". Some of these messages can also be turned into g_warning()/g_critical() by setting LIBNM_CLIENT_DEBUG=warning,error. Together with G_DEBUG=fatal-warnings, this turns them into assertions. Note that such "assertion failures" might also happen because of a server bug (or change). Thus these are not common assertions that indicate a bug in libnm and are thus not armed unless explicitly requested. In our CI we should now always run with LIBNM_CLIENT_DEBUG=warning,error and G_DEBUG=fatal-warnings and to catch bugs. Note that currently NetworkManager has bugs in this regard, so enabling this will result in assertion failures. That should be fixed first. - Note that this changes the order in which we emit "notify:devices" and "device-added" signals. I think it makes the most sense to emit first "device-removed", then "notify:devices", and finally "device-added" signals. This changes behavior for commit 52ae28f6e5bf ('libnm: queue added/removed signals and suppress uninitialized notifications'), but I don't think that users should actually rely on the order. Still, the new order makes the most sense to me. - In NetworkManager, profiles can be invisible to the user by setting "connection.permissions". Such profiles would be hidden by NMClient's nm_client_get_connections() and their "connection-added"/"connection-removed" signals. Note that NMActiveConnection's nm_active_connection_get_connection() and NMDevice's nm_device_get_available_connections() still exposes such hidden NMRemoteConnection instances. This behavior was preserved. NUMBERS ------- I compared 3 versions of libnm. [1] 962297f9085d, current tip of nm-1-20 branch [2] 4fad8c7c642e, current master, immediate parent of this patch [3] this patch All tests were done on Fedora 31, x86_64, gcc 9.2.1-1.fc31. The libraries were build with $ ./contrib/fedora/rpm/build_clean.sh -g -w test -W debug Note that RPM build already stripped the library. --- N1) File size of libnm.so.0.1.0 in bytes. There currently seems to be a issue on Fedora 31 generating wrong ELF notes. Usually, libnm is smaller but in these tests it had large (and bogus) ELF notes. Anyway, the point is to show the relative sizes, so it doesn't matter). [1] 4075552 (102.7%) [2] 3969624 (100.0%) [3] 3705208 ( 93.3%) --- N2) `size /usr/lib64/libnm.so.0.1.0`: text data bss dec hex filename [1] 1314569 (102.0%) 69980 ( 94.8%) 10632 ( 80.4%) 1395181 (101.4%) 1549ed /usr/lib64/libnm.so.0.1.0 [2] 1288410 (100.0%) 73796 (100.0%) 13224 (100.0%) 1375430 (100.0%) 14fcc6 /usr/lib64/libnm.so.0.1.0 [3] 1229066 ( 95.4%) 65248 ( 88.4%) 13400 (101.3%) 1307714 ( 95.1%) 13f442 /usr/lib64/libnm.so.0.1.0 --- N3) Performance test with test-client.py. With checkout of [2], run ``` prepare_checkout() { rm -rf /tmp/nm-test && \ git checkout -B test 4fad8c7c642e && \ git clean -fdx && \ ./autogen.sh --prefix=/tmp/nm-test && \ make -j 5 install && \ make -j 5 check-local-clients-tests-test-client } prepare_test() { NM_TEST_REGENERATE=1 NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v } do_test() { for i in {1..10}; do NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v || return -1 done echo "done!" } prepare_checkout prepare_test time do_test ``` [1] real 2m14.497s (101.3%) user 5m26.651s (100.3%) sys 1m40.453s (101.4%) [2] real 2m12.800s (100.0%) user 5m25.619s (100.0%) sys 1m39.065s (100.0%) [3] real 1m54.915s ( 86.5%) user 4m18.585s ( 79.4%) sys 1m32.066s ( 92.9%) --- N4) Performance. Run NetworkManager from build [2] and setup a large number of profiles (551 profiles and 515 devices, mostly unrealized). This setup is already at the edge of what NetworkManager currently can handle. Of course, that is a different issue. Here we just check how long plain `nmcli` takes on the system. ``` do_cleanup() { for UUID in $(nmcli -g NAME,UUID connection show | sed -n 's/^xx-c-.*:\([^:]\+\)$/\1/p'); do nmcli connection delete uuid "$UUID" done for DEVICE in $(nmcli -g DEVICE device status | grep '^xx-i-'); do nmcli device delete "$DEVICE" done } do_setup() { do_cleanup for i in {1..30}; do nmcli connection add type bond autoconnect no con-name xx-c-bond-$i ifname xx-i-bond-$i ipv4.method disabled ipv6.method ignore for j in $(seq $i 30); do nmcli connection add type vlan autoconnect no con-name xx-c-vlan-$i-$j vlan.id $j ifname xx-i-vlan-$i-$j vlan.parent xx-i-bond-$i ipv4.method disabled ipv6.method ignore done done systemctl restart NetworkManager.service sleep 5 } do_test() { perf stat -r 50 -B nmcli 1>/dev/null } do_test ``` [1] Performance counter stats for 'nmcli' (50 runs): 456.33 msec task-clock:u # 1.093 CPUs utilized ( +- 0.44% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,900 page-faults:u # 0.013 M/sec ( +- 0.02% ) 1,408,675,453 cycles:u # 3.087 GHz ( +- 0.48% ) 1,594,741,060 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 368,744,018 branches:u # 808.061 M/sec ( +- 0.02% ) 4,566,058 branch-misses:u # 1.24% of all branches ( +- 0.76% ) 0.41761 +- 0.00282 seconds time elapsed ( +- 0.68% ) [2] Performance counter stats for 'nmcli' (50 runs): 477.99 msec task-clock:u # 1.088 CPUs utilized ( +- 0.36% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,948 page-faults:u # 0.012 M/sec ( +- 0.03% ) 1,471,133,482 cycles:u # 3.078 GHz ( +- 0.36% ) 1,655,275,369 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 382,595,152 branches:u # 800.433 M/sec ( +- 0.02% ) 4,746,070 branch-misses:u # 1.24% of all branches ( +- 0.49% ) 0.43923 +- 0.00242 seconds time elapsed ( +- 0.55% ) [3] Performance counter stats for 'nmcli' (50 runs): 352.36 msec task-clock:u # 1.027 CPUs utilized ( +- 0.32% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 4,790 page-faults:u # 0.014 M/sec ( +- 0.26% ) 1,092,341,186 cycles:u # 3.100 GHz ( +- 0.26% ) 1,209,045,283 instructions:u # 1.11 insn per cycle ( +- 0.02% ) 281,708,462 branches:u # 799.499 M/sec ( +- 0.01% ) 3,101,031 branch-misses:u # 1.10% of all branches ( +- 0.61% ) 0.34296 +- 0.00120 seconds time elapsed ( +- 0.35% ) --- N5) same setup as N4), but run `PAGER= /bin/time -v nmcli`: [1] Command being timed: "nmcli" User time (seconds): 0.42 System time (seconds): 0.04 Percent of CPU this job got: 107% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.43 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34456 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6128 Voluntary context switches: 1298 Involuntary context switches: 1106 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [2] Command being timed: "nmcli" User time (seconds): 0.44 System time (seconds): 0.04 Percent of CPU this job got: 108% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.44 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34452 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6169 Voluntary context switches: 1849 Involuntary context switches: 142 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [3] Command being timed: "nmcli" User time (seconds): 0.32 System time (seconds): 0.02 Percent of CPU this job got: 102% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.34 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 29196 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 5059 Voluntary context switches: 919 Involuntary context switches: 685 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 --- N6) same setup as N4), but run `nmcli monitor` and look at `ps aux` for the RSS size. USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND [1] me 1492900 21.0 0.2 461348 33248 pts/10 Sl+ 15:02 0:00 nmcli monitor [2] me 1490721 5.0 0.2 461496 33548 pts/10 Sl+ 15:00 0:00 nmcli monitor [3] me 1495801 16.5 0.1 459476 28692 pts/10 Sl+ 15:04 0:00 nmcli monitor
2019-10-30 11:42:58 +01:00
g_type_class_add_private (klass, sizeof (NMDevicePrivate));
object_class->get_property = get_property;
object_class->set_property = set_property;
object_class->finalize = finalize;
libnm: refactor caching of D-Bus objects in NMClient No longer use GDBusObjectMangaerClient and gdbus-codegen generated classes for the NMClient cache. Instead, use GDBusConnection directly and a custom implementation (NMLDBusObject) for caching D-Bus' ObjectManager data. CHANGES ------- - This is a complete rework. I think the previous implementation was difficult to understand. There were unfixed bugs and nobody understood the code well enough to fix them. Maybe somebody out there understood the code, but I certainly did not. At least nobody provided patches to fix those issues. I do believe that this implementation is more straightforward and easier to understand. It removes a lot of layers of code. Whether this claim of simplicity is true, each reader must decide for himself/herself. Note that it is still fairly complex. - There was a lingering performance issue with large number of D-Bus objects. The patch tries hard that the implementation scales well. Of course, when we cache N objects that have N-to-M references to other, we still are fundamentally O(N*M) for runtime and memory consumption (with M being the number of references between objects). But each part should behave efficiently and well. - Play well with GMainContext. libnm code (NMClient) is generally not thread safe. However, it should work to use multiple instances in parallel, as long as each access to a NMClient is through the caller's GMainContext. This follows glib's style and effectively allows to use NMClient in a multi threaded scenario. This implies to stick to a main context upon construction and ensure that callbacks are only invoked when iterating that context. Also, NMClient itself shall never iterate the caller's context. This also means, libnm must never use g_idle_add() or g_timeout_add(), as those enqueue sources in the g_main_context_default() context. - Get ordering of messages right. All events are consistently enqueued in a GMainContext and processed strictly in order. For example, previously "nm-object.c" tried to combine signals and emit them on an idle handler. That is wrong, signals must be emitted in the right order and when they happen. Note that when using GInitable's synchronous initialization to initialize the NMClient instance, NMClient internally still operates fully asynchronously. In that case NMClient has an internal main context. - NMClient takes over most of the functionality. When using D-Bus' ObjectManager interface, one needs to handle basically the entire state of the D-Bus interface. That cannot be separated well into distinct parts, and even if you try, you just end up having closely related code in different source files. Spreading related code does not make it easier to understand, on the contrary. That means, NMClient is inherently complex as it contains most of the logic. I think that is not avoidable, but it's not as bad as it sounds. - NMClient processes D-Bus messages and state changes in separate steps. First NMClient unpacks the message (e.g. _dbus_handle_properties_changed()) and keeps track of the changed data. Then we update the GObject instances (_dbus_handle_obj_changed_dbus()) without emitting any signals yet. Finally, we emit all signals and notifications that were collected (_dbus_handle_changes_commit()). Note that for example during the initial GetManagedObjects() reply, NMClient receive a large amount of state at once. But we first apply all the changes to our GObject instances before emitting any signals. The result is that signals are always emitted in a moment when the cache is consistent. The unavoidable downside is that when you receive a property changed signal, possibly many other properties changed already and more signals are about to be emitted. - NMDeviceWifi no longer modifies the content of the cache from client side during poke_wireless_devices_with_rf_status(). The content of the cache should be determined by D-Bus alone and follow what NetworkManager service exposes. Local modifications should be avoided. - This aims to bring no API/ABI change, though it does of course bring various subtle changes in behavior. Those should be all for the better, but the goal is not to break any existing clients. This does change internal (albeit externally visible) API, like dropping NM_OBJECT_DBUS_OBJECT_MANAGER property and NMObject no longer implementing GInitableIface and GAsyncInitableIface. - Some uses of gdbus-codegen classes remain in NMVpnPluginOld, NMVpnServicePlugin and NMSecretAgentOld. These are independent of NMClient/NMObject and should be reworked separately. - While we no longer use generated classes from gdbus-codegen, we don't need more glue code than before. Also before we constructed NMPropertiesInfo and a had large amount of code to propagate properties from NMDBus* to NMObject. That got completely reworked, but did not fundamentally change. You still need about the same effort to create the NMLDBusMetaIface. Not using generated bindings did not make anything worse (which tells about the usefulness of generated code, at least in the way it was used). - NMLDBusMetaIface and other meta data is static and immutable. This avoids copying them around. Also, macros like NML_DBUS_META_PROPERTY_INIT_U() have compile time checks to ensure the property types matches. It's pretty hard to misuse them because it won't compile. - The meta data now explicitly encodes the expected D-Bus types and makes sure never to accept wrong data. That would only matter when the server (accidentally or intentionally) exposes unexpected types on D-Bus. I don't think that was previously ensured in all cases. For example, demarshal_generic() only cared about the GObject property type, it didn't know the expected D-Bus type. - Previously GDBusObjectManager would sometimes emit warnings (g_log()). Those probably indicated real bugs. In any case, it prevented us from running CI with G_DEBUG=fatal-warnings, because there would be just too many unrelated crashes. Now we log debug messages that can be enabled with "LIBNM_CLIENT_DEBUG=trace". Some of these messages can also be turned into g_warning()/g_critical() by setting LIBNM_CLIENT_DEBUG=warning,error. Together with G_DEBUG=fatal-warnings, this turns them into assertions. Note that such "assertion failures" might also happen because of a server bug (or change). Thus these are not common assertions that indicate a bug in libnm and are thus not armed unless explicitly requested. In our CI we should now always run with LIBNM_CLIENT_DEBUG=warning,error and G_DEBUG=fatal-warnings and to catch bugs. Note that currently NetworkManager has bugs in this regard, so enabling this will result in assertion failures. That should be fixed first. - Note that this changes the order in which we emit "notify:devices" and "device-added" signals. I think it makes the most sense to emit first "device-removed", then "notify:devices", and finally "device-added" signals. This changes behavior for commit 52ae28f6e5bf ('libnm: queue added/removed signals and suppress uninitialized notifications'), but I don't think that users should actually rely on the order. Still, the new order makes the most sense to me. - In NetworkManager, profiles can be invisible to the user by setting "connection.permissions". Such profiles would be hidden by NMClient's nm_client_get_connections() and their "connection-added"/"connection-removed" signals. Note that NMActiveConnection's nm_active_connection_get_connection() and NMDevice's nm_device_get_available_connections() still exposes such hidden NMRemoteConnection instances. This behavior was preserved. NUMBERS ------- I compared 3 versions of libnm. [1] 962297f9085d, current tip of nm-1-20 branch [2] 4fad8c7c642e, current master, immediate parent of this patch [3] this patch All tests were done on Fedora 31, x86_64, gcc 9.2.1-1.fc31. The libraries were build with $ ./contrib/fedora/rpm/build_clean.sh -g -w test -W debug Note that RPM build already stripped the library. --- N1) File size of libnm.so.0.1.0 in bytes. There currently seems to be a issue on Fedora 31 generating wrong ELF notes. Usually, libnm is smaller but in these tests it had large (and bogus) ELF notes. Anyway, the point is to show the relative sizes, so it doesn't matter). [1] 4075552 (102.7%) [2] 3969624 (100.0%) [3] 3705208 ( 93.3%) --- N2) `size /usr/lib64/libnm.so.0.1.0`: text data bss dec hex filename [1] 1314569 (102.0%) 69980 ( 94.8%) 10632 ( 80.4%) 1395181 (101.4%) 1549ed /usr/lib64/libnm.so.0.1.0 [2] 1288410 (100.0%) 73796 (100.0%) 13224 (100.0%) 1375430 (100.0%) 14fcc6 /usr/lib64/libnm.so.0.1.0 [3] 1229066 ( 95.4%) 65248 ( 88.4%) 13400 (101.3%) 1307714 ( 95.1%) 13f442 /usr/lib64/libnm.so.0.1.0 --- N3) Performance test with test-client.py. With checkout of [2], run ``` prepare_checkout() { rm -rf /tmp/nm-test && \ git checkout -B test 4fad8c7c642e && \ git clean -fdx && \ ./autogen.sh --prefix=/tmp/nm-test && \ make -j 5 install && \ make -j 5 check-local-clients-tests-test-client } prepare_test() { NM_TEST_REGENERATE=1 NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v } do_test() { for i in {1..10}; do NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v || return -1 done echo "done!" } prepare_checkout prepare_test time do_test ``` [1] real 2m14.497s (101.3%) user 5m26.651s (100.3%) sys 1m40.453s (101.4%) [2] real 2m12.800s (100.0%) user 5m25.619s (100.0%) sys 1m39.065s (100.0%) [3] real 1m54.915s ( 86.5%) user 4m18.585s ( 79.4%) sys 1m32.066s ( 92.9%) --- N4) Performance. Run NetworkManager from build [2] and setup a large number of profiles (551 profiles and 515 devices, mostly unrealized). This setup is already at the edge of what NetworkManager currently can handle. Of course, that is a different issue. Here we just check how long plain `nmcli` takes on the system. ``` do_cleanup() { for UUID in $(nmcli -g NAME,UUID connection show | sed -n 's/^xx-c-.*:\([^:]\+\)$/\1/p'); do nmcli connection delete uuid "$UUID" done for DEVICE in $(nmcli -g DEVICE device status | grep '^xx-i-'); do nmcli device delete "$DEVICE" done } do_setup() { do_cleanup for i in {1..30}; do nmcli connection add type bond autoconnect no con-name xx-c-bond-$i ifname xx-i-bond-$i ipv4.method disabled ipv6.method ignore for j in $(seq $i 30); do nmcli connection add type vlan autoconnect no con-name xx-c-vlan-$i-$j vlan.id $j ifname xx-i-vlan-$i-$j vlan.parent xx-i-bond-$i ipv4.method disabled ipv6.method ignore done done systemctl restart NetworkManager.service sleep 5 } do_test() { perf stat -r 50 -B nmcli 1>/dev/null } do_test ``` [1] Performance counter stats for 'nmcli' (50 runs): 456.33 msec task-clock:u # 1.093 CPUs utilized ( +- 0.44% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,900 page-faults:u # 0.013 M/sec ( +- 0.02% ) 1,408,675,453 cycles:u # 3.087 GHz ( +- 0.48% ) 1,594,741,060 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 368,744,018 branches:u # 808.061 M/sec ( +- 0.02% ) 4,566,058 branch-misses:u # 1.24% of all branches ( +- 0.76% ) 0.41761 +- 0.00282 seconds time elapsed ( +- 0.68% ) [2] Performance counter stats for 'nmcli' (50 runs): 477.99 msec task-clock:u # 1.088 CPUs utilized ( +- 0.36% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,948 page-faults:u # 0.012 M/sec ( +- 0.03% ) 1,471,133,482 cycles:u # 3.078 GHz ( +- 0.36% ) 1,655,275,369 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 382,595,152 branches:u # 800.433 M/sec ( +- 0.02% ) 4,746,070 branch-misses:u # 1.24% of all branches ( +- 0.49% ) 0.43923 +- 0.00242 seconds time elapsed ( +- 0.55% ) [3] Performance counter stats for 'nmcli' (50 runs): 352.36 msec task-clock:u # 1.027 CPUs utilized ( +- 0.32% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 4,790 page-faults:u # 0.014 M/sec ( +- 0.26% ) 1,092,341,186 cycles:u # 3.100 GHz ( +- 0.26% ) 1,209,045,283 instructions:u # 1.11 insn per cycle ( +- 0.02% ) 281,708,462 branches:u # 799.499 M/sec ( +- 0.01% ) 3,101,031 branch-misses:u # 1.10% of all branches ( +- 0.61% ) 0.34296 +- 0.00120 seconds time elapsed ( +- 0.35% ) --- N5) same setup as N4), but run `PAGER= /bin/time -v nmcli`: [1] Command being timed: "nmcli" User time (seconds): 0.42 System time (seconds): 0.04 Percent of CPU this job got: 107% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.43 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34456 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6128 Voluntary context switches: 1298 Involuntary context switches: 1106 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [2] Command being timed: "nmcli" User time (seconds): 0.44 System time (seconds): 0.04 Percent of CPU this job got: 108% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.44 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34452 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6169 Voluntary context switches: 1849 Involuntary context switches: 142 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [3] Command being timed: "nmcli" User time (seconds): 0.32 System time (seconds): 0.02 Percent of CPU this job got: 102% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.34 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 29196 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 5059 Voluntary context switches: 919 Involuntary context switches: 685 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 --- N6) same setup as N4), but run `nmcli monitor` and look at `ps aux` for the RSS size. USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND [1] me 1492900 21.0 0.2 461348 33248 pts/10 Sl+ 15:02 0:00 nmcli monitor [2] me 1490721 5.0 0.2 461496 33548 pts/10 Sl+ 15:00 0:00 nmcli monitor [3] me 1495801 16.5 0.1 459476 28692 pts/10 Sl+ 15:04 0:00 nmcli monitor
2019-10-30 11:42:58 +01:00
nm_object_class->register_client = register_client;
_NM_OBJECT_CLASS_INIT_PRIV_PTR_INDIRECT (nm_object_class, NMDevice);
libnm: refactor caching of D-Bus objects in NMClient No longer use GDBusObjectMangaerClient and gdbus-codegen generated classes for the NMClient cache. Instead, use GDBusConnection directly and a custom implementation (NMLDBusObject) for caching D-Bus' ObjectManager data. CHANGES ------- - This is a complete rework. I think the previous implementation was difficult to understand. There were unfixed bugs and nobody understood the code well enough to fix them. Maybe somebody out there understood the code, but I certainly did not. At least nobody provided patches to fix those issues. I do believe that this implementation is more straightforward and easier to understand. It removes a lot of layers of code. Whether this claim of simplicity is true, each reader must decide for himself/herself. Note that it is still fairly complex. - There was a lingering performance issue with large number of D-Bus objects. The patch tries hard that the implementation scales well. Of course, when we cache N objects that have N-to-M references to other, we still are fundamentally O(N*M) for runtime and memory consumption (with M being the number of references between objects). But each part should behave efficiently and well. - Play well with GMainContext. libnm code (NMClient) is generally not thread safe. However, it should work to use multiple instances in parallel, as long as each access to a NMClient is through the caller's GMainContext. This follows glib's style and effectively allows to use NMClient in a multi threaded scenario. This implies to stick to a main context upon construction and ensure that callbacks are only invoked when iterating that context. Also, NMClient itself shall never iterate the caller's context. This also means, libnm must never use g_idle_add() or g_timeout_add(), as those enqueue sources in the g_main_context_default() context. - Get ordering of messages right. All events are consistently enqueued in a GMainContext and processed strictly in order. For example, previously "nm-object.c" tried to combine signals and emit them on an idle handler. That is wrong, signals must be emitted in the right order and when they happen. Note that when using GInitable's synchronous initialization to initialize the NMClient instance, NMClient internally still operates fully asynchronously. In that case NMClient has an internal main context. - NMClient takes over most of the functionality. When using D-Bus' ObjectManager interface, one needs to handle basically the entire state of the D-Bus interface. That cannot be separated well into distinct parts, and even if you try, you just end up having closely related code in different source files. Spreading related code does not make it easier to understand, on the contrary. That means, NMClient is inherently complex as it contains most of the logic. I think that is not avoidable, but it's not as bad as it sounds. - NMClient processes D-Bus messages and state changes in separate steps. First NMClient unpacks the message (e.g. _dbus_handle_properties_changed()) and keeps track of the changed data. Then we update the GObject instances (_dbus_handle_obj_changed_dbus()) without emitting any signals yet. Finally, we emit all signals and notifications that were collected (_dbus_handle_changes_commit()). Note that for example during the initial GetManagedObjects() reply, NMClient receive a large amount of state at once. But we first apply all the changes to our GObject instances before emitting any signals. The result is that signals are always emitted in a moment when the cache is consistent. The unavoidable downside is that when you receive a property changed signal, possibly many other properties changed already and more signals are about to be emitted. - NMDeviceWifi no longer modifies the content of the cache from client side during poke_wireless_devices_with_rf_status(). The content of the cache should be determined by D-Bus alone and follow what NetworkManager service exposes. Local modifications should be avoided. - This aims to bring no API/ABI change, though it does of course bring various subtle changes in behavior. Those should be all for the better, but the goal is not to break any existing clients. This does change internal (albeit externally visible) API, like dropping NM_OBJECT_DBUS_OBJECT_MANAGER property and NMObject no longer implementing GInitableIface and GAsyncInitableIface. - Some uses of gdbus-codegen classes remain in NMVpnPluginOld, NMVpnServicePlugin and NMSecretAgentOld. These are independent of NMClient/NMObject and should be reworked separately. - While we no longer use generated classes from gdbus-codegen, we don't need more glue code than before. Also before we constructed NMPropertiesInfo and a had large amount of code to propagate properties from NMDBus* to NMObject. That got completely reworked, but did not fundamentally change. You still need about the same effort to create the NMLDBusMetaIface. Not using generated bindings did not make anything worse (which tells about the usefulness of generated code, at least in the way it was used). - NMLDBusMetaIface and other meta data is static and immutable. This avoids copying them around. Also, macros like NML_DBUS_META_PROPERTY_INIT_U() have compile time checks to ensure the property types matches. It's pretty hard to misuse them because it won't compile. - The meta data now explicitly encodes the expected D-Bus types and makes sure never to accept wrong data. That would only matter when the server (accidentally or intentionally) exposes unexpected types on D-Bus. I don't think that was previously ensured in all cases. For example, demarshal_generic() only cared about the GObject property type, it didn't know the expected D-Bus type. - Previously GDBusObjectManager would sometimes emit warnings (g_log()). Those probably indicated real bugs. In any case, it prevented us from running CI with G_DEBUG=fatal-warnings, because there would be just too many unrelated crashes. Now we log debug messages that can be enabled with "LIBNM_CLIENT_DEBUG=trace". Some of these messages can also be turned into g_warning()/g_critical() by setting LIBNM_CLIENT_DEBUG=warning,error. Together with G_DEBUG=fatal-warnings, this turns them into assertions. Note that such "assertion failures" might also happen because of a server bug (or change). Thus these are not common assertions that indicate a bug in libnm and are thus not armed unless explicitly requested. In our CI we should now always run with LIBNM_CLIENT_DEBUG=warning,error and G_DEBUG=fatal-warnings and to catch bugs. Note that currently NetworkManager has bugs in this regard, so enabling this will result in assertion failures. That should be fixed first. - Note that this changes the order in which we emit "notify:devices" and "device-added" signals. I think it makes the most sense to emit first "device-removed", then "notify:devices", and finally "device-added" signals. This changes behavior for commit 52ae28f6e5bf ('libnm: queue added/removed signals and suppress uninitialized notifications'), but I don't think that users should actually rely on the order. Still, the new order makes the most sense to me. - In NetworkManager, profiles can be invisible to the user by setting "connection.permissions". Such profiles would be hidden by NMClient's nm_client_get_connections() and their "connection-added"/"connection-removed" signals. Note that NMActiveConnection's nm_active_connection_get_connection() and NMDevice's nm_device_get_available_connections() still exposes such hidden NMRemoteConnection instances. This behavior was preserved. NUMBERS ------- I compared 3 versions of libnm. [1] 962297f9085d, current tip of nm-1-20 branch [2] 4fad8c7c642e, current master, immediate parent of this patch [3] this patch All tests were done on Fedora 31, x86_64, gcc 9.2.1-1.fc31. The libraries were build with $ ./contrib/fedora/rpm/build_clean.sh -g -w test -W debug Note that RPM build already stripped the library. --- N1) File size of libnm.so.0.1.0 in bytes. There currently seems to be a issue on Fedora 31 generating wrong ELF notes. Usually, libnm is smaller but in these tests it had large (and bogus) ELF notes. Anyway, the point is to show the relative sizes, so it doesn't matter). [1] 4075552 (102.7%) [2] 3969624 (100.0%) [3] 3705208 ( 93.3%) --- N2) `size /usr/lib64/libnm.so.0.1.0`: text data bss dec hex filename [1] 1314569 (102.0%) 69980 ( 94.8%) 10632 ( 80.4%) 1395181 (101.4%) 1549ed /usr/lib64/libnm.so.0.1.0 [2] 1288410 (100.0%) 73796 (100.0%) 13224 (100.0%) 1375430 (100.0%) 14fcc6 /usr/lib64/libnm.so.0.1.0 [3] 1229066 ( 95.4%) 65248 ( 88.4%) 13400 (101.3%) 1307714 ( 95.1%) 13f442 /usr/lib64/libnm.so.0.1.0 --- N3) Performance test with test-client.py. With checkout of [2], run ``` prepare_checkout() { rm -rf /tmp/nm-test && \ git checkout -B test 4fad8c7c642e && \ git clean -fdx && \ ./autogen.sh --prefix=/tmp/nm-test && \ make -j 5 install && \ make -j 5 check-local-clients-tests-test-client } prepare_test() { NM_TEST_REGENERATE=1 NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v } do_test() { for i in {1..10}; do NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v || return -1 done echo "done!" } prepare_checkout prepare_test time do_test ``` [1] real 2m14.497s (101.3%) user 5m26.651s (100.3%) sys 1m40.453s (101.4%) [2] real 2m12.800s (100.0%) user 5m25.619s (100.0%) sys 1m39.065s (100.0%) [3] real 1m54.915s ( 86.5%) user 4m18.585s ( 79.4%) sys 1m32.066s ( 92.9%) --- N4) Performance. Run NetworkManager from build [2] and setup a large number of profiles (551 profiles and 515 devices, mostly unrealized). This setup is already at the edge of what NetworkManager currently can handle. Of course, that is a different issue. Here we just check how long plain `nmcli` takes on the system. ``` do_cleanup() { for UUID in $(nmcli -g NAME,UUID connection show | sed -n 's/^xx-c-.*:\([^:]\+\)$/\1/p'); do nmcli connection delete uuid "$UUID" done for DEVICE in $(nmcli -g DEVICE device status | grep '^xx-i-'); do nmcli device delete "$DEVICE" done } do_setup() { do_cleanup for i in {1..30}; do nmcli connection add type bond autoconnect no con-name xx-c-bond-$i ifname xx-i-bond-$i ipv4.method disabled ipv6.method ignore for j in $(seq $i 30); do nmcli connection add type vlan autoconnect no con-name xx-c-vlan-$i-$j vlan.id $j ifname xx-i-vlan-$i-$j vlan.parent xx-i-bond-$i ipv4.method disabled ipv6.method ignore done done systemctl restart NetworkManager.service sleep 5 } do_test() { perf stat -r 50 -B nmcli 1>/dev/null } do_test ``` [1] Performance counter stats for 'nmcli' (50 runs): 456.33 msec task-clock:u # 1.093 CPUs utilized ( +- 0.44% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,900 page-faults:u # 0.013 M/sec ( +- 0.02% ) 1,408,675,453 cycles:u # 3.087 GHz ( +- 0.48% ) 1,594,741,060 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 368,744,018 branches:u # 808.061 M/sec ( +- 0.02% ) 4,566,058 branch-misses:u # 1.24% of all branches ( +- 0.76% ) 0.41761 +- 0.00282 seconds time elapsed ( +- 0.68% ) [2] Performance counter stats for 'nmcli' (50 runs): 477.99 msec task-clock:u # 1.088 CPUs utilized ( +- 0.36% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,948 page-faults:u # 0.012 M/sec ( +- 0.03% ) 1,471,133,482 cycles:u # 3.078 GHz ( +- 0.36% ) 1,655,275,369 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 382,595,152 branches:u # 800.433 M/sec ( +- 0.02% ) 4,746,070 branch-misses:u # 1.24% of all branches ( +- 0.49% ) 0.43923 +- 0.00242 seconds time elapsed ( +- 0.55% ) [3] Performance counter stats for 'nmcli' (50 runs): 352.36 msec task-clock:u # 1.027 CPUs utilized ( +- 0.32% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 4,790 page-faults:u # 0.014 M/sec ( +- 0.26% ) 1,092,341,186 cycles:u # 3.100 GHz ( +- 0.26% ) 1,209,045,283 instructions:u # 1.11 insn per cycle ( +- 0.02% ) 281,708,462 branches:u # 799.499 M/sec ( +- 0.01% ) 3,101,031 branch-misses:u # 1.10% of all branches ( +- 0.61% ) 0.34296 +- 0.00120 seconds time elapsed ( +- 0.35% ) --- N5) same setup as N4), but run `PAGER= /bin/time -v nmcli`: [1] Command being timed: "nmcli" User time (seconds): 0.42 System time (seconds): 0.04 Percent of CPU this job got: 107% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.43 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34456 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6128 Voluntary context switches: 1298 Involuntary context switches: 1106 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [2] Command being timed: "nmcli" User time (seconds): 0.44 System time (seconds): 0.04 Percent of CPU this job got: 108% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.44 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34452 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6169 Voluntary context switches: 1849 Involuntary context switches: 142 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [3] Command being timed: "nmcli" User time (seconds): 0.32 System time (seconds): 0.02 Percent of CPU this job got: 102% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.34 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 29196 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 5059 Voluntary context switches: 919 Involuntary context switches: 685 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 --- N6) same setup as N4), but run `nmcli monitor` and look at `ps aux` for the RSS size. USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND [1] me 1492900 21.0 0.2 461348 33248 pts/10 Sl+ 15:02 0:00 nmcli monitor [2] me 1490721 5.0 0.2 461496 33548 pts/10 Sl+ 15:00 0:00 nmcli monitor [3] me 1495801 16.5 0.1 459476 28692 pts/10 Sl+ 15:04 0:00 nmcli monitor
2019-10-30 11:42:58 +01:00
_NM_OBJECT_CLASS_INIT_PROPERTY_O_FIELDS_N (nm_object_class, NMDevicePrivate, property_o);
_NM_OBJECT_CLASS_INIT_PROPERTY_AO_FIELDS_1 (nm_object_class, NMDevicePrivate, available_connections);
klass->connection_compatible = connection_compatible;
/**
* NMDevice:interface:
*
* The interface of the device.
**/
obj_properties[PROP_INTERFACE] =
g_param_spec_string (NM_DEVICE_INTERFACE, "", "",
NULL,
G_PARAM_READABLE |
G_PARAM_STATIC_STRINGS);
/**
* NMDevice:ip-interface:
*
* The IP interface of the device which should be used for all IP-related
* operations like addressing and routing.
**/
obj_properties[PROP_IP_INTERFACE] =
g_param_spec_string (NM_DEVICE_IP_INTERFACE, "", "",
NULL,
G_PARAM_READABLE |
G_PARAM_STATIC_STRINGS);
/**
* NMDevice:device-type:
*
* The numeric type of the device.
**/
obj_properties[PROP_DEVICE_TYPE] =
g_param_spec_enum (NM_DEVICE_DEVICE_TYPE, "", "",
NM_TYPE_DEVICE_TYPE,
NM_DEVICE_TYPE_UNKNOWN,
G_PARAM_READABLE |
G_PARAM_STATIC_STRINGS);
/**
* NMDevice:udi:
*
* An operating-system specific device hardware identifier; this is not
* unique to a specific hardware device across reboots or hotplugs. It
* is an opaque string which for some device types (Bluetooth, Modem)
* contains an identifier provided by the underlying hardware service daemon
* such as Bluez or ModemManager, and clients can use this property to
* request more information about the device from those services.
**/
obj_properties[PROP_UDI] =
g_param_spec_string (NM_DEVICE_UDI, "", "",
NULL,
G_PARAM_READABLE |
G_PARAM_STATIC_STRINGS);
/**
* NMDevice:path:
*
* The device path as exposed by the udev property ID_PATH.
*
* The string is backslash escaped (C escaping) for invalid
* characters. The escaping can be reverted with g_strcompress(),
* however the result may not be valid UTF-8.
*
* Since: 1.26
**/
obj_properties[PROP_PATH] =
g_param_spec_string (NM_DEVICE_PATH, "", "",
NULL,
G_PARAM_READABLE |
G_PARAM_STATIC_STRINGS);
/**
* NMDevice:driver:
*
* The driver of the device.
**/
obj_properties[PROP_DRIVER] =
g_param_spec_string (NM_DEVICE_DRIVER, "", "",
NULL,
G_PARAM_READABLE |
G_PARAM_STATIC_STRINGS);
/**
* NMDevice:driver-version:
*
* The version of the device driver.
**/
obj_properties[PROP_DRIVER_VERSION] =
g_param_spec_string (NM_DEVICE_DRIVER_VERSION, "", "",
NULL,
G_PARAM_READABLE |
G_PARAM_STATIC_STRINGS);
/**
* NMDevice:firmware-version:
*
* The firmware version of the device.
**/
obj_properties[PROP_FIRMWARE_VERSION] =
g_param_spec_string (NM_DEVICE_FIRMWARE_VERSION, "", "",
NULL,
G_PARAM_READABLE |
G_PARAM_STATIC_STRINGS);
/**
* NMDevice:capabilities:
*
* The capabilities of the device.
**/
obj_properties[PROP_CAPABILITIES] =
g_param_spec_flags (NM_DEVICE_CAPABILITIES, "", "",
NM_TYPE_DEVICE_CAPABILITIES,
NM_DEVICE_CAP_NONE,
G_PARAM_READABLE |
G_PARAM_STATIC_STRINGS);
/**
* NMDevice:real:
*
* Whether the device is real or is a placeholder device that could
* be created automatically by NetworkManager if one of its
* #NMDevice:available-connections was activated.
*
* Since: 1.2
**/
obj_properties[PROP_REAL] =
g_param_spec_boolean (NM_DEVICE_REAL, "", "",
FALSE,
G_PARAM_READABLE |
G_PARAM_STATIC_STRINGS);
/**
* NMDevice:managed:
*
* Whether the device is managed by NetworkManager.
**/
obj_properties[PROP_MANAGED] =
g_param_spec_boolean (NM_DEVICE_MANAGED, "", "",
FALSE,
G_PARAM_READABLE |
G_PARAM_STATIC_STRINGS);
/**
* NMDevice:autoconnect:
*
* Whether the device can auto-activate a connection.
libnm: deprecate synchronous/blocking API in libnm Note that D-Bus is fundamentally asynchronous. Doing blocking calls on top of D-Bus is odd, especially for libnm's NMClient. That is because NMClient essentially is a client-side cache of the objects from the D-Bus interface. This cache should be filled exclusively by (asynchronous) D-Bus events (PropertiesChanged). So, making a blocking D-Bus call means to wait for a response and return it, while queuing all messages that are received in the meantime. Basically there are three ways how a synchronous API on NMClient could behave: 1) the call just calls g_dbus_connection_call_sync(). This means that libnm sends a D-Bus request via GDBusConnection, and blockingly waits for the response. All D-Bus messages that get received in the meantime are queued in the GMainContext that belongs to NMClient. That means, none of these D-Bus events are processed until we iterate the GMainContext after the call returns. The effect is, that NMClient (and all cached objects in there) are unaffected by the D-Bus request. Most of the synchronous API calls in libnm are of this kind. The problem is that the strict ordering of D-Bus events gets violated. For some API this is not an immediate problem. Take for example nm_device_wifi_request_scan(). The call merely blockingly tells NetworkManager to start scanning, but since NetworkManager's D-Bus API does not directly expose any state that tells whether we are currently scanning, this out of order processing of the D-Bus request is a small issue. The problem is more obvious for nm_client_networking_set_enabled(). After calling it, NM_CLIENT_NETWORKING_ENABLED is still unaffected and unchanged, because the PropertiesChanged signal from D-Bus is not yet processed. This means, while you make such a blocking call, NMClient's state does not change. But usually you perform the synchronous call to change some state. In this form, the blocking call is not useful, because NMClient only changes the state after iterating the GMainContext, and not after the blocking call returns. 2) like 1), but after making the blocking g_dbus_connection_call_sync(), update the NMClient cache artificially. This is what nm_manager_check_connectivity() does, to "fix" bgo#784629. This also has the problem of out-of-order events, but it kinda solves the problem of not changing the state during the blocking call. But it does so by hacking the state of the cache. I think this is really wrong because the state should only be updated from the ordered stream of D-Bus messages (PropertiesChanged signal and similar). When libnm decides to modify the state, there may be already D-Bus messages queued that affect this very state. 3) instead of calling g_dbus_connection_call_sync(), use the asynchronous g_dbus_connection_call(). If we would use a sepaate GMainContext for all D-Bus related calls, we could ensure that while we block for the response, we iterate that internal main context. This might be nice, because all events are processed in order and after the blocking call returns, the NMClient state is up to date. The are problems however: current blocking API does not do this, so it's a significant change in behavior. Also, it might be unexpected to the user that during the blocking call the entire content of NMClient's cache might change and all pointers to the cache might be invalidated. Also, of course NMClient would invoke signals for all the changes that happen. Another problem is that this would be more effort to implement and it involves a small performance overhead for all D-Bus related calls (because we have to serialize all events in an internal GMainContext first and then invoke them on the caller's context). Also, if the users wants this behavior, they could implement it themself by running libnm in their own GMainContext. Note that libnm might have bugs to make that really working, but that should be fixed instead of adding such synchrnous API behavior. Read also [1], for why blocking calls are wrong. [1] https://smcv.pseudorandom.co.uk/2008/11/nonblocking/ So, all possible behaviors for synchronous API have severe behavioural issues. Mark all this API as deprecated. Also, this serves the purpose of identifying blocking D-Bus calls in libnm. Note that "deprecated" here does not really mean that the API is going to be removed. We don't break API. The user may: - continue to use this API. It's deprecated, awkward and discouraged, but if it works, by all means use it. - use asynchronous API. That's the only sensible way to use D-Bus. If libnm lacks a certain asynchronous counterpart, it should be added. - use GDBusConnection directly. There really isn't anything wrong with D-Bus or GDBusConnection. This deprecated API is just a wrapper around g_dbus_connection_call_sync(). You may call it directly without feeling dirty. --- The only other remainging API is the synchronous GInitable call for NMClient. That is an entirely separate beast and not particularly wrong (from an API point of view). Note that synchronous API in NMSecretAgentOld, NMVpnPluginOld and NMVpnServicePlugin as not deprecated here. These types are not part of the D-Bus cache and while they have similar issues, it's less severe because they have less state.
2019-09-04 13:58:43 +02:00
*
* The property setter is a synchronous D-Bus call. This is deprecated since 1.22.
**/
obj_properties[PROP_AUTOCONNECT] =
g_param_spec_boolean (NM_DEVICE_AUTOCONNECT, "", "",
FALSE,
G_PARAM_READWRITE |
G_PARAM_STATIC_STRINGS);
/**
* NMDevice:firmware-missing:
*
* When %TRUE indicates the device is likely missing firmware required
* for its operation.
**/
obj_properties[PROP_FIRMWARE_MISSING] =
g_param_spec_boolean (NM_DEVICE_FIRMWARE_MISSING, "", "",
FALSE,
G_PARAM_READABLE |
G_PARAM_STATIC_STRINGS);
/**
* NMDevice:nm-plugin-missing:
*
* When %TRUE indicates that the NetworkManager plugin for the device
* is not installed.
*
* Since: 1.2
**/
obj_properties[PROP_NM_PLUGIN_MISSING] =
g_param_spec_boolean (NM_DEVICE_NM_PLUGIN_MISSING, "", "",
FALSE,
G_PARAM_READABLE |
G_PARAM_STATIC_STRINGS);
/**
* NMDevice:ip4-config:
*
* The #NMIP4Config of the device.
**/
obj_properties[PROP_IP4_CONFIG] =
g_param_spec_object (NM_DEVICE_IP4_CONFIG, "", "",
NM_TYPE_IP_CONFIG,
G_PARAM_READABLE |
G_PARAM_STATIC_STRINGS);
/**
* NMDevice:dhcp4-config:
*
* The IPv4 #NMDhcpConfig of the device.
**/
obj_properties[PROP_DHCP4_CONFIG] =
g_param_spec_object (NM_DEVICE_DHCP4_CONFIG, "", "",
NM_TYPE_DHCP_CONFIG,
G_PARAM_READABLE |
G_PARAM_STATIC_STRINGS);
/**
* NMDevice:ip6-config:
*
* The IPv6 #NMIPConfig of the device.
**/
obj_properties[PROP_IP6_CONFIG] =
g_param_spec_object (NM_DEVICE_IP6_CONFIG, "", "",
NM_TYPE_IP_CONFIG,
G_PARAM_READABLE |
G_PARAM_STATIC_STRINGS);
/**
* NMDevice:dhcp6-config:
*
* The IPv6 #NMDhcpConfig of the device.
**/
obj_properties[PROP_DHCP6_CONFIG] =
g_param_spec_object (NM_DEVICE_DHCP6_CONFIG, "", "",
NM_TYPE_DHCP_CONFIG,
G_PARAM_READABLE |
G_PARAM_STATIC_STRINGS);
/**
* NMDevice:ip4-connectivity:
*
* The IPv4 connectivity state of the device.
*
* Since: 1.16
**/
obj_properties[PROP_IP4_CONNECTIVITY] =
g_param_spec_enum (NM_DEVICE_IP4_CONNECTIVITY, "", "",
NM_TYPE_CONNECTIVITY_STATE,
NM_CONNECTIVITY_UNKNOWN,
G_PARAM_READABLE |
G_PARAM_STATIC_STRINGS);
/**
* NMDevice:ip6-connectivity:
*
* The IPv6 connectivity state of the device.
*
* Since: 1.16
**/
obj_properties[PROP_IP6_CONNECTIVITY] =
g_param_spec_enum (NM_DEVICE_IP6_CONNECTIVITY, "", "",
NM_TYPE_CONNECTIVITY_STATE,
NM_CONNECTIVITY_UNKNOWN,
G_PARAM_READABLE |
G_PARAM_STATIC_STRINGS);
/**
* NMDevice:state:
*
* The state of the device.
**/
obj_properties[PROP_STATE] =
g_param_spec_enum (NM_DEVICE_STATE, "", "",
NM_TYPE_DEVICE_STATE,
NM_DEVICE_STATE_UNKNOWN,
G_PARAM_READABLE |
G_PARAM_STATIC_STRINGS);
/**
* NMDevice:state-reason:
*
* The reason for the device state.
**/
obj_properties[PROP_STATE_REASON] =
g_param_spec_uint (NM_DEVICE_STATE_REASON, "", "",
0, G_MAXUINT32, 0,
G_PARAM_READABLE |
G_PARAM_STATIC_STRINGS);
/**
* NMDevice:active-connection:
*
* The #NMActiveConnection object that "owns" this device during activation.
**/
obj_properties[PROP_ACTIVE_CONNECTION] =
g_param_spec_object (NM_DEVICE_ACTIVE_CONNECTION, "", "",
NM_TYPE_ACTIVE_CONNECTION,
G_PARAM_READABLE |
G_PARAM_STATIC_STRINGS);
/**
* NMDevice:available-connections: (type GPtrArray(NMRemoteConnection))
*
* The available connections of the device
**/
obj_properties[PROP_AVAILABLE_CONNECTIONS] =
g_param_spec_boxed (NM_DEVICE_AVAILABLE_CONNECTIONS, "", "",
G_TYPE_PTR_ARRAY,
G_PARAM_READABLE |
G_PARAM_STATIC_STRINGS);
/**
* NMDevice:vendor:
*
* The vendor string of the device.
**/
obj_properties[PROP_VENDOR] =
g_param_spec_string (NM_DEVICE_VENDOR, "", "",
NULL,
G_PARAM_READABLE |
G_PARAM_STATIC_STRINGS);
/**
* NMDevice:product:
*
* The product string of the device.
**/
obj_properties[PROP_PRODUCT] =
g_param_spec_string (NM_DEVICE_PRODUCT, "", "",
NULL,
G_PARAM_READABLE |
G_PARAM_STATIC_STRINGS);
/**
* NMDevice:physical-port-id:
*
* The physical port ID of the device. (See
* nm_device_get_physical_port_id().)
**/
obj_properties[PROP_PHYSICAL_PORT_ID] =
g_param_spec_string (NM_DEVICE_PHYSICAL_PORT_ID, "", "",
NULL,
G_PARAM_READABLE |
G_PARAM_STATIC_STRINGS);
/**
* NMDevice:mtu:
*
* The MTU of the device.
**/
obj_properties[PROP_MTU] =
g_param_spec_uint (NM_DEVICE_MTU, "", "",
0, G_MAXUINT32, 0,
G_PARAM_READABLE |
G_PARAM_STATIC_STRINGS);
/**
* NMDevice:metered:
*
* Whether the device is metered.
*
* Since: 1.2
**/
obj_properties[PROP_METERED] =
g_param_spec_uint (NM_DEVICE_METERED, "", "",
0, G_MAXUINT32, NM_METERED_UNKNOWN,
G_PARAM_READABLE |
G_PARAM_STATIC_STRINGS);
/**
* NMDevice:lldp-neighbors:
*
* The LLDP neighbors.
**/
obj_properties[PROP_LLDP_NEIGHBORS] =
g_param_spec_boxed (NM_DEVICE_LLDP_NEIGHBORS, "", "",
G_TYPE_PTR_ARRAY,
G_PARAM_READABLE |
G_PARAM_STATIC_STRINGS);
/**
* NMDevice:interface-flags:
*
* The interface flags.
*
* Since: 1.22
**/
obj_properties[PROP_INTERFACE_FLAGS] =
g_param_spec_uint (NM_DEVICE_INTERFACE_FLAGS, "", "",
0, G_MAXUINT32, 0,
G_PARAM_READABLE |
G_PARAM_STATIC_STRINGS);
/**
* NMDevice:hw-address:
*
* The hardware address of the device.
*
* Since: 1.24
**/
obj_properties[PROP_HW_ADDRESS] =
g_param_spec_string (NM_DEVICE_HW_ADDRESS, "", "",
NULL,
G_PARAM_READABLE |
G_PARAM_STATIC_STRINGS);
libnm: refactor caching of D-Bus objects in NMClient No longer use GDBusObjectMangaerClient and gdbus-codegen generated classes for the NMClient cache. Instead, use GDBusConnection directly and a custom implementation (NMLDBusObject) for caching D-Bus' ObjectManager data. CHANGES ------- - This is a complete rework. I think the previous implementation was difficult to understand. There were unfixed bugs and nobody understood the code well enough to fix them. Maybe somebody out there understood the code, but I certainly did not. At least nobody provided patches to fix those issues. I do believe that this implementation is more straightforward and easier to understand. It removes a lot of layers of code. Whether this claim of simplicity is true, each reader must decide for himself/herself. Note that it is still fairly complex. - There was a lingering performance issue with large number of D-Bus objects. The patch tries hard that the implementation scales well. Of course, when we cache N objects that have N-to-M references to other, we still are fundamentally O(N*M) for runtime and memory consumption (with M being the number of references between objects). But each part should behave efficiently and well. - Play well with GMainContext. libnm code (NMClient) is generally not thread safe. However, it should work to use multiple instances in parallel, as long as each access to a NMClient is through the caller's GMainContext. This follows glib's style and effectively allows to use NMClient in a multi threaded scenario. This implies to stick to a main context upon construction and ensure that callbacks are only invoked when iterating that context. Also, NMClient itself shall never iterate the caller's context. This also means, libnm must never use g_idle_add() or g_timeout_add(), as those enqueue sources in the g_main_context_default() context. - Get ordering of messages right. All events are consistently enqueued in a GMainContext and processed strictly in order. For example, previously "nm-object.c" tried to combine signals and emit them on an idle handler. That is wrong, signals must be emitted in the right order and when they happen. Note that when using GInitable's synchronous initialization to initialize the NMClient instance, NMClient internally still operates fully asynchronously. In that case NMClient has an internal main context. - NMClient takes over most of the functionality. When using D-Bus' ObjectManager interface, one needs to handle basically the entire state of the D-Bus interface. That cannot be separated well into distinct parts, and even if you try, you just end up having closely related code in different source files. Spreading related code does not make it easier to understand, on the contrary. That means, NMClient is inherently complex as it contains most of the logic. I think that is not avoidable, but it's not as bad as it sounds. - NMClient processes D-Bus messages and state changes in separate steps. First NMClient unpacks the message (e.g. _dbus_handle_properties_changed()) and keeps track of the changed data. Then we update the GObject instances (_dbus_handle_obj_changed_dbus()) without emitting any signals yet. Finally, we emit all signals and notifications that were collected (_dbus_handle_changes_commit()). Note that for example during the initial GetManagedObjects() reply, NMClient receive a large amount of state at once. But we first apply all the changes to our GObject instances before emitting any signals. The result is that signals are always emitted in a moment when the cache is consistent. The unavoidable downside is that when you receive a property changed signal, possibly many other properties changed already and more signals are about to be emitted. - NMDeviceWifi no longer modifies the content of the cache from client side during poke_wireless_devices_with_rf_status(). The content of the cache should be determined by D-Bus alone and follow what NetworkManager service exposes. Local modifications should be avoided. - This aims to bring no API/ABI change, though it does of course bring various subtle changes in behavior. Those should be all for the better, but the goal is not to break any existing clients. This does change internal (albeit externally visible) API, like dropping NM_OBJECT_DBUS_OBJECT_MANAGER property and NMObject no longer implementing GInitableIface and GAsyncInitableIface. - Some uses of gdbus-codegen classes remain in NMVpnPluginOld, NMVpnServicePlugin and NMSecretAgentOld. These are independent of NMClient/NMObject and should be reworked separately. - While we no longer use generated classes from gdbus-codegen, we don't need more glue code than before. Also before we constructed NMPropertiesInfo and a had large amount of code to propagate properties from NMDBus* to NMObject. That got completely reworked, but did not fundamentally change. You still need about the same effort to create the NMLDBusMetaIface. Not using generated bindings did not make anything worse (which tells about the usefulness of generated code, at least in the way it was used). - NMLDBusMetaIface and other meta data is static and immutable. This avoids copying them around. Also, macros like NML_DBUS_META_PROPERTY_INIT_U() have compile time checks to ensure the property types matches. It's pretty hard to misuse them because it won't compile. - The meta data now explicitly encodes the expected D-Bus types and makes sure never to accept wrong data. That would only matter when the server (accidentally or intentionally) exposes unexpected types on D-Bus. I don't think that was previously ensured in all cases. For example, demarshal_generic() only cared about the GObject property type, it didn't know the expected D-Bus type. - Previously GDBusObjectManager would sometimes emit warnings (g_log()). Those probably indicated real bugs. In any case, it prevented us from running CI with G_DEBUG=fatal-warnings, because there would be just too many unrelated crashes. Now we log debug messages that can be enabled with "LIBNM_CLIENT_DEBUG=trace". Some of these messages can also be turned into g_warning()/g_critical() by setting LIBNM_CLIENT_DEBUG=warning,error. Together with G_DEBUG=fatal-warnings, this turns them into assertions. Note that such "assertion failures" might also happen because of a server bug (or change). Thus these are not common assertions that indicate a bug in libnm and are thus not armed unless explicitly requested. In our CI we should now always run with LIBNM_CLIENT_DEBUG=warning,error and G_DEBUG=fatal-warnings and to catch bugs. Note that currently NetworkManager has bugs in this regard, so enabling this will result in assertion failures. That should be fixed first. - Note that this changes the order in which we emit "notify:devices" and "device-added" signals. I think it makes the most sense to emit first "device-removed", then "notify:devices", and finally "device-added" signals. This changes behavior for commit 52ae28f6e5bf ('libnm: queue added/removed signals and suppress uninitialized notifications'), but I don't think that users should actually rely on the order. Still, the new order makes the most sense to me. - In NetworkManager, profiles can be invisible to the user by setting "connection.permissions". Such profiles would be hidden by NMClient's nm_client_get_connections() and their "connection-added"/"connection-removed" signals. Note that NMActiveConnection's nm_active_connection_get_connection() and NMDevice's nm_device_get_available_connections() still exposes such hidden NMRemoteConnection instances. This behavior was preserved. NUMBERS ------- I compared 3 versions of libnm. [1] 962297f9085d, current tip of nm-1-20 branch [2] 4fad8c7c642e, current master, immediate parent of this patch [3] this patch All tests were done on Fedora 31, x86_64, gcc 9.2.1-1.fc31. The libraries were build with $ ./contrib/fedora/rpm/build_clean.sh -g -w test -W debug Note that RPM build already stripped the library. --- N1) File size of libnm.so.0.1.0 in bytes. There currently seems to be a issue on Fedora 31 generating wrong ELF notes. Usually, libnm is smaller but in these tests it had large (and bogus) ELF notes. Anyway, the point is to show the relative sizes, so it doesn't matter). [1] 4075552 (102.7%) [2] 3969624 (100.0%) [3] 3705208 ( 93.3%) --- N2) `size /usr/lib64/libnm.so.0.1.0`: text data bss dec hex filename [1] 1314569 (102.0%) 69980 ( 94.8%) 10632 ( 80.4%) 1395181 (101.4%) 1549ed /usr/lib64/libnm.so.0.1.0 [2] 1288410 (100.0%) 73796 (100.0%) 13224 (100.0%) 1375430 (100.0%) 14fcc6 /usr/lib64/libnm.so.0.1.0 [3] 1229066 ( 95.4%) 65248 ( 88.4%) 13400 (101.3%) 1307714 ( 95.1%) 13f442 /usr/lib64/libnm.so.0.1.0 --- N3) Performance test with test-client.py. With checkout of [2], run ``` prepare_checkout() { rm -rf /tmp/nm-test && \ git checkout -B test 4fad8c7c642e && \ git clean -fdx && \ ./autogen.sh --prefix=/tmp/nm-test && \ make -j 5 install && \ make -j 5 check-local-clients-tests-test-client } prepare_test() { NM_TEST_REGENERATE=1 NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v } do_test() { for i in {1..10}; do NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v || return -1 done echo "done!" } prepare_checkout prepare_test time do_test ``` [1] real 2m14.497s (101.3%) user 5m26.651s (100.3%) sys 1m40.453s (101.4%) [2] real 2m12.800s (100.0%) user 5m25.619s (100.0%) sys 1m39.065s (100.0%) [3] real 1m54.915s ( 86.5%) user 4m18.585s ( 79.4%) sys 1m32.066s ( 92.9%) --- N4) Performance. Run NetworkManager from build [2] and setup a large number of profiles (551 profiles and 515 devices, mostly unrealized). This setup is already at the edge of what NetworkManager currently can handle. Of course, that is a different issue. Here we just check how long plain `nmcli` takes on the system. ``` do_cleanup() { for UUID in $(nmcli -g NAME,UUID connection show | sed -n 's/^xx-c-.*:\([^:]\+\)$/\1/p'); do nmcli connection delete uuid "$UUID" done for DEVICE in $(nmcli -g DEVICE device status | grep '^xx-i-'); do nmcli device delete "$DEVICE" done } do_setup() { do_cleanup for i in {1..30}; do nmcli connection add type bond autoconnect no con-name xx-c-bond-$i ifname xx-i-bond-$i ipv4.method disabled ipv6.method ignore for j in $(seq $i 30); do nmcli connection add type vlan autoconnect no con-name xx-c-vlan-$i-$j vlan.id $j ifname xx-i-vlan-$i-$j vlan.parent xx-i-bond-$i ipv4.method disabled ipv6.method ignore done done systemctl restart NetworkManager.service sleep 5 } do_test() { perf stat -r 50 -B nmcli 1>/dev/null } do_test ``` [1] Performance counter stats for 'nmcli' (50 runs): 456.33 msec task-clock:u # 1.093 CPUs utilized ( +- 0.44% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,900 page-faults:u # 0.013 M/sec ( +- 0.02% ) 1,408,675,453 cycles:u # 3.087 GHz ( +- 0.48% ) 1,594,741,060 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 368,744,018 branches:u # 808.061 M/sec ( +- 0.02% ) 4,566,058 branch-misses:u # 1.24% of all branches ( +- 0.76% ) 0.41761 +- 0.00282 seconds time elapsed ( +- 0.68% ) [2] Performance counter stats for 'nmcli' (50 runs): 477.99 msec task-clock:u # 1.088 CPUs utilized ( +- 0.36% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,948 page-faults:u # 0.012 M/sec ( +- 0.03% ) 1,471,133,482 cycles:u # 3.078 GHz ( +- 0.36% ) 1,655,275,369 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 382,595,152 branches:u # 800.433 M/sec ( +- 0.02% ) 4,746,070 branch-misses:u # 1.24% of all branches ( +- 0.49% ) 0.43923 +- 0.00242 seconds time elapsed ( +- 0.55% ) [3] Performance counter stats for 'nmcli' (50 runs): 352.36 msec task-clock:u # 1.027 CPUs utilized ( +- 0.32% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 4,790 page-faults:u # 0.014 M/sec ( +- 0.26% ) 1,092,341,186 cycles:u # 3.100 GHz ( +- 0.26% ) 1,209,045,283 instructions:u # 1.11 insn per cycle ( +- 0.02% ) 281,708,462 branches:u # 799.499 M/sec ( +- 0.01% ) 3,101,031 branch-misses:u # 1.10% of all branches ( +- 0.61% ) 0.34296 +- 0.00120 seconds time elapsed ( +- 0.35% ) --- N5) same setup as N4), but run `PAGER= /bin/time -v nmcli`: [1] Command being timed: "nmcli" User time (seconds): 0.42 System time (seconds): 0.04 Percent of CPU this job got: 107% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.43 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34456 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6128 Voluntary context switches: 1298 Involuntary context switches: 1106 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [2] Command being timed: "nmcli" User time (seconds): 0.44 System time (seconds): 0.04 Percent of CPU this job got: 108% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.44 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34452 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6169 Voluntary context switches: 1849 Involuntary context switches: 142 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [3] Command being timed: "nmcli" User time (seconds): 0.32 System time (seconds): 0.02 Percent of CPU this job got: 102% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.34 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 29196 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 5059 Voluntary context switches: 919 Involuntary context switches: 685 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 --- N6) same setup as N4), but run `nmcli monitor` and look at `ps aux` for the RSS size. USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND [1] me 1492900 21.0 0.2 461348 33248 pts/10 Sl+ 15:02 0:00 nmcli monitor [2] me 1490721 5.0 0.2 461496 33548 pts/10 Sl+ 15:00 0:00 nmcli monitor [3] me 1495801 16.5 0.1 459476 28692 pts/10 Sl+ 15:04 0:00 nmcli monitor
2019-10-30 11:42:58 +01:00
_nml_dbus_meta_class_init_with_properties (object_class, &_nml_dbus_meta_iface_nm_device);
/**
* NMDevice::state-changed:
* @device: the device object that received the signal
* @new_state: the new state of the device
* @old_state: the previous state of the device
* @reason: the reason describing the state change
*
* Notifies the state change of a #NMDevice.
**/
signals[STATE_CHANGED] =
g_signal_new ("state-changed",
G_OBJECT_CLASS_TYPE (object_class),
G_SIGNAL_RUN_FIRST,
libnm: refactor caching of D-Bus objects in NMClient No longer use GDBusObjectMangaerClient and gdbus-codegen generated classes for the NMClient cache. Instead, use GDBusConnection directly and a custom implementation (NMLDBusObject) for caching D-Bus' ObjectManager data. CHANGES ------- - This is a complete rework. I think the previous implementation was difficult to understand. There were unfixed bugs and nobody understood the code well enough to fix them. Maybe somebody out there understood the code, but I certainly did not. At least nobody provided patches to fix those issues. I do believe that this implementation is more straightforward and easier to understand. It removes a lot of layers of code. Whether this claim of simplicity is true, each reader must decide for himself/herself. Note that it is still fairly complex. - There was a lingering performance issue with large number of D-Bus objects. The patch tries hard that the implementation scales well. Of course, when we cache N objects that have N-to-M references to other, we still are fundamentally O(N*M) for runtime and memory consumption (with M being the number of references between objects). But each part should behave efficiently and well. - Play well with GMainContext. libnm code (NMClient) is generally not thread safe. However, it should work to use multiple instances in parallel, as long as each access to a NMClient is through the caller's GMainContext. This follows glib's style and effectively allows to use NMClient in a multi threaded scenario. This implies to stick to a main context upon construction and ensure that callbacks are only invoked when iterating that context. Also, NMClient itself shall never iterate the caller's context. This also means, libnm must never use g_idle_add() or g_timeout_add(), as those enqueue sources in the g_main_context_default() context. - Get ordering of messages right. All events are consistently enqueued in a GMainContext and processed strictly in order. For example, previously "nm-object.c" tried to combine signals and emit them on an idle handler. That is wrong, signals must be emitted in the right order and when they happen. Note that when using GInitable's synchronous initialization to initialize the NMClient instance, NMClient internally still operates fully asynchronously. In that case NMClient has an internal main context. - NMClient takes over most of the functionality. When using D-Bus' ObjectManager interface, one needs to handle basically the entire state of the D-Bus interface. That cannot be separated well into distinct parts, and even if you try, you just end up having closely related code in different source files. Spreading related code does not make it easier to understand, on the contrary. That means, NMClient is inherently complex as it contains most of the logic. I think that is not avoidable, but it's not as bad as it sounds. - NMClient processes D-Bus messages and state changes in separate steps. First NMClient unpacks the message (e.g. _dbus_handle_properties_changed()) and keeps track of the changed data. Then we update the GObject instances (_dbus_handle_obj_changed_dbus()) without emitting any signals yet. Finally, we emit all signals and notifications that were collected (_dbus_handle_changes_commit()). Note that for example during the initial GetManagedObjects() reply, NMClient receive a large amount of state at once. But we first apply all the changes to our GObject instances before emitting any signals. The result is that signals are always emitted in a moment when the cache is consistent. The unavoidable downside is that when you receive a property changed signal, possibly many other properties changed already and more signals are about to be emitted. - NMDeviceWifi no longer modifies the content of the cache from client side during poke_wireless_devices_with_rf_status(). The content of the cache should be determined by D-Bus alone and follow what NetworkManager service exposes. Local modifications should be avoided. - This aims to bring no API/ABI change, though it does of course bring various subtle changes in behavior. Those should be all for the better, but the goal is not to break any existing clients. This does change internal (albeit externally visible) API, like dropping NM_OBJECT_DBUS_OBJECT_MANAGER property and NMObject no longer implementing GInitableIface and GAsyncInitableIface. - Some uses of gdbus-codegen classes remain in NMVpnPluginOld, NMVpnServicePlugin and NMSecretAgentOld. These are independent of NMClient/NMObject and should be reworked separately. - While we no longer use generated classes from gdbus-codegen, we don't need more glue code than before. Also before we constructed NMPropertiesInfo and a had large amount of code to propagate properties from NMDBus* to NMObject. That got completely reworked, but did not fundamentally change. You still need about the same effort to create the NMLDBusMetaIface. Not using generated bindings did not make anything worse (which tells about the usefulness of generated code, at least in the way it was used). - NMLDBusMetaIface and other meta data is static and immutable. This avoids copying them around. Also, macros like NML_DBUS_META_PROPERTY_INIT_U() have compile time checks to ensure the property types matches. It's pretty hard to misuse them because it won't compile. - The meta data now explicitly encodes the expected D-Bus types and makes sure never to accept wrong data. That would only matter when the server (accidentally or intentionally) exposes unexpected types on D-Bus. I don't think that was previously ensured in all cases. For example, demarshal_generic() only cared about the GObject property type, it didn't know the expected D-Bus type. - Previously GDBusObjectManager would sometimes emit warnings (g_log()). Those probably indicated real bugs. In any case, it prevented us from running CI with G_DEBUG=fatal-warnings, because there would be just too many unrelated crashes. Now we log debug messages that can be enabled with "LIBNM_CLIENT_DEBUG=trace". Some of these messages can also be turned into g_warning()/g_critical() by setting LIBNM_CLIENT_DEBUG=warning,error. Together with G_DEBUG=fatal-warnings, this turns them into assertions. Note that such "assertion failures" might also happen because of a server bug (or change). Thus these are not common assertions that indicate a bug in libnm and are thus not armed unless explicitly requested. In our CI we should now always run with LIBNM_CLIENT_DEBUG=warning,error and G_DEBUG=fatal-warnings and to catch bugs. Note that currently NetworkManager has bugs in this regard, so enabling this will result in assertion failures. That should be fixed first. - Note that this changes the order in which we emit "notify:devices" and "device-added" signals. I think it makes the most sense to emit first "device-removed", then "notify:devices", and finally "device-added" signals. This changes behavior for commit 52ae28f6e5bf ('libnm: queue added/removed signals and suppress uninitialized notifications'), but I don't think that users should actually rely on the order. Still, the new order makes the most sense to me. - In NetworkManager, profiles can be invisible to the user by setting "connection.permissions". Such profiles would be hidden by NMClient's nm_client_get_connections() and their "connection-added"/"connection-removed" signals. Note that NMActiveConnection's nm_active_connection_get_connection() and NMDevice's nm_device_get_available_connections() still exposes such hidden NMRemoteConnection instances. This behavior was preserved. NUMBERS ------- I compared 3 versions of libnm. [1] 962297f9085d, current tip of nm-1-20 branch [2] 4fad8c7c642e, current master, immediate parent of this patch [3] this patch All tests were done on Fedora 31, x86_64, gcc 9.2.1-1.fc31. The libraries were build with $ ./contrib/fedora/rpm/build_clean.sh -g -w test -W debug Note that RPM build already stripped the library. --- N1) File size of libnm.so.0.1.0 in bytes. There currently seems to be a issue on Fedora 31 generating wrong ELF notes. Usually, libnm is smaller but in these tests it had large (and bogus) ELF notes. Anyway, the point is to show the relative sizes, so it doesn't matter). [1] 4075552 (102.7%) [2] 3969624 (100.0%) [3] 3705208 ( 93.3%) --- N2) `size /usr/lib64/libnm.so.0.1.0`: text data bss dec hex filename [1] 1314569 (102.0%) 69980 ( 94.8%) 10632 ( 80.4%) 1395181 (101.4%) 1549ed /usr/lib64/libnm.so.0.1.0 [2] 1288410 (100.0%) 73796 (100.0%) 13224 (100.0%) 1375430 (100.0%) 14fcc6 /usr/lib64/libnm.so.0.1.0 [3] 1229066 ( 95.4%) 65248 ( 88.4%) 13400 (101.3%) 1307714 ( 95.1%) 13f442 /usr/lib64/libnm.so.0.1.0 --- N3) Performance test with test-client.py. With checkout of [2], run ``` prepare_checkout() { rm -rf /tmp/nm-test && \ git checkout -B test 4fad8c7c642e && \ git clean -fdx && \ ./autogen.sh --prefix=/tmp/nm-test && \ make -j 5 install && \ make -j 5 check-local-clients-tests-test-client } prepare_test() { NM_TEST_REGENERATE=1 NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v } do_test() { for i in {1..10}; do NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v || return -1 done echo "done!" } prepare_checkout prepare_test time do_test ``` [1] real 2m14.497s (101.3%) user 5m26.651s (100.3%) sys 1m40.453s (101.4%) [2] real 2m12.800s (100.0%) user 5m25.619s (100.0%) sys 1m39.065s (100.0%) [3] real 1m54.915s ( 86.5%) user 4m18.585s ( 79.4%) sys 1m32.066s ( 92.9%) --- N4) Performance. Run NetworkManager from build [2] and setup a large number of profiles (551 profiles and 515 devices, mostly unrealized). This setup is already at the edge of what NetworkManager currently can handle. Of course, that is a different issue. Here we just check how long plain `nmcli` takes on the system. ``` do_cleanup() { for UUID in $(nmcli -g NAME,UUID connection show | sed -n 's/^xx-c-.*:\([^:]\+\)$/\1/p'); do nmcli connection delete uuid "$UUID" done for DEVICE in $(nmcli -g DEVICE device status | grep '^xx-i-'); do nmcli device delete "$DEVICE" done } do_setup() { do_cleanup for i in {1..30}; do nmcli connection add type bond autoconnect no con-name xx-c-bond-$i ifname xx-i-bond-$i ipv4.method disabled ipv6.method ignore for j in $(seq $i 30); do nmcli connection add type vlan autoconnect no con-name xx-c-vlan-$i-$j vlan.id $j ifname xx-i-vlan-$i-$j vlan.parent xx-i-bond-$i ipv4.method disabled ipv6.method ignore done done systemctl restart NetworkManager.service sleep 5 } do_test() { perf stat -r 50 -B nmcli 1>/dev/null } do_test ``` [1] Performance counter stats for 'nmcli' (50 runs): 456.33 msec task-clock:u # 1.093 CPUs utilized ( +- 0.44% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,900 page-faults:u # 0.013 M/sec ( +- 0.02% ) 1,408,675,453 cycles:u # 3.087 GHz ( +- 0.48% ) 1,594,741,060 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 368,744,018 branches:u # 808.061 M/sec ( +- 0.02% ) 4,566,058 branch-misses:u # 1.24% of all branches ( +- 0.76% ) 0.41761 +- 0.00282 seconds time elapsed ( +- 0.68% ) [2] Performance counter stats for 'nmcli' (50 runs): 477.99 msec task-clock:u # 1.088 CPUs utilized ( +- 0.36% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,948 page-faults:u # 0.012 M/sec ( +- 0.03% ) 1,471,133,482 cycles:u # 3.078 GHz ( +- 0.36% ) 1,655,275,369 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 382,595,152 branches:u # 800.433 M/sec ( +- 0.02% ) 4,746,070 branch-misses:u # 1.24% of all branches ( +- 0.49% ) 0.43923 +- 0.00242 seconds time elapsed ( +- 0.55% ) [3] Performance counter stats for 'nmcli' (50 runs): 352.36 msec task-clock:u # 1.027 CPUs utilized ( +- 0.32% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 4,790 page-faults:u # 0.014 M/sec ( +- 0.26% ) 1,092,341,186 cycles:u # 3.100 GHz ( +- 0.26% ) 1,209,045,283 instructions:u # 1.11 insn per cycle ( +- 0.02% ) 281,708,462 branches:u # 799.499 M/sec ( +- 0.01% ) 3,101,031 branch-misses:u # 1.10% of all branches ( +- 0.61% ) 0.34296 +- 0.00120 seconds time elapsed ( +- 0.35% ) --- N5) same setup as N4), but run `PAGER= /bin/time -v nmcli`: [1] Command being timed: "nmcli" User time (seconds): 0.42 System time (seconds): 0.04 Percent of CPU this job got: 107% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.43 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34456 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6128 Voluntary context switches: 1298 Involuntary context switches: 1106 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [2] Command being timed: "nmcli" User time (seconds): 0.44 System time (seconds): 0.04 Percent of CPU this job got: 108% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.44 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34452 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6169 Voluntary context switches: 1849 Involuntary context switches: 142 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [3] Command being timed: "nmcli" User time (seconds): 0.32 System time (seconds): 0.02 Percent of CPU this job got: 102% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.34 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 29196 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 5059 Voluntary context switches: 919 Involuntary context switches: 685 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 --- N6) same setup as N4), but run `nmcli monitor` and look at `ps aux` for the RSS size. USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND [1] me 1492900 21.0 0.2 461348 33248 pts/10 Sl+ 15:02 0:00 nmcli monitor [2] me 1490721 5.0 0.2 461496 33548 pts/10 Sl+ 15:00 0:00 nmcli monitor [3] me 1495801 16.5 0.1 459476 28692 pts/10 Sl+ 15:04 0:00 nmcli monitor
2019-10-30 11:42:58 +01:00
0, NULL, NULL, NULL,
G_TYPE_NONE, 3,
G_TYPE_UINT, G_TYPE_UINT, G_TYPE_UINT);
}
/**
* nm_device_get_iface:
* @device: a #NMDevice
*
* Gets the interface name of the #NMDevice.
*
* Returns: the interface of the device. This is the internal string used by the
* device, and must not be modified.
**/
const char *
nm_device_get_iface (NMDevice *device)
{
g_return_val_if_fail (NM_IS_DEVICE (device), NULL);
libnm: refactor caching of D-Bus objects in NMClient No longer use GDBusObjectMangaerClient and gdbus-codegen generated classes for the NMClient cache. Instead, use GDBusConnection directly and a custom implementation (NMLDBusObject) for caching D-Bus' ObjectManager data. CHANGES ------- - This is a complete rework. I think the previous implementation was difficult to understand. There were unfixed bugs and nobody understood the code well enough to fix them. Maybe somebody out there understood the code, but I certainly did not. At least nobody provided patches to fix those issues. I do believe that this implementation is more straightforward and easier to understand. It removes a lot of layers of code. Whether this claim of simplicity is true, each reader must decide for himself/herself. Note that it is still fairly complex. - There was a lingering performance issue with large number of D-Bus objects. The patch tries hard that the implementation scales well. Of course, when we cache N objects that have N-to-M references to other, we still are fundamentally O(N*M) for runtime and memory consumption (with M being the number of references between objects). But each part should behave efficiently and well. - Play well with GMainContext. libnm code (NMClient) is generally not thread safe. However, it should work to use multiple instances in parallel, as long as each access to a NMClient is through the caller's GMainContext. This follows glib's style and effectively allows to use NMClient in a multi threaded scenario. This implies to stick to a main context upon construction and ensure that callbacks are only invoked when iterating that context. Also, NMClient itself shall never iterate the caller's context. This also means, libnm must never use g_idle_add() or g_timeout_add(), as those enqueue sources in the g_main_context_default() context. - Get ordering of messages right. All events are consistently enqueued in a GMainContext and processed strictly in order. For example, previously "nm-object.c" tried to combine signals and emit them on an idle handler. That is wrong, signals must be emitted in the right order and when they happen. Note that when using GInitable's synchronous initialization to initialize the NMClient instance, NMClient internally still operates fully asynchronously. In that case NMClient has an internal main context. - NMClient takes over most of the functionality. When using D-Bus' ObjectManager interface, one needs to handle basically the entire state of the D-Bus interface. That cannot be separated well into distinct parts, and even if you try, you just end up having closely related code in different source files. Spreading related code does not make it easier to understand, on the contrary. That means, NMClient is inherently complex as it contains most of the logic. I think that is not avoidable, but it's not as bad as it sounds. - NMClient processes D-Bus messages and state changes in separate steps. First NMClient unpacks the message (e.g. _dbus_handle_properties_changed()) and keeps track of the changed data. Then we update the GObject instances (_dbus_handle_obj_changed_dbus()) without emitting any signals yet. Finally, we emit all signals and notifications that were collected (_dbus_handle_changes_commit()). Note that for example during the initial GetManagedObjects() reply, NMClient receive a large amount of state at once. But we first apply all the changes to our GObject instances before emitting any signals. The result is that signals are always emitted in a moment when the cache is consistent. The unavoidable downside is that when you receive a property changed signal, possibly many other properties changed already and more signals are about to be emitted. - NMDeviceWifi no longer modifies the content of the cache from client side during poke_wireless_devices_with_rf_status(). The content of the cache should be determined by D-Bus alone and follow what NetworkManager service exposes. Local modifications should be avoided. - This aims to bring no API/ABI change, though it does of course bring various subtle changes in behavior. Those should be all for the better, but the goal is not to break any existing clients. This does change internal (albeit externally visible) API, like dropping NM_OBJECT_DBUS_OBJECT_MANAGER property and NMObject no longer implementing GInitableIface and GAsyncInitableIface. - Some uses of gdbus-codegen classes remain in NMVpnPluginOld, NMVpnServicePlugin and NMSecretAgentOld. These are independent of NMClient/NMObject and should be reworked separately. - While we no longer use generated classes from gdbus-codegen, we don't need more glue code than before. Also before we constructed NMPropertiesInfo and a had large amount of code to propagate properties from NMDBus* to NMObject. That got completely reworked, but did not fundamentally change. You still need about the same effort to create the NMLDBusMetaIface. Not using generated bindings did not make anything worse (which tells about the usefulness of generated code, at least in the way it was used). - NMLDBusMetaIface and other meta data is static and immutable. This avoids copying them around. Also, macros like NML_DBUS_META_PROPERTY_INIT_U() have compile time checks to ensure the property types matches. It's pretty hard to misuse them because it won't compile. - The meta data now explicitly encodes the expected D-Bus types and makes sure never to accept wrong data. That would only matter when the server (accidentally or intentionally) exposes unexpected types on D-Bus. I don't think that was previously ensured in all cases. For example, demarshal_generic() only cared about the GObject property type, it didn't know the expected D-Bus type. - Previously GDBusObjectManager would sometimes emit warnings (g_log()). Those probably indicated real bugs. In any case, it prevented us from running CI with G_DEBUG=fatal-warnings, because there would be just too many unrelated crashes. Now we log debug messages that can be enabled with "LIBNM_CLIENT_DEBUG=trace". Some of these messages can also be turned into g_warning()/g_critical() by setting LIBNM_CLIENT_DEBUG=warning,error. Together with G_DEBUG=fatal-warnings, this turns them into assertions. Note that such "assertion failures" might also happen because of a server bug (or change). Thus these are not common assertions that indicate a bug in libnm and are thus not armed unless explicitly requested. In our CI we should now always run with LIBNM_CLIENT_DEBUG=warning,error and G_DEBUG=fatal-warnings and to catch bugs. Note that currently NetworkManager has bugs in this regard, so enabling this will result in assertion failures. That should be fixed first. - Note that this changes the order in which we emit "notify:devices" and "device-added" signals. I think it makes the most sense to emit first "device-removed", then "notify:devices", and finally "device-added" signals. This changes behavior for commit 52ae28f6e5bf ('libnm: queue added/removed signals and suppress uninitialized notifications'), but I don't think that users should actually rely on the order. Still, the new order makes the most sense to me. - In NetworkManager, profiles can be invisible to the user by setting "connection.permissions". Such profiles would be hidden by NMClient's nm_client_get_connections() and their "connection-added"/"connection-removed" signals. Note that NMActiveConnection's nm_active_connection_get_connection() and NMDevice's nm_device_get_available_connections() still exposes such hidden NMRemoteConnection instances. This behavior was preserved. NUMBERS ------- I compared 3 versions of libnm. [1] 962297f9085d, current tip of nm-1-20 branch [2] 4fad8c7c642e, current master, immediate parent of this patch [3] this patch All tests were done on Fedora 31, x86_64, gcc 9.2.1-1.fc31. The libraries were build with $ ./contrib/fedora/rpm/build_clean.sh -g -w test -W debug Note that RPM build already stripped the library. --- N1) File size of libnm.so.0.1.0 in bytes. There currently seems to be a issue on Fedora 31 generating wrong ELF notes. Usually, libnm is smaller but in these tests it had large (and bogus) ELF notes. Anyway, the point is to show the relative sizes, so it doesn't matter). [1] 4075552 (102.7%) [2] 3969624 (100.0%) [3] 3705208 ( 93.3%) --- N2) `size /usr/lib64/libnm.so.0.1.0`: text data bss dec hex filename [1] 1314569 (102.0%) 69980 ( 94.8%) 10632 ( 80.4%) 1395181 (101.4%) 1549ed /usr/lib64/libnm.so.0.1.0 [2] 1288410 (100.0%) 73796 (100.0%) 13224 (100.0%) 1375430 (100.0%) 14fcc6 /usr/lib64/libnm.so.0.1.0 [3] 1229066 ( 95.4%) 65248 ( 88.4%) 13400 (101.3%) 1307714 ( 95.1%) 13f442 /usr/lib64/libnm.so.0.1.0 --- N3) Performance test with test-client.py. With checkout of [2], run ``` prepare_checkout() { rm -rf /tmp/nm-test && \ git checkout -B test 4fad8c7c642e && \ git clean -fdx && \ ./autogen.sh --prefix=/tmp/nm-test && \ make -j 5 install && \ make -j 5 check-local-clients-tests-test-client } prepare_test() { NM_TEST_REGENERATE=1 NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v } do_test() { for i in {1..10}; do NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v || return -1 done echo "done!" } prepare_checkout prepare_test time do_test ``` [1] real 2m14.497s (101.3%) user 5m26.651s (100.3%) sys 1m40.453s (101.4%) [2] real 2m12.800s (100.0%) user 5m25.619s (100.0%) sys 1m39.065s (100.0%) [3] real 1m54.915s ( 86.5%) user 4m18.585s ( 79.4%) sys 1m32.066s ( 92.9%) --- N4) Performance. Run NetworkManager from build [2] and setup a large number of profiles (551 profiles and 515 devices, mostly unrealized). This setup is already at the edge of what NetworkManager currently can handle. Of course, that is a different issue. Here we just check how long plain `nmcli` takes on the system. ``` do_cleanup() { for UUID in $(nmcli -g NAME,UUID connection show | sed -n 's/^xx-c-.*:\([^:]\+\)$/\1/p'); do nmcli connection delete uuid "$UUID" done for DEVICE in $(nmcli -g DEVICE device status | grep '^xx-i-'); do nmcli device delete "$DEVICE" done } do_setup() { do_cleanup for i in {1..30}; do nmcli connection add type bond autoconnect no con-name xx-c-bond-$i ifname xx-i-bond-$i ipv4.method disabled ipv6.method ignore for j in $(seq $i 30); do nmcli connection add type vlan autoconnect no con-name xx-c-vlan-$i-$j vlan.id $j ifname xx-i-vlan-$i-$j vlan.parent xx-i-bond-$i ipv4.method disabled ipv6.method ignore done done systemctl restart NetworkManager.service sleep 5 } do_test() { perf stat -r 50 -B nmcli 1>/dev/null } do_test ``` [1] Performance counter stats for 'nmcli' (50 runs): 456.33 msec task-clock:u # 1.093 CPUs utilized ( +- 0.44% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,900 page-faults:u # 0.013 M/sec ( +- 0.02% ) 1,408,675,453 cycles:u # 3.087 GHz ( +- 0.48% ) 1,594,741,060 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 368,744,018 branches:u # 808.061 M/sec ( +- 0.02% ) 4,566,058 branch-misses:u # 1.24% of all branches ( +- 0.76% ) 0.41761 +- 0.00282 seconds time elapsed ( +- 0.68% ) [2] Performance counter stats for 'nmcli' (50 runs): 477.99 msec task-clock:u # 1.088 CPUs utilized ( +- 0.36% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,948 page-faults:u # 0.012 M/sec ( +- 0.03% ) 1,471,133,482 cycles:u # 3.078 GHz ( +- 0.36% ) 1,655,275,369 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 382,595,152 branches:u # 800.433 M/sec ( +- 0.02% ) 4,746,070 branch-misses:u # 1.24% of all branches ( +- 0.49% ) 0.43923 +- 0.00242 seconds time elapsed ( +- 0.55% ) [3] Performance counter stats for 'nmcli' (50 runs): 352.36 msec task-clock:u # 1.027 CPUs utilized ( +- 0.32% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 4,790 page-faults:u # 0.014 M/sec ( +- 0.26% ) 1,092,341,186 cycles:u # 3.100 GHz ( +- 0.26% ) 1,209,045,283 instructions:u # 1.11 insn per cycle ( +- 0.02% ) 281,708,462 branches:u # 799.499 M/sec ( +- 0.01% ) 3,101,031 branch-misses:u # 1.10% of all branches ( +- 0.61% ) 0.34296 +- 0.00120 seconds time elapsed ( +- 0.35% ) --- N5) same setup as N4), but run `PAGER= /bin/time -v nmcli`: [1] Command being timed: "nmcli" User time (seconds): 0.42 System time (seconds): 0.04 Percent of CPU this job got: 107% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.43 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34456 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6128 Voluntary context switches: 1298 Involuntary context switches: 1106 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [2] Command being timed: "nmcli" User time (seconds): 0.44 System time (seconds): 0.04 Percent of CPU this job got: 108% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.44 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34452 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6169 Voluntary context switches: 1849 Involuntary context switches: 142 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [3] Command being timed: "nmcli" User time (seconds): 0.32 System time (seconds): 0.02 Percent of CPU this job got: 102% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.34 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 29196 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 5059 Voluntary context switches: 919 Involuntary context switches: 685 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 --- N6) same setup as N4), but run `nmcli monitor` and look at `ps aux` for the RSS size. USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND [1] me 1492900 21.0 0.2 461348 33248 pts/10 Sl+ 15:02 0:00 nmcli monitor [2] me 1490721 5.0 0.2 461496 33548 pts/10 Sl+ 15:00 0:00 nmcli monitor [3] me 1495801 16.5 0.1 459476 28692 pts/10 Sl+ 15:04 0:00 nmcli monitor
2019-10-30 11:42:58 +01:00
return _nml_coerce_property_str_not_empty (NM_DEVICE_GET_PRIVATE (device)->interface);
}
/**
* nm_device_get_ip_iface:
* @device: a #NMDevice
*
* Gets the IP interface name of the #NMDevice over which IP traffic flows
* when the device is in the ACTIVATED state.
*
* Returns: the IP traffic interface of the device. This is the internal string
* used by the device, and must not be modified.
**/
const char *
nm_device_get_ip_iface (NMDevice *device)
{
g_return_val_if_fail (NM_IS_DEVICE (device), NULL);
libnm: refactor caching of D-Bus objects in NMClient No longer use GDBusObjectMangaerClient and gdbus-codegen generated classes for the NMClient cache. Instead, use GDBusConnection directly and a custom implementation (NMLDBusObject) for caching D-Bus' ObjectManager data. CHANGES ------- - This is a complete rework. I think the previous implementation was difficult to understand. There were unfixed bugs and nobody understood the code well enough to fix them. Maybe somebody out there understood the code, but I certainly did not. At least nobody provided patches to fix those issues. I do believe that this implementation is more straightforward and easier to understand. It removes a lot of layers of code. Whether this claim of simplicity is true, each reader must decide for himself/herself. Note that it is still fairly complex. - There was a lingering performance issue with large number of D-Bus objects. The patch tries hard that the implementation scales well. Of course, when we cache N objects that have N-to-M references to other, we still are fundamentally O(N*M) for runtime and memory consumption (with M being the number of references between objects). But each part should behave efficiently and well. - Play well with GMainContext. libnm code (NMClient) is generally not thread safe. However, it should work to use multiple instances in parallel, as long as each access to a NMClient is through the caller's GMainContext. This follows glib's style and effectively allows to use NMClient in a multi threaded scenario. This implies to stick to a main context upon construction and ensure that callbacks are only invoked when iterating that context. Also, NMClient itself shall never iterate the caller's context. This also means, libnm must never use g_idle_add() or g_timeout_add(), as those enqueue sources in the g_main_context_default() context. - Get ordering of messages right. All events are consistently enqueued in a GMainContext and processed strictly in order. For example, previously "nm-object.c" tried to combine signals and emit them on an idle handler. That is wrong, signals must be emitted in the right order and when they happen. Note that when using GInitable's synchronous initialization to initialize the NMClient instance, NMClient internally still operates fully asynchronously. In that case NMClient has an internal main context. - NMClient takes over most of the functionality. When using D-Bus' ObjectManager interface, one needs to handle basically the entire state of the D-Bus interface. That cannot be separated well into distinct parts, and even if you try, you just end up having closely related code in different source files. Spreading related code does not make it easier to understand, on the contrary. That means, NMClient is inherently complex as it contains most of the logic. I think that is not avoidable, but it's not as bad as it sounds. - NMClient processes D-Bus messages and state changes in separate steps. First NMClient unpacks the message (e.g. _dbus_handle_properties_changed()) and keeps track of the changed data. Then we update the GObject instances (_dbus_handle_obj_changed_dbus()) without emitting any signals yet. Finally, we emit all signals and notifications that were collected (_dbus_handle_changes_commit()). Note that for example during the initial GetManagedObjects() reply, NMClient receive a large amount of state at once. But we first apply all the changes to our GObject instances before emitting any signals. The result is that signals are always emitted in a moment when the cache is consistent. The unavoidable downside is that when you receive a property changed signal, possibly many other properties changed already and more signals are about to be emitted. - NMDeviceWifi no longer modifies the content of the cache from client side during poke_wireless_devices_with_rf_status(). The content of the cache should be determined by D-Bus alone and follow what NetworkManager service exposes. Local modifications should be avoided. - This aims to bring no API/ABI change, though it does of course bring various subtle changes in behavior. Those should be all for the better, but the goal is not to break any existing clients. This does change internal (albeit externally visible) API, like dropping NM_OBJECT_DBUS_OBJECT_MANAGER property and NMObject no longer implementing GInitableIface and GAsyncInitableIface. - Some uses of gdbus-codegen classes remain in NMVpnPluginOld, NMVpnServicePlugin and NMSecretAgentOld. These are independent of NMClient/NMObject and should be reworked separately. - While we no longer use generated classes from gdbus-codegen, we don't need more glue code than before. Also before we constructed NMPropertiesInfo and a had large amount of code to propagate properties from NMDBus* to NMObject. That got completely reworked, but did not fundamentally change. You still need about the same effort to create the NMLDBusMetaIface. Not using generated bindings did not make anything worse (which tells about the usefulness of generated code, at least in the way it was used). - NMLDBusMetaIface and other meta data is static and immutable. This avoids copying them around. Also, macros like NML_DBUS_META_PROPERTY_INIT_U() have compile time checks to ensure the property types matches. It's pretty hard to misuse them because it won't compile. - The meta data now explicitly encodes the expected D-Bus types and makes sure never to accept wrong data. That would only matter when the server (accidentally or intentionally) exposes unexpected types on D-Bus. I don't think that was previously ensured in all cases. For example, demarshal_generic() only cared about the GObject property type, it didn't know the expected D-Bus type. - Previously GDBusObjectManager would sometimes emit warnings (g_log()). Those probably indicated real bugs. In any case, it prevented us from running CI with G_DEBUG=fatal-warnings, because there would be just too many unrelated crashes. Now we log debug messages that can be enabled with "LIBNM_CLIENT_DEBUG=trace". Some of these messages can also be turned into g_warning()/g_critical() by setting LIBNM_CLIENT_DEBUG=warning,error. Together with G_DEBUG=fatal-warnings, this turns them into assertions. Note that such "assertion failures" might also happen because of a server bug (or change). Thus these are not common assertions that indicate a bug in libnm and are thus not armed unless explicitly requested. In our CI we should now always run with LIBNM_CLIENT_DEBUG=warning,error and G_DEBUG=fatal-warnings and to catch bugs. Note that currently NetworkManager has bugs in this regard, so enabling this will result in assertion failures. That should be fixed first. - Note that this changes the order in which we emit "notify:devices" and "device-added" signals. I think it makes the most sense to emit first "device-removed", then "notify:devices", and finally "device-added" signals. This changes behavior for commit 52ae28f6e5bf ('libnm: queue added/removed signals and suppress uninitialized notifications'), but I don't think that users should actually rely on the order. Still, the new order makes the most sense to me. - In NetworkManager, profiles can be invisible to the user by setting "connection.permissions". Such profiles would be hidden by NMClient's nm_client_get_connections() and their "connection-added"/"connection-removed" signals. Note that NMActiveConnection's nm_active_connection_get_connection() and NMDevice's nm_device_get_available_connections() still exposes such hidden NMRemoteConnection instances. This behavior was preserved. NUMBERS ------- I compared 3 versions of libnm. [1] 962297f9085d, current tip of nm-1-20 branch [2] 4fad8c7c642e, current master, immediate parent of this patch [3] this patch All tests were done on Fedora 31, x86_64, gcc 9.2.1-1.fc31. The libraries were build with $ ./contrib/fedora/rpm/build_clean.sh -g -w test -W debug Note that RPM build already stripped the library. --- N1) File size of libnm.so.0.1.0 in bytes. There currently seems to be a issue on Fedora 31 generating wrong ELF notes. Usually, libnm is smaller but in these tests it had large (and bogus) ELF notes. Anyway, the point is to show the relative sizes, so it doesn't matter). [1] 4075552 (102.7%) [2] 3969624 (100.0%) [3] 3705208 ( 93.3%) --- N2) `size /usr/lib64/libnm.so.0.1.0`: text data bss dec hex filename [1] 1314569 (102.0%) 69980 ( 94.8%) 10632 ( 80.4%) 1395181 (101.4%) 1549ed /usr/lib64/libnm.so.0.1.0 [2] 1288410 (100.0%) 73796 (100.0%) 13224 (100.0%) 1375430 (100.0%) 14fcc6 /usr/lib64/libnm.so.0.1.0 [3] 1229066 ( 95.4%) 65248 ( 88.4%) 13400 (101.3%) 1307714 ( 95.1%) 13f442 /usr/lib64/libnm.so.0.1.0 --- N3) Performance test with test-client.py. With checkout of [2], run ``` prepare_checkout() { rm -rf /tmp/nm-test && \ git checkout -B test 4fad8c7c642e && \ git clean -fdx && \ ./autogen.sh --prefix=/tmp/nm-test && \ make -j 5 install && \ make -j 5 check-local-clients-tests-test-client } prepare_test() { NM_TEST_REGENERATE=1 NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v } do_test() { for i in {1..10}; do NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v || return -1 done echo "done!" } prepare_checkout prepare_test time do_test ``` [1] real 2m14.497s (101.3%) user 5m26.651s (100.3%) sys 1m40.453s (101.4%) [2] real 2m12.800s (100.0%) user 5m25.619s (100.0%) sys 1m39.065s (100.0%) [3] real 1m54.915s ( 86.5%) user 4m18.585s ( 79.4%) sys 1m32.066s ( 92.9%) --- N4) Performance. Run NetworkManager from build [2] and setup a large number of profiles (551 profiles and 515 devices, mostly unrealized). This setup is already at the edge of what NetworkManager currently can handle. Of course, that is a different issue. Here we just check how long plain `nmcli` takes on the system. ``` do_cleanup() { for UUID in $(nmcli -g NAME,UUID connection show | sed -n 's/^xx-c-.*:\([^:]\+\)$/\1/p'); do nmcli connection delete uuid "$UUID" done for DEVICE in $(nmcli -g DEVICE device status | grep '^xx-i-'); do nmcli device delete "$DEVICE" done } do_setup() { do_cleanup for i in {1..30}; do nmcli connection add type bond autoconnect no con-name xx-c-bond-$i ifname xx-i-bond-$i ipv4.method disabled ipv6.method ignore for j in $(seq $i 30); do nmcli connection add type vlan autoconnect no con-name xx-c-vlan-$i-$j vlan.id $j ifname xx-i-vlan-$i-$j vlan.parent xx-i-bond-$i ipv4.method disabled ipv6.method ignore done done systemctl restart NetworkManager.service sleep 5 } do_test() { perf stat -r 50 -B nmcli 1>/dev/null } do_test ``` [1] Performance counter stats for 'nmcli' (50 runs): 456.33 msec task-clock:u # 1.093 CPUs utilized ( +- 0.44% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,900 page-faults:u # 0.013 M/sec ( +- 0.02% ) 1,408,675,453 cycles:u # 3.087 GHz ( +- 0.48% ) 1,594,741,060 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 368,744,018 branches:u # 808.061 M/sec ( +- 0.02% ) 4,566,058 branch-misses:u # 1.24% of all branches ( +- 0.76% ) 0.41761 +- 0.00282 seconds time elapsed ( +- 0.68% ) [2] Performance counter stats for 'nmcli' (50 runs): 477.99 msec task-clock:u # 1.088 CPUs utilized ( +- 0.36% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,948 page-faults:u # 0.012 M/sec ( +- 0.03% ) 1,471,133,482 cycles:u # 3.078 GHz ( +- 0.36% ) 1,655,275,369 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 382,595,152 branches:u # 800.433 M/sec ( +- 0.02% ) 4,746,070 branch-misses:u # 1.24% of all branches ( +- 0.49% ) 0.43923 +- 0.00242 seconds time elapsed ( +- 0.55% ) [3] Performance counter stats for 'nmcli' (50 runs): 352.36 msec task-clock:u # 1.027 CPUs utilized ( +- 0.32% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 4,790 page-faults:u # 0.014 M/sec ( +- 0.26% ) 1,092,341,186 cycles:u # 3.100 GHz ( +- 0.26% ) 1,209,045,283 instructions:u # 1.11 insn per cycle ( +- 0.02% ) 281,708,462 branches:u # 799.499 M/sec ( +- 0.01% ) 3,101,031 branch-misses:u # 1.10% of all branches ( +- 0.61% ) 0.34296 +- 0.00120 seconds time elapsed ( +- 0.35% ) --- N5) same setup as N4), but run `PAGER= /bin/time -v nmcli`: [1] Command being timed: "nmcli" User time (seconds): 0.42 System time (seconds): 0.04 Percent of CPU this job got: 107% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.43 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34456 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6128 Voluntary context switches: 1298 Involuntary context switches: 1106 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [2] Command being timed: "nmcli" User time (seconds): 0.44 System time (seconds): 0.04 Percent of CPU this job got: 108% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.44 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34452 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6169 Voluntary context switches: 1849 Involuntary context switches: 142 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [3] Command being timed: "nmcli" User time (seconds): 0.32 System time (seconds): 0.02 Percent of CPU this job got: 102% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.34 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 29196 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 5059 Voluntary context switches: 919 Involuntary context switches: 685 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 --- N6) same setup as N4), but run `nmcli monitor` and look at `ps aux` for the RSS size. USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND [1] me 1492900 21.0 0.2 461348 33248 pts/10 Sl+ 15:02 0:00 nmcli monitor [2] me 1490721 5.0 0.2 461496 33548 pts/10 Sl+ 15:00 0:00 nmcli monitor [3] me 1495801 16.5 0.1 459476 28692 pts/10 Sl+ 15:04 0:00 nmcli monitor
2019-10-30 11:42:58 +01:00
return _nml_coerce_property_str_not_empty (NM_DEVICE_GET_PRIVATE (device)->ip_interface);
}
/**
* nm_device_get_device_type:
* @device: a #NMDevice
*
* Returns the numeric type of the #NMDevice, ie Ethernet, Wi-Fi, etc.
*
* Returns: the device type
**/
NMDeviceType
nm_device_get_device_type (NMDevice *self)
{
g_return_val_if_fail (NM_IS_DEVICE (self), NM_DEVICE_TYPE_UNKNOWN);
return coerce_type (NM_DEVICE_GET_PRIVATE (self)->device_type);
}
/**
* nm_device_get_udi:
* @device: a #NMDevice
*
* Gets the Unique Device Identifier of the #NMDevice.
*
* Returns: the Unique Device Identifier of the device. This identifier may be
* used to gather more information about the device from various operating
* system services like udev or sysfs.
**/
const char *
nm_device_get_udi (NMDevice *device)
{
g_return_val_if_fail (NM_IS_DEVICE (device), NULL);
return _nml_coerce_property_str_not_empty (NM_DEVICE_GET_PRIVATE (device)->udi);
}
/**
* nm_device_get_path:
* @device: a #NMDevice
*
* Gets the path of the #NMDevice as exposed by the udev property ID_PATH.
*
* Returns: the path of the device.
*
* The string is backslash escaped (C escaping) for invalid characters. The escaping
* can be reverted with g_strcompress(), however the result may not be valid UTF-8.
*
* Since: 1.26
**/
const char *
nm_device_get_path (NMDevice *device)
{
g_return_val_if_fail (NM_IS_DEVICE (device), NULL);
return _nml_coerce_property_str_not_empty (NM_DEVICE_GET_PRIVATE (device)->path);
}
/**
* nm_device_get_driver:
* @device: a #NMDevice
*
* Gets the driver of the #NMDevice.
*
* Returns: the driver of the device. This is the internal string used by the
* device, and must not be modified.
**/
const char *
nm_device_get_driver (NMDevice *device)
{
g_return_val_if_fail (NM_IS_DEVICE (device), NULL);
return _nml_coerce_property_str_not_empty (NM_DEVICE_GET_PRIVATE (device)->driver);
}
/**
* nm_device_get_driver_version:
* @device: a #NMDevice
*
* Gets the driver version of the #NMDevice.
*
* Returns: the version of the device driver. This is the internal string used by the
* device, and must not be modified.
**/
const char *
nm_device_get_driver_version (NMDevice *device)
{
g_return_val_if_fail (NM_IS_DEVICE (device), NULL);
return _nml_coerce_property_str_not_empty (NM_DEVICE_GET_PRIVATE (device)->driver_version);
}
/**
* nm_device_get_firmware_version:
* @device: a #NMDevice
*
* Gets the firmware version of the #NMDevice.
*
* Returns: the firmware version of the device. This is the internal string used by the
* device, and must not be modified.
**/
const char *
nm_device_get_firmware_version (NMDevice *device)
{
g_return_val_if_fail (NM_IS_DEVICE (device), NULL);
return _nml_coerce_property_str_not_empty (NM_DEVICE_GET_PRIVATE (device)->firmware_version);
}
/**
* nm_device_get_type_description:
* @device: a #NMDevice
*
* Gets a (non-localized) description of the type of device that
* @device is.
*
* Returns: the type description of the device. This is the internal
* string used by the device, and must not be modified.
**/
const char *
nm_device_get_type_description (NMDevice *device)
{
NMDevicePrivate *priv = NM_DEVICE_GET_PRIVATE (device);
const char *desc, *typename;
/* BEWARE: this function should return the same value
* as nm_device_get_type_description() in nm-core. */
g_return_val_if_fail (NM_IS_DEVICE (device), NULL);
if (priv->type_description)
return _nml_coerce_property_str_not_empty (priv->type_description);
if (NM_DEVICE_GET_CLASS (device)->get_type_description) {
desc = NM_DEVICE_GET_CLASS (device)->get_type_description (device);
if (desc)
return desc;
}
typename = G_OBJECT_TYPE_NAME (device);
if (g_str_has_prefix (typename, "NMDevice"))
typename += 8;
priv->type_description = g_ascii_strdown (typename, -1);
return _nml_coerce_property_str_not_empty (priv->type_description);
}
NMLDBusNotifyUpdatePropFlags
_nm_device_notify_update_prop_hw_address (NMClient *client,
NMLDBusObject *dbobj,
const NMLDBusMetaIface *meta_iface,
guint dbus_property_idx,
GVariant *value)
{
NMDevice *self = NM_DEVICE (dbobj->nmobj);
NMDevicePrivate *priv = NM_DEVICE_GET_PRIVATE (self);
gboolean is_new = (meta_iface == &_nml_dbus_meta_iface_nm_device);
gboolean changed = FALSE;
if ( !is_new
&& priv->hw_address_is_new) {
/* once the instance is marked to honor the new property, the
* changed signal for the old variant gets ignored. */
goto out;
}
if (!value) {
if (nm_clear_g_free (&priv->hw_address))
changed = TRUE;
goto out;
}
priv->hw_address_is_new = is_new;
nm_utils_strdup_reset (&priv->hw_address,
_nml_coerce_property_str_not_empty (g_variant_get_string (value, NULL)));
/* always emit a changed signal here, even if "priv->hw_address" might be unchanged.
* We want to emit the signal because we received a PropertiesChanged signal on D-Bus,
* even if nothing actually changed. */
changed = TRUE;
out:
if (changed) {
_nm_client_queue_notify_object (client,
self,
obj_properties[PROP_HW_ADDRESS]);
}
return NML_DBUS_NOTIFY_UPDATE_PROP_FLAGS_NONE;
}
/**
* nm_device_get_hw_address:
* @device: a #NMDevice
*
* Gets the current a hardware address (MAC) for the @device.
*
* Returns: the current MAC of the device, or %NULL.
* This is the internal string used by the device, and must not be modified.
**/
const char *
nm_device_get_hw_address (NMDevice *device)
{
NMDevicePrivate *priv;
g_return_val_if_fail (NM_IS_DEVICE (device), NULL);
priv = NM_DEVICE_GET_PRIVATE (device);
nm_assert (!nm_streq0 (priv->hw_address, ""));
return priv->hw_address;
}
/**
* nm_device_get_capabilities:
* @device: a #NMDevice
*
* Gets the device' capabilities.
*
* Returns: the capabilities
**/
NMDeviceCapabilities
nm_device_get_capabilities (NMDevice *device)
{
g_return_val_if_fail (NM_IS_DEVICE (device), 0);
return NM_DEVICE_GET_PRIVATE (device)->capabilities;
}
/**
* nm_device_get_managed:
* @device: a #NMDevice
*
* Whether the #NMDevice is managed by NetworkManager.
*
* Returns: %TRUE if the device is managed by NetworkManager
**/
gboolean
nm_device_get_managed (NMDevice *device)
{
g_return_val_if_fail (NM_IS_DEVICE (device), 0);
return NM_DEVICE_GET_PRIVATE (device)->managed;
}
/**
* nm_device_set_managed:
* @device: a #NMDevice
* @managed: %TRUE to make the device managed by NetworkManager.
*
* Enables or disables management of #NMDevice by NetworkManager.
*
* Since: 1.2
libnm: deprecate synchronous/blocking API in libnm Note that D-Bus is fundamentally asynchronous. Doing blocking calls on top of D-Bus is odd, especially for libnm's NMClient. That is because NMClient essentially is a client-side cache of the objects from the D-Bus interface. This cache should be filled exclusively by (asynchronous) D-Bus events (PropertiesChanged). So, making a blocking D-Bus call means to wait for a response and return it, while queuing all messages that are received in the meantime. Basically there are three ways how a synchronous API on NMClient could behave: 1) the call just calls g_dbus_connection_call_sync(). This means that libnm sends a D-Bus request via GDBusConnection, and blockingly waits for the response. All D-Bus messages that get received in the meantime are queued in the GMainContext that belongs to NMClient. That means, none of these D-Bus events are processed until we iterate the GMainContext after the call returns. The effect is, that NMClient (and all cached objects in there) are unaffected by the D-Bus request. Most of the synchronous API calls in libnm are of this kind. The problem is that the strict ordering of D-Bus events gets violated. For some API this is not an immediate problem. Take for example nm_device_wifi_request_scan(). The call merely blockingly tells NetworkManager to start scanning, but since NetworkManager's D-Bus API does not directly expose any state that tells whether we are currently scanning, this out of order processing of the D-Bus request is a small issue. The problem is more obvious for nm_client_networking_set_enabled(). After calling it, NM_CLIENT_NETWORKING_ENABLED is still unaffected and unchanged, because the PropertiesChanged signal from D-Bus is not yet processed. This means, while you make such a blocking call, NMClient's state does not change. But usually you perform the synchronous call to change some state. In this form, the blocking call is not useful, because NMClient only changes the state after iterating the GMainContext, and not after the blocking call returns. 2) like 1), but after making the blocking g_dbus_connection_call_sync(), update the NMClient cache artificially. This is what nm_manager_check_connectivity() does, to "fix" bgo#784629. This also has the problem of out-of-order events, but it kinda solves the problem of not changing the state during the blocking call. But it does so by hacking the state of the cache. I think this is really wrong because the state should only be updated from the ordered stream of D-Bus messages (PropertiesChanged signal and similar). When libnm decides to modify the state, there may be already D-Bus messages queued that affect this very state. 3) instead of calling g_dbus_connection_call_sync(), use the asynchronous g_dbus_connection_call(). If we would use a sepaate GMainContext for all D-Bus related calls, we could ensure that while we block for the response, we iterate that internal main context. This might be nice, because all events are processed in order and after the blocking call returns, the NMClient state is up to date. The are problems however: current blocking API does not do this, so it's a significant change in behavior. Also, it might be unexpected to the user that during the blocking call the entire content of NMClient's cache might change and all pointers to the cache might be invalidated. Also, of course NMClient would invoke signals for all the changes that happen. Another problem is that this would be more effort to implement and it involves a small performance overhead for all D-Bus related calls (because we have to serialize all events in an internal GMainContext first and then invoke them on the caller's context). Also, if the users wants this behavior, they could implement it themself by running libnm in their own GMainContext. Note that libnm might have bugs to make that really working, but that should be fixed instead of adding such synchrnous API behavior. Read also [1], for why blocking calls are wrong. [1] https://smcv.pseudorandom.co.uk/2008/11/nonblocking/ So, all possible behaviors for synchronous API have severe behavioural issues. Mark all this API as deprecated. Also, this serves the purpose of identifying blocking D-Bus calls in libnm. Note that "deprecated" here does not really mean that the API is going to be removed. We don't break API. The user may: - continue to use this API. It's deprecated, awkward and discouraged, but if it works, by all means use it. - use asynchronous API. That's the only sensible way to use D-Bus. If libnm lacks a certain asynchronous counterpart, it should be added. - use GDBusConnection directly. There really isn't anything wrong with D-Bus or GDBusConnection. This deprecated API is just a wrapper around g_dbus_connection_call_sync(). You may call it directly without feeling dirty. --- The only other remainging API is the synchronous GInitable call for NMClient. That is an entirely separate beast and not particularly wrong (from an API point of view). Note that synchronous API in NMSecretAgentOld, NMVpnPluginOld and NMVpnServicePlugin as not deprecated here. These types are not part of the D-Bus cache and while they have similar issues, it's less severe because they have less state.
2019-09-04 13:58:43 +02:00
*
libnm: advise using D-Bus instead of deprecated synchronous methods With 1.22, various synchronous functions for invoking D-Bus methods were deprecated. The reason was that D-Bus is fundamentally asynchronous, and providing synchronous API in NMClient is inherently wrong. That is because NMClient essentially is a cache of the D-Bus API, and invoking g_dbus_connection_call_sync() messes up the order of events from D-Bus. In particular, when the synchronous function completes, the content of the cache does not yet reflect the change. Since they got deprecated, the question is with what to replace them. Instead of adding a (e.g.) nm_client_networking_set_enabled_async() for nm_client_networking_set_enabled(), just expect the user to call D-Bus directly. D-Bus itself defines a reasonable API, and with GDBusConnection it is fine (and convenient) to just call D-Bus operations directly. Often libraries try to abstract D-Bus by providing convenience wrappers around D-Bus API. I think that often is wrong and unnecessary. Note that libnm's NMClient does a lot more than just wrapping simple D-Bus calls. It provides a complete client-side cache of the D-Bus interface. As such, what libnm's NMClient does is more than simple wrappers around D-Bus. NMClient is a reasonable thing to do. However, it is unnecessary to add API like nm_client_networking_set_enabled_async() that only calls g_dbus_connection_call(). Don't pretend that we would need such trivial wrappers in libnm. Instead, recommend to use g_dbus_connection_call(). Or alternatively, the convenience wrappers nm_client_dbus_call() and nm_client_dbus_set_property().
2020-03-13 18:24:37 +01:00
* Deprecated: 1.22: Use the async command nm_client_dbus_set_property() on
* nm_object_get_path(), interface %NM_DBUS_INTERFACE_DEVICE to set the
* "Managed" property to a "(b)" boolean value.
* This function is deprecated because it calls a synchronous D-Bus method
* and modifies the content of the NMClient cache client side. Also, it does
* not emit a property changed signal.
**/
void
nm_device_set_managed (NMDevice *device, gboolean managed)
{
g_return_if_fail (NM_IS_DEVICE (device));
managed = !!managed;
NM_DEVICE_GET_PRIVATE (device)->managed = managed;
libnm: refactor caching of D-Bus objects in NMClient No longer use GDBusObjectMangaerClient and gdbus-codegen generated classes for the NMClient cache. Instead, use GDBusConnection directly and a custom implementation (NMLDBusObject) for caching D-Bus' ObjectManager data. CHANGES ------- - This is a complete rework. I think the previous implementation was difficult to understand. There were unfixed bugs and nobody understood the code well enough to fix them. Maybe somebody out there understood the code, but I certainly did not. At least nobody provided patches to fix those issues. I do believe that this implementation is more straightforward and easier to understand. It removes a lot of layers of code. Whether this claim of simplicity is true, each reader must decide for himself/herself. Note that it is still fairly complex. - There was a lingering performance issue with large number of D-Bus objects. The patch tries hard that the implementation scales well. Of course, when we cache N objects that have N-to-M references to other, we still are fundamentally O(N*M) for runtime and memory consumption (with M being the number of references between objects). But each part should behave efficiently and well. - Play well with GMainContext. libnm code (NMClient) is generally not thread safe. However, it should work to use multiple instances in parallel, as long as each access to a NMClient is through the caller's GMainContext. This follows glib's style and effectively allows to use NMClient in a multi threaded scenario. This implies to stick to a main context upon construction and ensure that callbacks are only invoked when iterating that context. Also, NMClient itself shall never iterate the caller's context. This also means, libnm must never use g_idle_add() or g_timeout_add(), as those enqueue sources in the g_main_context_default() context. - Get ordering of messages right. All events are consistently enqueued in a GMainContext and processed strictly in order. For example, previously "nm-object.c" tried to combine signals and emit them on an idle handler. That is wrong, signals must be emitted in the right order and when they happen. Note that when using GInitable's synchronous initialization to initialize the NMClient instance, NMClient internally still operates fully asynchronously. In that case NMClient has an internal main context. - NMClient takes over most of the functionality. When using D-Bus' ObjectManager interface, one needs to handle basically the entire state of the D-Bus interface. That cannot be separated well into distinct parts, and even if you try, you just end up having closely related code in different source files. Spreading related code does not make it easier to understand, on the contrary. That means, NMClient is inherently complex as it contains most of the logic. I think that is not avoidable, but it's not as bad as it sounds. - NMClient processes D-Bus messages and state changes in separate steps. First NMClient unpacks the message (e.g. _dbus_handle_properties_changed()) and keeps track of the changed data. Then we update the GObject instances (_dbus_handle_obj_changed_dbus()) without emitting any signals yet. Finally, we emit all signals and notifications that were collected (_dbus_handle_changes_commit()). Note that for example during the initial GetManagedObjects() reply, NMClient receive a large amount of state at once. But we first apply all the changes to our GObject instances before emitting any signals. The result is that signals are always emitted in a moment when the cache is consistent. The unavoidable downside is that when you receive a property changed signal, possibly many other properties changed already and more signals are about to be emitted. - NMDeviceWifi no longer modifies the content of the cache from client side during poke_wireless_devices_with_rf_status(). The content of the cache should be determined by D-Bus alone and follow what NetworkManager service exposes. Local modifications should be avoided. - This aims to bring no API/ABI change, though it does of course bring various subtle changes in behavior. Those should be all for the better, but the goal is not to break any existing clients. This does change internal (albeit externally visible) API, like dropping NM_OBJECT_DBUS_OBJECT_MANAGER property and NMObject no longer implementing GInitableIface and GAsyncInitableIface. - Some uses of gdbus-codegen classes remain in NMVpnPluginOld, NMVpnServicePlugin and NMSecretAgentOld. These are independent of NMClient/NMObject and should be reworked separately. - While we no longer use generated classes from gdbus-codegen, we don't need more glue code than before. Also before we constructed NMPropertiesInfo and a had large amount of code to propagate properties from NMDBus* to NMObject. That got completely reworked, but did not fundamentally change. You still need about the same effort to create the NMLDBusMetaIface. Not using generated bindings did not make anything worse (which tells about the usefulness of generated code, at least in the way it was used). - NMLDBusMetaIface and other meta data is static and immutable. This avoids copying them around. Also, macros like NML_DBUS_META_PROPERTY_INIT_U() have compile time checks to ensure the property types matches. It's pretty hard to misuse them because it won't compile. - The meta data now explicitly encodes the expected D-Bus types and makes sure never to accept wrong data. That would only matter when the server (accidentally or intentionally) exposes unexpected types on D-Bus. I don't think that was previously ensured in all cases. For example, demarshal_generic() only cared about the GObject property type, it didn't know the expected D-Bus type. - Previously GDBusObjectManager would sometimes emit warnings (g_log()). Those probably indicated real bugs. In any case, it prevented us from running CI with G_DEBUG=fatal-warnings, because there would be just too many unrelated crashes. Now we log debug messages that can be enabled with "LIBNM_CLIENT_DEBUG=trace". Some of these messages can also be turned into g_warning()/g_critical() by setting LIBNM_CLIENT_DEBUG=warning,error. Together with G_DEBUG=fatal-warnings, this turns them into assertions. Note that such "assertion failures" might also happen because of a server bug (or change). Thus these are not common assertions that indicate a bug in libnm and are thus not armed unless explicitly requested. In our CI we should now always run with LIBNM_CLIENT_DEBUG=warning,error and G_DEBUG=fatal-warnings and to catch bugs. Note that currently NetworkManager has bugs in this regard, so enabling this will result in assertion failures. That should be fixed first. - Note that this changes the order in which we emit "notify:devices" and "device-added" signals. I think it makes the most sense to emit first "device-removed", then "notify:devices", and finally "device-added" signals. This changes behavior for commit 52ae28f6e5bf ('libnm: queue added/removed signals and suppress uninitialized notifications'), but I don't think that users should actually rely on the order. Still, the new order makes the most sense to me. - In NetworkManager, profiles can be invisible to the user by setting "connection.permissions". Such profiles would be hidden by NMClient's nm_client_get_connections() and their "connection-added"/"connection-removed" signals. Note that NMActiveConnection's nm_active_connection_get_connection() and NMDevice's nm_device_get_available_connections() still exposes such hidden NMRemoteConnection instances. This behavior was preserved. NUMBERS ------- I compared 3 versions of libnm. [1] 962297f9085d, current tip of nm-1-20 branch [2] 4fad8c7c642e, current master, immediate parent of this patch [3] this patch All tests were done on Fedora 31, x86_64, gcc 9.2.1-1.fc31. The libraries were build with $ ./contrib/fedora/rpm/build_clean.sh -g -w test -W debug Note that RPM build already stripped the library. --- N1) File size of libnm.so.0.1.0 in bytes. There currently seems to be a issue on Fedora 31 generating wrong ELF notes. Usually, libnm is smaller but in these tests it had large (and bogus) ELF notes. Anyway, the point is to show the relative sizes, so it doesn't matter). [1] 4075552 (102.7%) [2] 3969624 (100.0%) [3] 3705208 ( 93.3%) --- N2) `size /usr/lib64/libnm.so.0.1.0`: text data bss dec hex filename [1] 1314569 (102.0%) 69980 ( 94.8%) 10632 ( 80.4%) 1395181 (101.4%) 1549ed /usr/lib64/libnm.so.0.1.0 [2] 1288410 (100.0%) 73796 (100.0%) 13224 (100.0%) 1375430 (100.0%) 14fcc6 /usr/lib64/libnm.so.0.1.0 [3] 1229066 ( 95.4%) 65248 ( 88.4%) 13400 (101.3%) 1307714 ( 95.1%) 13f442 /usr/lib64/libnm.so.0.1.0 --- N3) Performance test with test-client.py. With checkout of [2], run ``` prepare_checkout() { rm -rf /tmp/nm-test && \ git checkout -B test 4fad8c7c642e && \ git clean -fdx && \ ./autogen.sh --prefix=/tmp/nm-test && \ make -j 5 install && \ make -j 5 check-local-clients-tests-test-client } prepare_test() { NM_TEST_REGENERATE=1 NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v } do_test() { for i in {1..10}; do NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v || return -1 done echo "done!" } prepare_checkout prepare_test time do_test ``` [1] real 2m14.497s (101.3%) user 5m26.651s (100.3%) sys 1m40.453s (101.4%) [2] real 2m12.800s (100.0%) user 5m25.619s (100.0%) sys 1m39.065s (100.0%) [3] real 1m54.915s ( 86.5%) user 4m18.585s ( 79.4%) sys 1m32.066s ( 92.9%) --- N4) Performance. Run NetworkManager from build [2] and setup a large number of profiles (551 profiles and 515 devices, mostly unrealized). This setup is already at the edge of what NetworkManager currently can handle. Of course, that is a different issue. Here we just check how long plain `nmcli` takes on the system. ``` do_cleanup() { for UUID in $(nmcli -g NAME,UUID connection show | sed -n 's/^xx-c-.*:\([^:]\+\)$/\1/p'); do nmcli connection delete uuid "$UUID" done for DEVICE in $(nmcli -g DEVICE device status | grep '^xx-i-'); do nmcli device delete "$DEVICE" done } do_setup() { do_cleanup for i in {1..30}; do nmcli connection add type bond autoconnect no con-name xx-c-bond-$i ifname xx-i-bond-$i ipv4.method disabled ipv6.method ignore for j in $(seq $i 30); do nmcli connection add type vlan autoconnect no con-name xx-c-vlan-$i-$j vlan.id $j ifname xx-i-vlan-$i-$j vlan.parent xx-i-bond-$i ipv4.method disabled ipv6.method ignore done done systemctl restart NetworkManager.service sleep 5 } do_test() { perf stat -r 50 -B nmcli 1>/dev/null } do_test ``` [1] Performance counter stats for 'nmcli' (50 runs): 456.33 msec task-clock:u # 1.093 CPUs utilized ( +- 0.44% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,900 page-faults:u # 0.013 M/sec ( +- 0.02% ) 1,408,675,453 cycles:u # 3.087 GHz ( +- 0.48% ) 1,594,741,060 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 368,744,018 branches:u # 808.061 M/sec ( +- 0.02% ) 4,566,058 branch-misses:u # 1.24% of all branches ( +- 0.76% ) 0.41761 +- 0.00282 seconds time elapsed ( +- 0.68% ) [2] Performance counter stats for 'nmcli' (50 runs): 477.99 msec task-clock:u # 1.088 CPUs utilized ( +- 0.36% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,948 page-faults:u # 0.012 M/sec ( +- 0.03% ) 1,471,133,482 cycles:u # 3.078 GHz ( +- 0.36% ) 1,655,275,369 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 382,595,152 branches:u # 800.433 M/sec ( +- 0.02% ) 4,746,070 branch-misses:u # 1.24% of all branches ( +- 0.49% ) 0.43923 +- 0.00242 seconds time elapsed ( +- 0.55% ) [3] Performance counter stats for 'nmcli' (50 runs): 352.36 msec task-clock:u # 1.027 CPUs utilized ( +- 0.32% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 4,790 page-faults:u # 0.014 M/sec ( +- 0.26% ) 1,092,341,186 cycles:u # 3.100 GHz ( +- 0.26% ) 1,209,045,283 instructions:u # 1.11 insn per cycle ( +- 0.02% ) 281,708,462 branches:u # 799.499 M/sec ( +- 0.01% ) 3,101,031 branch-misses:u # 1.10% of all branches ( +- 0.61% ) 0.34296 +- 0.00120 seconds time elapsed ( +- 0.35% ) --- N5) same setup as N4), but run `PAGER= /bin/time -v nmcli`: [1] Command being timed: "nmcli" User time (seconds): 0.42 System time (seconds): 0.04 Percent of CPU this job got: 107% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.43 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34456 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6128 Voluntary context switches: 1298 Involuntary context switches: 1106 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [2] Command being timed: "nmcli" User time (seconds): 0.44 System time (seconds): 0.04 Percent of CPU this job got: 108% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.44 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34452 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6169 Voluntary context switches: 1849 Involuntary context switches: 142 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [3] Command being timed: "nmcli" User time (seconds): 0.32 System time (seconds): 0.02 Percent of CPU this job got: 102% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.34 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 29196 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 5059 Voluntary context switches: 919 Involuntary context switches: 685 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 --- N6) same setup as N4), but run `nmcli monitor` and look at `ps aux` for the RSS size. USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND [1] me 1492900 21.0 0.2 461348 33248 pts/10 Sl+ 15:02 0:00 nmcli monitor [2] me 1490721 5.0 0.2 461496 33548 pts/10 Sl+ 15:00 0:00 nmcli monitor [3] me 1495801 16.5 0.1 459476 28692 pts/10 Sl+ 15:04 0:00 nmcli monitor
2019-10-30 11:42:58 +01:00
_nm_client_set_property_sync_legacy (_nm_object_get_client (device),
_nm_object_get_path (device),
NM_DBUS_INTERFACE_DEVICE,
"Managed",
"b",
managed);
}
/**
* nm_device_get_autoconnect:
* @device: a #NMDevice
*
* Whether the #NMDevice can be autoconnected.
*
* Returns: %TRUE if the device is allowed to be autoconnected
**/
gboolean
nm_device_get_autoconnect (NMDevice *device)
{
g_return_val_if_fail (NM_IS_DEVICE (device), FALSE);
return NM_DEVICE_GET_PRIVATE (device)->autoconnect;
}
/**
* nm_device_set_autoconnect:
* @device: a #NMDevice
* @autoconnect: %TRUE to enable autoconnecting
*
* Enables or disables automatic activation of the #NMDevice.
libnm: deprecate synchronous/blocking API in libnm Note that D-Bus is fundamentally asynchronous. Doing blocking calls on top of D-Bus is odd, especially for libnm's NMClient. That is because NMClient essentially is a client-side cache of the objects from the D-Bus interface. This cache should be filled exclusively by (asynchronous) D-Bus events (PropertiesChanged). So, making a blocking D-Bus call means to wait for a response and return it, while queuing all messages that are received in the meantime. Basically there are three ways how a synchronous API on NMClient could behave: 1) the call just calls g_dbus_connection_call_sync(). This means that libnm sends a D-Bus request via GDBusConnection, and blockingly waits for the response. All D-Bus messages that get received in the meantime are queued in the GMainContext that belongs to NMClient. That means, none of these D-Bus events are processed until we iterate the GMainContext after the call returns. The effect is, that NMClient (and all cached objects in there) are unaffected by the D-Bus request. Most of the synchronous API calls in libnm are of this kind. The problem is that the strict ordering of D-Bus events gets violated. For some API this is not an immediate problem. Take for example nm_device_wifi_request_scan(). The call merely blockingly tells NetworkManager to start scanning, but since NetworkManager's D-Bus API does not directly expose any state that tells whether we are currently scanning, this out of order processing of the D-Bus request is a small issue. The problem is more obvious for nm_client_networking_set_enabled(). After calling it, NM_CLIENT_NETWORKING_ENABLED is still unaffected and unchanged, because the PropertiesChanged signal from D-Bus is not yet processed. This means, while you make such a blocking call, NMClient's state does not change. But usually you perform the synchronous call to change some state. In this form, the blocking call is not useful, because NMClient only changes the state after iterating the GMainContext, and not after the blocking call returns. 2) like 1), but after making the blocking g_dbus_connection_call_sync(), update the NMClient cache artificially. This is what nm_manager_check_connectivity() does, to "fix" bgo#784629. This also has the problem of out-of-order events, but it kinda solves the problem of not changing the state during the blocking call. But it does so by hacking the state of the cache. I think this is really wrong because the state should only be updated from the ordered stream of D-Bus messages (PropertiesChanged signal and similar). When libnm decides to modify the state, there may be already D-Bus messages queued that affect this very state. 3) instead of calling g_dbus_connection_call_sync(), use the asynchronous g_dbus_connection_call(). If we would use a sepaate GMainContext for all D-Bus related calls, we could ensure that while we block for the response, we iterate that internal main context. This might be nice, because all events are processed in order and after the blocking call returns, the NMClient state is up to date. The are problems however: current blocking API does not do this, so it's a significant change in behavior. Also, it might be unexpected to the user that during the blocking call the entire content of NMClient's cache might change and all pointers to the cache might be invalidated. Also, of course NMClient would invoke signals for all the changes that happen. Another problem is that this would be more effort to implement and it involves a small performance overhead for all D-Bus related calls (because we have to serialize all events in an internal GMainContext first and then invoke them on the caller's context). Also, if the users wants this behavior, they could implement it themself by running libnm in their own GMainContext. Note that libnm might have bugs to make that really working, but that should be fixed instead of adding such synchrnous API behavior. Read also [1], for why blocking calls are wrong. [1] https://smcv.pseudorandom.co.uk/2008/11/nonblocking/ So, all possible behaviors for synchronous API have severe behavioural issues. Mark all this API as deprecated. Also, this serves the purpose of identifying blocking D-Bus calls in libnm. Note that "deprecated" here does not really mean that the API is going to be removed. We don't break API. The user may: - continue to use this API. It's deprecated, awkward and discouraged, but if it works, by all means use it. - use asynchronous API. That's the only sensible way to use D-Bus. If libnm lacks a certain asynchronous counterpart, it should be added. - use GDBusConnection directly. There really isn't anything wrong with D-Bus or GDBusConnection. This deprecated API is just a wrapper around g_dbus_connection_call_sync(). You may call it directly without feeling dirty. --- The only other remainging API is the synchronous GInitable call for NMClient. That is an entirely separate beast and not particularly wrong (from an API point of view). Note that synchronous API in NMSecretAgentOld, NMVpnPluginOld and NMVpnServicePlugin as not deprecated here. These types are not part of the D-Bus cache and while they have similar issues, it's less severe because they have less state.
2019-09-04 13:58:43 +02:00
*
libnm: advise using D-Bus instead of deprecated synchronous methods With 1.22, various synchronous functions for invoking D-Bus methods were deprecated. The reason was that D-Bus is fundamentally asynchronous, and providing synchronous API in NMClient is inherently wrong. That is because NMClient essentially is a cache of the D-Bus API, and invoking g_dbus_connection_call_sync() messes up the order of events from D-Bus. In particular, when the synchronous function completes, the content of the cache does not yet reflect the change. Since they got deprecated, the question is with what to replace them. Instead of adding a (e.g.) nm_client_networking_set_enabled_async() for nm_client_networking_set_enabled(), just expect the user to call D-Bus directly. D-Bus itself defines a reasonable API, and with GDBusConnection it is fine (and convenient) to just call D-Bus operations directly. Often libraries try to abstract D-Bus by providing convenience wrappers around D-Bus API. I think that often is wrong and unnecessary. Note that libnm's NMClient does a lot more than just wrapping simple D-Bus calls. It provides a complete client-side cache of the D-Bus interface. As such, what libnm's NMClient does is more than simple wrappers around D-Bus. NMClient is a reasonable thing to do. However, it is unnecessary to add API like nm_client_networking_set_enabled_async() that only calls g_dbus_connection_call(). Don't pretend that we would need such trivial wrappers in libnm. Instead, recommend to use g_dbus_connection_call(). Or alternatively, the convenience wrappers nm_client_dbus_call() and nm_client_dbus_set_property().
2020-03-13 18:24:37 +01:00
* Deprecated: 1.22: Use the async command nm_client_dbus_set_property() on
* nm_object_get_path(), %NM_DBUS_INTERFACE_DEVICE to set "AutoConnect" property to a "(b)" value.
* This function is deprecated because it calls a synchronous D-Bus method
* and modifies the content of the NMClient cache client side.
**/
void
nm_device_set_autoconnect (NMDevice *device, gboolean autoconnect)
{
g_return_if_fail (NM_IS_DEVICE (device));
NM_DEVICE_GET_PRIVATE (device)->autoconnect = autoconnect;
libnm: refactor caching of D-Bus objects in NMClient No longer use GDBusObjectMangaerClient and gdbus-codegen generated classes for the NMClient cache. Instead, use GDBusConnection directly and a custom implementation (NMLDBusObject) for caching D-Bus' ObjectManager data. CHANGES ------- - This is a complete rework. I think the previous implementation was difficult to understand. There were unfixed bugs and nobody understood the code well enough to fix them. Maybe somebody out there understood the code, but I certainly did not. At least nobody provided patches to fix those issues. I do believe that this implementation is more straightforward and easier to understand. It removes a lot of layers of code. Whether this claim of simplicity is true, each reader must decide for himself/herself. Note that it is still fairly complex. - There was a lingering performance issue with large number of D-Bus objects. The patch tries hard that the implementation scales well. Of course, when we cache N objects that have N-to-M references to other, we still are fundamentally O(N*M) for runtime and memory consumption (with M being the number of references between objects). But each part should behave efficiently and well. - Play well with GMainContext. libnm code (NMClient) is generally not thread safe. However, it should work to use multiple instances in parallel, as long as each access to a NMClient is through the caller's GMainContext. This follows glib's style and effectively allows to use NMClient in a multi threaded scenario. This implies to stick to a main context upon construction and ensure that callbacks are only invoked when iterating that context. Also, NMClient itself shall never iterate the caller's context. This also means, libnm must never use g_idle_add() or g_timeout_add(), as those enqueue sources in the g_main_context_default() context. - Get ordering of messages right. All events are consistently enqueued in a GMainContext and processed strictly in order. For example, previously "nm-object.c" tried to combine signals and emit them on an idle handler. That is wrong, signals must be emitted in the right order and when they happen. Note that when using GInitable's synchronous initialization to initialize the NMClient instance, NMClient internally still operates fully asynchronously. In that case NMClient has an internal main context. - NMClient takes over most of the functionality. When using D-Bus' ObjectManager interface, one needs to handle basically the entire state of the D-Bus interface. That cannot be separated well into distinct parts, and even if you try, you just end up having closely related code in different source files. Spreading related code does not make it easier to understand, on the contrary. That means, NMClient is inherently complex as it contains most of the logic. I think that is not avoidable, but it's not as bad as it sounds. - NMClient processes D-Bus messages and state changes in separate steps. First NMClient unpacks the message (e.g. _dbus_handle_properties_changed()) and keeps track of the changed data. Then we update the GObject instances (_dbus_handle_obj_changed_dbus()) without emitting any signals yet. Finally, we emit all signals and notifications that were collected (_dbus_handle_changes_commit()). Note that for example during the initial GetManagedObjects() reply, NMClient receive a large amount of state at once. But we first apply all the changes to our GObject instances before emitting any signals. The result is that signals are always emitted in a moment when the cache is consistent. The unavoidable downside is that when you receive a property changed signal, possibly many other properties changed already and more signals are about to be emitted. - NMDeviceWifi no longer modifies the content of the cache from client side during poke_wireless_devices_with_rf_status(). The content of the cache should be determined by D-Bus alone and follow what NetworkManager service exposes. Local modifications should be avoided. - This aims to bring no API/ABI change, though it does of course bring various subtle changes in behavior. Those should be all for the better, but the goal is not to break any existing clients. This does change internal (albeit externally visible) API, like dropping NM_OBJECT_DBUS_OBJECT_MANAGER property and NMObject no longer implementing GInitableIface and GAsyncInitableIface. - Some uses of gdbus-codegen classes remain in NMVpnPluginOld, NMVpnServicePlugin and NMSecretAgentOld. These are independent of NMClient/NMObject and should be reworked separately. - While we no longer use generated classes from gdbus-codegen, we don't need more glue code than before. Also before we constructed NMPropertiesInfo and a had large amount of code to propagate properties from NMDBus* to NMObject. That got completely reworked, but did not fundamentally change. You still need about the same effort to create the NMLDBusMetaIface. Not using generated bindings did not make anything worse (which tells about the usefulness of generated code, at least in the way it was used). - NMLDBusMetaIface and other meta data is static and immutable. This avoids copying them around. Also, macros like NML_DBUS_META_PROPERTY_INIT_U() have compile time checks to ensure the property types matches. It's pretty hard to misuse them because it won't compile. - The meta data now explicitly encodes the expected D-Bus types and makes sure never to accept wrong data. That would only matter when the server (accidentally or intentionally) exposes unexpected types on D-Bus. I don't think that was previously ensured in all cases. For example, demarshal_generic() only cared about the GObject property type, it didn't know the expected D-Bus type. - Previously GDBusObjectManager would sometimes emit warnings (g_log()). Those probably indicated real bugs. In any case, it prevented us from running CI with G_DEBUG=fatal-warnings, because there would be just too many unrelated crashes. Now we log debug messages that can be enabled with "LIBNM_CLIENT_DEBUG=trace". Some of these messages can also be turned into g_warning()/g_critical() by setting LIBNM_CLIENT_DEBUG=warning,error. Together with G_DEBUG=fatal-warnings, this turns them into assertions. Note that such "assertion failures" might also happen because of a server bug (or change). Thus these are not common assertions that indicate a bug in libnm and are thus not armed unless explicitly requested. In our CI we should now always run with LIBNM_CLIENT_DEBUG=warning,error and G_DEBUG=fatal-warnings and to catch bugs. Note that currently NetworkManager has bugs in this regard, so enabling this will result in assertion failures. That should be fixed first. - Note that this changes the order in which we emit "notify:devices" and "device-added" signals. I think it makes the most sense to emit first "device-removed", then "notify:devices", and finally "device-added" signals. This changes behavior for commit 52ae28f6e5bf ('libnm: queue added/removed signals and suppress uninitialized notifications'), but I don't think that users should actually rely on the order. Still, the new order makes the most sense to me. - In NetworkManager, profiles can be invisible to the user by setting "connection.permissions". Such profiles would be hidden by NMClient's nm_client_get_connections() and their "connection-added"/"connection-removed" signals. Note that NMActiveConnection's nm_active_connection_get_connection() and NMDevice's nm_device_get_available_connections() still exposes such hidden NMRemoteConnection instances. This behavior was preserved. NUMBERS ------- I compared 3 versions of libnm. [1] 962297f9085d, current tip of nm-1-20 branch [2] 4fad8c7c642e, current master, immediate parent of this patch [3] this patch All tests were done on Fedora 31, x86_64, gcc 9.2.1-1.fc31. The libraries were build with $ ./contrib/fedora/rpm/build_clean.sh -g -w test -W debug Note that RPM build already stripped the library. --- N1) File size of libnm.so.0.1.0 in bytes. There currently seems to be a issue on Fedora 31 generating wrong ELF notes. Usually, libnm is smaller but in these tests it had large (and bogus) ELF notes. Anyway, the point is to show the relative sizes, so it doesn't matter). [1] 4075552 (102.7%) [2] 3969624 (100.0%) [3] 3705208 ( 93.3%) --- N2) `size /usr/lib64/libnm.so.0.1.0`: text data bss dec hex filename [1] 1314569 (102.0%) 69980 ( 94.8%) 10632 ( 80.4%) 1395181 (101.4%) 1549ed /usr/lib64/libnm.so.0.1.0 [2] 1288410 (100.0%) 73796 (100.0%) 13224 (100.0%) 1375430 (100.0%) 14fcc6 /usr/lib64/libnm.so.0.1.0 [3] 1229066 ( 95.4%) 65248 ( 88.4%) 13400 (101.3%) 1307714 ( 95.1%) 13f442 /usr/lib64/libnm.so.0.1.0 --- N3) Performance test with test-client.py. With checkout of [2], run ``` prepare_checkout() { rm -rf /tmp/nm-test && \ git checkout -B test 4fad8c7c642e && \ git clean -fdx && \ ./autogen.sh --prefix=/tmp/nm-test && \ make -j 5 install && \ make -j 5 check-local-clients-tests-test-client } prepare_test() { NM_TEST_REGENERATE=1 NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v } do_test() { for i in {1..10}; do NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v || return -1 done echo "done!" } prepare_checkout prepare_test time do_test ``` [1] real 2m14.497s (101.3%) user 5m26.651s (100.3%) sys 1m40.453s (101.4%) [2] real 2m12.800s (100.0%) user 5m25.619s (100.0%) sys 1m39.065s (100.0%) [3] real 1m54.915s ( 86.5%) user 4m18.585s ( 79.4%) sys 1m32.066s ( 92.9%) --- N4) Performance. Run NetworkManager from build [2] and setup a large number of profiles (551 profiles and 515 devices, mostly unrealized). This setup is already at the edge of what NetworkManager currently can handle. Of course, that is a different issue. Here we just check how long plain `nmcli` takes on the system. ``` do_cleanup() { for UUID in $(nmcli -g NAME,UUID connection show | sed -n 's/^xx-c-.*:\([^:]\+\)$/\1/p'); do nmcli connection delete uuid "$UUID" done for DEVICE in $(nmcli -g DEVICE device status | grep '^xx-i-'); do nmcli device delete "$DEVICE" done } do_setup() { do_cleanup for i in {1..30}; do nmcli connection add type bond autoconnect no con-name xx-c-bond-$i ifname xx-i-bond-$i ipv4.method disabled ipv6.method ignore for j in $(seq $i 30); do nmcli connection add type vlan autoconnect no con-name xx-c-vlan-$i-$j vlan.id $j ifname xx-i-vlan-$i-$j vlan.parent xx-i-bond-$i ipv4.method disabled ipv6.method ignore done done systemctl restart NetworkManager.service sleep 5 } do_test() { perf stat -r 50 -B nmcli 1>/dev/null } do_test ``` [1] Performance counter stats for 'nmcli' (50 runs): 456.33 msec task-clock:u # 1.093 CPUs utilized ( +- 0.44% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,900 page-faults:u # 0.013 M/sec ( +- 0.02% ) 1,408,675,453 cycles:u # 3.087 GHz ( +- 0.48% ) 1,594,741,060 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 368,744,018 branches:u # 808.061 M/sec ( +- 0.02% ) 4,566,058 branch-misses:u # 1.24% of all branches ( +- 0.76% ) 0.41761 +- 0.00282 seconds time elapsed ( +- 0.68% ) [2] Performance counter stats for 'nmcli' (50 runs): 477.99 msec task-clock:u # 1.088 CPUs utilized ( +- 0.36% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,948 page-faults:u # 0.012 M/sec ( +- 0.03% ) 1,471,133,482 cycles:u # 3.078 GHz ( +- 0.36% ) 1,655,275,369 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 382,595,152 branches:u # 800.433 M/sec ( +- 0.02% ) 4,746,070 branch-misses:u # 1.24% of all branches ( +- 0.49% ) 0.43923 +- 0.00242 seconds time elapsed ( +- 0.55% ) [3] Performance counter stats for 'nmcli' (50 runs): 352.36 msec task-clock:u # 1.027 CPUs utilized ( +- 0.32% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 4,790 page-faults:u # 0.014 M/sec ( +- 0.26% ) 1,092,341,186 cycles:u # 3.100 GHz ( +- 0.26% ) 1,209,045,283 instructions:u # 1.11 insn per cycle ( +- 0.02% ) 281,708,462 branches:u # 799.499 M/sec ( +- 0.01% ) 3,101,031 branch-misses:u # 1.10% of all branches ( +- 0.61% ) 0.34296 +- 0.00120 seconds time elapsed ( +- 0.35% ) --- N5) same setup as N4), but run `PAGER= /bin/time -v nmcli`: [1] Command being timed: "nmcli" User time (seconds): 0.42 System time (seconds): 0.04 Percent of CPU this job got: 107% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.43 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34456 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6128 Voluntary context switches: 1298 Involuntary context switches: 1106 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [2] Command being timed: "nmcli" User time (seconds): 0.44 System time (seconds): 0.04 Percent of CPU this job got: 108% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.44 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34452 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6169 Voluntary context switches: 1849 Involuntary context switches: 142 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [3] Command being timed: "nmcli" User time (seconds): 0.32 System time (seconds): 0.02 Percent of CPU this job got: 102% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.34 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 29196 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 5059 Voluntary context switches: 919 Involuntary context switches: 685 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 --- N6) same setup as N4), but run `nmcli monitor` and look at `ps aux` for the RSS size. USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND [1] me 1492900 21.0 0.2 461348 33248 pts/10 Sl+ 15:02 0:00 nmcli monitor [2] me 1490721 5.0 0.2 461496 33548 pts/10 Sl+ 15:00 0:00 nmcli monitor [3] me 1495801 16.5 0.1 459476 28692 pts/10 Sl+ 15:04 0:00 nmcli monitor
2019-10-30 11:42:58 +01:00
_nm_client_set_property_sync_legacy (_nm_object_get_client (device),
_nm_object_get_path (device),
NM_DBUS_INTERFACE_DEVICE,
"AutoConnect",
"b",
autoconnect);
}
/**
* nm_device_get_firmware_missing:
* @device: a #NMDevice
*
* Indicates that firmware required for the device's operation is likely
* to be missing.
*
* Returns: %TRUE if firmware required for the device's operation is likely
* to be missing.
**/
gboolean
nm_device_get_firmware_missing (NMDevice *device)
{
g_return_val_if_fail (NM_IS_DEVICE (device), 0);
return NM_DEVICE_GET_PRIVATE (device)->firmware_missing;
}
/**
* nm_device_get_nm_plugin_missing:
* @device: a #NMDevice
*
* Indicates that the NetworkManager plugin for the device is not installed.
*
* Returns: %TRUE if the device plugin not installed.
*
* Since: 1.2
**/
gboolean
nm_device_get_nm_plugin_missing (NMDevice *device)
{
g_return_val_if_fail (NM_IS_DEVICE (device), FALSE);
return NM_DEVICE_GET_PRIVATE (device)->nm_plugin_missing;
}
/**
* nm_device_get_ip4_config:
* @device: a #NMDevice
*
* Gets the current IPv4 #NMIPConfig associated with the #NMDevice.
*
* You can alternatively use nm_active_connection_get_ip4_config(), which also
* works with VPN connections.
*
* Returns: (transfer none): the IPv4 #NMIPConfig, or %NULL if the device is not
* activated.
**/
NMIPConfig *
nm_device_get_ip4_config (NMDevice *device)
{
g_return_val_if_fail (NM_IS_DEVICE (device), NULL);
libnm: refactor caching of D-Bus objects in NMClient No longer use GDBusObjectMangaerClient and gdbus-codegen generated classes for the NMClient cache. Instead, use GDBusConnection directly and a custom implementation (NMLDBusObject) for caching D-Bus' ObjectManager data. CHANGES ------- - This is a complete rework. I think the previous implementation was difficult to understand. There were unfixed bugs and nobody understood the code well enough to fix them. Maybe somebody out there understood the code, but I certainly did not. At least nobody provided patches to fix those issues. I do believe that this implementation is more straightforward and easier to understand. It removes a lot of layers of code. Whether this claim of simplicity is true, each reader must decide for himself/herself. Note that it is still fairly complex. - There was a lingering performance issue with large number of D-Bus objects. The patch tries hard that the implementation scales well. Of course, when we cache N objects that have N-to-M references to other, we still are fundamentally O(N*M) for runtime and memory consumption (with M being the number of references between objects). But each part should behave efficiently and well. - Play well with GMainContext. libnm code (NMClient) is generally not thread safe. However, it should work to use multiple instances in parallel, as long as each access to a NMClient is through the caller's GMainContext. This follows glib's style and effectively allows to use NMClient in a multi threaded scenario. This implies to stick to a main context upon construction and ensure that callbacks are only invoked when iterating that context. Also, NMClient itself shall never iterate the caller's context. This also means, libnm must never use g_idle_add() or g_timeout_add(), as those enqueue sources in the g_main_context_default() context. - Get ordering of messages right. All events are consistently enqueued in a GMainContext and processed strictly in order. For example, previously "nm-object.c" tried to combine signals and emit them on an idle handler. That is wrong, signals must be emitted in the right order and when they happen. Note that when using GInitable's synchronous initialization to initialize the NMClient instance, NMClient internally still operates fully asynchronously. In that case NMClient has an internal main context. - NMClient takes over most of the functionality. When using D-Bus' ObjectManager interface, one needs to handle basically the entire state of the D-Bus interface. That cannot be separated well into distinct parts, and even if you try, you just end up having closely related code in different source files. Spreading related code does not make it easier to understand, on the contrary. That means, NMClient is inherently complex as it contains most of the logic. I think that is not avoidable, but it's not as bad as it sounds. - NMClient processes D-Bus messages and state changes in separate steps. First NMClient unpacks the message (e.g. _dbus_handle_properties_changed()) and keeps track of the changed data. Then we update the GObject instances (_dbus_handle_obj_changed_dbus()) without emitting any signals yet. Finally, we emit all signals and notifications that were collected (_dbus_handle_changes_commit()). Note that for example during the initial GetManagedObjects() reply, NMClient receive a large amount of state at once. But we first apply all the changes to our GObject instances before emitting any signals. The result is that signals are always emitted in a moment when the cache is consistent. The unavoidable downside is that when you receive a property changed signal, possibly many other properties changed already and more signals are about to be emitted. - NMDeviceWifi no longer modifies the content of the cache from client side during poke_wireless_devices_with_rf_status(). The content of the cache should be determined by D-Bus alone and follow what NetworkManager service exposes. Local modifications should be avoided. - This aims to bring no API/ABI change, though it does of course bring various subtle changes in behavior. Those should be all for the better, but the goal is not to break any existing clients. This does change internal (albeit externally visible) API, like dropping NM_OBJECT_DBUS_OBJECT_MANAGER property and NMObject no longer implementing GInitableIface and GAsyncInitableIface. - Some uses of gdbus-codegen classes remain in NMVpnPluginOld, NMVpnServicePlugin and NMSecretAgentOld. These are independent of NMClient/NMObject and should be reworked separately. - While we no longer use generated classes from gdbus-codegen, we don't need more glue code than before. Also before we constructed NMPropertiesInfo and a had large amount of code to propagate properties from NMDBus* to NMObject. That got completely reworked, but did not fundamentally change. You still need about the same effort to create the NMLDBusMetaIface. Not using generated bindings did not make anything worse (which tells about the usefulness of generated code, at least in the way it was used). - NMLDBusMetaIface and other meta data is static and immutable. This avoids copying them around. Also, macros like NML_DBUS_META_PROPERTY_INIT_U() have compile time checks to ensure the property types matches. It's pretty hard to misuse them because it won't compile. - The meta data now explicitly encodes the expected D-Bus types and makes sure never to accept wrong data. That would only matter when the server (accidentally or intentionally) exposes unexpected types on D-Bus. I don't think that was previously ensured in all cases. For example, demarshal_generic() only cared about the GObject property type, it didn't know the expected D-Bus type. - Previously GDBusObjectManager would sometimes emit warnings (g_log()). Those probably indicated real bugs. In any case, it prevented us from running CI with G_DEBUG=fatal-warnings, because there would be just too many unrelated crashes. Now we log debug messages that can be enabled with "LIBNM_CLIENT_DEBUG=trace". Some of these messages can also be turned into g_warning()/g_critical() by setting LIBNM_CLIENT_DEBUG=warning,error. Together with G_DEBUG=fatal-warnings, this turns them into assertions. Note that such "assertion failures" might also happen because of a server bug (or change). Thus these are not common assertions that indicate a bug in libnm and are thus not armed unless explicitly requested. In our CI we should now always run with LIBNM_CLIENT_DEBUG=warning,error and G_DEBUG=fatal-warnings and to catch bugs. Note that currently NetworkManager has bugs in this regard, so enabling this will result in assertion failures. That should be fixed first. - Note that this changes the order in which we emit "notify:devices" and "device-added" signals. I think it makes the most sense to emit first "device-removed", then "notify:devices", and finally "device-added" signals. This changes behavior for commit 52ae28f6e5bf ('libnm: queue added/removed signals and suppress uninitialized notifications'), but I don't think that users should actually rely on the order. Still, the new order makes the most sense to me. - In NetworkManager, profiles can be invisible to the user by setting "connection.permissions". Such profiles would be hidden by NMClient's nm_client_get_connections() and their "connection-added"/"connection-removed" signals. Note that NMActiveConnection's nm_active_connection_get_connection() and NMDevice's nm_device_get_available_connections() still exposes such hidden NMRemoteConnection instances. This behavior was preserved. NUMBERS ------- I compared 3 versions of libnm. [1] 962297f9085d, current tip of nm-1-20 branch [2] 4fad8c7c642e, current master, immediate parent of this patch [3] this patch All tests were done on Fedora 31, x86_64, gcc 9.2.1-1.fc31. The libraries were build with $ ./contrib/fedora/rpm/build_clean.sh -g -w test -W debug Note that RPM build already stripped the library. --- N1) File size of libnm.so.0.1.0 in bytes. There currently seems to be a issue on Fedora 31 generating wrong ELF notes. Usually, libnm is smaller but in these tests it had large (and bogus) ELF notes. Anyway, the point is to show the relative sizes, so it doesn't matter). [1] 4075552 (102.7%) [2] 3969624 (100.0%) [3] 3705208 ( 93.3%) --- N2) `size /usr/lib64/libnm.so.0.1.0`: text data bss dec hex filename [1] 1314569 (102.0%) 69980 ( 94.8%) 10632 ( 80.4%) 1395181 (101.4%) 1549ed /usr/lib64/libnm.so.0.1.0 [2] 1288410 (100.0%) 73796 (100.0%) 13224 (100.0%) 1375430 (100.0%) 14fcc6 /usr/lib64/libnm.so.0.1.0 [3] 1229066 ( 95.4%) 65248 ( 88.4%) 13400 (101.3%) 1307714 ( 95.1%) 13f442 /usr/lib64/libnm.so.0.1.0 --- N3) Performance test with test-client.py. With checkout of [2], run ``` prepare_checkout() { rm -rf /tmp/nm-test && \ git checkout -B test 4fad8c7c642e && \ git clean -fdx && \ ./autogen.sh --prefix=/tmp/nm-test && \ make -j 5 install && \ make -j 5 check-local-clients-tests-test-client } prepare_test() { NM_TEST_REGENERATE=1 NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v } do_test() { for i in {1..10}; do NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v || return -1 done echo "done!" } prepare_checkout prepare_test time do_test ``` [1] real 2m14.497s (101.3%) user 5m26.651s (100.3%) sys 1m40.453s (101.4%) [2] real 2m12.800s (100.0%) user 5m25.619s (100.0%) sys 1m39.065s (100.0%) [3] real 1m54.915s ( 86.5%) user 4m18.585s ( 79.4%) sys 1m32.066s ( 92.9%) --- N4) Performance. Run NetworkManager from build [2] and setup a large number of profiles (551 profiles and 515 devices, mostly unrealized). This setup is already at the edge of what NetworkManager currently can handle. Of course, that is a different issue. Here we just check how long plain `nmcli` takes on the system. ``` do_cleanup() { for UUID in $(nmcli -g NAME,UUID connection show | sed -n 's/^xx-c-.*:\([^:]\+\)$/\1/p'); do nmcli connection delete uuid "$UUID" done for DEVICE in $(nmcli -g DEVICE device status | grep '^xx-i-'); do nmcli device delete "$DEVICE" done } do_setup() { do_cleanup for i in {1..30}; do nmcli connection add type bond autoconnect no con-name xx-c-bond-$i ifname xx-i-bond-$i ipv4.method disabled ipv6.method ignore for j in $(seq $i 30); do nmcli connection add type vlan autoconnect no con-name xx-c-vlan-$i-$j vlan.id $j ifname xx-i-vlan-$i-$j vlan.parent xx-i-bond-$i ipv4.method disabled ipv6.method ignore done done systemctl restart NetworkManager.service sleep 5 } do_test() { perf stat -r 50 -B nmcli 1>/dev/null } do_test ``` [1] Performance counter stats for 'nmcli' (50 runs): 456.33 msec task-clock:u # 1.093 CPUs utilized ( +- 0.44% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,900 page-faults:u # 0.013 M/sec ( +- 0.02% ) 1,408,675,453 cycles:u # 3.087 GHz ( +- 0.48% ) 1,594,741,060 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 368,744,018 branches:u # 808.061 M/sec ( +- 0.02% ) 4,566,058 branch-misses:u # 1.24% of all branches ( +- 0.76% ) 0.41761 +- 0.00282 seconds time elapsed ( +- 0.68% ) [2] Performance counter stats for 'nmcli' (50 runs): 477.99 msec task-clock:u # 1.088 CPUs utilized ( +- 0.36% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,948 page-faults:u # 0.012 M/sec ( +- 0.03% ) 1,471,133,482 cycles:u # 3.078 GHz ( +- 0.36% ) 1,655,275,369 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 382,595,152 branches:u # 800.433 M/sec ( +- 0.02% ) 4,746,070 branch-misses:u # 1.24% of all branches ( +- 0.49% ) 0.43923 +- 0.00242 seconds time elapsed ( +- 0.55% ) [3] Performance counter stats for 'nmcli' (50 runs): 352.36 msec task-clock:u # 1.027 CPUs utilized ( +- 0.32% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 4,790 page-faults:u # 0.014 M/sec ( +- 0.26% ) 1,092,341,186 cycles:u # 3.100 GHz ( +- 0.26% ) 1,209,045,283 instructions:u # 1.11 insn per cycle ( +- 0.02% ) 281,708,462 branches:u # 799.499 M/sec ( +- 0.01% ) 3,101,031 branch-misses:u # 1.10% of all branches ( +- 0.61% ) 0.34296 +- 0.00120 seconds time elapsed ( +- 0.35% ) --- N5) same setup as N4), but run `PAGER= /bin/time -v nmcli`: [1] Command being timed: "nmcli" User time (seconds): 0.42 System time (seconds): 0.04 Percent of CPU this job got: 107% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.43 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34456 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6128 Voluntary context switches: 1298 Involuntary context switches: 1106 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [2] Command being timed: "nmcli" User time (seconds): 0.44 System time (seconds): 0.04 Percent of CPU this job got: 108% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.44 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34452 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6169 Voluntary context switches: 1849 Involuntary context switches: 142 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [3] Command being timed: "nmcli" User time (seconds): 0.32 System time (seconds): 0.02 Percent of CPU this job got: 102% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.34 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 29196 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 5059 Voluntary context switches: 919 Involuntary context switches: 685 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 --- N6) same setup as N4), but run `nmcli monitor` and look at `ps aux` for the RSS size. USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND [1] me 1492900 21.0 0.2 461348 33248 pts/10 Sl+ 15:02 0:00 nmcli monitor [2] me 1490721 5.0 0.2 461496 33548 pts/10 Sl+ 15:00 0:00 nmcli monitor [3] me 1495801 16.5 0.1 459476 28692 pts/10 Sl+ 15:04 0:00 nmcli monitor
2019-10-30 11:42:58 +01:00
return nml_dbus_property_o_get_obj (&NM_DEVICE_GET_PRIVATE (device)->property_o[PROPERTY_O_IDX_IP4_CONFIG]);
}
/**
* nm_device_get_dhcp4_config:
* @device: a #NMDevice
*
* Gets the current IPv4 #NMDhcpConfig associated with the #NMDevice.
*
* You can alternatively use nm_active_connection_get_dhcp4_config(), which also
* works with VPN connections.
*
* Returns: (transfer none): the IPv4 #NMDhcpConfig, or %NULL if the device is
* not activated or not using DHCP.
**/
NMDhcpConfig *
nm_device_get_dhcp4_config (NMDevice *device)
{
g_return_val_if_fail (NM_IS_DEVICE (device), NULL);
libnm: refactor caching of D-Bus objects in NMClient No longer use GDBusObjectMangaerClient and gdbus-codegen generated classes for the NMClient cache. Instead, use GDBusConnection directly and a custom implementation (NMLDBusObject) for caching D-Bus' ObjectManager data. CHANGES ------- - This is a complete rework. I think the previous implementation was difficult to understand. There were unfixed bugs and nobody understood the code well enough to fix them. Maybe somebody out there understood the code, but I certainly did not. At least nobody provided patches to fix those issues. I do believe that this implementation is more straightforward and easier to understand. It removes a lot of layers of code. Whether this claim of simplicity is true, each reader must decide for himself/herself. Note that it is still fairly complex. - There was a lingering performance issue with large number of D-Bus objects. The patch tries hard that the implementation scales well. Of course, when we cache N objects that have N-to-M references to other, we still are fundamentally O(N*M) for runtime and memory consumption (with M being the number of references between objects). But each part should behave efficiently and well. - Play well with GMainContext. libnm code (NMClient) is generally not thread safe. However, it should work to use multiple instances in parallel, as long as each access to a NMClient is through the caller's GMainContext. This follows glib's style and effectively allows to use NMClient in a multi threaded scenario. This implies to stick to a main context upon construction and ensure that callbacks are only invoked when iterating that context. Also, NMClient itself shall never iterate the caller's context. This also means, libnm must never use g_idle_add() or g_timeout_add(), as those enqueue sources in the g_main_context_default() context. - Get ordering of messages right. All events are consistently enqueued in a GMainContext and processed strictly in order. For example, previously "nm-object.c" tried to combine signals and emit them on an idle handler. That is wrong, signals must be emitted in the right order and when they happen. Note that when using GInitable's synchronous initialization to initialize the NMClient instance, NMClient internally still operates fully asynchronously. In that case NMClient has an internal main context. - NMClient takes over most of the functionality. When using D-Bus' ObjectManager interface, one needs to handle basically the entire state of the D-Bus interface. That cannot be separated well into distinct parts, and even if you try, you just end up having closely related code in different source files. Spreading related code does not make it easier to understand, on the contrary. That means, NMClient is inherently complex as it contains most of the logic. I think that is not avoidable, but it's not as bad as it sounds. - NMClient processes D-Bus messages and state changes in separate steps. First NMClient unpacks the message (e.g. _dbus_handle_properties_changed()) and keeps track of the changed data. Then we update the GObject instances (_dbus_handle_obj_changed_dbus()) without emitting any signals yet. Finally, we emit all signals and notifications that were collected (_dbus_handle_changes_commit()). Note that for example during the initial GetManagedObjects() reply, NMClient receive a large amount of state at once. But we first apply all the changes to our GObject instances before emitting any signals. The result is that signals are always emitted in a moment when the cache is consistent. The unavoidable downside is that when you receive a property changed signal, possibly many other properties changed already and more signals are about to be emitted. - NMDeviceWifi no longer modifies the content of the cache from client side during poke_wireless_devices_with_rf_status(). The content of the cache should be determined by D-Bus alone and follow what NetworkManager service exposes. Local modifications should be avoided. - This aims to bring no API/ABI change, though it does of course bring various subtle changes in behavior. Those should be all for the better, but the goal is not to break any existing clients. This does change internal (albeit externally visible) API, like dropping NM_OBJECT_DBUS_OBJECT_MANAGER property and NMObject no longer implementing GInitableIface and GAsyncInitableIface. - Some uses of gdbus-codegen classes remain in NMVpnPluginOld, NMVpnServicePlugin and NMSecretAgentOld. These are independent of NMClient/NMObject and should be reworked separately. - While we no longer use generated classes from gdbus-codegen, we don't need more glue code than before. Also before we constructed NMPropertiesInfo and a had large amount of code to propagate properties from NMDBus* to NMObject. That got completely reworked, but did not fundamentally change. You still need about the same effort to create the NMLDBusMetaIface. Not using generated bindings did not make anything worse (which tells about the usefulness of generated code, at least in the way it was used). - NMLDBusMetaIface and other meta data is static and immutable. This avoids copying them around. Also, macros like NML_DBUS_META_PROPERTY_INIT_U() have compile time checks to ensure the property types matches. It's pretty hard to misuse them because it won't compile. - The meta data now explicitly encodes the expected D-Bus types and makes sure never to accept wrong data. That would only matter when the server (accidentally or intentionally) exposes unexpected types on D-Bus. I don't think that was previously ensured in all cases. For example, demarshal_generic() only cared about the GObject property type, it didn't know the expected D-Bus type. - Previously GDBusObjectManager would sometimes emit warnings (g_log()). Those probably indicated real bugs. In any case, it prevented us from running CI with G_DEBUG=fatal-warnings, because there would be just too many unrelated crashes. Now we log debug messages that can be enabled with "LIBNM_CLIENT_DEBUG=trace". Some of these messages can also be turned into g_warning()/g_critical() by setting LIBNM_CLIENT_DEBUG=warning,error. Together with G_DEBUG=fatal-warnings, this turns them into assertions. Note that such "assertion failures" might also happen because of a server bug (or change). Thus these are not common assertions that indicate a bug in libnm and are thus not armed unless explicitly requested. In our CI we should now always run with LIBNM_CLIENT_DEBUG=warning,error and G_DEBUG=fatal-warnings and to catch bugs. Note that currently NetworkManager has bugs in this regard, so enabling this will result in assertion failures. That should be fixed first. - Note that this changes the order in which we emit "notify:devices" and "device-added" signals. I think it makes the most sense to emit first "device-removed", then "notify:devices", and finally "device-added" signals. This changes behavior for commit 52ae28f6e5bf ('libnm: queue added/removed signals and suppress uninitialized notifications'), but I don't think that users should actually rely on the order. Still, the new order makes the most sense to me. - In NetworkManager, profiles can be invisible to the user by setting "connection.permissions". Such profiles would be hidden by NMClient's nm_client_get_connections() and their "connection-added"/"connection-removed" signals. Note that NMActiveConnection's nm_active_connection_get_connection() and NMDevice's nm_device_get_available_connections() still exposes such hidden NMRemoteConnection instances. This behavior was preserved. NUMBERS ------- I compared 3 versions of libnm. [1] 962297f9085d, current tip of nm-1-20 branch [2] 4fad8c7c642e, current master, immediate parent of this patch [3] this patch All tests were done on Fedora 31, x86_64, gcc 9.2.1-1.fc31. The libraries were build with $ ./contrib/fedora/rpm/build_clean.sh -g -w test -W debug Note that RPM build already stripped the library. --- N1) File size of libnm.so.0.1.0 in bytes. There currently seems to be a issue on Fedora 31 generating wrong ELF notes. Usually, libnm is smaller but in these tests it had large (and bogus) ELF notes. Anyway, the point is to show the relative sizes, so it doesn't matter). [1] 4075552 (102.7%) [2] 3969624 (100.0%) [3] 3705208 ( 93.3%) --- N2) `size /usr/lib64/libnm.so.0.1.0`: text data bss dec hex filename [1] 1314569 (102.0%) 69980 ( 94.8%) 10632 ( 80.4%) 1395181 (101.4%) 1549ed /usr/lib64/libnm.so.0.1.0 [2] 1288410 (100.0%) 73796 (100.0%) 13224 (100.0%) 1375430 (100.0%) 14fcc6 /usr/lib64/libnm.so.0.1.0 [3] 1229066 ( 95.4%) 65248 ( 88.4%) 13400 (101.3%) 1307714 ( 95.1%) 13f442 /usr/lib64/libnm.so.0.1.0 --- N3) Performance test with test-client.py. With checkout of [2], run ``` prepare_checkout() { rm -rf /tmp/nm-test && \ git checkout -B test 4fad8c7c642e && \ git clean -fdx && \ ./autogen.sh --prefix=/tmp/nm-test && \ make -j 5 install && \ make -j 5 check-local-clients-tests-test-client } prepare_test() { NM_TEST_REGENERATE=1 NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v } do_test() { for i in {1..10}; do NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v || return -1 done echo "done!" } prepare_checkout prepare_test time do_test ``` [1] real 2m14.497s (101.3%) user 5m26.651s (100.3%) sys 1m40.453s (101.4%) [2] real 2m12.800s (100.0%) user 5m25.619s (100.0%) sys 1m39.065s (100.0%) [3] real 1m54.915s ( 86.5%) user 4m18.585s ( 79.4%) sys 1m32.066s ( 92.9%) --- N4) Performance. Run NetworkManager from build [2] and setup a large number of profiles (551 profiles and 515 devices, mostly unrealized). This setup is already at the edge of what NetworkManager currently can handle. Of course, that is a different issue. Here we just check how long plain `nmcli` takes on the system. ``` do_cleanup() { for UUID in $(nmcli -g NAME,UUID connection show | sed -n 's/^xx-c-.*:\([^:]\+\)$/\1/p'); do nmcli connection delete uuid "$UUID" done for DEVICE in $(nmcli -g DEVICE device status | grep '^xx-i-'); do nmcli device delete "$DEVICE" done } do_setup() { do_cleanup for i in {1..30}; do nmcli connection add type bond autoconnect no con-name xx-c-bond-$i ifname xx-i-bond-$i ipv4.method disabled ipv6.method ignore for j in $(seq $i 30); do nmcli connection add type vlan autoconnect no con-name xx-c-vlan-$i-$j vlan.id $j ifname xx-i-vlan-$i-$j vlan.parent xx-i-bond-$i ipv4.method disabled ipv6.method ignore done done systemctl restart NetworkManager.service sleep 5 } do_test() { perf stat -r 50 -B nmcli 1>/dev/null } do_test ``` [1] Performance counter stats for 'nmcli' (50 runs): 456.33 msec task-clock:u # 1.093 CPUs utilized ( +- 0.44% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,900 page-faults:u # 0.013 M/sec ( +- 0.02% ) 1,408,675,453 cycles:u # 3.087 GHz ( +- 0.48% ) 1,594,741,060 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 368,744,018 branches:u # 808.061 M/sec ( +- 0.02% ) 4,566,058 branch-misses:u # 1.24% of all branches ( +- 0.76% ) 0.41761 +- 0.00282 seconds time elapsed ( +- 0.68% ) [2] Performance counter stats for 'nmcli' (50 runs): 477.99 msec task-clock:u # 1.088 CPUs utilized ( +- 0.36% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,948 page-faults:u # 0.012 M/sec ( +- 0.03% ) 1,471,133,482 cycles:u # 3.078 GHz ( +- 0.36% ) 1,655,275,369 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 382,595,152 branches:u # 800.433 M/sec ( +- 0.02% ) 4,746,070 branch-misses:u # 1.24% of all branches ( +- 0.49% ) 0.43923 +- 0.00242 seconds time elapsed ( +- 0.55% ) [3] Performance counter stats for 'nmcli' (50 runs): 352.36 msec task-clock:u # 1.027 CPUs utilized ( +- 0.32% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 4,790 page-faults:u # 0.014 M/sec ( +- 0.26% ) 1,092,341,186 cycles:u # 3.100 GHz ( +- 0.26% ) 1,209,045,283 instructions:u # 1.11 insn per cycle ( +- 0.02% ) 281,708,462 branches:u # 799.499 M/sec ( +- 0.01% ) 3,101,031 branch-misses:u # 1.10% of all branches ( +- 0.61% ) 0.34296 +- 0.00120 seconds time elapsed ( +- 0.35% ) --- N5) same setup as N4), but run `PAGER= /bin/time -v nmcli`: [1] Command being timed: "nmcli" User time (seconds): 0.42 System time (seconds): 0.04 Percent of CPU this job got: 107% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.43 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34456 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6128 Voluntary context switches: 1298 Involuntary context switches: 1106 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [2] Command being timed: "nmcli" User time (seconds): 0.44 System time (seconds): 0.04 Percent of CPU this job got: 108% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.44 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34452 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6169 Voluntary context switches: 1849 Involuntary context switches: 142 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [3] Command being timed: "nmcli" User time (seconds): 0.32 System time (seconds): 0.02 Percent of CPU this job got: 102% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.34 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 29196 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 5059 Voluntary context switches: 919 Involuntary context switches: 685 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 --- N6) same setup as N4), but run `nmcli monitor` and look at `ps aux` for the RSS size. USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND [1] me 1492900 21.0 0.2 461348 33248 pts/10 Sl+ 15:02 0:00 nmcli monitor [2] me 1490721 5.0 0.2 461496 33548 pts/10 Sl+ 15:00 0:00 nmcli monitor [3] me 1495801 16.5 0.1 459476 28692 pts/10 Sl+ 15:04 0:00 nmcli monitor
2019-10-30 11:42:58 +01:00
return nml_dbus_property_o_get_obj (&NM_DEVICE_GET_PRIVATE (device)->property_o[PROPERTY_O_IDX_DHCP4_CONFIG]);
}
/**
* nm_device_get_ip6_config:
* @device: a #NMDevice
*
* Gets the current IPv6 #NMIPConfig associated with the #NMDevice.
*
* You can alternatively use nm_active_connection_get_ip6_config(), which also
* works with VPN connections.
*
* Returns: (transfer none): the IPv6 #NMIPConfig or %NULL if the device is not activated.
**/
NMIPConfig *
nm_device_get_ip6_config (NMDevice *device)
{
g_return_val_if_fail (NM_IS_DEVICE (device), NULL);
libnm: refactor caching of D-Bus objects in NMClient No longer use GDBusObjectMangaerClient and gdbus-codegen generated classes for the NMClient cache. Instead, use GDBusConnection directly and a custom implementation (NMLDBusObject) for caching D-Bus' ObjectManager data. CHANGES ------- - This is a complete rework. I think the previous implementation was difficult to understand. There were unfixed bugs and nobody understood the code well enough to fix them. Maybe somebody out there understood the code, but I certainly did not. At least nobody provided patches to fix those issues. I do believe that this implementation is more straightforward and easier to understand. It removes a lot of layers of code. Whether this claim of simplicity is true, each reader must decide for himself/herself. Note that it is still fairly complex. - There was a lingering performance issue with large number of D-Bus objects. The patch tries hard that the implementation scales well. Of course, when we cache N objects that have N-to-M references to other, we still are fundamentally O(N*M) for runtime and memory consumption (with M being the number of references between objects). But each part should behave efficiently and well. - Play well with GMainContext. libnm code (NMClient) is generally not thread safe. However, it should work to use multiple instances in parallel, as long as each access to a NMClient is through the caller's GMainContext. This follows glib's style and effectively allows to use NMClient in a multi threaded scenario. This implies to stick to a main context upon construction and ensure that callbacks are only invoked when iterating that context. Also, NMClient itself shall never iterate the caller's context. This also means, libnm must never use g_idle_add() or g_timeout_add(), as those enqueue sources in the g_main_context_default() context. - Get ordering of messages right. All events are consistently enqueued in a GMainContext and processed strictly in order. For example, previously "nm-object.c" tried to combine signals and emit them on an idle handler. That is wrong, signals must be emitted in the right order and when they happen. Note that when using GInitable's synchronous initialization to initialize the NMClient instance, NMClient internally still operates fully asynchronously. In that case NMClient has an internal main context. - NMClient takes over most of the functionality. When using D-Bus' ObjectManager interface, one needs to handle basically the entire state of the D-Bus interface. That cannot be separated well into distinct parts, and even if you try, you just end up having closely related code in different source files. Spreading related code does not make it easier to understand, on the contrary. That means, NMClient is inherently complex as it contains most of the logic. I think that is not avoidable, but it's not as bad as it sounds. - NMClient processes D-Bus messages and state changes in separate steps. First NMClient unpacks the message (e.g. _dbus_handle_properties_changed()) and keeps track of the changed data. Then we update the GObject instances (_dbus_handle_obj_changed_dbus()) without emitting any signals yet. Finally, we emit all signals and notifications that were collected (_dbus_handle_changes_commit()). Note that for example during the initial GetManagedObjects() reply, NMClient receive a large amount of state at once. But we first apply all the changes to our GObject instances before emitting any signals. The result is that signals are always emitted in a moment when the cache is consistent. The unavoidable downside is that when you receive a property changed signal, possibly many other properties changed already and more signals are about to be emitted. - NMDeviceWifi no longer modifies the content of the cache from client side during poke_wireless_devices_with_rf_status(). The content of the cache should be determined by D-Bus alone and follow what NetworkManager service exposes. Local modifications should be avoided. - This aims to bring no API/ABI change, though it does of course bring various subtle changes in behavior. Those should be all for the better, but the goal is not to break any existing clients. This does change internal (albeit externally visible) API, like dropping NM_OBJECT_DBUS_OBJECT_MANAGER property and NMObject no longer implementing GInitableIface and GAsyncInitableIface. - Some uses of gdbus-codegen classes remain in NMVpnPluginOld, NMVpnServicePlugin and NMSecretAgentOld. These are independent of NMClient/NMObject and should be reworked separately. - While we no longer use generated classes from gdbus-codegen, we don't need more glue code than before. Also before we constructed NMPropertiesInfo and a had large amount of code to propagate properties from NMDBus* to NMObject. That got completely reworked, but did not fundamentally change. You still need about the same effort to create the NMLDBusMetaIface. Not using generated bindings did not make anything worse (which tells about the usefulness of generated code, at least in the way it was used). - NMLDBusMetaIface and other meta data is static and immutable. This avoids copying them around. Also, macros like NML_DBUS_META_PROPERTY_INIT_U() have compile time checks to ensure the property types matches. It's pretty hard to misuse them because it won't compile. - The meta data now explicitly encodes the expected D-Bus types and makes sure never to accept wrong data. That would only matter when the server (accidentally or intentionally) exposes unexpected types on D-Bus. I don't think that was previously ensured in all cases. For example, demarshal_generic() only cared about the GObject property type, it didn't know the expected D-Bus type. - Previously GDBusObjectManager would sometimes emit warnings (g_log()). Those probably indicated real bugs. In any case, it prevented us from running CI with G_DEBUG=fatal-warnings, because there would be just too many unrelated crashes. Now we log debug messages that can be enabled with "LIBNM_CLIENT_DEBUG=trace". Some of these messages can also be turned into g_warning()/g_critical() by setting LIBNM_CLIENT_DEBUG=warning,error. Together with G_DEBUG=fatal-warnings, this turns them into assertions. Note that such "assertion failures" might also happen because of a server bug (or change). Thus these are not common assertions that indicate a bug in libnm and are thus not armed unless explicitly requested. In our CI we should now always run with LIBNM_CLIENT_DEBUG=warning,error and G_DEBUG=fatal-warnings and to catch bugs. Note that currently NetworkManager has bugs in this regard, so enabling this will result in assertion failures. That should be fixed first. - Note that this changes the order in which we emit "notify:devices" and "device-added" signals. I think it makes the most sense to emit first "device-removed", then "notify:devices", and finally "device-added" signals. This changes behavior for commit 52ae28f6e5bf ('libnm: queue added/removed signals and suppress uninitialized notifications'), but I don't think that users should actually rely on the order. Still, the new order makes the most sense to me. - In NetworkManager, profiles can be invisible to the user by setting "connection.permissions". Such profiles would be hidden by NMClient's nm_client_get_connections() and their "connection-added"/"connection-removed" signals. Note that NMActiveConnection's nm_active_connection_get_connection() and NMDevice's nm_device_get_available_connections() still exposes such hidden NMRemoteConnection instances. This behavior was preserved. NUMBERS ------- I compared 3 versions of libnm. [1] 962297f9085d, current tip of nm-1-20 branch [2] 4fad8c7c642e, current master, immediate parent of this patch [3] this patch All tests were done on Fedora 31, x86_64, gcc 9.2.1-1.fc31. The libraries were build with $ ./contrib/fedora/rpm/build_clean.sh -g -w test -W debug Note that RPM build already stripped the library. --- N1) File size of libnm.so.0.1.0 in bytes. There currently seems to be a issue on Fedora 31 generating wrong ELF notes. Usually, libnm is smaller but in these tests it had large (and bogus) ELF notes. Anyway, the point is to show the relative sizes, so it doesn't matter). [1] 4075552 (102.7%) [2] 3969624 (100.0%) [3] 3705208 ( 93.3%) --- N2) `size /usr/lib64/libnm.so.0.1.0`: text data bss dec hex filename [1] 1314569 (102.0%) 69980 ( 94.8%) 10632 ( 80.4%) 1395181 (101.4%) 1549ed /usr/lib64/libnm.so.0.1.0 [2] 1288410 (100.0%) 73796 (100.0%) 13224 (100.0%) 1375430 (100.0%) 14fcc6 /usr/lib64/libnm.so.0.1.0 [3] 1229066 ( 95.4%) 65248 ( 88.4%) 13400 (101.3%) 1307714 ( 95.1%) 13f442 /usr/lib64/libnm.so.0.1.0 --- N3) Performance test with test-client.py. With checkout of [2], run ``` prepare_checkout() { rm -rf /tmp/nm-test && \ git checkout -B test 4fad8c7c642e && \ git clean -fdx && \ ./autogen.sh --prefix=/tmp/nm-test && \ make -j 5 install && \ make -j 5 check-local-clients-tests-test-client } prepare_test() { NM_TEST_REGENERATE=1 NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v } do_test() { for i in {1..10}; do NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v || return -1 done echo "done!" } prepare_checkout prepare_test time do_test ``` [1] real 2m14.497s (101.3%) user 5m26.651s (100.3%) sys 1m40.453s (101.4%) [2] real 2m12.800s (100.0%) user 5m25.619s (100.0%) sys 1m39.065s (100.0%) [3] real 1m54.915s ( 86.5%) user 4m18.585s ( 79.4%) sys 1m32.066s ( 92.9%) --- N4) Performance. Run NetworkManager from build [2] and setup a large number of profiles (551 profiles and 515 devices, mostly unrealized). This setup is already at the edge of what NetworkManager currently can handle. Of course, that is a different issue. Here we just check how long plain `nmcli` takes on the system. ``` do_cleanup() { for UUID in $(nmcli -g NAME,UUID connection show | sed -n 's/^xx-c-.*:\([^:]\+\)$/\1/p'); do nmcli connection delete uuid "$UUID" done for DEVICE in $(nmcli -g DEVICE device status | grep '^xx-i-'); do nmcli device delete "$DEVICE" done } do_setup() { do_cleanup for i in {1..30}; do nmcli connection add type bond autoconnect no con-name xx-c-bond-$i ifname xx-i-bond-$i ipv4.method disabled ipv6.method ignore for j in $(seq $i 30); do nmcli connection add type vlan autoconnect no con-name xx-c-vlan-$i-$j vlan.id $j ifname xx-i-vlan-$i-$j vlan.parent xx-i-bond-$i ipv4.method disabled ipv6.method ignore done done systemctl restart NetworkManager.service sleep 5 } do_test() { perf stat -r 50 -B nmcli 1>/dev/null } do_test ``` [1] Performance counter stats for 'nmcli' (50 runs): 456.33 msec task-clock:u # 1.093 CPUs utilized ( +- 0.44% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,900 page-faults:u # 0.013 M/sec ( +- 0.02% ) 1,408,675,453 cycles:u # 3.087 GHz ( +- 0.48% ) 1,594,741,060 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 368,744,018 branches:u # 808.061 M/sec ( +- 0.02% ) 4,566,058 branch-misses:u # 1.24% of all branches ( +- 0.76% ) 0.41761 +- 0.00282 seconds time elapsed ( +- 0.68% ) [2] Performance counter stats for 'nmcli' (50 runs): 477.99 msec task-clock:u # 1.088 CPUs utilized ( +- 0.36% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,948 page-faults:u # 0.012 M/sec ( +- 0.03% ) 1,471,133,482 cycles:u # 3.078 GHz ( +- 0.36% ) 1,655,275,369 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 382,595,152 branches:u # 800.433 M/sec ( +- 0.02% ) 4,746,070 branch-misses:u # 1.24% of all branches ( +- 0.49% ) 0.43923 +- 0.00242 seconds time elapsed ( +- 0.55% ) [3] Performance counter stats for 'nmcli' (50 runs): 352.36 msec task-clock:u # 1.027 CPUs utilized ( +- 0.32% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 4,790 page-faults:u # 0.014 M/sec ( +- 0.26% ) 1,092,341,186 cycles:u # 3.100 GHz ( +- 0.26% ) 1,209,045,283 instructions:u # 1.11 insn per cycle ( +- 0.02% ) 281,708,462 branches:u # 799.499 M/sec ( +- 0.01% ) 3,101,031 branch-misses:u # 1.10% of all branches ( +- 0.61% ) 0.34296 +- 0.00120 seconds time elapsed ( +- 0.35% ) --- N5) same setup as N4), but run `PAGER= /bin/time -v nmcli`: [1] Command being timed: "nmcli" User time (seconds): 0.42 System time (seconds): 0.04 Percent of CPU this job got: 107% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.43 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34456 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6128 Voluntary context switches: 1298 Involuntary context switches: 1106 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [2] Command being timed: "nmcli" User time (seconds): 0.44 System time (seconds): 0.04 Percent of CPU this job got: 108% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.44 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34452 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6169 Voluntary context switches: 1849 Involuntary context switches: 142 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [3] Command being timed: "nmcli" User time (seconds): 0.32 System time (seconds): 0.02 Percent of CPU this job got: 102% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.34 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 29196 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 5059 Voluntary context switches: 919 Involuntary context switches: 685 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 --- N6) same setup as N4), but run `nmcli monitor` and look at `ps aux` for the RSS size. USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND [1] me 1492900 21.0 0.2 461348 33248 pts/10 Sl+ 15:02 0:00 nmcli monitor [2] me 1490721 5.0 0.2 461496 33548 pts/10 Sl+ 15:00 0:00 nmcli monitor [3] me 1495801 16.5 0.1 459476 28692 pts/10 Sl+ 15:04 0:00 nmcli monitor
2019-10-30 11:42:58 +01:00
return nml_dbus_property_o_get_obj (&NM_DEVICE_GET_PRIVATE (device)->property_o[PROPERTY_O_IDX_IP6_CONFIG]);
}
/**
* nm_device_get_dhcp6_config:
* @device: a #NMDevice
*
* Gets the current IPv6 #NMDhcpConfig associated with the #NMDevice.
*
* You can alternatively use nm_active_connection_get_dhcp6_config(), which also
* works with VPN connections.
*
* Returns: (transfer none): the IPv6 #NMDhcpConfig, or %NULL if the device is
* not activated or not using DHCPv6.
**/
NMDhcpConfig *
nm_device_get_dhcp6_config (NMDevice *device)
{
g_return_val_if_fail (NM_IS_DEVICE (device), NULL);
libnm: refactor caching of D-Bus objects in NMClient No longer use GDBusObjectMangaerClient and gdbus-codegen generated classes for the NMClient cache. Instead, use GDBusConnection directly and a custom implementation (NMLDBusObject) for caching D-Bus' ObjectManager data. CHANGES ------- - This is a complete rework. I think the previous implementation was difficult to understand. There were unfixed bugs and nobody understood the code well enough to fix them. Maybe somebody out there understood the code, but I certainly did not. At least nobody provided patches to fix those issues. I do believe that this implementation is more straightforward and easier to understand. It removes a lot of layers of code. Whether this claim of simplicity is true, each reader must decide for himself/herself. Note that it is still fairly complex. - There was a lingering performance issue with large number of D-Bus objects. The patch tries hard that the implementation scales well. Of course, when we cache N objects that have N-to-M references to other, we still are fundamentally O(N*M) for runtime and memory consumption (with M being the number of references between objects). But each part should behave efficiently and well. - Play well with GMainContext. libnm code (NMClient) is generally not thread safe. However, it should work to use multiple instances in parallel, as long as each access to a NMClient is through the caller's GMainContext. This follows glib's style and effectively allows to use NMClient in a multi threaded scenario. This implies to stick to a main context upon construction and ensure that callbacks are only invoked when iterating that context. Also, NMClient itself shall never iterate the caller's context. This also means, libnm must never use g_idle_add() or g_timeout_add(), as those enqueue sources in the g_main_context_default() context. - Get ordering of messages right. All events are consistently enqueued in a GMainContext and processed strictly in order. For example, previously "nm-object.c" tried to combine signals and emit them on an idle handler. That is wrong, signals must be emitted in the right order and when they happen. Note that when using GInitable's synchronous initialization to initialize the NMClient instance, NMClient internally still operates fully asynchronously. In that case NMClient has an internal main context. - NMClient takes over most of the functionality. When using D-Bus' ObjectManager interface, one needs to handle basically the entire state of the D-Bus interface. That cannot be separated well into distinct parts, and even if you try, you just end up having closely related code in different source files. Spreading related code does not make it easier to understand, on the contrary. That means, NMClient is inherently complex as it contains most of the logic. I think that is not avoidable, but it's not as bad as it sounds. - NMClient processes D-Bus messages and state changes in separate steps. First NMClient unpacks the message (e.g. _dbus_handle_properties_changed()) and keeps track of the changed data. Then we update the GObject instances (_dbus_handle_obj_changed_dbus()) without emitting any signals yet. Finally, we emit all signals and notifications that were collected (_dbus_handle_changes_commit()). Note that for example during the initial GetManagedObjects() reply, NMClient receive a large amount of state at once. But we first apply all the changes to our GObject instances before emitting any signals. The result is that signals are always emitted in a moment when the cache is consistent. The unavoidable downside is that when you receive a property changed signal, possibly many other properties changed already and more signals are about to be emitted. - NMDeviceWifi no longer modifies the content of the cache from client side during poke_wireless_devices_with_rf_status(). The content of the cache should be determined by D-Bus alone and follow what NetworkManager service exposes. Local modifications should be avoided. - This aims to bring no API/ABI change, though it does of course bring various subtle changes in behavior. Those should be all for the better, but the goal is not to break any existing clients. This does change internal (albeit externally visible) API, like dropping NM_OBJECT_DBUS_OBJECT_MANAGER property and NMObject no longer implementing GInitableIface and GAsyncInitableIface. - Some uses of gdbus-codegen classes remain in NMVpnPluginOld, NMVpnServicePlugin and NMSecretAgentOld. These are independent of NMClient/NMObject and should be reworked separately. - While we no longer use generated classes from gdbus-codegen, we don't need more glue code than before. Also before we constructed NMPropertiesInfo and a had large amount of code to propagate properties from NMDBus* to NMObject. That got completely reworked, but did not fundamentally change. You still need about the same effort to create the NMLDBusMetaIface. Not using generated bindings did not make anything worse (which tells about the usefulness of generated code, at least in the way it was used). - NMLDBusMetaIface and other meta data is static and immutable. This avoids copying them around. Also, macros like NML_DBUS_META_PROPERTY_INIT_U() have compile time checks to ensure the property types matches. It's pretty hard to misuse them because it won't compile. - The meta data now explicitly encodes the expected D-Bus types and makes sure never to accept wrong data. That would only matter when the server (accidentally or intentionally) exposes unexpected types on D-Bus. I don't think that was previously ensured in all cases. For example, demarshal_generic() only cared about the GObject property type, it didn't know the expected D-Bus type. - Previously GDBusObjectManager would sometimes emit warnings (g_log()). Those probably indicated real bugs. In any case, it prevented us from running CI with G_DEBUG=fatal-warnings, because there would be just too many unrelated crashes. Now we log debug messages that can be enabled with "LIBNM_CLIENT_DEBUG=trace". Some of these messages can also be turned into g_warning()/g_critical() by setting LIBNM_CLIENT_DEBUG=warning,error. Together with G_DEBUG=fatal-warnings, this turns them into assertions. Note that such "assertion failures" might also happen because of a server bug (or change). Thus these are not common assertions that indicate a bug in libnm and are thus not armed unless explicitly requested. In our CI we should now always run with LIBNM_CLIENT_DEBUG=warning,error and G_DEBUG=fatal-warnings and to catch bugs. Note that currently NetworkManager has bugs in this regard, so enabling this will result in assertion failures. That should be fixed first. - Note that this changes the order in which we emit "notify:devices" and "device-added" signals. I think it makes the most sense to emit first "device-removed", then "notify:devices", and finally "device-added" signals. This changes behavior for commit 52ae28f6e5bf ('libnm: queue added/removed signals and suppress uninitialized notifications'), but I don't think that users should actually rely on the order. Still, the new order makes the most sense to me. - In NetworkManager, profiles can be invisible to the user by setting "connection.permissions". Such profiles would be hidden by NMClient's nm_client_get_connections() and their "connection-added"/"connection-removed" signals. Note that NMActiveConnection's nm_active_connection_get_connection() and NMDevice's nm_device_get_available_connections() still exposes such hidden NMRemoteConnection instances. This behavior was preserved. NUMBERS ------- I compared 3 versions of libnm. [1] 962297f9085d, current tip of nm-1-20 branch [2] 4fad8c7c642e, current master, immediate parent of this patch [3] this patch All tests were done on Fedora 31, x86_64, gcc 9.2.1-1.fc31. The libraries were build with $ ./contrib/fedora/rpm/build_clean.sh -g -w test -W debug Note that RPM build already stripped the library. --- N1) File size of libnm.so.0.1.0 in bytes. There currently seems to be a issue on Fedora 31 generating wrong ELF notes. Usually, libnm is smaller but in these tests it had large (and bogus) ELF notes. Anyway, the point is to show the relative sizes, so it doesn't matter). [1] 4075552 (102.7%) [2] 3969624 (100.0%) [3] 3705208 ( 93.3%) --- N2) `size /usr/lib64/libnm.so.0.1.0`: text data bss dec hex filename [1] 1314569 (102.0%) 69980 ( 94.8%) 10632 ( 80.4%) 1395181 (101.4%) 1549ed /usr/lib64/libnm.so.0.1.0 [2] 1288410 (100.0%) 73796 (100.0%) 13224 (100.0%) 1375430 (100.0%) 14fcc6 /usr/lib64/libnm.so.0.1.0 [3] 1229066 ( 95.4%) 65248 ( 88.4%) 13400 (101.3%) 1307714 ( 95.1%) 13f442 /usr/lib64/libnm.so.0.1.0 --- N3) Performance test with test-client.py. With checkout of [2], run ``` prepare_checkout() { rm -rf /tmp/nm-test && \ git checkout -B test 4fad8c7c642e && \ git clean -fdx && \ ./autogen.sh --prefix=/tmp/nm-test && \ make -j 5 install && \ make -j 5 check-local-clients-tests-test-client } prepare_test() { NM_TEST_REGENERATE=1 NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v } do_test() { for i in {1..10}; do NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v || return -1 done echo "done!" } prepare_checkout prepare_test time do_test ``` [1] real 2m14.497s (101.3%) user 5m26.651s (100.3%) sys 1m40.453s (101.4%) [2] real 2m12.800s (100.0%) user 5m25.619s (100.0%) sys 1m39.065s (100.0%) [3] real 1m54.915s ( 86.5%) user 4m18.585s ( 79.4%) sys 1m32.066s ( 92.9%) --- N4) Performance. Run NetworkManager from build [2] and setup a large number of profiles (551 profiles and 515 devices, mostly unrealized). This setup is already at the edge of what NetworkManager currently can handle. Of course, that is a different issue. Here we just check how long plain `nmcli` takes on the system. ``` do_cleanup() { for UUID in $(nmcli -g NAME,UUID connection show | sed -n 's/^xx-c-.*:\([^:]\+\)$/\1/p'); do nmcli connection delete uuid "$UUID" done for DEVICE in $(nmcli -g DEVICE device status | grep '^xx-i-'); do nmcli device delete "$DEVICE" done } do_setup() { do_cleanup for i in {1..30}; do nmcli connection add type bond autoconnect no con-name xx-c-bond-$i ifname xx-i-bond-$i ipv4.method disabled ipv6.method ignore for j in $(seq $i 30); do nmcli connection add type vlan autoconnect no con-name xx-c-vlan-$i-$j vlan.id $j ifname xx-i-vlan-$i-$j vlan.parent xx-i-bond-$i ipv4.method disabled ipv6.method ignore done done systemctl restart NetworkManager.service sleep 5 } do_test() { perf stat -r 50 -B nmcli 1>/dev/null } do_test ``` [1] Performance counter stats for 'nmcli' (50 runs): 456.33 msec task-clock:u # 1.093 CPUs utilized ( +- 0.44% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,900 page-faults:u # 0.013 M/sec ( +- 0.02% ) 1,408,675,453 cycles:u # 3.087 GHz ( +- 0.48% ) 1,594,741,060 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 368,744,018 branches:u # 808.061 M/sec ( +- 0.02% ) 4,566,058 branch-misses:u # 1.24% of all branches ( +- 0.76% ) 0.41761 +- 0.00282 seconds time elapsed ( +- 0.68% ) [2] Performance counter stats for 'nmcli' (50 runs): 477.99 msec task-clock:u # 1.088 CPUs utilized ( +- 0.36% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,948 page-faults:u # 0.012 M/sec ( +- 0.03% ) 1,471,133,482 cycles:u # 3.078 GHz ( +- 0.36% ) 1,655,275,369 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 382,595,152 branches:u # 800.433 M/sec ( +- 0.02% ) 4,746,070 branch-misses:u # 1.24% of all branches ( +- 0.49% ) 0.43923 +- 0.00242 seconds time elapsed ( +- 0.55% ) [3] Performance counter stats for 'nmcli' (50 runs): 352.36 msec task-clock:u # 1.027 CPUs utilized ( +- 0.32% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 4,790 page-faults:u # 0.014 M/sec ( +- 0.26% ) 1,092,341,186 cycles:u # 3.100 GHz ( +- 0.26% ) 1,209,045,283 instructions:u # 1.11 insn per cycle ( +- 0.02% ) 281,708,462 branches:u # 799.499 M/sec ( +- 0.01% ) 3,101,031 branch-misses:u # 1.10% of all branches ( +- 0.61% ) 0.34296 +- 0.00120 seconds time elapsed ( +- 0.35% ) --- N5) same setup as N4), but run `PAGER= /bin/time -v nmcli`: [1] Command being timed: "nmcli" User time (seconds): 0.42 System time (seconds): 0.04 Percent of CPU this job got: 107% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.43 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34456 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6128 Voluntary context switches: 1298 Involuntary context switches: 1106 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [2] Command being timed: "nmcli" User time (seconds): 0.44 System time (seconds): 0.04 Percent of CPU this job got: 108% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.44 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34452 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6169 Voluntary context switches: 1849 Involuntary context switches: 142 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [3] Command being timed: "nmcli" User time (seconds): 0.32 System time (seconds): 0.02 Percent of CPU this job got: 102% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.34 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 29196 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 5059 Voluntary context switches: 919 Involuntary context switches: 685 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 --- N6) same setup as N4), but run `nmcli monitor` and look at `ps aux` for the RSS size. USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND [1] me 1492900 21.0 0.2 461348 33248 pts/10 Sl+ 15:02 0:00 nmcli monitor [2] me 1490721 5.0 0.2 461496 33548 pts/10 Sl+ 15:00 0:00 nmcli monitor [3] me 1495801 16.5 0.1 459476 28692 pts/10 Sl+ 15:04 0:00 nmcli monitor
2019-10-30 11:42:58 +01:00
return nml_dbus_property_o_get_obj (&NM_DEVICE_GET_PRIVATE (device)->property_o[PROPERTY_O_IDX_DHCP6_CONFIG]);
}
/**
* nm_device_get_connectivity:
* @device: a #NMDevice
* @addr_family: network address family
*
* The connectivity state of the device for given address family.
* Supported address families are %AF_INET for IPv4, %AF_INET6
* for IPv6 or %AF_UNSPEC for any.
*
* Returns: the current connectivity state
*
* Since: 1.16
**/
NMConnectivityState
nm_device_get_connectivity (NMDevice *device, int addr_family)
{
NMDevicePrivate *priv = NM_DEVICE_GET_PRIVATE (device);
switch (addr_family) {
case AF_INET:
return priv->ip4_connectivity;
case AF_INET6:
return priv->ip6_connectivity;
case AF_UNSPEC:
return NM_MAX (priv->ip4_connectivity, priv->ip6_connectivity);
default:
g_return_val_if_reached (NM_CONNECTIVITY_UNKNOWN);
}
}
/**
* nm_device_get_interface_flags:
* @device: a #NMDevice
*
* Gets the interface flags of the device.
*
* Returns: the flags
*
* Since: 1.22
**/
NMDeviceInterfaceFlags
nm_device_get_interface_flags (NMDevice *device)
{
g_return_val_if_fail (NM_IS_DEVICE (device), NM_DEVICE_INTERFACE_FLAG_NONE);
return NM_DEVICE_GET_PRIVATE (device)->interface_flags;
}
/**
* nm_device_get_state:
* @device: a #NMDevice
*
* Gets the current #NMDevice state.
*
* Returns: the current device state
**/
NMDeviceState
nm_device_get_state (NMDevice *device)
{
g_return_val_if_fail (NM_IS_DEVICE (device), NM_DEVICE_STATE_UNKNOWN);
return NM_DEVICE_GET_PRIVATE (device)->state;
}
/**
* nm_device_get_state_reason:
* @device: a #NMDevice
*
* Gets the reason for entering the current #NMDevice state.
*
* Returns: the reason for entering the current device state
**/
NMDeviceStateReason
nm_device_get_state_reason (NMDevice *device)
{
g_return_val_if_fail (NM_IS_DEVICE (device), NM_DEVICE_STATE_REASON_UNKNOWN);
libnm: refactor caching of D-Bus objects in NMClient No longer use GDBusObjectMangaerClient and gdbus-codegen generated classes for the NMClient cache. Instead, use GDBusConnection directly and a custom implementation (NMLDBusObject) for caching D-Bus' ObjectManager data. CHANGES ------- - This is a complete rework. I think the previous implementation was difficult to understand. There were unfixed bugs and nobody understood the code well enough to fix them. Maybe somebody out there understood the code, but I certainly did not. At least nobody provided patches to fix those issues. I do believe that this implementation is more straightforward and easier to understand. It removes a lot of layers of code. Whether this claim of simplicity is true, each reader must decide for himself/herself. Note that it is still fairly complex. - There was a lingering performance issue with large number of D-Bus objects. The patch tries hard that the implementation scales well. Of course, when we cache N objects that have N-to-M references to other, we still are fundamentally O(N*M) for runtime and memory consumption (with M being the number of references between objects). But each part should behave efficiently and well. - Play well with GMainContext. libnm code (NMClient) is generally not thread safe. However, it should work to use multiple instances in parallel, as long as each access to a NMClient is through the caller's GMainContext. This follows glib's style and effectively allows to use NMClient in a multi threaded scenario. This implies to stick to a main context upon construction and ensure that callbacks are only invoked when iterating that context. Also, NMClient itself shall never iterate the caller's context. This also means, libnm must never use g_idle_add() or g_timeout_add(), as those enqueue sources in the g_main_context_default() context. - Get ordering of messages right. All events are consistently enqueued in a GMainContext and processed strictly in order. For example, previously "nm-object.c" tried to combine signals and emit them on an idle handler. That is wrong, signals must be emitted in the right order and when they happen. Note that when using GInitable's synchronous initialization to initialize the NMClient instance, NMClient internally still operates fully asynchronously. In that case NMClient has an internal main context. - NMClient takes over most of the functionality. When using D-Bus' ObjectManager interface, one needs to handle basically the entire state of the D-Bus interface. That cannot be separated well into distinct parts, and even if you try, you just end up having closely related code in different source files. Spreading related code does not make it easier to understand, on the contrary. That means, NMClient is inherently complex as it contains most of the logic. I think that is not avoidable, but it's not as bad as it sounds. - NMClient processes D-Bus messages and state changes in separate steps. First NMClient unpacks the message (e.g. _dbus_handle_properties_changed()) and keeps track of the changed data. Then we update the GObject instances (_dbus_handle_obj_changed_dbus()) without emitting any signals yet. Finally, we emit all signals and notifications that were collected (_dbus_handle_changes_commit()). Note that for example during the initial GetManagedObjects() reply, NMClient receive a large amount of state at once. But we first apply all the changes to our GObject instances before emitting any signals. The result is that signals are always emitted in a moment when the cache is consistent. The unavoidable downside is that when you receive a property changed signal, possibly many other properties changed already and more signals are about to be emitted. - NMDeviceWifi no longer modifies the content of the cache from client side during poke_wireless_devices_with_rf_status(). The content of the cache should be determined by D-Bus alone and follow what NetworkManager service exposes. Local modifications should be avoided. - This aims to bring no API/ABI change, though it does of course bring various subtle changes in behavior. Those should be all for the better, but the goal is not to break any existing clients. This does change internal (albeit externally visible) API, like dropping NM_OBJECT_DBUS_OBJECT_MANAGER property and NMObject no longer implementing GInitableIface and GAsyncInitableIface. - Some uses of gdbus-codegen classes remain in NMVpnPluginOld, NMVpnServicePlugin and NMSecretAgentOld. These are independent of NMClient/NMObject and should be reworked separately. - While we no longer use generated classes from gdbus-codegen, we don't need more glue code than before. Also before we constructed NMPropertiesInfo and a had large amount of code to propagate properties from NMDBus* to NMObject. That got completely reworked, but did not fundamentally change. You still need about the same effort to create the NMLDBusMetaIface. Not using generated bindings did not make anything worse (which tells about the usefulness of generated code, at least in the way it was used). - NMLDBusMetaIface and other meta data is static and immutable. This avoids copying them around. Also, macros like NML_DBUS_META_PROPERTY_INIT_U() have compile time checks to ensure the property types matches. It's pretty hard to misuse them because it won't compile. - The meta data now explicitly encodes the expected D-Bus types and makes sure never to accept wrong data. That would only matter when the server (accidentally or intentionally) exposes unexpected types on D-Bus. I don't think that was previously ensured in all cases. For example, demarshal_generic() only cared about the GObject property type, it didn't know the expected D-Bus type. - Previously GDBusObjectManager would sometimes emit warnings (g_log()). Those probably indicated real bugs. In any case, it prevented us from running CI with G_DEBUG=fatal-warnings, because there would be just too many unrelated crashes. Now we log debug messages that can be enabled with "LIBNM_CLIENT_DEBUG=trace". Some of these messages can also be turned into g_warning()/g_critical() by setting LIBNM_CLIENT_DEBUG=warning,error. Together with G_DEBUG=fatal-warnings, this turns them into assertions. Note that such "assertion failures" might also happen because of a server bug (or change). Thus these are not common assertions that indicate a bug in libnm and are thus not armed unless explicitly requested. In our CI we should now always run with LIBNM_CLIENT_DEBUG=warning,error and G_DEBUG=fatal-warnings and to catch bugs. Note that currently NetworkManager has bugs in this regard, so enabling this will result in assertion failures. That should be fixed first. - Note that this changes the order in which we emit "notify:devices" and "device-added" signals. I think it makes the most sense to emit first "device-removed", then "notify:devices", and finally "device-added" signals. This changes behavior for commit 52ae28f6e5bf ('libnm: queue added/removed signals and suppress uninitialized notifications'), but I don't think that users should actually rely on the order. Still, the new order makes the most sense to me. - In NetworkManager, profiles can be invisible to the user by setting "connection.permissions". Such profiles would be hidden by NMClient's nm_client_get_connections() and their "connection-added"/"connection-removed" signals. Note that NMActiveConnection's nm_active_connection_get_connection() and NMDevice's nm_device_get_available_connections() still exposes such hidden NMRemoteConnection instances. This behavior was preserved. NUMBERS ------- I compared 3 versions of libnm. [1] 962297f9085d, current tip of nm-1-20 branch [2] 4fad8c7c642e, current master, immediate parent of this patch [3] this patch All tests were done on Fedora 31, x86_64, gcc 9.2.1-1.fc31. The libraries were build with $ ./contrib/fedora/rpm/build_clean.sh -g -w test -W debug Note that RPM build already stripped the library. --- N1) File size of libnm.so.0.1.0 in bytes. There currently seems to be a issue on Fedora 31 generating wrong ELF notes. Usually, libnm is smaller but in these tests it had large (and bogus) ELF notes. Anyway, the point is to show the relative sizes, so it doesn't matter). [1] 4075552 (102.7%) [2] 3969624 (100.0%) [3] 3705208 ( 93.3%) --- N2) `size /usr/lib64/libnm.so.0.1.0`: text data bss dec hex filename [1] 1314569 (102.0%) 69980 ( 94.8%) 10632 ( 80.4%) 1395181 (101.4%) 1549ed /usr/lib64/libnm.so.0.1.0 [2] 1288410 (100.0%) 73796 (100.0%) 13224 (100.0%) 1375430 (100.0%) 14fcc6 /usr/lib64/libnm.so.0.1.0 [3] 1229066 ( 95.4%) 65248 ( 88.4%) 13400 (101.3%) 1307714 ( 95.1%) 13f442 /usr/lib64/libnm.so.0.1.0 --- N3) Performance test with test-client.py. With checkout of [2], run ``` prepare_checkout() { rm -rf /tmp/nm-test && \ git checkout -B test 4fad8c7c642e && \ git clean -fdx && \ ./autogen.sh --prefix=/tmp/nm-test && \ make -j 5 install && \ make -j 5 check-local-clients-tests-test-client } prepare_test() { NM_TEST_REGENERATE=1 NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v } do_test() { for i in {1..10}; do NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v || return -1 done echo "done!" } prepare_checkout prepare_test time do_test ``` [1] real 2m14.497s (101.3%) user 5m26.651s (100.3%) sys 1m40.453s (101.4%) [2] real 2m12.800s (100.0%) user 5m25.619s (100.0%) sys 1m39.065s (100.0%) [3] real 1m54.915s ( 86.5%) user 4m18.585s ( 79.4%) sys 1m32.066s ( 92.9%) --- N4) Performance. Run NetworkManager from build [2] and setup a large number of profiles (551 profiles and 515 devices, mostly unrealized). This setup is already at the edge of what NetworkManager currently can handle. Of course, that is a different issue. Here we just check how long plain `nmcli` takes on the system. ``` do_cleanup() { for UUID in $(nmcli -g NAME,UUID connection show | sed -n 's/^xx-c-.*:\([^:]\+\)$/\1/p'); do nmcli connection delete uuid "$UUID" done for DEVICE in $(nmcli -g DEVICE device status | grep '^xx-i-'); do nmcli device delete "$DEVICE" done } do_setup() { do_cleanup for i in {1..30}; do nmcli connection add type bond autoconnect no con-name xx-c-bond-$i ifname xx-i-bond-$i ipv4.method disabled ipv6.method ignore for j in $(seq $i 30); do nmcli connection add type vlan autoconnect no con-name xx-c-vlan-$i-$j vlan.id $j ifname xx-i-vlan-$i-$j vlan.parent xx-i-bond-$i ipv4.method disabled ipv6.method ignore done done systemctl restart NetworkManager.service sleep 5 } do_test() { perf stat -r 50 -B nmcli 1>/dev/null } do_test ``` [1] Performance counter stats for 'nmcli' (50 runs): 456.33 msec task-clock:u # 1.093 CPUs utilized ( +- 0.44% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,900 page-faults:u # 0.013 M/sec ( +- 0.02% ) 1,408,675,453 cycles:u # 3.087 GHz ( +- 0.48% ) 1,594,741,060 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 368,744,018 branches:u # 808.061 M/sec ( +- 0.02% ) 4,566,058 branch-misses:u # 1.24% of all branches ( +- 0.76% ) 0.41761 +- 0.00282 seconds time elapsed ( +- 0.68% ) [2] Performance counter stats for 'nmcli' (50 runs): 477.99 msec task-clock:u # 1.088 CPUs utilized ( +- 0.36% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,948 page-faults:u # 0.012 M/sec ( +- 0.03% ) 1,471,133,482 cycles:u # 3.078 GHz ( +- 0.36% ) 1,655,275,369 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 382,595,152 branches:u # 800.433 M/sec ( +- 0.02% ) 4,746,070 branch-misses:u # 1.24% of all branches ( +- 0.49% ) 0.43923 +- 0.00242 seconds time elapsed ( +- 0.55% ) [3] Performance counter stats for 'nmcli' (50 runs): 352.36 msec task-clock:u # 1.027 CPUs utilized ( +- 0.32% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 4,790 page-faults:u # 0.014 M/sec ( +- 0.26% ) 1,092,341,186 cycles:u # 3.100 GHz ( +- 0.26% ) 1,209,045,283 instructions:u # 1.11 insn per cycle ( +- 0.02% ) 281,708,462 branches:u # 799.499 M/sec ( +- 0.01% ) 3,101,031 branch-misses:u # 1.10% of all branches ( +- 0.61% ) 0.34296 +- 0.00120 seconds time elapsed ( +- 0.35% ) --- N5) same setup as N4), but run `PAGER= /bin/time -v nmcli`: [1] Command being timed: "nmcli" User time (seconds): 0.42 System time (seconds): 0.04 Percent of CPU this job got: 107% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.43 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34456 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6128 Voluntary context switches: 1298 Involuntary context switches: 1106 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [2] Command being timed: "nmcli" User time (seconds): 0.44 System time (seconds): 0.04 Percent of CPU this job got: 108% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.44 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34452 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6169 Voluntary context switches: 1849 Involuntary context switches: 142 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [3] Command being timed: "nmcli" User time (seconds): 0.32 System time (seconds): 0.02 Percent of CPU this job got: 102% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.34 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 29196 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 5059 Voluntary context switches: 919 Involuntary context switches: 685 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 --- N6) same setup as N4), but run `nmcli monitor` and look at `ps aux` for the RSS size. USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND [1] me 1492900 21.0 0.2 461348 33248 pts/10 Sl+ 15:02 0:00 nmcli monitor [2] me 1490721 5.0 0.2 461496 33548 pts/10 Sl+ 15:00 0:00 nmcli monitor [3] me 1495801 16.5 0.1 459476 28692 pts/10 Sl+ 15:04 0:00 nmcli monitor
2019-10-30 11:42:58 +01:00
return NM_DEVICE_GET_PRIVATE (device)->state_reason;
}
/**
* nm_device_get_active_connection:
* @device: a #NMDevice
*
* Gets the #NMActiveConnection object which owns this device during activation.
*
* Returns: (transfer none): the #NMActiveConnection or %NULL if the device is
* not part of an active connection
**/
NMActiveConnection *
nm_device_get_active_connection (NMDevice *device)
{
NMActiveConnection *ac;
g_return_val_if_fail (NM_IS_DEVICE (device), NULL);
ac = nml_dbus_property_o_get_obj (&NM_DEVICE_GET_PRIVATE (device)->property_o[PROPERTY_O_IDX_ACTIVE_CONNECTION]);
nm_assert (!ac || NM_IS_ACTIVE_CONNECTION (ac));
return ac;
}
/**
* nm_device_get_available_connections:
* @device: a #NMDevice
*
* Gets the #NMRemoteConnections currently known to the daemon that could
* be activated on @device.
*
* Returns: (element-type NMRemoteConnection): the #GPtrArray
* containing #NMRemoteConnections. This is the internal copy used by
* the connection, and must not be modified.
**/
const GPtrArray *
nm_device_get_available_connections (NMDevice *device)
{
g_return_val_if_fail (NM_IS_DEVICE (device), NULL);
libnm: refactor caching of D-Bus objects in NMClient No longer use GDBusObjectMangaerClient and gdbus-codegen generated classes for the NMClient cache. Instead, use GDBusConnection directly and a custom implementation (NMLDBusObject) for caching D-Bus' ObjectManager data. CHANGES ------- - This is a complete rework. I think the previous implementation was difficult to understand. There were unfixed bugs and nobody understood the code well enough to fix them. Maybe somebody out there understood the code, but I certainly did not. At least nobody provided patches to fix those issues. I do believe that this implementation is more straightforward and easier to understand. It removes a lot of layers of code. Whether this claim of simplicity is true, each reader must decide for himself/herself. Note that it is still fairly complex. - There was a lingering performance issue with large number of D-Bus objects. The patch tries hard that the implementation scales well. Of course, when we cache N objects that have N-to-M references to other, we still are fundamentally O(N*M) for runtime and memory consumption (with M being the number of references between objects). But each part should behave efficiently and well. - Play well with GMainContext. libnm code (NMClient) is generally not thread safe. However, it should work to use multiple instances in parallel, as long as each access to a NMClient is through the caller's GMainContext. This follows glib's style and effectively allows to use NMClient in a multi threaded scenario. This implies to stick to a main context upon construction and ensure that callbacks are only invoked when iterating that context. Also, NMClient itself shall never iterate the caller's context. This also means, libnm must never use g_idle_add() or g_timeout_add(), as those enqueue sources in the g_main_context_default() context. - Get ordering of messages right. All events are consistently enqueued in a GMainContext and processed strictly in order. For example, previously "nm-object.c" tried to combine signals and emit them on an idle handler. That is wrong, signals must be emitted in the right order and when they happen. Note that when using GInitable's synchronous initialization to initialize the NMClient instance, NMClient internally still operates fully asynchronously. In that case NMClient has an internal main context. - NMClient takes over most of the functionality. When using D-Bus' ObjectManager interface, one needs to handle basically the entire state of the D-Bus interface. That cannot be separated well into distinct parts, and even if you try, you just end up having closely related code in different source files. Spreading related code does not make it easier to understand, on the contrary. That means, NMClient is inherently complex as it contains most of the logic. I think that is not avoidable, but it's not as bad as it sounds. - NMClient processes D-Bus messages and state changes in separate steps. First NMClient unpacks the message (e.g. _dbus_handle_properties_changed()) and keeps track of the changed data. Then we update the GObject instances (_dbus_handle_obj_changed_dbus()) without emitting any signals yet. Finally, we emit all signals and notifications that were collected (_dbus_handle_changes_commit()). Note that for example during the initial GetManagedObjects() reply, NMClient receive a large amount of state at once. But we first apply all the changes to our GObject instances before emitting any signals. The result is that signals are always emitted in a moment when the cache is consistent. The unavoidable downside is that when you receive a property changed signal, possibly many other properties changed already and more signals are about to be emitted. - NMDeviceWifi no longer modifies the content of the cache from client side during poke_wireless_devices_with_rf_status(). The content of the cache should be determined by D-Bus alone and follow what NetworkManager service exposes. Local modifications should be avoided. - This aims to bring no API/ABI change, though it does of course bring various subtle changes in behavior. Those should be all for the better, but the goal is not to break any existing clients. This does change internal (albeit externally visible) API, like dropping NM_OBJECT_DBUS_OBJECT_MANAGER property and NMObject no longer implementing GInitableIface and GAsyncInitableIface. - Some uses of gdbus-codegen classes remain in NMVpnPluginOld, NMVpnServicePlugin and NMSecretAgentOld. These are independent of NMClient/NMObject and should be reworked separately. - While we no longer use generated classes from gdbus-codegen, we don't need more glue code than before. Also before we constructed NMPropertiesInfo and a had large amount of code to propagate properties from NMDBus* to NMObject. That got completely reworked, but did not fundamentally change. You still need about the same effort to create the NMLDBusMetaIface. Not using generated bindings did not make anything worse (which tells about the usefulness of generated code, at least in the way it was used). - NMLDBusMetaIface and other meta data is static and immutable. This avoids copying them around. Also, macros like NML_DBUS_META_PROPERTY_INIT_U() have compile time checks to ensure the property types matches. It's pretty hard to misuse them because it won't compile. - The meta data now explicitly encodes the expected D-Bus types and makes sure never to accept wrong data. That would only matter when the server (accidentally or intentionally) exposes unexpected types on D-Bus. I don't think that was previously ensured in all cases. For example, demarshal_generic() only cared about the GObject property type, it didn't know the expected D-Bus type. - Previously GDBusObjectManager would sometimes emit warnings (g_log()). Those probably indicated real bugs. In any case, it prevented us from running CI with G_DEBUG=fatal-warnings, because there would be just too many unrelated crashes. Now we log debug messages that can be enabled with "LIBNM_CLIENT_DEBUG=trace". Some of these messages can also be turned into g_warning()/g_critical() by setting LIBNM_CLIENT_DEBUG=warning,error. Together with G_DEBUG=fatal-warnings, this turns them into assertions. Note that such "assertion failures" might also happen because of a server bug (or change). Thus these are not common assertions that indicate a bug in libnm and are thus not armed unless explicitly requested. In our CI we should now always run with LIBNM_CLIENT_DEBUG=warning,error and G_DEBUG=fatal-warnings and to catch bugs. Note that currently NetworkManager has bugs in this regard, so enabling this will result in assertion failures. That should be fixed first. - Note that this changes the order in which we emit "notify:devices" and "device-added" signals. I think it makes the most sense to emit first "device-removed", then "notify:devices", and finally "device-added" signals. This changes behavior for commit 52ae28f6e5bf ('libnm: queue added/removed signals and suppress uninitialized notifications'), but I don't think that users should actually rely on the order. Still, the new order makes the most sense to me. - In NetworkManager, profiles can be invisible to the user by setting "connection.permissions". Such profiles would be hidden by NMClient's nm_client_get_connections() and their "connection-added"/"connection-removed" signals. Note that NMActiveConnection's nm_active_connection_get_connection() and NMDevice's nm_device_get_available_connections() still exposes such hidden NMRemoteConnection instances. This behavior was preserved. NUMBERS ------- I compared 3 versions of libnm. [1] 962297f9085d, current tip of nm-1-20 branch [2] 4fad8c7c642e, current master, immediate parent of this patch [3] this patch All tests were done on Fedora 31, x86_64, gcc 9.2.1-1.fc31. The libraries were build with $ ./contrib/fedora/rpm/build_clean.sh -g -w test -W debug Note that RPM build already stripped the library. --- N1) File size of libnm.so.0.1.0 in bytes. There currently seems to be a issue on Fedora 31 generating wrong ELF notes. Usually, libnm is smaller but in these tests it had large (and bogus) ELF notes. Anyway, the point is to show the relative sizes, so it doesn't matter). [1] 4075552 (102.7%) [2] 3969624 (100.0%) [3] 3705208 ( 93.3%) --- N2) `size /usr/lib64/libnm.so.0.1.0`: text data bss dec hex filename [1] 1314569 (102.0%) 69980 ( 94.8%) 10632 ( 80.4%) 1395181 (101.4%) 1549ed /usr/lib64/libnm.so.0.1.0 [2] 1288410 (100.0%) 73796 (100.0%) 13224 (100.0%) 1375430 (100.0%) 14fcc6 /usr/lib64/libnm.so.0.1.0 [3] 1229066 ( 95.4%) 65248 ( 88.4%) 13400 (101.3%) 1307714 ( 95.1%) 13f442 /usr/lib64/libnm.so.0.1.0 --- N3) Performance test with test-client.py. With checkout of [2], run ``` prepare_checkout() { rm -rf /tmp/nm-test && \ git checkout -B test 4fad8c7c642e && \ git clean -fdx && \ ./autogen.sh --prefix=/tmp/nm-test && \ make -j 5 install && \ make -j 5 check-local-clients-tests-test-client } prepare_test() { NM_TEST_REGENERATE=1 NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v } do_test() { for i in {1..10}; do NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v || return -1 done echo "done!" } prepare_checkout prepare_test time do_test ``` [1] real 2m14.497s (101.3%) user 5m26.651s (100.3%) sys 1m40.453s (101.4%) [2] real 2m12.800s (100.0%) user 5m25.619s (100.0%) sys 1m39.065s (100.0%) [3] real 1m54.915s ( 86.5%) user 4m18.585s ( 79.4%) sys 1m32.066s ( 92.9%) --- N4) Performance. Run NetworkManager from build [2] and setup a large number of profiles (551 profiles and 515 devices, mostly unrealized). This setup is already at the edge of what NetworkManager currently can handle. Of course, that is a different issue. Here we just check how long plain `nmcli` takes on the system. ``` do_cleanup() { for UUID in $(nmcli -g NAME,UUID connection show | sed -n 's/^xx-c-.*:\([^:]\+\)$/\1/p'); do nmcli connection delete uuid "$UUID" done for DEVICE in $(nmcli -g DEVICE device status | grep '^xx-i-'); do nmcli device delete "$DEVICE" done } do_setup() { do_cleanup for i in {1..30}; do nmcli connection add type bond autoconnect no con-name xx-c-bond-$i ifname xx-i-bond-$i ipv4.method disabled ipv6.method ignore for j in $(seq $i 30); do nmcli connection add type vlan autoconnect no con-name xx-c-vlan-$i-$j vlan.id $j ifname xx-i-vlan-$i-$j vlan.parent xx-i-bond-$i ipv4.method disabled ipv6.method ignore done done systemctl restart NetworkManager.service sleep 5 } do_test() { perf stat -r 50 -B nmcli 1>/dev/null } do_test ``` [1] Performance counter stats for 'nmcli' (50 runs): 456.33 msec task-clock:u # 1.093 CPUs utilized ( +- 0.44% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,900 page-faults:u # 0.013 M/sec ( +- 0.02% ) 1,408,675,453 cycles:u # 3.087 GHz ( +- 0.48% ) 1,594,741,060 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 368,744,018 branches:u # 808.061 M/sec ( +- 0.02% ) 4,566,058 branch-misses:u # 1.24% of all branches ( +- 0.76% ) 0.41761 +- 0.00282 seconds time elapsed ( +- 0.68% ) [2] Performance counter stats for 'nmcli' (50 runs): 477.99 msec task-clock:u # 1.088 CPUs utilized ( +- 0.36% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,948 page-faults:u # 0.012 M/sec ( +- 0.03% ) 1,471,133,482 cycles:u # 3.078 GHz ( +- 0.36% ) 1,655,275,369 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 382,595,152 branches:u # 800.433 M/sec ( +- 0.02% ) 4,746,070 branch-misses:u # 1.24% of all branches ( +- 0.49% ) 0.43923 +- 0.00242 seconds time elapsed ( +- 0.55% ) [3] Performance counter stats for 'nmcli' (50 runs): 352.36 msec task-clock:u # 1.027 CPUs utilized ( +- 0.32% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 4,790 page-faults:u # 0.014 M/sec ( +- 0.26% ) 1,092,341,186 cycles:u # 3.100 GHz ( +- 0.26% ) 1,209,045,283 instructions:u # 1.11 insn per cycle ( +- 0.02% ) 281,708,462 branches:u # 799.499 M/sec ( +- 0.01% ) 3,101,031 branch-misses:u # 1.10% of all branches ( +- 0.61% ) 0.34296 +- 0.00120 seconds time elapsed ( +- 0.35% ) --- N5) same setup as N4), but run `PAGER= /bin/time -v nmcli`: [1] Command being timed: "nmcli" User time (seconds): 0.42 System time (seconds): 0.04 Percent of CPU this job got: 107% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.43 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34456 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6128 Voluntary context switches: 1298 Involuntary context switches: 1106 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [2] Command being timed: "nmcli" User time (seconds): 0.44 System time (seconds): 0.04 Percent of CPU this job got: 108% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.44 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34452 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6169 Voluntary context switches: 1849 Involuntary context switches: 142 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [3] Command being timed: "nmcli" User time (seconds): 0.32 System time (seconds): 0.02 Percent of CPU this job got: 102% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.34 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 29196 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 5059 Voluntary context switches: 919 Involuntary context switches: 685 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 --- N6) same setup as N4), but run `nmcli monitor` and look at `ps aux` for the RSS size. USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND [1] me 1492900 21.0 0.2 461348 33248 pts/10 Sl+ 15:02 0:00 nmcli monitor [2] me 1490721 5.0 0.2 461496 33548 pts/10 Sl+ 15:00 0:00 nmcli monitor [3] me 1495801 16.5 0.1 459476 28692 pts/10 Sl+ 15:04 0:00 nmcli monitor
2019-10-30 11:42:58 +01:00
return nml_dbus_property_ao_get_objs_as_ptrarray (&NM_DEVICE_GET_PRIVATE (device)->available_connections);
}
static const char *
get_type_name (NMDevice *device)
{
switch (nm_device_get_device_type (device)) {
case NM_DEVICE_TYPE_ETHERNET:
return _("Ethernet");
case NM_DEVICE_TYPE_WIFI:
return _("Wi-Fi");
case NM_DEVICE_TYPE_BT:
return _("Bluetooth");
case NM_DEVICE_TYPE_OLPC_MESH:
return _("OLPC Mesh");
case NM_DEVICE_TYPE_OVS_INTERFACE:
return _("Open vSwitch Interface");
case NM_DEVICE_TYPE_OVS_PORT:
return _("Open vSwitch Port");
case NM_DEVICE_TYPE_OVS_BRIDGE:
return _("Open vSwitch Bridge");
case NM_DEVICE_TYPE_WIMAX:
return _("WiMAX");
case NM_DEVICE_TYPE_MODEM:
return _("Mobile Broadband");
case NM_DEVICE_TYPE_INFINIBAND:
return _("InfiniBand");
case NM_DEVICE_TYPE_BOND:
return _("Bond");
case NM_DEVICE_TYPE_TEAM:
return _("Team");
case NM_DEVICE_TYPE_BRIDGE:
return _("Bridge");
case NM_DEVICE_TYPE_VLAN:
return _("VLAN");
case NM_DEVICE_TYPE_ADSL:
return _("ADSL");
case NM_DEVICE_TYPE_MACVLAN:
return _("MACVLAN");
case NM_DEVICE_TYPE_VXLAN:
return _("VXLAN");
case NM_DEVICE_TYPE_IP_TUNNEL:
return _("IPTunnel");
case NM_DEVICE_TYPE_TUN:
return _("Tun");
case NM_DEVICE_TYPE_VETH:
return _("Veth");
case NM_DEVICE_TYPE_MACSEC:
return _("MACsec");
case NM_DEVICE_TYPE_DUMMY:
return _("Dummy");
case NM_DEVICE_TYPE_PPP:
return _("PPP");
2018-03-09 16:26:25 +01:00
case NM_DEVICE_TYPE_WPAN:
return _("IEEE 802.15.4");
2018-05-22 16:25:54 +02:00
case NM_DEVICE_TYPE_6LOWPAN:
return _("6LoWPAN");
case NM_DEVICE_TYPE_WIREGUARD:
return _("WireGuard");
case NM_DEVICE_TYPE_WIFI_P2P:
return _("Wi-Fi P2P");
case NM_DEVICE_TYPE_VRF:
return _("VRF");
case NM_DEVICE_TYPE_GENERIC:
case NM_DEVICE_TYPE_UNUSED1:
case NM_DEVICE_TYPE_UNUSED2:
case NM_DEVICE_TYPE_UNKNOWN:
break;
}
return _("Unknown");
}
static char *
get_device_type_name_with_iface (NMDevice *device)
{
const char *type_name = get_type_name (device);
switch (nm_device_get_device_type (device)) {
case NM_DEVICE_TYPE_BOND:
case NM_DEVICE_TYPE_TEAM:
case NM_DEVICE_TYPE_BRIDGE:
case NM_DEVICE_TYPE_VLAN:
return g_strdup_printf ("%s (%s)", type_name, nm_device_get_iface (device));
default:
return g_strdup (type_name);
}
}
static char *
get_device_generic_type_name_with_iface (NMDevice *device)
{
switch (nm_device_get_device_type (device)) {
case NM_DEVICE_TYPE_ETHERNET:
case NM_DEVICE_TYPE_INFINIBAND:
return g_strdup (_("Wired"));
default:
return get_device_type_name_with_iface (device);
}
}
static const char *
get_bus_name (NMDevice *device)
{
NMDevicePrivate *priv = NM_DEVICE_GET_PRIVATE (device);
struct udev_device *udevice;
libnm: refactor caching of D-Bus objects in NMClient No longer use GDBusObjectMangaerClient and gdbus-codegen generated classes for the NMClient cache. Instead, use GDBusConnection directly and a custom implementation (NMLDBusObject) for caching D-Bus' ObjectManager data. CHANGES ------- - This is a complete rework. I think the previous implementation was difficult to understand. There were unfixed bugs and nobody understood the code well enough to fix them. Maybe somebody out there understood the code, but I certainly did not. At least nobody provided patches to fix those issues. I do believe that this implementation is more straightforward and easier to understand. It removes a lot of layers of code. Whether this claim of simplicity is true, each reader must decide for himself/herself. Note that it is still fairly complex. - There was a lingering performance issue with large number of D-Bus objects. The patch tries hard that the implementation scales well. Of course, when we cache N objects that have N-to-M references to other, we still are fundamentally O(N*M) for runtime and memory consumption (with M being the number of references between objects). But each part should behave efficiently and well. - Play well with GMainContext. libnm code (NMClient) is generally not thread safe. However, it should work to use multiple instances in parallel, as long as each access to a NMClient is through the caller's GMainContext. This follows glib's style and effectively allows to use NMClient in a multi threaded scenario. This implies to stick to a main context upon construction and ensure that callbacks are only invoked when iterating that context. Also, NMClient itself shall never iterate the caller's context. This also means, libnm must never use g_idle_add() or g_timeout_add(), as those enqueue sources in the g_main_context_default() context. - Get ordering of messages right. All events are consistently enqueued in a GMainContext and processed strictly in order. For example, previously "nm-object.c" tried to combine signals and emit them on an idle handler. That is wrong, signals must be emitted in the right order and when they happen. Note that when using GInitable's synchronous initialization to initialize the NMClient instance, NMClient internally still operates fully asynchronously. In that case NMClient has an internal main context. - NMClient takes over most of the functionality. When using D-Bus' ObjectManager interface, one needs to handle basically the entire state of the D-Bus interface. That cannot be separated well into distinct parts, and even if you try, you just end up having closely related code in different source files. Spreading related code does not make it easier to understand, on the contrary. That means, NMClient is inherently complex as it contains most of the logic. I think that is not avoidable, but it's not as bad as it sounds. - NMClient processes D-Bus messages and state changes in separate steps. First NMClient unpacks the message (e.g. _dbus_handle_properties_changed()) and keeps track of the changed data. Then we update the GObject instances (_dbus_handle_obj_changed_dbus()) without emitting any signals yet. Finally, we emit all signals and notifications that were collected (_dbus_handle_changes_commit()). Note that for example during the initial GetManagedObjects() reply, NMClient receive a large amount of state at once. But we first apply all the changes to our GObject instances before emitting any signals. The result is that signals are always emitted in a moment when the cache is consistent. The unavoidable downside is that when you receive a property changed signal, possibly many other properties changed already and more signals are about to be emitted. - NMDeviceWifi no longer modifies the content of the cache from client side during poke_wireless_devices_with_rf_status(). The content of the cache should be determined by D-Bus alone and follow what NetworkManager service exposes. Local modifications should be avoided. - This aims to bring no API/ABI change, though it does of course bring various subtle changes in behavior. Those should be all for the better, but the goal is not to break any existing clients. This does change internal (albeit externally visible) API, like dropping NM_OBJECT_DBUS_OBJECT_MANAGER property and NMObject no longer implementing GInitableIface and GAsyncInitableIface. - Some uses of gdbus-codegen classes remain in NMVpnPluginOld, NMVpnServicePlugin and NMSecretAgentOld. These are independent of NMClient/NMObject and should be reworked separately. - While we no longer use generated classes from gdbus-codegen, we don't need more glue code than before. Also before we constructed NMPropertiesInfo and a had large amount of code to propagate properties from NMDBus* to NMObject. That got completely reworked, but did not fundamentally change. You still need about the same effort to create the NMLDBusMetaIface. Not using generated bindings did not make anything worse (which tells about the usefulness of generated code, at least in the way it was used). - NMLDBusMetaIface and other meta data is static and immutable. This avoids copying them around. Also, macros like NML_DBUS_META_PROPERTY_INIT_U() have compile time checks to ensure the property types matches. It's pretty hard to misuse them because it won't compile. - The meta data now explicitly encodes the expected D-Bus types and makes sure never to accept wrong data. That would only matter when the server (accidentally or intentionally) exposes unexpected types on D-Bus. I don't think that was previously ensured in all cases. For example, demarshal_generic() only cared about the GObject property type, it didn't know the expected D-Bus type. - Previously GDBusObjectManager would sometimes emit warnings (g_log()). Those probably indicated real bugs. In any case, it prevented us from running CI with G_DEBUG=fatal-warnings, because there would be just too many unrelated crashes. Now we log debug messages that can be enabled with "LIBNM_CLIENT_DEBUG=trace". Some of these messages can also be turned into g_warning()/g_critical() by setting LIBNM_CLIENT_DEBUG=warning,error. Together with G_DEBUG=fatal-warnings, this turns them into assertions. Note that such "assertion failures" might also happen because of a server bug (or change). Thus these are not common assertions that indicate a bug in libnm and are thus not armed unless explicitly requested. In our CI we should now always run with LIBNM_CLIENT_DEBUG=warning,error and G_DEBUG=fatal-warnings and to catch bugs. Note that currently NetworkManager has bugs in this regard, so enabling this will result in assertion failures. That should be fixed first. - Note that this changes the order in which we emit "notify:devices" and "device-added" signals. I think it makes the most sense to emit first "device-removed", then "notify:devices", and finally "device-added" signals. This changes behavior for commit 52ae28f6e5bf ('libnm: queue added/removed signals and suppress uninitialized notifications'), but I don't think that users should actually rely on the order. Still, the new order makes the most sense to me. - In NetworkManager, profiles can be invisible to the user by setting "connection.permissions". Such profiles would be hidden by NMClient's nm_client_get_connections() and their "connection-added"/"connection-removed" signals. Note that NMActiveConnection's nm_active_connection_get_connection() and NMDevice's nm_device_get_available_connections() still exposes such hidden NMRemoteConnection instances. This behavior was preserved. NUMBERS ------- I compared 3 versions of libnm. [1] 962297f9085d, current tip of nm-1-20 branch [2] 4fad8c7c642e, current master, immediate parent of this patch [3] this patch All tests were done on Fedora 31, x86_64, gcc 9.2.1-1.fc31. The libraries were build with $ ./contrib/fedora/rpm/build_clean.sh -g -w test -W debug Note that RPM build already stripped the library. --- N1) File size of libnm.so.0.1.0 in bytes. There currently seems to be a issue on Fedora 31 generating wrong ELF notes. Usually, libnm is smaller but in these tests it had large (and bogus) ELF notes. Anyway, the point is to show the relative sizes, so it doesn't matter). [1] 4075552 (102.7%) [2] 3969624 (100.0%) [3] 3705208 ( 93.3%) --- N2) `size /usr/lib64/libnm.so.0.1.0`: text data bss dec hex filename [1] 1314569 (102.0%) 69980 ( 94.8%) 10632 ( 80.4%) 1395181 (101.4%) 1549ed /usr/lib64/libnm.so.0.1.0 [2] 1288410 (100.0%) 73796 (100.0%) 13224 (100.0%) 1375430 (100.0%) 14fcc6 /usr/lib64/libnm.so.0.1.0 [3] 1229066 ( 95.4%) 65248 ( 88.4%) 13400 (101.3%) 1307714 ( 95.1%) 13f442 /usr/lib64/libnm.so.0.1.0 --- N3) Performance test with test-client.py. With checkout of [2], run ``` prepare_checkout() { rm -rf /tmp/nm-test && \ git checkout -B test 4fad8c7c642e && \ git clean -fdx && \ ./autogen.sh --prefix=/tmp/nm-test && \ make -j 5 install && \ make -j 5 check-local-clients-tests-test-client } prepare_test() { NM_TEST_REGENERATE=1 NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v } do_test() { for i in {1..10}; do NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v || return -1 done echo "done!" } prepare_checkout prepare_test time do_test ``` [1] real 2m14.497s (101.3%) user 5m26.651s (100.3%) sys 1m40.453s (101.4%) [2] real 2m12.800s (100.0%) user 5m25.619s (100.0%) sys 1m39.065s (100.0%) [3] real 1m54.915s ( 86.5%) user 4m18.585s ( 79.4%) sys 1m32.066s ( 92.9%) --- N4) Performance. Run NetworkManager from build [2] and setup a large number of profiles (551 profiles and 515 devices, mostly unrealized). This setup is already at the edge of what NetworkManager currently can handle. Of course, that is a different issue. Here we just check how long plain `nmcli` takes on the system. ``` do_cleanup() { for UUID in $(nmcli -g NAME,UUID connection show | sed -n 's/^xx-c-.*:\([^:]\+\)$/\1/p'); do nmcli connection delete uuid "$UUID" done for DEVICE in $(nmcli -g DEVICE device status | grep '^xx-i-'); do nmcli device delete "$DEVICE" done } do_setup() { do_cleanup for i in {1..30}; do nmcli connection add type bond autoconnect no con-name xx-c-bond-$i ifname xx-i-bond-$i ipv4.method disabled ipv6.method ignore for j in $(seq $i 30); do nmcli connection add type vlan autoconnect no con-name xx-c-vlan-$i-$j vlan.id $j ifname xx-i-vlan-$i-$j vlan.parent xx-i-bond-$i ipv4.method disabled ipv6.method ignore done done systemctl restart NetworkManager.service sleep 5 } do_test() { perf stat -r 50 -B nmcli 1>/dev/null } do_test ``` [1] Performance counter stats for 'nmcli' (50 runs): 456.33 msec task-clock:u # 1.093 CPUs utilized ( +- 0.44% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,900 page-faults:u # 0.013 M/sec ( +- 0.02% ) 1,408,675,453 cycles:u # 3.087 GHz ( +- 0.48% ) 1,594,741,060 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 368,744,018 branches:u # 808.061 M/sec ( +- 0.02% ) 4,566,058 branch-misses:u # 1.24% of all branches ( +- 0.76% ) 0.41761 +- 0.00282 seconds time elapsed ( +- 0.68% ) [2] Performance counter stats for 'nmcli' (50 runs): 477.99 msec task-clock:u # 1.088 CPUs utilized ( +- 0.36% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,948 page-faults:u # 0.012 M/sec ( +- 0.03% ) 1,471,133,482 cycles:u # 3.078 GHz ( +- 0.36% ) 1,655,275,369 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 382,595,152 branches:u # 800.433 M/sec ( +- 0.02% ) 4,746,070 branch-misses:u # 1.24% of all branches ( +- 0.49% ) 0.43923 +- 0.00242 seconds time elapsed ( +- 0.55% ) [3] Performance counter stats for 'nmcli' (50 runs): 352.36 msec task-clock:u # 1.027 CPUs utilized ( +- 0.32% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 4,790 page-faults:u # 0.014 M/sec ( +- 0.26% ) 1,092,341,186 cycles:u # 3.100 GHz ( +- 0.26% ) 1,209,045,283 instructions:u # 1.11 insn per cycle ( +- 0.02% ) 281,708,462 branches:u # 799.499 M/sec ( +- 0.01% ) 3,101,031 branch-misses:u # 1.10% of all branches ( +- 0.61% ) 0.34296 +- 0.00120 seconds time elapsed ( +- 0.35% ) --- N5) same setup as N4), but run `PAGER= /bin/time -v nmcli`: [1] Command being timed: "nmcli" User time (seconds): 0.42 System time (seconds): 0.04 Percent of CPU this job got: 107% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.43 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34456 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6128 Voluntary context switches: 1298 Involuntary context switches: 1106 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [2] Command being timed: "nmcli" User time (seconds): 0.44 System time (seconds): 0.04 Percent of CPU this job got: 108% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.44 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34452 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6169 Voluntary context switches: 1849 Involuntary context switches: 142 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [3] Command being timed: "nmcli" User time (seconds): 0.32 System time (seconds): 0.02 Percent of CPU this job got: 102% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.34 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 29196 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 5059 Voluntary context switches: 919 Involuntary context switches: 685 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 --- N6) same setup as N4), but run `nmcli monitor` and look at `ps aux` for the RSS size. USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND [1] me 1492900 21.0 0.2 461348 33248 pts/10 Sl+ 15:02 0:00 nmcli monitor [2] me 1490721 5.0 0.2 461496 33548 pts/10 Sl+ 15:00 0:00 nmcli monitor [3] me 1495801 16.5 0.1 459476 28692 pts/10 Sl+ 15:04 0:00 nmcli monitor
2019-10-30 11:42:58 +01:00
const char *ifname;
const char *bus;
if (priv->bus_name)
goto out;
if (!priv->udev)
return NULL;
ifname = nm_device_get_iface (device);
if (!ifname)
return NULL;
udevice = udev_device_new_from_subsystem_sysname (priv->udev, "net", ifname);
if (!udevice) {
udevice = udev_device_new_from_subsystem_sysname (priv->udev, "tty", ifname);
if (!udevice)
return NULL;
}
bus = udev_device_get_property_value (udevice, "ID_BUS");
if (!g_strcmp0 (bus, "pci"))
priv->bus_name = g_strdup (_("PCI"));
else if (!g_strcmp0 (bus, "usb"))
priv->bus_name = g_strdup (_("USB"));
else {
/* Use "" instead of NULL so we can tell later that we've
* already tried.
*/
priv->bus_name = g_strdup ("");
}
udev_device_unref (udevice);
out:
if (*priv->bus_name)
return priv->bus_name;
else
return NULL;
}
static char *
_get_udev_property (NMDevice *device,
const char *enc_prop, /* ID_XXX_ENC */
const char *db_prop) /* ID_XXX_FROM_DATABASE */
{
NMDevicePrivate *priv = NM_DEVICE_GET_PRIVATE (device);
libnm: refactor caching of D-Bus objects in NMClient No longer use GDBusObjectMangaerClient and gdbus-codegen generated classes for the NMClient cache. Instead, use GDBusConnection directly and a custom implementation (NMLDBusObject) for caching D-Bus' ObjectManager data. CHANGES ------- - This is a complete rework. I think the previous implementation was difficult to understand. There were unfixed bugs and nobody understood the code well enough to fix them. Maybe somebody out there understood the code, but I certainly did not. At least nobody provided patches to fix those issues. I do believe that this implementation is more straightforward and easier to understand. It removes a lot of layers of code. Whether this claim of simplicity is true, each reader must decide for himself/herself. Note that it is still fairly complex. - There was a lingering performance issue with large number of D-Bus objects. The patch tries hard that the implementation scales well. Of course, when we cache N objects that have N-to-M references to other, we still are fundamentally O(N*M) for runtime and memory consumption (with M being the number of references between objects). But each part should behave efficiently and well. - Play well with GMainContext. libnm code (NMClient) is generally not thread safe. However, it should work to use multiple instances in parallel, as long as each access to a NMClient is through the caller's GMainContext. This follows glib's style and effectively allows to use NMClient in a multi threaded scenario. This implies to stick to a main context upon construction and ensure that callbacks are only invoked when iterating that context. Also, NMClient itself shall never iterate the caller's context. This also means, libnm must never use g_idle_add() or g_timeout_add(), as those enqueue sources in the g_main_context_default() context. - Get ordering of messages right. All events are consistently enqueued in a GMainContext and processed strictly in order. For example, previously "nm-object.c" tried to combine signals and emit them on an idle handler. That is wrong, signals must be emitted in the right order and when they happen. Note that when using GInitable's synchronous initialization to initialize the NMClient instance, NMClient internally still operates fully asynchronously. In that case NMClient has an internal main context. - NMClient takes over most of the functionality. When using D-Bus' ObjectManager interface, one needs to handle basically the entire state of the D-Bus interface. That cannot be separated well into distinct parts, and even if you try, you just end up having closely related code in different source files. Spreading related code does not make it easier to understand, on the contrary. That means, NMClient is inherently complex as it contains most of the logic. I think that is not avoidable, but it's not as bad as it sounds. - NMClient processes D-Bus messages and state changes in separate steps. First NMClient unpacks the message (e.g. _dbus_handle_properties_changed()) and keeps track of the changed data. Then we update the GObject instances (_dbus_handle_obj_changed_dbus()) without emitting any signals yet. Finally, we emit all signals and notifications that were collected (_dbus_handle_changes_commit()). Note that for example during the initial GetManagedObjects() reply, NMClient receive a large amount of state at once. But we first apply all the changes to our GObject instances before emitting any signals. The result is that signals are always emitted in a moment when the cache is consistent. The unavoidable downside is that when you receive a property changed signal, possibly many other properties changed already and more signals are about to be emitted. - NMDeviceWifi no longer modifies the content of the cache from client side during poke_wireless_devices_with_rf_status(). The content of the cache should be determined by D-Bus alone and follow what NetworkManager service exposes. Local modifications should be avoided. - This aims to bring no API/ABI change, though it does of course bring various subtle changes in behavior. Those should be all for the better, but the goal is not to break any existing clients. This does change internal (albeit externally visible) API, like dropping NM_OBJECT_DBUS_OBJECT_MANAGER property and NMObject no longer implementing GInitableIface and GAsyncInitableIface. - Some uses of gdbus-codegen classes remain in NMVpnPluginOld, NMVpnServicePlugin and NMSecretAgentOld. These are independent of NMClient/NMObject and should be reworked separately. - While we no longer use generated classes from gdbus-codegen, we don't need more glue code than before. Also before we constructed NMPropertiesInfo and a had large amount of code to propagate properties from NMDBus* to NMObject. That got completely reworked, but did not fundamentally change. You still need about the same effort to create the NMLDBusMetaIface. Not using generated bindings did not make anything worse (which tells about the usefulness of generated code, at least in the way it was used). - NMLDBusMetaIface and other meta data is static and immutable. This avoids copying them around. Also, macros like NML_DBUS_META_PROPERTY_INIT_U() have compile time checks to ensure the property types matches. It's pretty hard to misuse them because it won't compile. - The meta data now explicitly encodes the expected D-Bus types and makes sure never to accept wrong data. That would only matter when the server (accidentally or intentionally) exposes unexpected types on D-Bus. I don't think that was previously ensured in all cases. For example, demarshal_generic() only cared about the GObject property type, it didn't know the expected D-Bus type. - Previously GDBusObjectManager would sometimes emit warnings (g_log()). Those probably indicated real bugs. In any case, it prevented us from running CI with G_DEBUG=fatal-warnings, because there would be just too many unrelated crashes. Now we log debug messages that can be enabled with "LIBNM_CLIENT_DEBUG=trace". Some of these messages can also be turned into g_warning()/g_critical() by setting LIBNM_CLIENT_DEBUG=warning,error. Together with G_DEBUG=fatal-warnings, this turns them into assertions. Note that such "assertion failures" might also happen because of a server bug (or change). Thus these are not common assertions that indicate a bug in libnm and are thus not armed unless explicitly requested. In our CI we should now always run with LIBNM_CLIENT_DEBUG=warning,error and G_DEBUG=fatal-warnings and to catch bugs. Note that currently NetworkManager has bugs in this regard, so enabling this will result in assertion failures. That should be fixed first. - Note that this changes the order in which we emit "notify:devices" and "device-added" signals. I think it makes the most sense to emit first "device-removed", then "notify:devices", and finally "device-added" signals. This changes behavior for commit 52ae28f6e5bf ('libnm: queue added/removed signals and suppress uninitialized notifications'), but I don't think that users should actually rely on the order. Still, the new order makes the most sense to me. - In NetworkManager, profiles can be invisible to the user by setting "connection.permissions". Such profiles would be hidden by NMClient's nm_client_get_connections() and their "connection-added"/"connection-removed" signals. Note that NMActiveConnection's nm_active_connection_get_connection() and NMDevice's nm_device_get_available_connections() still exposes such hidden NMRemoteConnection instances. This behavior was preserved. NUMBERS ------- I compared 3 versions of libnm. [1] 962297f9085d, current tip of nm-1-20 branch [2] 4fad8c7c642e, current master, immediate parent of this patch [3] this patch All tests were done on Fedora 31, x86_64, gcc 9.2.1-1.fc31. The libraries were build with $ ./contrib/fedora/rpm/build_clean.sh -g -w test -W debug Note that RPM build already stripped the library. --- N1) File size of libnm.so.0.1.0 in bytes. There currently seems to be a issue on Fedora 31 generating wrong ELF notes. Usually, libnm is smaller but in these tests it had large (and bogus) ELF notes. Anyway, the point is to show the relative sizes, so it doesn't matter). [1] 4075552 (102.7%) [2] 3969624 (100.0%) [3] 3705208 ( 93.3%) --- N2) `size /usr/lib64/libnm.so.0.1.0`: text data bss dec hex filename [1] 1314569 (102.0%) 69980 ( 94.8%) 10632 ( 80.4%) 1395181 (101.4%) 1549ed /usr/lib64/libnm.so.0.1.0 [2] 1288410 (100.0%) 73796 (100.0%) 13224 (100.0%) 1375430 (100.0%) 14fcc6 /usr/lib64/libnm.so.0.1.0 [3] 1229066 ( 95.4%) 65248 ( 88.4%) 13400 (101.3%) 1307714 ( 95.1%) 13f442 /usr/lib64/libnm.so.0.1.0 --- N3) Performance test with test-client.py. With checkout of [2], run ``` prepare_checkout() { rm -rf /tmp/nm-test && \ git checkout -B test 4fad8c7c642e && \ git clean -fdx && \ ./autogen.sh --prefix=/tmp/nm-test && \ make -j 5 install && \ make -j 5 check-local-clients-tests-test-client } prepare_test() { NM_TEST_REGENERATE=1 NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v } do_test() { for i in {1..10}; do NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v || return -1 done echo "done!" } prepare_checkout prepare_test time do_test ``` [1] real 2m14.497s (101.3%) user 5m26.651s (100.3%) sys 1m40.453s (101.4%) [2] real 2m12.800s (100.0%) user 5m25.619s (100.0%) sys 1m39.065s (100.0%) [3] real 1m54.915s ( 86.5%) user 4m18.585s ( 79.4%) sys 1m32.066s ( 92.9%) --- N4) Performance. Run NetworkManager from build [2] and setup a large number of profiles (551 profiles and 515 devices, mostly unrealized). This setup is already at the edge of what NetworkManager currently can handle. Of course, that is a different issue. Here we just check how long plain `nmcli` takes on the system. ``` do_cleanup() { for UUID in $(nmcli -g NAME,UUID connection show | sed -n 's/^xx-c-.*:\([^:]\+\)$/\1/p'); do nmcli connection delete uuid "$UUID" done for DEVICE in $(nmcli -g DEVICE device status | grep '^xx-i-'); do nmcli device delete "$DEVICE" done } do_setup() { do_cleanup for i in {1..30}; do nmcli connection add type bond autoconnect no con-name xx-c-bond-$i ifname xx-i-bond-$i ipv4.method disabled ipv6.method ignore for j in $(seq $i 30); do nmcli connection add type vlan autoconnect no con-name xx-c-vlan-$i-$j vlan.id $j ifname xx-i-vlan-$i-$j vlan.parent xx-i-bond-$i ipv4.method disabled ipv6.method ignore done done systemctl restart NetworkManager.service sleep 5 } do_test() { perf stat -r 50 -B nmcli 1>/dev/null } do_test ``` [1] Performance counter stats for 'nmcli' (50 runs): 456.33 msec task-clock:u # 1.093 CPUs utilized ( +- 0.44% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,900 page-faults:u # 0.013 M/sec ( +- 0.02% ) 1,408,675,453 cycles:u # 3.087 GHz ( +- 0.48% ) 1,594,741,060 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 368,744,018 branches:u # 808.061 M/sec ( +- 0.02% ) 4,566,058 branch-misses:u # 1.24% of all branches ( +- 0.76% ) 0.41761 +- 0.00282 seconds time elapsed ( +- 0.68% ) [2] Performance counter stats for 'nmcli' (50 runs): 477.99 msec task-clock:u # 1.088 CPUs utilized ( +- 0.36% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,948 page-faults:u # 0.012 M/sec ( +- 0.03% ) 1,471,133,482 cycles:u # 3.078 GHz ( +- 0.36% ) 1,655,275,369 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 382,595,152 branches:u # 800.433 M/sec ( +- 0.02% ) 4,746,070 branch-misses:u # 1.24% of all branches ( +- 0.49% ) 0.43923 +- 0.00242 seconds time elapsed ( +- 0.55% ) [3] Performance counter stats for 'nmcli' (50 runs): 352.36 msec task-clock:u # 1.027 CPUs utilized ( +- 0.32% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 4,790 page-faults:u # 0.014 M/sec ( +- 0.26% ) 1,092,341,186 cycles:u # 3.100 GHz ( +- 0.26% ) 1,209,045,283 instructions:u # 1.11 insn per cycle ( +- 0.02% ) 281,708,462 branches:u # 799.499 M/sec ( +- 0.01% ) 3,101,031 branch-misses:u # 1.10% of all branches ( +- 0.61% ) 0.34296 +- 0.00120 seconds time elapsed ( +- 0.35% ) --- N5) same setup as N4), but run `PAGER= /bin/time -v nmcli`: [1] Command being timed: "nmcli" User time (seconds): 0.42 System time (seconds): 0.04 Percent of CPU this job got: 107% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.43 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34456 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6128 Voluntary context switches: 1298 Involuntary context switches: 1106 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [2] Command being timed: "nmcli" User time (seconds): 0.44 System time (seconds): 0.04 Percent of CPU this job got: 108% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.44 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34452 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6169 Voluntary context switches: 1849 Involuntary context switches: 142 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [3] Command being timed: "nmcli" User time (seconds): 0.32 System time (seconds): 0.02 Percent of CPU this job got: 102% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.34 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 29196 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 5059 Voluntary context switches: 919 Involuntary context switches: 685 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 --- N6) same setup as N4), but run `nmcli monitor` and look at `ps aux` for the RSS size. USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND [1] me 1492900 21.0 0.2 461348 33248 pts/10 Sl+ 15:02 0:00 nmcli monitor [2] me 1490721 5.0 0.2 461496 33548 pts/10 Sl+ 15:00 0:00 nmcli monitor [3] me 1495801 16.5 0.1 459476 28692 pts/10 Sl+ 15:04 0:00 nmcli monitor
2019-10-30 11:42:58 +01:00
struct udev_device *udev_device;
struct udev_device *tmpdev;
const char *ifname;
guint32 count = 0;
libnm: refactor caching of D-Bus objects in NMClient No longer use GDBusObjectMangaerClient and gdbus-codegen generated classes for the NMClient cache. Instead, use GDBusConnection directly and a custom implementation (NMLDBusObject) for caching D-Bus' ObjectManager data. CHANGES ------- - This is a complete rework. I think the previous implementation was difficult to understand. There were unfixed bugs and nobody understood the code well enough to fix them. Maybe somebody out there understood the code, but I certainly did not. At least nobody provided patches to fix those issues. I do believe that this implementation is more straightforward and easier to understand. It removes a lot of layers of code. Whether this claim of simplicity is true, each reader must decide for himself/herself. Note that it is still fairly complex. - There was a lingering performance issue with large number of D-Bus objects. The patch tries hard that the implementation scales well. Of course, when we cache N objects that have N-to-M references to other, we still are fundamentally O(N*M) for runtime and memory consumption (with M being the number of references between objects). But each part should behave efficiently and well. - Play well with GMainContext. libnm code (NMClient) is generally not thread safe. However, it should work to use multiple instances in parallel, as long as each access to a NMClient is through the caller's GMainContext. This follows glib's style and effectively allows to use NMClient in a multi threaded scenario. This implies to stick to a main context upon construction and ensure that callbacks are only invoked when iterating that context. Also, NMClient itself shall never iterate the caller's context. This also means, libnm must never use g_idle_add() or g_timeout_add(), as those enqueue sources in the g_main_context_default() context. - Get ordering of messages right. All events are consistently enqueued in a GMainContext and processed strictly in order. For example, previously "nm-object.c" tried to combine signals and emit them on an idle handler. That is wrong, signals must be emitted in the right order and when they happen. Note that when using GInitable's synchronous initialization to initialize the NMClient instance, NMClient internally still operates fully asynchronously. In that case NMClient has an internal main context. - NMClient takes over most of the functionality. When using D-Bus' ObjectManager interface, one needs to handle basically the entire state of the D-Bus interface. That cannot be separated well into distinct parts, and even if you try, you just end up having closely related code in different source files. Spreading related code does not make it easier to understand, on the contrary. That means, NMClient is inherently complex as it contains most of the logic. I think that is not avoidable, but it's not as bad as it sounds. - NMClient processes D-Bus messages and state changes in separate steps. First NMClient unpacks the message (e.g. _dbus_handle_properties_changed()) and keeps track of the changed data. Then we update the GObject instances (_dbus_handle_obj_changed_dbus()) without emitting any signals yet. Finally, we emit all signals and notifications that were collected (_dbus_handle_changes_commit()). Note that for example during the initial GetManagedObjects() reply, NMClient receive a large amount of state at once. But we first apply all the changes to our GObject instances before emitting any signals. The result is that signals are always emitted in a moment when the cache is consistent. The unavoidable downside is that when you receive a property changed signal, possibly many other properties changed already and more signals are about to be emitted. - NMDeviceWifi no longer modifies the content of the cache from client side during poke_wireless_devices_with_rf_status(). The content of the cache should be determined by D-Bus alone and follow what NetworkManager service exposes. Local modifications should be avoided. - This aims to bring no API/ABI change, though it does of course bring various subtle changes in behavior. Those should be all for the better, but the goal is not to break any existing clients. This does change internal (albeit externally visible) API, like dropping NM_OBJECT_DBUS_OBJECT_MANAGER property and NMObject no longer implementing GInitableIface and GAsyncInitableIface. - Some uses of gdbus-codegen classes remain in NMVpnPluginOld, NMVpnServicePlugin and NMSecretAgentOld. These are independent of NMClient/NMObject and should be reworked separately. - While we no longer use generated classes from gdbus-codegen, we don't need more glue code than before. Also before we constructed NMPropertiesInfo and a had large amount of code to propagate properties from NMDBus* to NMObject. That got completely reworked, but did not fundamentally change. You still need about the same effort to create the NMLDBusMetaIface. Not using generated bindings did not make anything worse (which tells about the usefulness of generated code, at least in the way it was used). - NMLDBusMetaIface and other meta data is static and immutable. This avoids copying them around. Also, macros like NML_DBUS_META_PROPERTY_INIT_U() have compile time checks to ensure the property types matches. It's pretty hard to misuse them because it won't compile. - The meta data now explicitly encodes the expected D-Bus types and makes sure never to accept wrong data. That would only matter when the server (accidentally or intentionally) exposes unexpected types on D-Bus. I don't think that was previously ensured in all cases. For example, demarshal_generic() only cared about the GObject property type, it didn't know the expected D-Bus type. - Previously GDBusObjectManager would sometimes emit warnings (g_log()). Those probably indicated real bugs. In any case, it prevented us from running CI with G_DEBUG=fatal-warnings, because there would be just too many unrelated crashes. Now we log debug messages that can be enabled with "LIBNM_CLIENT_DEBUG=trace". Some of these messages can also be turned into g_warning()/g_critical() by setting LIBNM_CLIENT_DEBUG=warning,error. Together with G_DEBUG=fatal-warnings, this turns them into assertions. Note that such "assertion failures" might also happen because of a server bug (or change). Thus these are not common assertions that indicate a bug in libnm and are thus not armed unless explicitly requested. In our CI we should now always run with LIBNM_CLIENT_DEBUG=warning,error and G_DEBUG=fatal-warnings and to catch bugs. Note that currently NetworkManager has bugs in this regard, so enabling this will result in assertion failures. That should be fixed first. - Note that this changes the order in which we emit "notify:devices" and "device-added" signals. I think it makes the most sense to emit first "device-removed", then "notify:devices", and finally "device-added" signals. This changes behavior for commit 52ae28f6e5bf ('libnm: queue added/removed signals and suppress uninitialized notifications'), but I don't think that users should actually rely on the order. Still, the new order makes the most sense to me. - In NetworkManager, profiles can be invisible to the user by setting "connection.permissions". Such profiles would be hidden by NMClient's nm_client_get_connections() and their "connection-added"/"connection-removed" signals. Note that NMActiveConnection's nm_active_connection_get_connection() and NMDevice's nm_device_get_available_connections() still exposes such hidden NMRemoteConnection instances. This behavior was preserved. NUMBERS ------- I compared 3 versions of libnm. [1] 962297f9085d, current tip of nm-1-20 branch [2] 4fad8c7c642e, current master, immediate parent of this patch [3] this patch All tests were done on Fedora 31, x86_64, gcc 9.2.1-1.fc31. The libraries were build with $ ./contrib/fedora/rpm/build_clean.sh -g -w test -W debug Note that RPM build already stripped the library. --- N1) File size of libnm.so.0.1.0 in bytes. There currently seems to be a issue on Fedora 31 generating wrong ELF notes. Usually, libnm is smaller but in these tests it had large (and bogus) ELF notes. Anyway, the point is to show the relative sizes, so it doesn't matter). [1] 4075552 (102.7%) [2] 3969624 (100.0%) [3] 3705208 ( 93.3%) --- N2) `size /usr/lib64/libnm.so.0.1.0`: text data bss dec hex filename [1] 1314569 (102.0%) 69980 ( 94.8%) 10632 ( 80.4%) 1395181 (101.4%) 1549ed /usr/lib64/libnm.so.0.1.0 [2] 1288410 (100.0%) 73796 (100.0%) 13224 (100.0%) 1375430 (100.0%) 14fcc6 /usr/lib64/libnm.so.0.1.0 [3] 1229066 ( 95.4%) 65248 ( 88.4%) 13400 (101.3%) 1307714 ( 95.1%) 13f442 /usr/lib64/libnm.so.0.1.0 --- N3) Performance test with test-client.py. With checkout of [2], run ``` prepare_checkout() { rm -rf /tmp/nm-test && \ git checkout -B test 4fad8c7c642e && \ git clean -fdx && \ ./autogen.sh --prefix=/tmp/nm-test && \ make -j 5 install && \ make -j 5 check-local-clients-tests-test-client } prepare_test() { NM_TEST_REGENERATE=1 NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v } do_test() { for i in {1..10}; do NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v || return -1 done echo "done!" } prepare_checkout prepare_test time do_test ``` [1] real 2m14.497s (101.3%) user 5m26.651s (100.3%) sys 1m40.453s (101.4%) [2] real 2m12.800s (100.0%) user 5m25.619s (100.0%) sys 1m39.065s (100.0%) [3] real 1m54.915s ( 86.5%) user 4m18.585s ( 79.4%) sys 1m32.066s ( 92.9%) --- N4) Performance. Run NetworkManager from build [2] and setup a large number of profiles (551 profiles and 515 devices, mostly unrealized). This setup is already at the edge of what NetworkManager currently can handle. Of course, that is a different issue. Here we just check how long plain `nmcli` takes on the system. ``` do_cleanup() { for UUID in $(nmcli -g NAME,UUID connection show | sed -n 's/^xx-c-.*:\([^:]\+\)$/\1/p'); do nmcli connection delete uuid "$UUID" done for DEVICE in $(nmcli -g DEVICE device status | grep '^xx-i-'); do nmcli device delete "$DEVICE" done } do_setup() { do_cleanup for i in {1..30}; do nmcli connection add type bond autoconnect no con-name xx-c-bond-$i ifname xx-i-bond-$i ipv4.method disabled ipv6.method ignore for j in $(seq $i 30); do nmcli connection add type vlan autoconnect no con-name xx-c-vlan-$i-$j vlan.id $j ifname xx-i-vlan-$i-$j vlan.parent xx-i-bond-$i ipv4.method disabled ipv6.method ignore done done systemctl restart NetworkManager.service sleep 5 } do_test() { perf stat -r 50 -B nmcli 1>/dev/null } do_test ``` [1] Performance counter stats for 'nmcli' (50 runs): 456.33 msec task-clock:u # 1.093 CPUs utilized ( +- 0.44% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,900 page-faults:u # 0.013 M/sec ( +- 0.02% ) 1,408,675,453 cycles:u # 3.087 GHz ( +- 0.48% ) 1,594,741,060 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 368,744,018 branches:u # 808.061 M/sec ( +- 0.02% ) 4,566,058 branch-misses:u # 1.24% of all branches ( +- 0.76% ) 0.41761 +- 0.00282 seconds time elapsed ( +- 0.68% ) [2] Performance counter stats for 'nmcli' (50 runs): 477.99 msec task-clock:u # 1.088 CPUs utilized ( +- 0.36% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,948 page-faults:u # 0.012 M/sec ( +- 0.03% ) 1,471,133,482 cycles:u # 3.078 GHz ( +- 0.36% ) 1,655,275,369 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 382,595,152 branches:u # 800.433 M/sec ( +- 0.02% ) 4,746,070 branch-misses:u # 1.24% of all branches ( +- 0.49% ) 0.43923 +- 0.00242 seconds time elapsed ( +- 0.55% ) [3] Performance counter stats for 'nmcli' (50 runs): 352.36 msec task-clock:u # 1.027 CPUs utilized ( +- 0.32% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 4,790 page-faults:u # 0.014 M/sec ( +- 0.26% ) 1,092,341,186 cycles:u # 3.100 GHz ( +- 0.26% ) 1,209,045,283 instructions:u # 1.11 insn per cycle ( +- 0.02% ) 281,708,462 branches:u # 799.499 M/sec ( +- 0.01% ) 3,101,031 branch-misses:u # 1.10% of all branches ( +- 0.61% ) 0.34296 +- 0.00120 seconds time elapsed ( +- 0.35% ) --- N5) same setup as N4), but run `PAGER= /bin/time -v nmcli`: [1] Command being timed: "nmcli" User time (seconds): 0.42 System time (seconds): 0.04 Percent of CPU this job got: 107% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.43 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34456 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6128 Voluntary context switches: 1298 Involuntary context switches: 1106 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [2] Command being timed: "nmcli" User time (seconds): 0.44 System time (seconds): 0.04 Percent of CPU this job got: 108% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.44 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34452 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6169 Voluntary context switches: 1849 Involuntary context switches: 142 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [3] Command being timed: "nmcli" User time (seconds): 0.32 System time (seconds): 0.02 Percent of CPU this job got: 102% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.34 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 29196 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 5059 Voluntary context switches: 919 Involuntary context switches: 685 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 --- N6) same setup as N4), but run `nmcli monitor` and look at `ps aux` for the RSS size. USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND [1] me 1492900 21.0 0.2 461348 33248 pts/10 Sl+ 15:02 0:00 nmcli monitor [2] me 1490721 5.0 0.2 461496 33548 pts/10 Sl+ 15:00 0:00 nmcli monitor [3] me 1495801 16.5 0.1 459476 28692 pts/10 Sl+ 15:04 0:00 nmcli monitor
2019-10-30 11:42:58 +01:00
char *enc_value = NULL;
char *db_value = NULL;
if (!priv->udev)
return NULL;
ifname = nm_device_get_iface (device);
if (!ifname)
return NULL;
udev_device = udev_device_new_from_subsystem_sysname (priv->udev, "net", ifname);
if (!udev_device) {
udev_device = udev_device_new_from_subsystem_sysname (priv->udev, "tty", ifname);
if (!udev_device)
return NULL;
}
/* Walk up the chain of the device and its parents a few steps to grab
* vendor and device ID information off it.
*/
tmpdev = udev_device;
while ((count++ < 3) && tmpdev && !enc_value) {
if (!enc_value)
enc_value = nm_udev_utils_property_decode_cp (udev_device_get_property_value (tmpdev, enc_prop));
if (!db_value)
db_value = g_strdup (udev_device_get_property_value (tmpdev, db_prop));
tmpdev = udev_device_get_parent (tmpdev);
}
udev_device_unref (udev_device);
/* Prefer the hwdata database value over what comes directly
* from the device. */
if (db_value) {
g_free (enc_value);
return db_value;
}
return enc_value;
}
static char *
_get_udev_property_utf8safe (NMDevice *device,
const char *enc_prop, /* ID_XXX_ENC */
const char *db_prop) /* ID_XXX_FROM_DATABASE */
{
return nm_utils_str_utf8safe_escape_take (_get_udev_property (device,
enc_prop,
db_prop),
NM_UTILS_STR_UTF8_SAFE_FLAG_ESCAPE_CTRL);
}
/**
* nm_device_get_product:
* @device: a #NMDevice
*
* Gets the product string of the #NMDevice.
*
* Returns: the product name of the device. This is the internal string used by the
* device, and must not be modified.
*
* The string is backslash escaped (C escaping) for invalid characters. The escaping
* can be reverted with g_strcompress(), however the result may not be valid UTF-8.
**/
const char *
nm_device_get_product (NMDevice *device)
{
NMDevicePrivate *priv;
g_return_val_if_fail (NM_IS_DEVICE (device), NULL);
priv = NM_DEVICE_GET_PRIVATE (device);
if (!priv->product) {
priv->product = _get_udev_property_utf8safe (device, "ID_MODEL_ENC", "ID_MODEL_FROM_DATABASE");
/* Sometimes ID_PRODUCT_FROM_DATABASE is used? */
if (!priv->product)
priv->product = _get_udev_property_utf8safe (device, "ID_MODEL_ENC", "ID_PRODUCT_FROM_DATABASE");
if (!priv->product)
priv->product = g_strdup ("");
}
return priv->product;
}
/**
* nm_device_get_vendor:
* @device: a #NMDevice
*
* Gets the vendor string of the #NMDevice.
*
* Returns: the vendor name of the device. This is the internal string used by the
* device, and must not be modified.
*
* The string is backslash escaped (C escaping) for invalid characters. The escaping
* can be reverted with g_strcompress(), however the result may not be valid UTF-8.
**/
const char *
nm_device_get_vendor (NMDevice *device)
{
NMDevicePrivate *priv;
g_return_val_if_fail (NM_IS_DEVICE (device), NULL);
priv = NM_DEVICE_GET_PRIVATE (device);
if (!priv->vendor)
priv->vendor = _get_udev_property_utf8safe (device, "ID_VENDOR_ENC", "ID_VENDOR_FROM_DATABASE");
if (!priv->vendor)
priv->vendor = g_strdup ("");
return priv->vendor;
}
static void
ensure_description (NMDevice *device)
{
NMDevicePrivate *priv = NM_DEVICE_GET_PRIVATE (device);
GParamSpec *name_prop;
gs_free char *short_product = NULL;
priv->short_vendor = nm_str_realloc (nm_utils_fixup_vendor_string (nm_device_get_vendor (device)));
/* Grab device's preferred name, if any */
name_prop = g_object_class_find_property (G_OBJECT_GET_CLASS (G_OBJECT (device)), "name");
if (name_prop) {
g_object_get (device, "name", &priv->description, NULL);
if (priv->description && priv->description[0])
return;
nm_clear_g_free (&priv->description);
}
if (!priv->short_vendor) {
priv->description = g_strdup (nm_device_get_iface (device) ?: "");
return;
}
short_product = nm_utils_fixup_product_string (nm_device_get_product (device));
if (short_product == NULL)
short_product = g_strdup (get_type_name (device));
/* Another quick hack; if all of the fixed up vendor string
* is found in product, ignore the vendor.
*/
{
gs_free char *pdown = g_ascii_strdown (short_product, -1);
gs_free char *vdown = g_ascii_strdown (priv->short_vendor, -1);
if (!strstr (pdown, vdown))
priv->description = g_strconcat (priv->short_vendor, " ", short_product, NULL);
else
priv->description = g_steal_pointer (&short_product);
}
}
static const char *
get_short_vendor (NMDevice *device)
{
NMDevicePrivate *priv;
g_return_val_if_fail (NM_IS_DEVICE (device), NULL);
priv = NM_DEVICE_GET_PRIVATE (device);
if (!priv->description)
ensure_description (device);
return priv->short_vendor;
}
/**
* nm_device_get_description:
* @device: an #NMDevice
*
* Gets a description of @device, based on its vendor and product names.
*
* Returns: a description of @device. If either the vendor or the
* product name is unknown, this returns the interface name.
*/
const char *
nm_device_get_description (NMDevice *device)
{
NMDevicePrivate *priv;
g_return_val_if_fail (NM_IS_DEVICE (device), NULL);
priv = NM_DEVICE_GET_PRIVATE (device);
if (!priv->description)
ensure_description (device);
return priv->description;
}
static gboolean
find_duplicates (char **names,
gboolean *duplicates,
int num_devices)
{
int i, j;
gboolean found_any = FALSE;
memset (duplicates, 0, num_devices * sizeof (gboolean));
for (i = 0; i < num_devices; i++) {
if (duplicates[i])
continue;
for (j = i + 1; j < num_devices; j++) {
if (duplicates[j])
continue;
if (!strcmp (names[i], names[j]))
duplicates[i] = duplicates[j] = found_any = TRUE;
}
}
return found_any;
}
/**
* nm_device_disambiguate_names:
* @devices: (array length=num_devices): an array of #NMDevice
* @num_devices: length of @devices
*
* Generates a list of short-ish unique presentation names for the
* devices in @devices.
*
* Returns: (transfer full) (array zero-terminated=1): the device names
*/
char **
nm_device_disambiguate_names (NMDevice **devices,
int num_devices)
{
char **names;
gboolean *duplicates;
int i;
names = g_new (char *, num_devices + 1);
duplicates = g_new (gboolean, num_devices);
/* Generic device name */
for (i = 0; i < num_devices; i++)
names[i] = get_device_generic_type_name_with_iface (devices[i]);
if (!find_duplicates (names, duplicates, num_devices))
goto done;
/* Try specific names (eg, "Ethernet" and "InfiniBand" rather
* than "Wired")
*/
for (i = 0; i < num_devices; i++) {
if (duplicates[i]) {
g_free (names[i]);
names[i] = get_device_type_name_with_iface (devices[i]);
}
}
if (!find_duplicates (names, duplicates, num_devices))
goto done;
/* Try prefixing bus name (eg, "PCI Ethernet" vs "USB Ethernet") */
for (i = 0; i < num_devices; i++) {
if (duplicates[i]) {
const char *bus = get_bus_name (devices[i]);
char *name;
if (!bus)
continue;
g_free (names[i]);
name = get_device_type_name_with_iface (devices[i]);
/* TRANSLATORS: the first %s is a bus name (eg, "USB") or
* product name, the second is a device type (eg,
* "Ethernet"). You can change this to something like
* "%2$s (%1$s)" if there's no grammatical way to combine
* the strings otherwise.
*/
names[i] = g_strdup_printf (C_("long device name", "%s %s"),
bus, name);
g_free (name);
}
}
if (!find_duplicates (names, duplicates, num_devices))
goto done;
/* Try prefixing vendor name */
for (i = 0; i < num_devices; i++) {
if (duplicates[i]) {
const char *vendor = get_short_vendor (devices[i]);
char *name;
if (!vendor)
continue;
g_free (names[i]);
name = get_device_type_name_with_iface (devices[i]);
names[i] = g_strdup_printf (C_("long device name", "%s %s"),
vendor,
get_type_name (devices[i]));
g_free (name);
}
}
if (!find_duplicates (names, duplicates, num_devices))
goto done;
/* If dealing with Bluetooth devices, try to distinguish them by
* device name.
*/
for (i = 0; i < num_devices; i++) {
if (duplicates[i] && NM_IS_DEVICE_BT (devices[i])) {
const char *devname = nm_device_bt_get_name (NM_DEVICE_BT (devices[i]));
char *name;
if (!devname)
continue;
g_free (names[i]);
name = get_device_type_name_with_iface (devices[i]);
names[i] = g_strdup_printf ("%s (%s)", name, devname);
g_free (name);
}
}
if (!find_duplicates (names, duplicates, num_devices))
goto done;
/* We have multiple identical network cards, so we have to differentiate
* them by interface name.
*/
for (i = 0; i < num_devices; i++) {
if (duplicates[i]) {
const char *interface = nm_device_get_iface (devices[i]);
if (!interface)
continue;
g_free (names[i]);
names[i] = g_strdup_printf ("%s (%s)",
get_type_name (devices[i]),
interface);
}
}
done:
g_free (duplicates);
names[num_devices] = NULL;
return names;
}
/**
* nm_device_get_physical_port_id:
* @device: a #NMDevice
*
* Gets the physical port ID of the #NMDevice. If non-%NULL, this is
* an opaque string that can be used to recognize when
* seemingly-unrelated #NMDevices are actually just different virtual
* ports on a single physical port. (Eg, NPAR / SR-IOV.)
*
* Returns: the physical port ID of the device, or %NULL if the port
* ID is unknown. This is the internal string used by the device and
* must not be modified.
**/
const char *
nm_device_get_physical_port_id (NMDevice *device)
{
g_return_val_if_fail (NM_IS_DEVICE (device), NULL);
return _nml_coerce_property_str_not_empty (NM_DEVICE_GET_PRIVATE (device)->physical_port_id);
}
/**
* nm_device_get_mtu:
* @device: a #NMDevice
*
* Gets the MTU of the #NMDevice.
*
2018-05-23 16:08:01 +02:00
* Returns: the MTU of the device in bytes.
**/
guint32
nm_device_get_mtu (NMDevice *device)
{
g_return_val_if_fail (NM_IS_DEVICE (device), 0);
return NM_DEVICE_GET_PRIVATE (device)->mtu;
}
/**
* nm_device_get_metered:
* @device: a #NMDevice
*
* Gets the metered setting of a #NMDevice.
*
* Returns: the metered setting.
*
Revert "all: change "Since: 1.2" to "Since: 1.0.4"/"Since: 1.0.6" for backported API" API should be added with "Since:" of the next release on the same branch. That means, new API on 1.1 branch (development), should be "Since: 1.2" and new API on 1.0 branch (stable) will be "Since: 1.0.x". Similarly, new API on master is NM_AVAILABLE_IN_1_2 and will be added with the linker version libnl_1_2 -- never the versions of minor releases. It is also strongly advised that for the 1.0 branch, we only add API that was previously formerly added on master. IOW, that we only do true backports of API that already exists on master. API that gets backported, must also be added to master via NM_BACKPORT_SYMBOL(). That gives ABI compatibility and an application that was build against 1.0.x will work with 1.y.z version (y > 0) without need for recompiling -- provided that 1.y.z also contains that API. There is one important caveat: if a major branch (e.g. current master) has a linker section of backported APIs (e.g. libnm_1_0_6), we must do the minor release (1.0.6) before the next major release (1.2). The reason is that after the major release, the linker section (libnm_1_0_6) must not be extended and thus the minor release (1.0.6) must be already released at that point. In general, users should avoid using backported API because it limits the ability to upgrade to arbitrary later versions. But together with the previous point (that we only backport API to minor releases), a user that uses backported API can be sure that a 1.y.z version is ABI compatible with 1.0.x, if the 1.y.z release date was after the release date of 1.0.x. This reverts commit 02a136682c749a0fd27853c0152d36c44635151f.
2015-08-22 00:57:30 +02:00
* Since: 1.2
**/
NMMetered
nm_device_get_metered (NMDevice *device)
{
g_return_val_if_fail (NM_IS_DEVICE (device), NM_METERED_UNKNOWN);
return NM_DEVICE_GET_PRIVATE (device)->metered;
}
NM_BACKPORT_SYMBOL (libnm_1_0_6, NMMetered, nm_device_get_metered, (NMDevice *device), (device));
/**
* nm_device_get_lldp_neighbors:
* @device: a #NMDevice
*
* Gets the list of neighbors discovered through LLDP.
*
* Returns: (element-type NMLldpNeighbor) (transfer none): the #GPtrArray
* containing #NMLldpNeighbor<!-- -->s. This is the internal copy used by the
* device and must not be modified. The library never modifies the returned
* array and thus it is safe for callers to reference and keep using it.
*
* Since: 1.2
**/
GPtrArray *
nm_device_get_lldp_neighbors (NMDevice *device)
{
libnm: refactor caching of D-Bus objects in NMClient No longer use GDBusObjectMangaerClient and gdbus-codegen generated classes for the NMClient cache. Instead, use GDBusConnection directly and a custom implementation (NMLDBusObject) for caching D-Bus' ObjectManager data. CHANGES ------- - This is a complete rework. I think the previous implementation was difficult to understand. There were unfixed bugs and nobody understood the code well enough to fix them. Maybe somebody out there understood the code, but I certainly did not. At least nobody provided patches to fix those issues. I do believe that this implementation is more straightforward and easier to understand. It removes a lot of layers of code. Whether this claim of simplicity is true, each reader must decide for himself/herself. Note that it is still fairly complex. - There was a lingering performance issue with large number of D-Bus objects. The patch tries hard that the implementation scales well. Of course, when we cache N objects that have N-to-M references to other, we still are fundamentally O(N*M) for runtime and memory consumption (with M being the number of references between objects). But each part should behave efficiently and well. - Play well with GMainContext. libnm code (NMClient) is generally not thread safe. However, it should work to use multiple instances in parallel, as long as each access to a NMClient is through the caller's GMainContext. This follows glib's style and effectively allows to use NMClient in a multi threaded scenario. This implies to stick to a main context upon construction and ensure that callbacks are only invoked when iterating that context. Also, NMClient itself shall never iterate the caller's context. This also means, libnm must never use g_idle_add() or g_timeout_add(), as those enqueue sources in the g_main_context_default() context. - Get ordering of messages right. All events are consistently enqueued in a GMainContext and processed strictly in order. For example, previously "nm-object.c" tried to combine signals and emit them on an idle handler. That is wrong, signals must be emitted in the right order and when they happen. Note that when using GInitable's synchronous initialization to initialize the NMClient instance, NMClient internally still operates fully asynchronously. In that case NMClient has an internal main context. - NMClient takes over most of the functionality. When using D-Bus' ObjectManager interface, one needs to handle basically the entire state of the D-Bus interface. That cannot be separated well into distinct parts, and even if you try, you just end up having closely related code in different source files. Spreading related code does not make it easier to understand, on the contrary. That means, NMClient is inherently complex as it contains most of the logic. I think that is not avoidable, but it's not as bad as it sounds. - NMClient processes D-Bus messages and state changes in separate steps. First NMClient unpacks the message (e.g. _dbus_handle_properties_changed()) and keeps track of the changed data. Then we update the GObject instances (_dbus_handle_obj_changed_dbus()) without emitting any signals yet. Finally, we emit all signals and notifications that were collected (_dbus_handle_changes_commit()). Note that for example during the initial GetManagedObjects() reply, NMClient receive a large amount of state at once. But we first apply all the changes to our GObject instances before emitting any signals. The result is that signals are always emitted in a moment when the cache is consistent. The unavoidable downside is that when you receive a property changed signal, possibly many other properties changed already and more signals are about to be emitted. - NMDeviceWifi no longer modifies the content of the cache from client side during poke_wireless_devices_with_rf_status(). The content of the cache should be determined by D-Bus alone and follow what NetworkManager service exposes. Local modifications should be avoided. - This aims to bring no API/ABI change, though it does of course bring various subtle changes in behavior. Those should be all for the better, but the goal is not to break any existing clients. This does change internal (albeit externally visible) API, like dropping NM_OBJECT_DBUS_OBJECT_MANAGER property and NMObject no longer implementing GInitableIface and GAsyncInitableIface. - Some uses of gdbus-codegen classes remain in NMVpnPluginOld, NMVpnServicePlugin and NMSecretAgentOld. These are independent of NMClient/NMObject and should be reworked separately. - While we no longer use generated classes from gdbus-codegen, we don't need more glue code than before. Also before we constructed NMPropertiesInfo and a had large amount of code to propagate properties from NMDBus* to NMObject. That got completely reworked, but did not fundamentally change. You still need about the same effort to create the NMLDBusMetaIface. Not using generated bindings did not make anything worse (which tells about the usefulness of generated code, at least in the way it was used). - NMLDBusMetaIface and other meta data is static and immutable. This avoids copying them around. Also, macros like NML_DBUS_META_PROPERTY_INIT_U() have compile time checks to ensure the property types matches. It's pretty hard to misuse them because it won't compile. - The meta data now explicitly encodes the expected D-Bus types and makes sure never to accept wrong data. That would only matter when the server (accidentally or intentionally) exposes unexpected types on D-Bus. I don't think that was previously ensured in all cases. For example, demarshal_generic() only cared about the GObject property type, it didn't know the expected D-Bus type. - Previously GDBusObjectManager would sometimes emit warnings (g_log()). Those probably indicated real bugs. In any case, it prevented us from running CI with G_DEBUG=fatal-warnings, because there would be just too many unrelated crashes. Now we log debug messages that can be enabled with "LIBNM_CLIENT_DEBUG=trace". Some of these messages can also be turned into g_warning()/g_critical() by setting LIBNM_CLIENT_DEBUG=warning,error. Together with G_DEBUG=fatal-warnings, this turns them into assertions. Note that such "assertion failures" might also happen because of a server bug (or change). Thus these are not common assertions that indicate a bug in libnm and are thus not armed unless explicitly requested. In our CI we should now always run with LIBNM_CLIENT_DEBUG=warning,error and G_DEBUG=fatal-warnings and to catch bugs. Note that currently NetworkManager has bugs in this regard, so enabling this will result in assertion failures. That should be fixed first. - Note that this changes the order in which we emit "notify:devices" and "device-added" signals. I think it makes the most sense to emit first "device-removed", then "notify:devices", and finally "device-added" signals. This changes behavior for commit 52ae28f6e5bf ('libnm: queue added/removed signals and suppress uninitialized notifications'), but I don't think that users should actually rely on the order. Still, the new order makes the most sense to me. - In NetworkManager, profiles can be invisible to the user by setting "connection.permissions". Such profiles would be hidden by NMClient's nm_client_get_connections() and their "connection-added"/"connection-removed" signals. Note that NMActiveConnection's nm_active_connection_get_connection() and NMDevice's nm_device_get_available_connections() still exposes such hidden NMRemoteConnection instances. This behavior was preserved. NUMBERS ------- I compared 3 versions of libnm. [1] 962297f9085d, current tip of nm-1-20 branch [2] 4fad8c7c642e, current master, immediate parent of this patch [3] this patch All tests were done on Fedora 31, x86_64, gcc 9.2.1-1.fc31. The libraries were build with $ ./contrib/fedora/rpm/build_clean.sh -g -w test -W debug Note that RPM build already stripped the library. --- N1) File size of libnm.so.0.1.0 in bytes. There currently seems to be a issue on Fedora 31 generating wrong ELF notes. Usually, libnm is smaller but in these tests it had large (and bogus) ELF notes. Anyway, the point is to show the relative sizes, so it doesn't matter). [1] 4075552 (102.7%) [2] 3969624 (100.0%) [3] 3705208 ( 93.3%) --- N2) `size /usr/lib64/libnm.so.0.1.0`: text data bss dec hex filename [1] 1314569 (102.0%) 69980 ( 94.8%) 10632 ( 80.4%) 1395181 (101.4%) 1549ed /usr/lib64/libnm.so.0.1.0 [2] 1288410 (100.0%) 73796 (100.0%) 13224 (100.0%) 1375430 (100.0%) 14fcc6 /usr/lib64/libnm.so.0.1.0 [3] 1229066 ( 95.4%) 65248 ( 88.4%) 13400 (101.3%) 1307714 ( 95.1%) 13f442 /usr/lib64/libnm.so.0.1.0 --- N3) Performance test with test-client.py. With checkout of [2], run ``` prepare_checkout() { rm -rf /tmp/nm-test && \ git checkout -B test 4fad8c7c642e && \ git clean -fdx && \ ./autogen.sh --prefix=/tmp/nm-test && \ make -j 5 install && \ make -j 5 check-local-clients-tests-test-client } prepare_test() { NM_TEST_REGENERATE=1 NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v } do_test() { for i in {1..10}; do NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v || return -1 done echo "done!" } prepare_checkout prepare_test time do_test ``` [1] real 2m14.497s (101.3%) user 5m26.651s (100.3%) sys 1m40.453s (101.4%) [2] real 2m12.800s (100.0%) user 5m25.619s (100.0%) sys 1m39.065s (100.0%) [3] real 1m54.915s ( 86.5%) user 4m18.585s ( 79.4%) sys 1m32.066s ( 92.9%) --- N4) Performance. Run NetworkManager from build [2] and setup a large number of profiles (551 profiles and 515 devices, mostly unrealized). This setup is already at the edge of what NetworkManager currently can handle. Of course, that is a different issue. Here we just check how long plain `nmcli` takes on the system. ``` do_cleanup() { for UUID in $(nmcli -g NAME,UUID connection show | sed -n 's/^xx-c-.*:\([^:]\+\)$/\1/p'); do nmcli connection delete uuid "$UUID" done for DEVICE in $(nmcli -g DEVICE device status | grep '^xx-i-'); do nmcli device delete "$DEVICE" done } do_setup() { do_cleanup for i in {1..30}; do nmcli connection add type bond autoconnect no con-name xx-c-bond-$i ifname xx-i-bond-$i ipv4.method disabled ipv6.method ignore for j in $(seq $i 30); do nmcli connection add type vlan autoconnect no con-name xx-c-vlan-$i-$j vlan.id $j ifname xx-i-vlan-$i-$j vlan.parent xx-i-bond-$i ipv4.method disabled ipv6.method ignore done done systemctl restart NetworkManager.service sleep 5 } do_test() { perf stat -r 50 -B nmcli 1>/dev/null } do_test ``` [1] Performance counter stats for 'nmcli' (50 runs): 456.33 msec task-clock:u # 1.093 CPUs utilized ( +- 0.44% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,900 page-faults:u # 0.013 M/sec ( +- 0.02% ) 1,408,675,453 cycles:u # 3.087 GHz ( +- 0.48% ) 1,594,741,060 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 368,744,018 branches:u # 808.061 M/sec ( +- 0.02% ) 4,566,058 branch-misses:u # 1.24% of all branches ( +- 0.76% ) 0.41761 +- 0.00282 seconds time elapsed ( +- 0.68% ) [2] Performance counter stats for 'nmcli' (50 runs): 477.99 msec task-clock:u # 1.088 CPUs utilized ( +- 0.36% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,948 page-faults:u # 0.012 M/sec ( +- 0.03% ) 1,471,133,482 cycles:u # 3.078 GHz ( +- 0.36% ) 1,655,275,369 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 382,595,152 branches:u # 800.433 M/sec ( +- 0.02% ) 4,746,070 branch-misses:u # 1.24% of all branches ( +- 0.49% ) 0.43923 +- 0.00242 seconds time elapsed ( +- 0.55% ) [3] Performance counter stats for 'nmcli' (50 runs): 352.36 msec task-clock:u # 1.027 CPUs utilized ( +- 0.32% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 4,790 page-faults:u # 0.014 M/sec ( +- 0.26% ) 1,092,341,186 cycles:u # 3.100 GHz ( +- 0.26% ) 1,209,045,283 instructions:u # 1.11 insn per cycle ( +- 0.02% ) 281,708,462 branches:u # 799.499 M/sec ( +- 0.01% ) 3,101,031 branch-misses:u # 1.10% of all branches ( +- 0.61% ) 0.34296 +- 0.00120 seconds time elapsed ( +- 0.35% ) --- N5) same setup as N4), but run `PAGER= /bin/time -v nmcli`: [1] Command being timed: "nmcli" User time (seconds): 0.42 System time (seconds): 0.04 Percent of CPU this job got: 107% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.43 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34456 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6128 Voluntary context switches: 1298 Involuntary context switches: 1106 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [2] Command being timed: "nmcli" User time (seconds): 0.44 System time (seconds): 0.04 Percent of CPU this job got: 108% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.44 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34452 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6169 Voluntary context switches: 1849 Involuntary context switches: 142 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [3] Command being timed: "nmcli" User time (seconds): 0.32 System time (seconds): 0.02 Percent of CPU this job got: 102% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.34 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 29196 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 5059 Voluntary context switches: 919 Involuntary context switches: 685 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 --- N6) same setup as N4), but run `nmcli monitor` and look at `ps aux` for the RSS size. USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND [1] me 1492900 21.0 0.2 461348 33248 pts/10 Sl+ 15:02 0:00 nmcli monitor [2] me 1490721 5.0 0.2 461496 33548 pts/10 Sl+ 15:00 0:00 nmcli monitor [3] me 1495801 16.5 0.1 459476 28692 pts/10 Sl+ 15:04 0:00 nmcli monitor
2019-10-30 11:42:58 +01:00
NMDevicePrivate *priv;
g_return_val_if_fail (NM_IS_DEVICE (device), NULL);
libnm: refactor caching of D-Bus objects in NMClient No longer use GDBusObjectMangaerClient and gdbus-codegen generated classes for the NMClient cache. Instead, use GDBusConnection directly and a custom implementation (NMLDBusObject) for caching D-Bus' ObjectManager data. CHANGES ------- - This is a complete rework. I think the previous implementation was difficult to understand. There were unfixed bugs and nobody understood the code well enough to fix them. Maybe somebody out there understood the code, but I certainly did not. At least nobody provided patches to fix those issues. I do believe that this implementation is more straightforward and easier to understand. It removes a lot of layers of code. Whether this claim of simplicity is true, each reader must decide for himself/herself. Note that it is still fairly complex. - There was a lingering performance issue with large number of D-Bus objects. The patch tries hard that the implementation scales well. Of course, when we cache N objects that have N-to-M references to other, we still are fundamentally O(N*M) for runtime and memory consumption (with M being the number of references between objects). But each part should behave efficiently and well. - Play well with GMainContext. libnm code (NMClient) is generally not thread safe. However, it should work to use multiple instances in parallel, as long as each access to a NMClient is through the caller's GMainContext. This follows glib's style and effectively allows to use NMClient in a multi threaded scenario. This implies to stick to a main context upon construction and ensure that callbacks are only invoked when iterating that context. Also, NMClient itself shall never iterate the caller's context. This also means, libnm must never use g_idle_add() or g_timeout_add(), as those enqueue sources in the g_main_context_default() context. - Get ordering of messages right. All events are consistently enqueued in a GMainContext and processed strictly in order. For example, previously "nm-object.c" tried to combine signals and emit them on an idle handler. That is wrong, signals must be emitted in the right order and when they happen. Note that when using GInitable's synchronous initialization to initialize the NMClient instance, NMClient internally still operates fully asynchronously. In that case NMClient has an internal main context. - NMClient takes over most of the functionality. When using D-Bus' ObjectManager interface, one needs to handle basically the entire state of the D-Bus interface. That cannot be separated well into distinct parts, and even if you try, you just end up having closely related code in different source files. Spreading related code does not make it easier to understand, on the contrary. That means, NMClient is inherently complex as it contains most of the logic. I think that is not avoidable, but it's not as bad as it sounds. - NMClient processes D-Bus messages and state changes in separate steps. First NMClient unpacks the message (e.g. _dbus_handle_properties_changed()) and keeps track of the changed data. Then we update the GObject instances (_dbus_handle_obj_changed_dbus()) without emitting any signals yet. Finally, we emit all signals and notifications that were collected (_dbus_handle_changes_commit()). Note that for example during the initial GetManagedObjects() reply, NMClient receive a large amount of state at once. But we first apply all the changes to our GObject instances before emitting any signals. The result is that signals are always emitted in a moment when the cache is consistent. The unavoidable downside is that when you receive a property changed signal, possibly many other properties changed already and more signals are about to be emitted. - NMDeviceWifi no longer modifies the content of the cache from client side during poke_wireless_devices_with_rf_status(). The content of the cache should be determined by D-Bus alone and follow what NetworkManager service exposes. Local modifications should be avoided. - This aims to bring no API/ABI change, though it does of course bring various subtle changes in behavior. Those should be all for the better, but the goal is not to break any existing clients. This does change internal (albeit externally visible) API, like dropping NM_OBJECT_DBUS_OBJECT_MANAGER property and NMObject no longer implementing GInitableIface and GAsyncInitableIface. - Some uses of gdbus-codegen classes remain in NMVpnPluginOld, NMVpnServicePlugin and NMSecretAgentOld. These are independent of NMClient/NMObject and should be reworked separately. - While we no longer use generated classes from gdbus-codegen, we don't need more glue code than before. Also before we constructed NMPropertiesInfo and a had large amount of code to propagate properties from NMDBus* to NMObject. That got completely reworked, but did not fundamentally change. You still need about the same effort to create the NMLDBusMetaIface. Not using generated bindings did not make anything worse (which tells about the usefulness of generated code, at least in the way it was used). - NMLDBusMetaIface and other meta data is static and immutable. This avoids copying them around. Also, macros like NML_DBUS_META_PROPERTY_INIT_U() have compile time checks to ensure the property types matches. It's pretty hard to misuse them because it won't compile. - The meta data now explicitly encodes the expected D-Bus types and makes sure never to accept wrong data. That would only matter when the server (accidentally or intentionally) exposes unexpected types on D-Bus. I don't think that was previously ensured in all cases. For example, demarshal_generic() only cared about the GObject property type, it didn't know the expected D-Bus type. - Previously GDBusObjectManager would sometimes emit warnings (g_log()). Those probably indicated real bugs. In any case, it prevented us from running CI with G_DEBUG=fatal-warnings, because there would be just too many unrelated crashes. Now we log debug messages that can be enabled with "LIBNM_CLIENT_DEBUG=trace". Some of these messages can also be turned into g_warning()/g_critical() by setting LIBNM_CLIENT_DEBUG=warning,error. Together with G_DEBUG=fatal-warnings, this turns them into assertions. Note that such "assertion failures" might also happen because of a server bug (or change). Thus these are not common assertions that indicate a bug in libnm and are thus not armed unless explicitly requested. In our CI we should now always run with LIBNM_CLIENT_DEBUG=warning,error and G_DEBUG=fatal-warnings and to catch bugs. Note that currently NetworkManager has bugs in this regard, so enabling this will result in assertion failures. That should be fixed first. - Note that this changes the order in which we emit "notify:devices" and "device-added" signals. I think it makes the most sense to emit first "device-removed", then "notify:devices", and finally "device-added" signals. This changes behavior for commit 52ae28f6e5bf ('libnm: queue added/removed signals and suppress uninitialized notifications'), but I don't think that users should actually rely on the order. Still, the new order makes the most sense to me. - In NetworkManager, profiles can be invisible to the user by setting "connection.permissions". Such profiles would be hidden by NMClient's nm_client_get_connections() and their "connection-added"/"connection-removed" signals. Note that NMActiveConnection's nm_active_connection_get_connection() and NMDevice's nm_device_get_available_connections() still exposes such hidden NMRemoteConnection instances. This behavior was preserved. NUMBERS ------- I compared 3 versions of libnm. [1] 962297f9085d, current tip of nm-1-20 branch [2] 4fad8c7c642e, current master, immediate parent of this patch [3] this patch All tests were done on Fedora 31, x86_64, gcc 9.2.1-1.fc31. The libraries were build with $ ./contrib/fedora/rpm/build_clean.sh -g -w test -W debug Note that RPM build already stripped the library. --- N1) File size of libnm.so.0.1.0 in bytes. There currently seems to be a issue on Fedora 31 generating wrong ELF notes. Usually, libnm is smaller but in these tests it had large (and bogus) ELF notes. Anyway, the point is to show the relative sizes, so it doesn't matter). [1] 4075552 (102.7%) [2] 3969624 (100.0%) [3] 3705208 ( 93.3%) --- N2) `size /usr/lib64/libnm.so.0.1.0`: text data bss dec hex filename [1] 1314569 (102.0%) 69980 ( 94.8%) 10632 ( 80.4%) 1395181 (101.4%) 1549ed /usr/lib64/libnm.so.0.1.0 [2] 1288410 (100.0%) 73796 (100.0%) 13224 (100.0%) 1375430 (100.0%) 14fcc6 /usr/lib64/libnm.so.0.1.0 [3] 1229066 ( 95.4%) 65248 ( 88.4%) 13400 (101.3%) 1307714 ( 95.1%) 13f442 /usr/lib64/libnm.so.0.1.0 --- N3) Performance test with test-client.py. With checkout of [2], run ``` prepare_checkout() { rm -rf /tmp/nm-test && \ git checkout -B test 4fad8c7c642e && \ git clean -fdx && \ ./autogen.sh --prefix=/tmp/nm-test && \ make -j 5 install && \ make -j 5 check-local-clients-tests-test-client } prepare_test() { NM_TEST_REGENERATE=1 NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v } do_test() { for i in {1..10}; do NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v || return -1 done echo "done!" } prepare_checkout prepare_test time do_test ``` [1] real 2m14.497s (101.3%) user 5m26.651s (100.3%) sys 1m40.453s (101.4%) [2] real 2m12.800s (100.0%) user 5m25.619s (100.0%) sys 1m39.065s (100.0%) [3] real 1m54.915s ( 86.5%) user 4m18.585s ( 79.4%) sys 1m32.066s ( 92.9%) --- N4) Performance. Run NetworkManager from build [2] and setup a large number of profiles (551 profiles and 515 devices, mostly unrealized). This setup is already at the edge of what NetworkManager currently can handle. Of course, that is a different issue. Here we just check how long plain `nmcli` takes on the system. ``` do_cleanup() { for UUID in $(nmcli -g NAME,UUID connection show | sed -n 's/^xx-c-.*:\([^:]\+\)$/\1/p'); do nmcli connection delete uuid "$UUID" done for DEVICE in $(nmcli -g DEVICE device status | grep '^xx-i-'); do nmcli device delete "$DEVICE" done } do_setup() { do_cleanup for i in {1..30}; do nmcli connection add type bond autoconnect no con-name xx-c-bond-$i ifname xx-i-bond-$i ipv4.method disabled ipv6.method ignore for j in $(seq $i 30); do nmcli connection add type vlan autoconnect no con-name xx-c-vlan-$i-$j vlan.id $j ifname xx-i-vlan-$i-$j vlan.parent xx-i-bond-$i ipv4.method disabled ipv6.method ignore done done systemctl restart NetworkManager.service sleep 5 } do_test() { perf stat -r 50 -B nmcli 1>/dev/null } do_test ``` [1] Performance counter stats for 'nmcli' (50 runs): 456.33 msec task-clock:u # 1.093 CPUs utilized ( +- 0.44% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,900 page-faults:u # 0.013 M/sec ( +- 0.02% ) 1,408,675,453 cycles:u # 3.087 GHz ( +- 0.48% ) 1,594,741,060 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 368,744,018 branches:u # 808.061 M/sec ( +- 0.02% ) 4,566,058 branch-misses:u # 1.24% of all branches ( +- 0.76% ) 0.41761 +- 0.00282 seconds time elapsed ( +- 0.68% ) [2] Performance counter stats for 'nmcli' (50 runs): 477.99 msec task-clock:u # 1.088 CPUs utilized ( +- 0.36% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,948 page-faults:u # 0.012 M/sec ( +- 0.03% ) 1,471,133,482 cycles:u # 3.078 GHz ( +- 0.36% ) 1,655,275,369 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 382,595,152 branches:u # 800.433 M/sec ( +- 0.02% ) 4,746,070 branch-misses:u # 1.24% of all branches ( +- 0.49% ) 0.43923 +- 0.00242 seconds time elapsed ( +- 0.55% ) [3] Performance counter stats for 'nmcli' (50 runs): 352.36 msec task-clock:u # 1.027 CPUs utilized ( +- 0.32% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 4,790 page-faults:u # 0.014 M/sec ( +- 0.26% ) 1,092,341,186 cycles:u # 3.100 GHz ( +- 0.26% ) 1,209,045,283 instructions:u # 1.11 insn per cycle ( +- 0.02% ) 281,708,462 branches:u # 799.499 M/sec ( +- 0.01% ) 3,101,031 branch-misses:u # 1.10% of all branches ( +- 0.61% ) 0.34296 +- 0.00120 seconds time elapsed ( +- 0.35% ) --- N5) same setup as N4), but run `PAGER= /bin/time -v nmcli`: [1] Command being timed: "nmcli" User time (seconds): 0.42 System time (seconds): 0.04 Percent of CPU this job got: 107% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.43 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34456 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6128 Voluntary context switches: 1298 Involuntary context switches: 1106 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [2] Command being timed: "nmcli" User time (seconds): 0.44 System time (seconds): 0.04 Percent of CPU this job got: 108% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.44 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34452 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6169 Voluntary context switches: 1849 Involuntary context switches: 142 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [3] Command being timed: "nmcli" User time (seconds): 0.32 System time (seconds): 0.02 Percent of CPU this job got: 102% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.34 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 29196 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 5059 Voluntary context switches: 919 Involuntary context switches: 685 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 --- N6) same setup as N4), but run `nmcli monitor` and look at `ps aux` for the RSS size. USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND [1] me 1492900 21.0 0.2 461348 33248 pts/10 Sl+ 15:02 0:00 nmcli monitor [2] me 1490721 5.0 0.2 461496 33548 pts/10 Sl+ 15:00 0:00 nmcli monitor [3] me 1495801 16.5 0.1 459476 28692 pts/10 Sl+ 15:04 0:00 nmcli monitor
2019-10-30 11:42:58 +01:00
priv = NM_DEVICE_GET_PRIVATE (device);
if (!priv->lldp_neighbors)
priv->lldp_neighbors = g_ptr_array_new_with_free_func ((GDestroyNotify) nm_lldp_neighbor_unref);
return priv->lldp_neighbors;
}
/**
* nm_device_is_real:
* @device: a #NMDevice
*
* Returns: %TRUE if the device exists, or %FALSE if it is a placeholder device
* that could be automatically created by NetworkManager if one of its
* #NMDevice:available-connections was activated.
*
* Since: 1.2
**/
gboolean
nm_device_is_real (NMDevice *device)
{
g_return_val_if_fail (NM_IS_DEVICE (device), FALSE);
return NM_DEVICE_GET_PRIVATE (device)->real;
}
/**
* nm_device_is_software:
* @device: a #NMDevice
*
* Whether the device is a software device.
*
* Returns: %TRUE if @device is a software device, %FALSE if it is a hardware device.
**/
gboolean
nm_device_is_software (NMDevice *device)
{
g_return_val_if_fail (NM_IS_DEVICE (device), FALSE);
return !!(NM_DEVICE_GET_PRIVATE (device)->capabilities & NM_DEVICE_CAP_IS_SOFTWARE);
}
/**
* nm_device_reapply:
* @device: a #NMDevice
* @connection: (allow-none): the #NMConnection to replace the applied
* settings with or %NULL to reuse existing
* @version_id: zero or the expected version id of the applied connection.
* If specified and the version id mismatches, the call fails without
* modification. This allows to catch concurrent accesses.
* @flags: always set this to zero
* @cancellable: a #GCancellable, or %NULL
* @error: location for a #GError, or %NULL
*
* Attempts to update device with changes to the currently active connection
* made since it was last applied.
*
* Returns: %TRUE on success, %FALSE on error, in which case @error will be set.
*
* Since: 1.2
libnm: deprecate synchronous/blocking API in libnm Note that D-Bus is fundamentally asynchronous. Doing blocking calls on top of D-Bus is odd, especially for libnm's NMClient. That is because NMClient essentially is a client-side cache of the objects from the D-Bus interface. This cache should be filled exclusively by (asynchronous) D-Bus events (PropertiesChanged). So, making a blocking D-Bus call means to wait for a response and return it, while queuing all messages that are received in the meantime. Basically there are three ways how a synchronous API on NMClient could behave: 1) the call just calls g_dbus_connection_call_sync(). This means that libnm sends a D-Bus request via GDBusConnection, and blockingly waits for the response. All D-Bus messages that get received in the meantime are queued in the GMainContext that belongs to NMClient. That means, none of these D-Bus events are processed until we iterate the GMainContext after the call returns. The effect is, that NMClient (and all cached objects in there) are unaffected by the D-Bus request. Most of the synchronous API calls in libnm are of this kind. The problem is that the strict ordering of D-Bus events gets violated. For some API this is not an immediate problem. Take for example nm_device_wifi_request_scan(). The call merely blockingly tells NetworkManager to start scanning, but since NetworkManager's D-Bus API does not directly expose any state that tells whether we are currently scanning, this out of order processing of the D-Bus request is a small issue. The problem is more obvious for nm_client_networking_set_enabled(). After calling it, NM_CLIENT_NETWORKING_ENABLED is still unaffected and unchanged, because the PropertiesChanged signal from D-Bus is not yet processed. This means, while you make such a blocking call, NMClient's state does not change. But usually you perform the synchronous call to change some state. In this form, the blocking call is not useful, because NMClient only changes the state after iterating the GMainContext, and not after the blocking call returns. 2) like 1), but after making the blocking g_dbus_connection_call_sync(), update the NMClient cache artificially. This is what nm_manager_check_connectivity() does, to "fix" bgo#784629. This also has the problem of out-of-order events, but it kinda solves the problem of not changing the state during the blocking call. But it does so by hacking the state of the cache. I think this is really wrong because the state should only be updated from the ordered stream of D-Bus messages (PropertiesChanged signal and similar). When libnm decides to modify the state, there may be already D-Bus messages queued that affect this very state. 3) instead of calling g_dbus_connection_call_sync(), use the asynchronous g_dbus_connection_call(). If we would use a sepaate GMainContext for all D-Bus related calls, we could ensure that while we block for the response, we iterate that internal main context. This might be nice, because all events are processed in order and after the blocking call returns, the NMClient state is up to date. The are problems however: current blocking API does not do this, so it's a significant change in behavior. Also, it might be unexpected to the user that during the blocking call the entire content of NMClient's cache might change and all pointers to the cache might be invalidated. Also, of course NMClient would invoke signals for all the changes that happen. Another problem is that this would be more effort to implement and it involves a small performance overhead for all D-Bus related calls (because we have to serialize all events in an internal GMainContext first and then invoke them on the caller's context). Also, if the users wants this behavior, they could implement it themself by running libnm in their own GMainContext. Note that libnm might have bugs to make that really working, but that should be fixed instead of adding such synchrnous API behavior. Read also [1], for why blocking calls are wrong. [1] https://smcv.pseudorandom.co.uk/2008/11/nonblocking/ So, all possible behaviors for synchronous API have severe behavioural issues. Mark all this API as deprecated. Also, this serves the purpose of identifying blocking D-Bus calls in libnm. Note that "deprecated" here does not really mean that the API is going to be removed. We don't break API. The user may: - continue to use this API. It's deprecated, awkward and discouraged, but if it works, by all means use it. - use asynchronous API. That's the only sensible way to use D-Bus. If libnm lacks a certain asynchronous counterpart, it should be added. - use GDBusConnection directly. There really isn't anything wrong with D-Bus or GDBusConnection. This deprecated API is just a wrapper around g_dbus_connection_call_sync(). You may call it directly without feeling dirty. --- The only other remainging API is the synchronous GInitable call for NMClient. That is an entirely separate beast and not particularly wrong (from an API point of view). Note that synchronous API in NMSecretAgentOld, NMVpnPluginOld and NMVpnServicePlugin as not deprecated here. These types are not part of the D-Bus cache and while they have similar issues, it's less severe because they have less state.
2019-09-04 13:58:43 +02:00
*
* Deprecated: 1.22: Use nm_device_reapply_async() or GDBusConnection.
**/
gboolean
nm_device_reapply (NMDevice *device,
NMConnection *connection,
guint64 version_id,
guint32 flags,
GCancellable *cancellable,
GError **error)
{
GVariant *arg_connection = NULL;
g_return_val_if_fail (NM_IS_DEVICE (device), FALSE);
g_return_val_if_fail (!connection || NM_IS_CONNECTION (connection), FALSE);
g_return_val_if_fail (!cancellable || G_IS_CANCELLABLE (cancellable), FALSE);
g_return_val_if_fail (!error || !*error, FALSE);
if (connection)
arg_connection = nm_connection_to_dbus (connection, NM_CONNECTION_SERIALIZE_ALL);
if (!arg_connection)
arg_connection = g_variant_new_array (G_VARIANT_TYPE ("{sa{sv}}"), NULL, 0);
libnm: refactor caching of D-Bus objects in NMClient No longer use GDBusObjectMangaerClient and gdbus-codegen generated classes for the NMClient cache. Instead, use GDBusConnection directly and a custom implementation (NMLDBusObject) for caching D-Bus' ObjectManager data. CHANGES ------- - This is a complete rework. I think the previous implementation was difficult to understand. There were unfixed bugs and nobody understood the code well enough to fix them. Maybe somebody out there understood the code, but I certainly did not. At least nobody provided patches to fix those issues. I do believe that this implementation is more straightforward and easier to understand. It removes a lot of layers of code. Whether this claim of simplicity is true, each reader must decide for himself/herself. Note that it is still fairly complex. - There was a lingering performance issue with large number of D-Bus objects. The patch tries hard that the implementation scales well. Of course, when we cache N objects that have N-to-M references to other, we still are fundamentally O(N*M) for runtime and memory consumption (with M being the number of references between objects). But each part should behave efficiently and well. - Play well with GMainContext. libnm code (NMClient) is generally not thread safe. However, it should work to use multiple instances in parallel, as long as each access to a NMClient is through the caller's GMainContext. This follows glib's style and effectively allows to use NMClient in a multi threaded scenario. This implies to stick to a main context upon construction and ensure that callbacks are only invoked when iterating that context. Also, NMClient itself shall never iterate the caller's context. This also means, libnm must never use g_idle_add() or g_timeout_add(), as those enqueue sources in the g_main_context_default() context. - Get ordering of messages right. All events are consistently enqueued in a GMainContext and processed strictly in order. For example, previously "nm-object.c" tried to combine signals and emit them on an idle handler. That is wrong, signals must be emitted in the right order and when they happen. Note that when using GInitable's synchronous initialization to initialize the NMClient instance, NMClient internally still operates fully asynchronously. In that case NMClient has an internal main context. - NMClient takes over most of the functionality. When using D-Bus' ObjectManager interface, one needs to handle basically the entire state of the D-Bus interface. That cannot be separated well into distinct parts, and even if you try, you just end up having closely related code in different source files. Spreading related code does not make it easier to understand, on the contrary. That means, NMClient is inherently complex as it contains most of the logic. I think that is not avoidable, but it's not as bad as it sounds. - NMClient processes D-Bus messages and state changes in separate steps. First NMClient unpacks the message (e.g. _dbus_handle_properties_changed()) and keeps track of the changed data. Then we update the GObject instances (_dbus_handle_obj_changed_dbus()) without emitting any signals yet. Finally, we emit all signals and notifications that were collected (_dbus_handle_changes_commit()). Note that for example during the initial GetManagedObjects() reply, NMClient receive a large amount of state at once. But we first apply all the changes to our GObject instances before emitting any signals. The result is that signals are always emitted in a moment when the cache is consistent. The unavoidable downside is that when you receive a property changed signal, possibly many other properties changed already and more signals are about to be emitted. - NMDeviceWifi no longer modifies the content of the cache from client side during poke_wireless_devices_with_rf_status(). The content of the cache should be determined by D-Bus alone and follow what NetworkManager service exposes. Local modifications should be avoided. - This aims to bring no API/ABI change, though it does of course bring various subtle changes in behavior. Those should be all for the better, but the goal is not to break any existing clients. This does change internal (albeit externally visible) API, like dropping NM_OBJECT_DBUS_OBJECT_MANAGER property and NMObject no longer implementing GInitableIface and GAsyncInitableIface. - Some uses of gdbus-codegen classes remain in NMVpnPluginOld, NMVpnServicePlugin and NMSecretAgentOld. These are independent of NMClient/NMObject and should be reworked separately. - While we no longer use generated classes from gdbus-codegen, we don't need more glue code than before. Also before we constructed NMPropertiesInfo and a had large amount of code to propagate properties from NMDBus* to NMObject. That got completely reworked, but did not fundamentally change. You still need about the same effort to create the NMLDBusMetaIface. Not using generated bindings did not make anything worse (which tells about the usefulness of generated code, at least in the way it was used). - NMLDBusMetaIface and other meta data is static and immutable. This avoids copying them around. Also, macros like NML_DBUS_META_PROPERTY_INIT_U() have compile time checks to ensure the property types matches. It's pretty hard to misuse them because it won't compile. - The meta data now explicitly encodes the expected D-Bus types and makes sure never to accept wrong data. That would only matter when the server (accidentally or intentionally) exposes unexpected types on D-Bus. I don't think that was previously ensured in all cases. For example, demarshal_generic() only cared about the GObject property type, it didn't know the expected D-Bus type. - Previously GDBusObjectManager would sometimes emit warnings (g_log()). Those probably indicated real bugs. In any case, it prevented us from running CI with G_DEBUG=fatal-warnings, because there would be just too many unrelated crashes. Now we log debug messages that can be enabled with "LIBNM_CLIENT_DEBUG=trace". Some of these messages can also be turned into g_warning()/g_critical() by setting LIBNM_CLIENT_DEBUG=warning,error. Together with G_DEBUG=fatal-warnings, this turns them into assertions. Note that such "assertion failures" might also happen because of a server bug (or change). Thus these are not common assertions that indicate a bug in libnm and are thus not armed unless explicitly requested. In our CI we should now always run with LIBNM_CLIENT_DEBUG=warning,error and G_DEBUG=fatal-warnings and to catch bugs. Note that currently NetworkManager has bugs in this regard, so enabling this will result in assertion failures. That should be fixed first. - Note that this changes the order in which we emit "notify:devices" and "device-added" signals. I think it makes the most sense to emit first "device-removed", then "notify:devices", and finally "device-added" signals. This changes behavior for commit 52ae28f6e5bf ('libnm: queue added/removed signals and suppress uninitialized notifications'), but I don't think that users should actually rely on the order. Still, the new order makes the most sense to me. - In NetworkManager, profiles can be invisible to the user by setting "connection.permissions". Such profiles would be hidden by NMClient's nm_client_get_connections() and their "connection-added"/"connection-removed" signals. Note that NMActiveConnection's nm_active_connection_get_connection() and NMDevice's nm_device_get_available_connections() still exposes such hidden NMRemoteConnection instances. This behavior was preserved. NUMBERS ------- I compared 3 versions of libnm. [1] 962297f9085d, current tip of nm-1-20 branch [2] 4fad8c7c642e, current master, immediate parent of this patch [3] this patch All tests were done on Fedora 31, x86_64, gcc 9.2.1-1.fc31. The libraries were build with $ ./contrib/fedora/rpm/build_clean.sh -g -w test -W debug Note that RPM build already stripped the library. --- N1) File size of libnm.so.0.1.0 in bytes. There currently seems to be a issue on Fedora 31 generating wrong ELF notes. Usually, libnm is smaller but in these tests it had large (and bogus) ELF notes. Anyway, the point is to show the relative sizes, so it doesn't matter). [1] 4075552 (102.7%) [2] 3969624 (100.0%) [3] 3705208 ( 93.3%) --- N2) `size /usr/lib64/libnm.so.0.1.0`: text data bss dec hex filename [1] 1314569 (102.0%) 69980 ( 94.8%) 10632 ( 80.4%) 1395181 (101.4%) 1549ed /usr/lib64/libnm.so.0.1.0 [2] 1288410 (100.0%) 73796 (100.0%) 13224 (100.0%) 1375430 (100.0%) 14fcc6 /usr/lib64/libnm.so.0.1.0 [3] 1229066 ( 95.4%) 65248 ( 88.4%) 13400 (101.3%) 1307714 ( 95.1%) 13f442 /usr/lib64/libnm.so.0.1.0 --- N3) Performance test with test-client.py. With checkout of [2], run ``` prepare_checkout() { rm -rf /tmp/nm-test && \ git checkout -B test 4fad8c7c642e && \ git clean -fdx && \ ./autogen.sh --prefix=/tmp/nm-test && \ make -j 5 install && \ make -j 5 check-local-clients-tests-test-client } prepare_test() { NM_TEST_REGENERATE=1 NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v } do_test() { for i in {1..10}; do NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v || return -1 done echo "done!" } prepare_checkout prepare_test time do_test ``` [1] real 2m14.497s (101.3%) user 5m26.651s (100.3%) sys 1m40.453s (101.4%) [2] real 2m12.800s (100.0%) user 5m25.619s (100.0%) sys 1m39.065s (100.0%) [3] real 1m54.915s ( 86.5%) user 4m18.585s ( 79.4%) sys 1m32.066s ( 92.9%) --- N4) Performance. Run NetworkManager from build [2] and setup a large number of profiles (551 profiles and 515 devices, mostly unrealized). This setup is already at the edge of what NetworkManager currently can handle. Of course, that is a different issue. Here we just check how long plain `nmcli` takes on the system. ``` do_cleanup() { for UUID in $(nmcli -g NAME,UUID connection show | sed -n 's/^xx-c-.*:\([^:]\+\)$/\1/p'); do nmcli connection delete uuid "$UUID" done for DEVICE in $(nmcli -g DEVICE device status | grep '^xx-i-'); do nmcli device delete "$DEVICE" done } do_setup() { do_cleanup for i in {1..30}; do nmcli connection add type bond autoconnect no con-name xx-c-bond-$i ifname xx-i-bond-$i ipv4.method disabled ipv6.method ignore for j in $(seq $i 30); do nmcli connection add type vlan autoconnect no con-name xx-c-vlan-$i-$j vlan.id $j ifname xx-i-vlan-$i-$j vlan.parent xx-i-bond-$i ipv4.method disabled ipv6.method ignore done done systemctl restart NetworkManager.service sleep 5 } do_test() { perf stat -r 50 -B nmcli 1>/dev/null } do_test ``` [1] Performance counter stats for 'nmcli' (50 runs): 456.33 msec task-clock:u # 1.093 CPUs utilized ( +- 0.44% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,900 page-faults:u # 0.013 M/sec ( +- 0.02% ) 1,408,675,453 cycles:u # 3.087 GHz ( +- 0.48% ) 1,594,741,060 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 368,744,018 branches:u # 808.061 M/sec ( +- 0.02% ) 4,566,058 branch-misses:u # 1.24% of all branches ( +- 0.76% ) 0.41761 +- 0.00282 seconds time elapsed ( +- 0.68% ) [2] Performance counter stats for 'nmcli' (50 runs): 477.99 msec task-clock:u # 1.088 CPUs utilized ( +- 0.36% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,948 page-faults:u # 0.012 M/sec ( +- 0.03% ) 1,471,133,482 cycles:u # 3.078 GHz ( +- 0.36% ) 1,655,275,369 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 382,595,152 branches:u # 800.433 M/sec ( +- 0.02% ) 4,746,070 branch-misses:u # 1.24% of all branches ( +- 0.49% ) 0.43923 +- 0.00242 seconds time elapsed ( +- 0.55% ) [3] Performance counter stats for 'nmcli' (50 runs): 352.36 msec task-clock:u # 1.027 CPUs utilized ( +- 0.32% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 4,790 page-faults:u # 0.014 M/sec ( +- 0.26% ) 1,092,341,186 cycles:u # 3.100 GHz ( +- 0.26% ) 1,209,045,283 instructions:u # 1.11 insn per cycle ( +- 0.02% ) 281,708,462 branches:u # 799.499 M/sec ( +- 0.01% ) 3,101,031 branch-misses:u # 1.10% of all branches ( +- 0.61% ) 0.34296 +- 0.00120 seconds time elapsed ( +- 0.35% ) --- N5) same setup as N4), but run `PAGER= /bin/time -v nmcli`: [1] Command being timed: "nmcli" User time (seconds): 0.42 System time (seconds): 0.04 Percent of CPU this job got: 107% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.43 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34456 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6128 Voluntary context switches: 1298 Involuntary context switches: 1106 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [2] Command being timed: "nmcli" User time (seconds): 0.44 System time (seconds): 0.04 Percent of CPU this job got: 108% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.44 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34452 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6169 Voluntary context switches: 1849 Involuntary context switches: 142 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [3] Command being timed: "nmcli" User time (seconds): 0.32 System time (seconds): 0.02 Percent of CPU this job got: 102% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.34 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 29196 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 5059 Voluntary context switches: 919 Involuntary context switches: 685 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 --- N6) same setup as N4), but run `nmcli monitor` and look at `ps aux` for the RSS size. USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND [1] me 1492900 21.0 0.2 461348 33248 pts/10 Sl+ 15:02 0:00 nmcli monitor [2] me 1490721 5.0 0.2 461496 33548 pts/10 Sl+ 15:00 0:00 nmcli monitor [3] me 1495801 16.5 0.1 459476 28692 pts/10 Sl+ 15:04 0:00 nmcli monitor
2019-10-30 11:42:58 +01:00
return _nm_client_dbus_call_sync_void (_nm_object_get_client (device),
cancellable,
libnm: refactor caching of D-Bus objects in NMClient No longer use GDBusObjectMangaerClient and gdbus-codegen generated classes for the NMClient cache. Instead, use GDBusConnection directly and a custom implementation (NMLDBusObject) for caching D-Bus' ObjectManager data. CHANGES ------- - This is a complete rework. I think the previous implementation was difficult to understand. There were unfixed bugs and nobody understood the code well enough to fix them. Maybe somebody out there understood the code, but I certainly did not. At least nobody provided patches to fix those issues. I do believe that this implementation is more straightforward and easier to understand. It removes a lot of layers of code. Whether this claim of simplicity is true, each reader must decide for himself/herself. Note that it is still fairly complex. - There was a lingering performance issue with large number of D-Bus objects. The patch tries hard that the implementation scales well. Of course, when we cache N objects that have N-to-M references to other, we still are fundamentally O(N*M) for runtime and memory consumption (with M being the number of references between objects). But each part should behave efficiently and well. - Play well with GMainContext. libnm code (NMClient) is generally not thread safe. However, it should work to use multiple instances in parallel, as long as each access to a NMClient is through the caller's GMainContext. This follows glib's style and effectively allows to use NMClient in a multi threaded scenario. This implies to stick to a main context upon construction and ensure that callbacks are only invoked when iterating that context. Also, NMClient itself shall never iterate the caller's context. This also means, libnm must never use g_idle_add() or g_timeout_add(), as those enqueue sources in the g_main_context_default() context. - Get ordering of messages right. All events are consistently enqueued in a GMainContext and processed strictly in order. For example, previously "nm-object.c" tried to combine signals and emit them on an idle handler. That is wrong, signals must be emitted in the right order and when they happen. Note that when using GInitable's synchronous initialization to initialize the NMClient instance, NMClient internally still operates fully asynchronously. In that case NMClient has an internal main context. - NMClient takes over most of the functionality. When using D-Bus' ObjectManager interface, one needs to handle basically the entire state of the D-Bus interface. That cannot be separated well into distinct parts, and even if you try, you just end up having closely related code in different source files. Spreading related code does not make it easier to understand, on the contrary. That means, NMClient is inherently complex as it contains most of the logic. I think that is not avoidable, but it's not as bad as it sounds. - NMClient processes D-Bus messages and state changes in separate steps. First NMClient unpacks the message (e.g. _dbus_handle_properties_changed()) and keeps track of the changed data. Then we update the GObject instances (_dbus_handle_obj_changed_dbus()) without emitting any signals yet. Finally, we emit all signals and notifications that were collected (_dbus_handle_changes_commit()). Note that for example during the initial GetManagedObjects() reply, NMClient receive a large amount of state at once. But we first apply all the changes to our GObject instances before emitting any signals. The result is that signals are always emitted in a moment when the cache is consistent. The unavoidable downside is that when you receive a property changed signal, possibly many other properties changed already and more signals are about to be emitted. - NMDeviceWifi no longer modifies the content of the cache from client side during poke_wireless_devices_with_rf_status(). The content of the cache should be determined by D-Bus alone and follow what NetworkManager service exposes. Local modifications should be avoided. - This aims to bring no API/ABI change, though it does of course bring various subtle changes in behavior. Those should be all for the better, but the goal is not to break any existing clients. This does change internal (albeit externally visible) API, like dropping NM_OBJECT_DBUS_OBJECT_MANAGER property and NMObject no longer implementing GInitableIface and GAsyncInitableIface. - Some uses of gdbus-codegen classes remain in NMVpnPluginOld, NMVpnServicePlugin and NMSecretAgentOld. These are independent of NMClient/NMObject and should be reworked separately. - While we no longer use generated classes from gdbus-codegen, we don't need more glue code than before. Also before we constructed NMPropertiesInfo and a had large amount of code to propagate properties from NMDBus* to NMObject. That got completely reworked, but did not fundamentally change. You still need about the same effort to create the NMLDBusMetaIface. Not using generated bindings did not make anything worse (which tells about the usefulness of generated code, at least in the way it was used). - NMLDBusMetaIface and other meta data is static and immutable. This avoids copying them around. Also, macros like NML_DBUS_META_PROPERTY_INIT_U() have compile time checks to ensure the property types matches. It's pretty hard to misuse them because it won't compile. - The meta data now explicitly encodes the expected D-Bus types and makes sure never to accept wrong data. That would only matter when the server (accidentally or intentionally) exposes unexpected types on D-Bus. I don't think that was previously ensured in all cases. For example, demarshal_generic() only cared about the GObject property type, it didn't know the expected D-Bus type. - Previously GDBusObjectManager would sometimes emit warnings (g_log()). Those probably indicated real bugs. In any case, it prevented us from running CI with G_DEBUG=fatal-warnings, because there would be just too many unrelated crashes. Now we log debug messages that can be enabled with "LIBNM_CLIENT_DEBUG=trace". Some of these messages can also be turned into g_warning()/g_critical() by setting LIBNM_CLIENT_DEBUG=warning,error. Together with G_DEBUG=fatal-warnings, this turns them into assertions. Note that such "assertion failures" might also happen because of a server bug (or change). Thus these are not common assertions that indicate a bug in libnm and are thus not armed unless explicitly requested. In our CI we should now always run with LIBNM_CLIENT_DEBUG=warning,error and G_DEBUG=fatal-warnings and to catch bugs. Note that currently NetworkManager has bugs in this regard, so enabling this will result in assertion failures. That should be fixed first. - Note that this changes the order in which we emit "notify:devices" and "device-added" signals. I think it makes the most sense to emit first "device-removed", then "notify:devices", and finally "device-added" signals. This changes behavior for commit 52ae28f6e5bf ('libnm: queue added/removed signals and suppress uninitialized notifications'), but I don't think that users should actually rely on the order. Still, the new order makes the most sense to me. - In NetworkManager, profiles can be invisible to the user by setting "connection.permissions". Such profiles would be hidden by NMClient's nm_client_get_connections() and their "connection-added"/"connection-removed" signals. Note that NMActiveConnection's nm_active_connection_get_connection() and NMDevice's nm_device_get_available_connections() still exposes such hidden NMRemoteConnection instances. This behavior was preserved. NUMBERS ------- I compared 3 versions of libnm. [1] 962297f9085d, current tip of nm-1-20 branch [2] 4fad8c7c642e, current master, immediate parent of this patch [3] this patch All tests were done on Fedora 31, x86_64, gcc 9.2.1-1.fc31. The libraries were build with $ ./contrib/fedora/rpm/build_clean.sh -g -w test -W debug Note that RPM build already stripped the library. --- N1) File size of libnm.so.0.1.0 in bytes. There currently seems to be a issue on Fedora 31 generating wrong ELF notes. Usually, libnm is smaller but in these tests it had large (and bogus) ELF notes. Anyway, the point is to show the relative sizes, so it doesn't matter). [1] 4075552 (102.7%) [2] 3969624 (100.0%) [3] 3705208 ( 93.3%) --- N2) `size /usr/lib64/libnm.so.0.1.0`: text data bss dec hex filename [1] 1314569 (102.0%) 69980 ( 94.8%) 10632 ( 80.4%) 1395181 (101.4%) 1549ed /usr/lib64/libnm.so.0.1.0 [2] 1288410 (100.0%) 73796 (100.0%) 13224 (100.0%) 1375430 (100.0%) 14fcc6 /usr/lib64/libnm.so.0.1.0 [3] 1229066 ( 95.4%) 65248 ( 88.4%) 13400 (101.3%) 1307714 ( 95.1%) 13f442 /usr/lib64/libnm.so.0.1.0 --- N3) Performance test with test-client.py. With checkout of [2], run ``` prepare_checkout() { rm -rf /tmp/nm-test && \ git checkout -B test 4fad8c7c642e && \ git clean -fdx && \ ./autogen.sh --prefix=/tmp/nm-test && \ make -j 5 install && \ make -j 5 check-local-clients-tests-test-client } prepare_test() { NM_TEST_REGENERATE=1 NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v } do_test() { for i in {1..10}; do NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v || return -1 done echo "done!" } prepare_checkout prepare_test time do_test ``` [1] real 2m14.497s (101.3%) user 5m26.651s (100.3%) sys 1m40.453s (101.4%) [2] real 2m12.800s (100.0%) user 5m25.619s (100.0%) sys 1m39.065s (100.0%) [3] real 1m54.915s ( 86.5%) user 4m18.585s ( 79.4%) sys 1m32.066s ( 92.9%) --- N4) Performance. Run NetworkManager from build [2] and setup a large number of profiles (551 profiles and 515 devices, mostly unrealized). This setup is already at the edge of what NetworkManager currently can handle. Of course, that is a different issue. Here we just check how long plain `nmcli` takes on the system. ``` do_cleanup() { for UUID in $(nmcli -g NAME,UUID connection show | sed -n 's/^xx-c-.*:\([^:]\+\)$/\1/p'); do nmcli connection delete uuid "$UUID" done for DEVICE in $(nmcli -g DEVICE device status | grep '^xx-i-'); do nmcli device delete "$DEVICE" done } do_setup() { do_cleanup for i in {1..30}; do nmcli connection add type bond autoconnect no con-name xx-c-bond-$i ifname xx-i-bond-$i ipv4.method disabled ipv6.method ignore for j in $(seq $i 30); do nmcli connection add type vlan autoconnect no con-name xx-c-vlan-$i-$j vlan.id $j ifname xx-i-vlan-$i-$j vlan.parent xx-i-bond-$i ipv4.method disabled ipv6.method ignore done done systemctl restart NetworkManager.service sleep 5 } do_test() { perf stat -r 50 -B nmcli 1>/dev/null } do_test ``` [1] Performance counter stats for 'nmcli' (50 runs): 456.33 msec task-clock:u # 1.093 CPUs utilized ( +- 0.44% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,900 page-faults:u # 0.013 M/sec ( +- 0.02% ) 1,408,675,453 cycles:u # 3.087 GHz ( +- 0.48% ) 1,594,741,060 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 368,744,018 branches:u # 808.061 M/sec ( +- 0.02% ) 4,566,058 branch-misses:u # 1.24% of all branches ( +- 0.76% ) 0.41761 +- 0.00282 seconds time elapsed ( +- 0.68% ) [2] Performance counter stats for 'nmcli' (50 runs): 477.99 msec task-clock:u # 1.088 CPUs utilized ( +- 0.36% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,948 page-faults:u # 0.012 M/sec ( +- 0.03% ) 1,471,133,482 cycles:u # 3.078 GHz ( +- 0.36% ) 1,655,275,369 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 382,595,152 branches:u # 800.433 M/sec ( +- 0.02% ) 4,746,070 branch-misses:u # 1.24% of all branches ( +- 0.49% ) 0.43923 +- 0.00242 seconds time elapsed ( +- 0.55% ) [3] Performance counter stats for 'nmcli' (50 runs): 352.36 msec task-clock:u # 1.027 CPUs utilized ( +- 0.32% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 4,790 page-faults:u # 0.014 M/sec ( +- 0.26% ) 1,092,341,186 cycles:u # 3.100 GHz ( +- 0.26% ) 1,209,045,283 instructions:u # 1.11 insn per cycle ( +- 0.02% ) 281,708,462 branches:u # 799.499 M/sec ( +- 0.01% ) 3,101,031 branch-misses:u # 1.10% of all branches ( +- 0.61% ) 0.34296 +- 0.00120 seconds time elapsed ( +- 0.35% ) --- N5) same setup as N4), but run `PAGER= /bin/time -v nmcli`: [1] Command being timed: "nmcli" User time (seconds): 0.42 System time (seconds): 0.04 Percent of CPU this job got: 107% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.43 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34456 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6128 Voluntary context switches: 1298 Involuntary context switches: 1106 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [2] Command being timed: "nmcli" User time (seconds): 0.44 System time (seconds): 0.04 Percent of CPU this job got: 108% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.44 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34452 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6169 Voluntary context switches: 1849 Involuntary context switches: 142 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [3] Command being timed: "nmcli" User time (seconds): 0.32 System time (seconds): 0.02 Percent of CPU this job got: 102% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.34 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 29196 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 5059 Voluntary context switches: 919 Involuntary context switches: 685 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 --- N6) same setup as N4), but run `nmcli monitor` and look at `ps aux` for the RSS size. USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND [1] me 1492900 21.0 0.2 461348 33248 pts/10 Sl+ 15:02 0:00 nmcli monitor [2] me 1490721 5.0 0.2 461496 33548 pts/10 Sl+ 15:00 0:00 nmcli monitor [3] me 1495801 16.5 0.1 459476 28692 pts/10 Sl+ 15:04 0:00 nmcli monitor
2019-10-30 11:42:58 +01:00
_nm_object_get_path (device),
NM_DBUS_INTERFACE_DEVICE,
"Reapply",
g_variant_new ("(@a{sa{sv}}tu)",
arg_connection,
version_id,
flags),
G_DBUS_CALL_FLAGS_NONE,
NM_DBUS_DEFAULT_TIMEOUT_MSEC,
TRUE,
error);
}
/**
* nm_device_reapply_async:
* @device: a #NMDevice
* @connection: (allow-none): the #NMConnection to replace the applied
* settings with or %NULL to reuse existing
* @version_id: zero or the expected version id of the applied
* connection. If specified and the version id mismatches, the call
* fails without modification. This allows to catch concurrent
* accesses.
* @flags: always set this to zero
* @cancellable: a #GCancellable, or %NULL
* @callback: callback to be called when the reapply operation completes
* @user_data: caller-specific data passed to @callback
*
* Asynchronously begins an attempt to update device with changes to the
* currently active connection made since it was last applied.
*
* Since: 1.2
**/
void
nm_device_reapply_async (NMDevice *device,
NMConnection *connection,
guint64 version_id,
guint32 flags,
GCancellable *cancellable,
GAsyncReadyCallback callback,
gpointer user_data)
{
GVariant *arg_connection = NULL;
g_return_if_fail (NM_IS_DEVICE (device));
g_return_if_fail (!connection || NM_IS_CONNECTION (connection));
g_return_if_fail (!cancellable || G_IS_CANCELLABLE (cancellable));
if (connection)
arg_connection = nm_connection_to_dbus (connection, NM_CONNECTION_SERIALIZE_ALL);
if (!arg_connection)
arg_connection = g_variant_new_array (G_VARIANT_TYPE ("{sa{sv}}"), NULL, 0);
libnm: refactor caching of D-Bus objects in NMClient No longer use GDBusObjectMangaerClient and gdbus-codegen generated classes for the NMClient cache. Instead, use GDBusConnection directly and a custom implementation (NMLDBusObject) for caching D-Bus' ObjectManager data. CHANGES ------- - This is a complete rework. I think the previous implementation was difficult to understand. There were unfixed bugs and nobody understood the code well enough to fix them. Maybe somebody out there understood the code, but I certainly did not. At least nobody provided patches to fix those issues. I do believe that this implementation is more straightforward and easier to understand. It removes a lot of layers of code. Whether this claim of simplicity is true, each reader must decide for himself/herself. Note that it is still fairly complex. - There was a lingering performance issue with large number of D-Bus objects. The patch tries hard that the implementation scales well. Of course, when we cache N objects that have N-to-M references to other, we still are fundamentally O(N*M) for runtime and memory consumption (with M being the number of references between objects). But each part should behave efficiently and well. - Play well with GMainContext. libnm code (NMClient) is generally not thread safe. However, it should work to use multiple instances in parallel, as long as each access to a NMClient is through the caller's GMainContext. This follows glib's style and effectively allows to use NMClient in a multi threaded scenario. This implies to stick to a main context upon construction and ensure that callbacks are only invoked when iterating that context. Also, NMClient itself shall never iterate the caller's context. This also means, libnm must never use g_idle_add() or g_timeout_add(), as those enqueue sources in the g_main_context_default() context. - Get ordering of messages right. All events are consistently enqueued in a GMainContext and processed strictly in order. For example, previously "nm-object.c" tried to combine signals and emit them on an idle handler. That is wrong, signals must be emitted in the right order and when they happen. Note that when using GInitable's synchronous initialization to initialize the NMClient instance, NMClient internally still operates fully asynchronously. In that case NMClient has an internal main context. - NMClient takes over most of the functionality. When using D-Bus' ObjectManager interface, one needs to handle basically the entire state of the D-Bus interface. That cannot be separated well into distinct parts, and even if you try, you just end up having closely related code in different source files. Spreading related code does not make it easier to understand, on the contrary. That means, NMClient is inherently complex as it contains most of the logic. I think that is not avoidable, but it's not as bad as it sounds. - NMClient processes D-Bus messages and state changes in separate steps. First NMClient unpacks the message (e.g. _dbus_handle_properties_changed()) and keeps track of the changed data. Then we update the GObject instances (_dbus_handle_obj_changed_dbus()) without emitting any signals yet. Finally, we emit all signals and notifications that were collected (_dbus_handle_changes_commit()). Note that for example during the initial GetManagedObjects() reply, NMClient receive a large amount of state at once. But we first apply all the changes to our GObject instances before emitting any signals. The result is that signals are always emitted in a moment when the cache is consistent. The unavoidable downside is that when you receive a property changed signal, possibly many other properties changed already and more signals are about to be emitted. - NMDeviceWifi no longer modifies the content of the cache from client side during poke_wireless_devices_with_rf_status(). The content of the cache should be determined by D-Bus alone and follow what NetworkManager service exposes. Local modifications should be avoided. - This aims to bring no API/ABI change, though it does of course bring various subtle changes in behavior. Those should be all for the better, but the goal is not to break any existing clients. This does change internal (albeit externally visible) API, like dropping NM_OBJECT_DBUS_OBJECT_MANAGER property and NMObject no longer implementing GInitableIface and GAsyncInitableIface. - Some uses of gdbus-codegen classes remain in NMVpnPluginOld, NMVpnServicePlugin and NMSecretAgentOld. These are independent of NMClient/NMObject and should be reworked separately. - While we no longer use generated classes from gdbus-codegen, we don't need more glue code than before. Also before we constructed NMPropertiesInfo and a had large amount of code to propagate properties from NMDBus* to NMObject. That got completely reworked, but did not fundamentally change. You still need about the same effort to create the NMLDBusMetaIface. Not using generated bindings did not make anything worse (which tells about the usefulness of generated code, at least in the way it was used). - NMLDBusMetaIface and other meta data is static and immutable. This avoids copying them around. Also, macros like NML_DBUS_META_PROPERTY_INIT_U() have compile time checks to ensure the property types matches. It's pretty hard to misuse them because it won't compile. - The meta data now explicitly encodes the expected D-Bus types and makes sure never to accept wrong data. That would only matter when the server (accidentally or intentionally) exposes unexpected types on D-Bus. I don't think that was previously ensured in all cases. For example, demarshal_generic() only cared about the GObject property type, it didn't know the expected D-Bus type. - Previously GDBusObjectManager would sometimes emit warnings (g_log()). Those probably indicated real bugs. In any case, it prevented us from running CI with G_DEBUG=fatal-warnings, because there would be just too many unrelated crashes. Now we log debug messages that can be enabled with "LIBNM_CLIENT_DEBUG=trace". Some of these messages can also be turned into g_warning()/g_critical() by setting LIBNM_CLIENT_DEBUG=warning,error. Together with G_DEBUG=fatal-warnings, this turns them into assertions. Note that such "assertion failures" might also happen because of a server bug (or change). Thus these are not common assertions that indicate a bug in libnm and are thus not armed unless explicitly requested. In our CI we should now always run with LIBNM_CLIENT_DEBUG=warning,error and G_DEBUG=fatal-warnings and to catch bugs. Note that currently NetworkManager has bugs in this regard, so enabling this will result in assertion failures. That should be fixed first. - Note that this changes the order in which we emit "notify:devices" and "device-added" signals. I think it makes the most sense to emit first "device-removed", then "notify:devices", and finally "device-added" signals. This changes behavior for commit 52ae28f6e5bf ('libnm: queue added/removed signals and suppress uninitialized notifications'), but I don't think that users should actually rely on the order. Still, the new order makes the most sense to me. - In NetworkManager, profiles can be invisible to the user by setting "connection.permissions". Such profiles would be hidden by NMClient's nm_client_get_connections() and their "connection-added"/"connection-removed" signals. Note that NMActiveConnection's nm_active_connection_get_connection() and NMDevice's nm_device_get_available_connections() still exposes such hidden NMRemoteConnection instances. This behavior was preserved. NUMBERS ------- I compared 3 versions of libnm. [1] 962297f9085d, current tip of nm-1-20 branch [2] 4fad8c7c642e, current master, immediate parent of this patch [3] this patch All tests were done on Fedora 31, x86_64, gcc 9.2.1-1.fc31. The libraries were build with $ ./contrib/fedora/rpm/build_clean.sh -g -w test -W debug Note that RPM build already stripped the library. --- N1) File size of libnm.so.0.1.0 in bytes. There currently seems to be a issue on Fedora 31 generating wrong ELF notes. Usually, libnm is smaller but in these tests it had large (and bogus) ELF notes. Anyway, the point is to show the relative sizes, so it doesn't matter). [1] 4075552 (102.7%) [2] 3969624 (100.0%) [3] 3705208 ( 93.3%) --- N2) `size /usr/lib64/libnm.so.0.1.0`: text data bss dec hex filename [1] 1314569 (102.0%) 69980 ( 94.8%) 10632 ( 80.4%) 1395181 (101.4%) 1549ed /usr/lib64/libnm.so.0.1.0 [2] 1288410 (100.0%) 73796 (100.0%) 13224 (100.0%) 1375430 (100.0%) 14fcc6 /usr/lib64/libnm.so.0.1.0 [3] 1229066 ( 95.4%) 65248 ( 88.4%) 13400 (101.3%) 1307714 ( 95.1%) 13f442 /usr/lib64/libnm.so.0.1.0 --- N3) Performance test with test-client.py. With checkout of [2], run ``` prepare_checkout() { rm -rf /tmp/nm-test && \ git checkout -B test 4fad8c7c642e && \ git clean -fdx && \ ./autogen.sh --prefix=/tmp/nm-test && \ make -j 5 install && \ make -j 5 check-local-clients-tests-test-client } prepare_test() { NM_TEST_REGENERATE=1 NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v } do_test() { for i in {1..10}; do NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v || return -1 done echo "done!" } prepare_checkout prepare_test time do_test ``` [1] real 2m14.497s (101.3%) user 5m26.651s (100.3%) sys 1m40.453s (101.4%) [2] real 2m12.800s (100.0%) user 5m25.619s (100.0%) sys 1m39.065s (100.0%) [3] real 1m54.915s ( 86.5%) user 4m18.585s ( 79.4%) sys 1m32.066s ( 92.9%) --- N4) Performance. Run NetworkManager from build [2] and setup a large number of profiles (551 profiles and 515 devices, mostly unrealized). This setup is already at the edge of what NetworkManager currently can handle. Of course, that is a different issue. Here we just check how long plain `nmcli` takes on the system. ``` do_cleanup() { for UUID in $(nmcli -g NAME,UUID connection show | sed -n 's/^xx-c-.*:\([^:]\+\)$/\1/p'); do nmcli connection delete uuid "$UUID" done for DEVICE in $(nmcli -g DEVICE device status | grep '^xx-i-'); do nmcli device delete "$DEVICE" done } do_setup() { do_cleanup for i in {1..30}; do nmcli connection add type bond autoconnect no con-name xx-c-bond-$i ifname xx-i-bond-$i ipv4.method disabled ipv6.method ignore for j in $(seq $i 30); do nmcli connection add type vlan autoconnect no con-name xx-c-vlan-$i-$j vlan.id $j ifname xx-i-vlan-$i-$j vlan.parent xx-i-bond-$i ipv4.method disabled ipv6.method ignore done done systemctl restart NetworkManager.service sleep 5 } do_test() { perf stat -r 50 -B nmcli 1>/dev/null } do_test ``` [1] Performance counter stats for 'nmcli' (50 runs): 456.33 msec task-clock:u # 1.093 CPUs utilized ( +- 0.44% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,900 page-faults:u # 0.013 M/sec ( +- 0.02% ) 1,408,675,453 cycles:u # 3.087 GHz ( +- 0.48% ) 1,594,741,060 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 368,744,018 branches:u # 808.061 M/sec ( +- 0.02% ) 4,566,058 branch-misses:u # 1.24% of all branches ( +- 0.76% ) 0.41761 +- 0.00282 seconds time elapsed ( +- 0.68% ) [2] Performance counter stats for 'nmcli' (50 runs): 477.99 msec task-clock:u # 1.088 CPUs utilized ( +- 0.36% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,948 page-faults:u # 0.012 M/sec ( +- 0.03% ) 1,471,133,482 cycles:u # 3.078 GHz ( +- 0.36% ) 1,655,275,369 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 382,595,152 branches:u # 800.433 M/sec ( +- 0.02% ) 4,746,070 branch-misses:u # 1.24% of all branches ( +- 0.49% ) 0.43923 +- 0.00242 seconds time elapsed ( +- 0.55% ) [3] Performance counter stats for 'nmcli' (50 runs): 352.36 msec task-clock:u # 1.027 CPUs utilized ( +- 0.32% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 4,790 page-faults:u # 0.014 M/sec ( +- 0.26% ) 1,092,341,186 cycles:u # 3.100 GHz ( +- 0.26% ) 1,209,045,283 instructions:u # 1.11 insn per cycle ( +- 0.02% ) 281,708,462 branches:u # 799.499 M/sec ( +- 0.01% ) 3,101,031 branch-misses:u # 1.10% of all branches ( +- 0.61% ) 0.34296 +- 0.00120 seconds time elapsed ( +- 0.35% ) --- N5) same setup as N4), but run `PAGER= /bin/time -v nmcli`: [1] Command being timed: "nmcli" User time (seconds): 0.42 System time (seconds): 0.04 Percent of CPU this job got: 107% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.43 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34456 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6128 Voluntary context switches: 1298 Involuntary context switches: 1106 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [2] Command being timed: "nmcli" User time (seconds): 0.44 System time (seconds): 0.04 Percent of CPU this job got: 108% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.44 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34452 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6169 Voluntary context switches: 1849 Involuntary context switches: 142 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [3] Command being timed: "nmcli" User time (seconds): 0.32 System time (seconds): 0.02 Percent of CPU this job got: 102% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.34 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 29196 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 5059 Voluntary context switches: 919 Involuntary context switches: 685 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 --- N6) same setup as N4), but run `nmcli monitor` and look at `ps aux` for the RSS size. USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND [1] me 1492900 21.0 0.2 461348 33248 pts/10 Sl+ 15:02 0:00 nmcli monitor [2] me 1490721 5.0 0.2 461496 33548 pts/10 Sl+ 15:00 0:00 nmcli monitor [3] me 1495801 16.5 0.1 459476 28692 pts/10 Sl+ 15:04 0:00 nmcli monitor
2019-10-30 11:42:58 +01:00
_nm_client_dbus_call (_nm_object_get_client (device),
device,
nm_device_reapply_async,
cancellable,
callback,
user_data,
libnm: refactor caching of D-Bus objects in NMClient No longer use GDBusObjectMangaerClient and gdbus-codegen generated classes for the NMClient cache. Instead, use GDBusConnection directly and a custom implementation (NMLDBusObject) for caching D-Bus' ObjectManager data. CHANGES ------- - This is a complete rework. I think the previous implementation was difficult to understand. There were unfixed bugs and nobody understood the code well enough to fix them. Maybe somebody out there understood the code, but I certainly did not. At least nobody provided patches to fix those issues. I do believe that this implementation is more straightforward and easier to understand. It removes a lot of layers of code. Whether this claim of simplicity is true, each reader must decide for himself/herself. Note that it is still fairly complex. - There was a lingering performance issue with large number of D-Bus objects. The patch tries hard that the implementation scales well. Of course, when we cache N objects that have N-to-M references to other, we still are fundamentally O(N*M) for runtime and memory consumption (with M being the number of references between objects). But each part should behave efficiently and well. - Play well with GMainContext. libnm code (NMClient) is generally not thread safe. However, it should work to use multiple instances in parallel, as long as each access to a NMClient is through the caller's GMainContext. This follows glib's style and effectively allows to use NMClient in a multi threaded scenario. This implies to stick to a main context upon construction and ensure that callbacks are only invoked when iterating that context. Also, NMClient itself shall never iterate the caller's context. This also means, libnm must never use g_idle_add() or g_timeout_add(), as those enqueue sources in the g_main_context_default() context. - Get ordering of messages right. All events are consistently enqueued in a GMainContext and processed strictly in order. For example, previously "nm-object.c" tried to combine signals and emit them on an idle handler. That is wrong, signals must be emitted in the right order and when they happen. Note that when using GInitable's synchronous initialization to initialize the NMClient instance, NMClient internally still operates fully asynchronously. In that case NMClient has an internal main context. - NMClient takes over most of the functionality. When using D-Bus' ObjectManager interface, one needs to handle basically the entire state of the D-Bus interface. That cannot be separated well into distinct parts, and even if you try, you just end up having closely related code in different source files. Spreading related code does not make it easier to understand, on the contrary. That means, NMClient is inherently complex as it contains most of the logic. I think that is not avoidable, but it's not as bad as it sounds. - NMClient processes D-Bus messages and state changes in separate steps. First NMClient unpacks the message (e.g. _dbus_handle_properties_changed()) and keeps track of the changed data. Then we update the GObject instances (_dbus_handle_obj_changed_dbus()) without emitting any signals yet. Finally, we emit all signals and notifications that were collected (_dbus_handle_changes_commit()). Note that for example during the initial GetManagedObjects() reply, NMClient receive a large amount of state at once. But we first apply all the changes to our GObject instances before emitting any signals. The result is that signals are always emitted in a moment when the cache is consistent. The unavoidable downside is that when you receive a property changed signal, possibly many other properties changed already and more signals are about to be emitted. - NMDeviceWifi no longer modifies the content of the cache from client side during poke_wireless_devices_with_rf_status(). The content of the cache should be determined by D-Bus alone and follow what NetworkManager service exposes. Local modifications should be avoided. - This aims to bring no API/ABI change, though it does of course bring various subtle changes in behavior. Those should be all for the better, but the goal is not to break any existing clients. This does change internal (albeit externally visible) API, like dropping NM_OBJECT_DBUS_OBJECT_MANAGER property and NMObject no longer implementing GInitableIface and GAsyncInitableIface. - Some uses of gdbus-codegen classes remain in NMVpnPluginOld, NMVpnServicePlugin and NMSecretAgentOld. These are independent of NMClient/NMObject and should be reworked separately. - While we no longer use generated classes from gdbus-codegen, we don't need more glue code than before. Also before we constructed NMPropertiesInfo and a had large amount of code to propagate properties from NMDBus* to NMObject. That got completely reworked, but did not fundamentally change. You still need about the same effort to create the NMLDBusMetaIface. Not using generated bindings did not make anything worse (which tells about the usefulness of generated code, at least in the way it was used). - NMLDBusMetaIface and other meta data is static and immutable. This avoids copying them around. Also, macros like NML_DBUS_META_PROPERTY_INIT_U() have compile time checks to ensure the property types matches. It's pretty hard to misuse them because it won't compile. - The meta data now explicitly encodes the expected D-Bus types and makes sure never to accept wrong data. That would only matter when the server (accidentally or intentionally) exposes unexpected types on D-Bus. I don't think that was previously ensured in all cases. For example, demarshal_generic() only cared about the GObject property type, it didn't know the expected D-Bus type. - Previously GDBusObjectManager would sometimes emit warnings (g_log()). Those probably indicated real bugs. In any case, it prevented us from running CI with G_DEBUG=fatal-warnings, because there would be just too many unrelated crashes. Now we log debug messages that can be enabled with "LIBNM_CLIENT_DEBUG=trace". Some of these messages can also be turned into g_warning()/g_critical() by setting LIBNM_CLIENT_DEBUG=warning,error. Together with G_DEBUG=fatal-warnings, this turns them into assertions. Note that such "assertion failures" might also happen because of a server bug (or change). Thus these are not common assertions that indicate a bug in libnm and are thus not armed unless explicitly requested. In our CI we should now always run with LIBNM_CLIENT_DEBUG=warning,error and G_DEBUG=fatal-warnings and to catch bugs. Note that currently NetworkManager has bugs in this regard, so enabling this will result in assertion failures. That should be fixed first. - Note that this changes the order in which we emit "notify:devices" and "device-added" signals. I think it makes the most sense to emit first "device-removed", then "notify:devices", and finally "device-added" signals. This changes behavior for commit 52ae28f6e5bf ('libnm: queue added/removed signals and suppress uninitialized notifications'), but I don't think that users should actually rely on the order. Still, the new order makes the most sense to me. - In NetworkManager, profiles can be invisible to the user by setting "connection.permissions". Such profiles would be hidden by NMClient's nm_client_get_connections() and their "connection-added"/"connection-removed" signals. Note that NMActiveConnection's nm_active_connection_get_connection() and NMDevice's nm_device_get_available_connections() still exposes such hidden NMRemoteConnection instances. This behavior was preserved. NUMBERS ------- I compared 3 versions of libnm. [1] 962297f9085d, current tip of nm-1-20 branch [2] 4fad8c7c642e, current master, immediate parent of this patch [3] this patch All tests were done on Fedora 31, x86_64, gcc 9.2.1-1.fc31. The libraries were build with $ ./contrib/fedora/rpm/build_clean.sh -g -w test -W debug Note that RPM build already stripped the library. --- N1) File size of libnm.so.0.1.0 in bytes. There currently seems to be a issue on Fedora 31 generating wrong ELF notes. Usually, libnm is smaller but in these tests it had large (and bogus) ELF notes. Anyway, the point is to show the relative sizes, so it doesn't matter). [1] 4075552 (102.7%) [2] 3969624 (100.0%) [3] 3705208 ( 93.3%) --- N2) `size /usr/lib64/libnm.so.0.1.0`: text data bss dec hex filename [1] 1314569 (102.0%) 69980 ( 94.8%) 10632 ( 80.4%) 1395181 (101.4%) 1549ed /usr/lib64/libnm.so.0.1.0 [2] 1288410 (100.0%) 73796 (100.0%) 13224 (100.0%) 1375430 (100.0%) 14fcc6 /usr/lib64/libnm.so.0.1.0 [3] 1229066 ( 95.4%) 65248 ( 88.4%) 13400 (101.3%) 1307714 ( 95.1%) 13f442 /usr/lib64/libnm.so.0.1.0 --- N3) Performance test with test-client.py. With checkout of [2], run ``` prepare_checkout() { rm -rf /tmp/nm-test && \ git checkout -B test 4fad8c7c642e && \ git clean -fdx && \ ./autogen.sh --prefix=/tmp/nm-test && \ make -j 5 install && \ make -j 5 check-local-clients-tests-test-client } prepare_test() { NM_TEST_REGENERATE=1 NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v } do_test() { for i in {1..10}; do NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v || return -1 done echo "done!" } prepare_checkout prepare_test time do_test ``` [1] real 2m14.497s (101.3%) user 5m26.651s (100.3%) sys 1m40.453s (101.4%) [2] real 2m12.800s (100.0%) user 5m25.619s (100.0%) sys 1m39.065s (100.0%) [3] real 1m54.915s ( 86.5%) user 4m18.585s ( 79.4%) sys 1m32.066s ( 92.9%) --- N4) Performance. Run NetworkManager from build [2] and setup a large number of profiles (551 profiles and 515 devices, mostly unrealized). This setup is already at the edge of what NetworkManager currently can handle. Of course, that is a different issue. Here we just check how long plain `nmcli` takes on the system. ``` do_cleanup() { for UUID in $(nmcli -g NAME,UUID connection show | sed -n 's/^xx-c-.*:\([^:]\+\)$/\1/p'); do nmcli connection delete uuid "$UUID" done for DEVICE in $(nmcli -g DEVICE device status | grep '^xx-i-'); do nmcli device delete "$DEVICE" done } do_setup() { do_cleanup for i in {1..30}; do nmcli connection add type bond autoconnect no con-name xx-c-bond-$i ifname xx-i-bond-$i ipv4.method disabled ipv6.method ignore for j in $(seq $i 30); do nmcli connection add type vlan autoconnect no con-name xx-c-vlan-$i-$j vlan.id $j ifname xx-i-vlan-$i-$j vlan.parent xx-i-bond-$i ipv4.method disabled ipv6.method ignore done done systemctl restart NetworkManager.service sleep 5 } do_test() { perf stat -r 50 -B nmcli 1>/dev/null } do_test ``` [1] Performance counter stats for 'nmcli' (50 runs): 456.33 msec task-clock:u # 1.093 CPUs utilized ( +- 0.44% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,900 page-faults:u # 0.013 M/sec ( +- 0.02% ) 1,408,675,453 cycles:u # 3.087 GHz ( +- 0.48% ) 1,594,741,060 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 368,744,018 branches:u # 808.061 M/sec ( +- 0.02% ) 4,566,058 branch-misses:u # 1.24% of all branches ( +- 0.76% ) 0.41761 +- 0.00282 seconds time elapsed ( +- 0.68% ) [2] Performance counter stats for 'nmcli' (50 runs): 477.99 msec task-clock:u # 1.088 CPUs utilized ( +- 0.36% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,948 page-faults:u # 0.012 M/sec ( +- 0.03% ) 1,471,133,482 cycles:u # 3.078 GHz ( +- 0.36% ) 1,655,275,369 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 382,595,152 branches:u # 800.433 M/sec ( +- 0.02% ) 4,746,070 branch-misses:u # 1.24% of all branches ( +- 0.49% ) 0.43923 +- 0.00242 seconds time elapsed ( +- 0.55% ) [3] Performance counter stats for 'nmcli' (50 runs): 352.36 msec task-clock:u # 1.027 CPUs utilized ( +- 0.32% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 4,790 page-faults:u # 0.014 M/sec ( +- 0.26% ) 1,092,341,186 cycles:u # 3.100 GHz ( +- 0.26% ) 1,209,045,283 instructions:u # 1.11 insn per cycle ( +- 0.02% ) 281,708,462 branches:u # 799.499 M/sec ( +- 0.01% ) 3,101,031 branch-misses:u # 1.10% of all branches ( +- 0.61% ) 0.34296 +- 0.00120 seconds time elapsed ( +- 0.35% ) --- N5) same setup as N4), but run `PAGER= /bin/time -v nmcli`: [1] Command being timed: "nmcli" User time (seconds): 0.42 System time (seconds): 0.04 Percent of CPU this job got: 107% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.43 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34456 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6128 Voluntary context switches: 1298 Involuntary context switches: 1106 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [2] Command being timed: "nmcli" User time (seconds): 0.44 System time (seconds): 0.04 Percent of CPU this job got: 108% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.44 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34452 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6169 Voluntary context switches: 1849 Involuntary context switches: 142 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [3] Command being timed: "nmcli" User time (seconds): 0.32 System time (seconds): 0.02 Percent of CPU this job got: 102% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.34 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 29196 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 5059 Voluntary context switches: 919 Involuntary context switches: 685 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 --- N6) same setup as N4), but run `nmcli monitor` and look at `ps aux` for the RSS size. USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND [1] me 1492900 21.0 0.2 461348 33248 pts/10 Sl+ 15:02 0:00 nmcli monitor [2] me 1490721 5.0 0.2 461496 33548 pts/10 Sl+ 15:00 0:00 nmcli monitor [3] me 1495801 16.5 0.1 459476 28692 pts/10 Sl+ 15:04 0:00 nmcli monitor
2019-10-30 11:42:58 +01:00
_nm_object_get_path (device),
NM_DBUS_INTERFACE_DEVICE,
"Reapply",
g_variant_new ("(@a{sa{sv}}tu)",
arg_connection,
version_id,
flags),
G_VARIANT_TYPE ("()"),
G_DBUS_CALL_FLAGS_NONE,
NM_DBUS_DEFAULT_TIMEOUT_MSEC,
nm_dbus_connection_call_finish_void_strip_dbus_error_cb);
}
/**
* nm_device_reapply_finish:
* @device: a #NMDevice
* @result: the result passed to the #GAsyncReadyCallback
* @error: location for a #GError, or %NULL
*
* Gets the result of a call to nm_device_reapply_async().
*
* Returns: %TRUE on success, %FALSE on error, in which case @error
* will be set.
*
* Since: 1.2
**/
gboolean
nm_device_reapply_finish (NMDevice *device,
GAsyncResult *result,
GError **error)
{
g_return_val_if_fail (NM_IS_DEVICE (device), FALSE);
g_return_val_if_fail (nm_g_task_is_valid (result, device, nm_device_reapply_async), FALSE);
return g_task_propagate_boolean (G_TASK (result), error);
}
/*****************************************************************************/
/**
* nm_device_get_applied_connection:
* @device: a #NMDevice
* @flags: the flags argument. Currently this value must always be zero.
* @version_id: (out) (allow-none): returns the current version id of
* the applied connection
* @cancellable: a #GCancellable, or %NULL
* @error: location for a #GError, or %NULL
*
* Fetch the currently applied connection on the device.
*
* Returns: (transfer full): a %NMConnection with the currently applied settings
* or %NULL on error.
*
* The connection is as received from D-Bus and might not validate according
* to nm_connection_verify().
*
* Since: 1.2
libnm: deprecate synchronous/blocking API in libnm Note that D-Bus is fundamentally asynchronous. Doing blocking calls on top of D-Bus is odd, especially for libnm's NMClient. That is because NMClient essentially is a client-side cache of the objects from the D-Bus interface. This cache should be filled exclusively by (asynchronous) D-Bus events (PropertiesChanged). So, making a blocking D-Bus call means to wait for a response and return it, while queuing all messages that are received in the meantime. Basically there are three ways how a synchronous API on NMClient could behave: 1) the call just calls g_dbus_connection_call_sync(). This means that libnm sends a D-Bus request via GDBusConnection, and blockingly waits for the response. All D-Bus messages that get received in the meantime are queued in the GMainContext that belongs to NMClient. That means, none of these D-Bus events are processed until we iterate the GMainContext after the call returns. The effect is, that NMClient (and all cached objects in there) are unaffected by the D-Bus request. Most of the synchronous API calls in libnm are of this kind. The problem is that the strict ordering of D-Bus events gets violated. For some API this is not an immediate problem. Take for example nm_device_wifi_request_scan(). The call merely blockingly tells NetworkManager to start scanning, but since NetworkManager's D-Bus API does not directly expose any state that tells whether we are currently scanning, this out of order processing of the D-Bus request is a small issue. The problem is more obvious for nm_client_networking_set_enabled(). After calling it, NM_CLIENT_NETWORKING_ENABLED is still unaffected and unchanged, because the PropertiesChanged signal from D-Bus is not yet processed. This means, while you make such a blocking call, NMClient's state does not change. But usually you perform the synchronous call to change some state. In this form, the blocking call is not useful, because NMClient only changes the state after iterating the GMainContext, and not after the blocking call returns. 2) like 1), but after making the blocking g_dbus_connection_call_sync(), update the NMClient cache artificially. This is what nm_manager_check_connectivity() does, to "fix" bgo#784629. This also has the problem of out-of-order events, but it kinda solves the problem of not changing the state during the blocking call. But it does so by hacking the state of the cache. I think this is really wrong because the state should only be updated from the ordered stream of D-Bus messages (PropertiesChanged signal and similar). When libnm decides to modify the state, there may be already D-Bus messages queued that affect this very state. 3) instead of calling g_dbus_connection_call_sync(), use the asynchronous g_dbus_connection_call(). If we would use a sepaate GMainContext for all D-Bus related calls, we could ensure that while we block for the response, we iterate that internal main context. This might be nice, because all events are processed in order and after the blocking call returns, the NMClient state is up to date. The are problems however: current blocking API does not do this, so it's a significant change in behavior. Also, it might be unexpected to the user that during the blocking call the entire content of NMClient's cache might change and all pointers to the cache might be invalidated. Also, of course NMClient would invoke signals for all the changes that happen. Another problem is that this would be more effort to implement and it involves a small performance overhead for all D-Bus related calls (because we have to serialize all events in an internal GMainContext first and then invoke them on the caller's context). Also, if the users wants this behavior, they could implement it themself by running libnm in their own GMainContext. Note that libnm might have bugs to make that really working, but that should be fixed instead of adding such synchrnous API behavior. Read also [1], for why blocking calls are wrong. [1] https://smcv.pseudorandom.co.uk/2008/11/nonblocking/ So, all possible behaviors for synchronous API have severe behavioural issues. Mark all this API as deprecated. Also, this serves the purpose of identifying blocking D-Bus calls in libnm. Note that "deprecated" here does not really mean that the API is going to be removed. We don't break API. The user may: - continue to use this API. It's deprecated, awkward and discouraged, but if it works, by all means use it. - use asynchronous API. That's the only sensible way to use D-Bus. If libnm lacks a certain asynchronous counterpart, it should be added. - use GDBusConnection directly. There really isn't anything wrong with D-Bus or GDBusConnection. This deprecated API is just a wrapper around g_dbus_connection_call_sync(). You may call it directly without feeling dirty. --- The only other remainging API is the synchronous GInitable call for NMClient. That is an entirely separate beast and not particularly wrong (from an API point of view). Note that synchronous API in NMSecretAgentOld, NMVpnPluginOld and NMVpnServicePlugin as not deprecated here. These types are not part of the D-Bus cache and while they have similar issues, it's less severe because they have less state.
2019-09-04 13:58:43 +02:00
*
* Deprecated: 1.22: Use nm_device_get_applied_connection_async() or GDBusConnection.
**/
NMConnection *
nm_device_get_applied_connection (NMDevice *device,
guint32 flags,
guint64 *version_id,
GCancellable *cancellable,
GError **error)
{
gs_unref_variant GVariant *ret = NULL;
gs_unref_variant GVariant *v_connection = NULL;
guint64 v_version_id;
NMConnection *connection;
g_return_val_if_fail (NM_IS_DEVICE (device), NULL);
g_return_val_if_fail (!cancellable || G_IS_CANCELLABLE (cancellable), NULL);
g_return_val_if_fail (!error || !*error, NULL);
libnm: refactor caching of D-Bus objects in NMClient No longer use GDBusObjectMangaerClient and gdbus-codegen generated classes for the NMClient cache. Instead, use GDBusConnection directly and a custom implementation (NMLDBusObject) for caching D-Bus' ObjectManager data. CHANGES ------- - This is a complete rework. I think the previous implementation was difficult to understand. There were unfixed bugs and nobody understood the code well enough to fix them. Maybe somebody out there understood the code, but I certainly did not. At least nobody provided patches to fix those issues. I do believe that this implementation is more straightforward and easier to understand. It removes a lot of layers of code. Whether this claim of simplicity is true, each reader must decide for himself/herself. Note that it is still fairly complex. - There was a lingering performance issue with large number of D-Bus objects. The patch tries hard that the implementation scales well. Of course, when we cache N objects that have N-to-M references to other, we still are fundamentally O(N*M) for runtime and memory consumption (with M being the number of references between objects). But each part should behave efficiently and well. - Play well with GMainContext. libnm code (NMClient) is generally not thread safe. However, it should work to use multiple instances in parallel, as long as each access to a NMClient is through the caller's GMainContext. This follows glib's style and effectively allows to use NMClient in a multi threaded scenario. This implies to stick to a main context upon construction and ensure that callbacks are only invoked when iterating that context. Also, NMClient itself shall never iterate the caller's context. This also means, libnm must never use g_idle_add() or g_timeout_add(), as those enqueue sources in the g_main_context_default() context. - Get ordering of messages right. All events are consistently enqueued in a GMainContext and processed strictly in order. For example, previously "nm-object.c" tried to combine signals and emit them on an idle handler. That is wrong, signals must be emitted in the right order and when they happen. Note that when using GInitable's synchronous initialization to initialize the NMClient instance, NMClient internally still operates fully asynchronously. In that case NMClient has an internal main context. - NMClient takes over most of the functionality. When using D-Bus' ObjectManager interface, one needs to handle basically the entire state of the D-Bus interface. That cannot be separated well into distinct parts, and even if you try, you just end up having closely related code in different source files. Spreading related code does not make it easier to understand, on the contrary. That means, NMClient is inherently complex as it contains most of the logic. I think that is not avoidable, but it's not as bad as it sounds. - NMClient processes D-Bus messages and state changes in separate steps. First NMClient unpacks the message (e.g. _dbus_handle_properties_changed()) and keeps track of the changed data. Then we update the GObject instances (_dbus_handle_obj_changed_dbus()) without emitting any signals yet. Finally, we emit all signals and notifications that were collected (_dbus_handle_changes_commit()). Note that for example during the initial GetManagedObjects() reply, NMClient receive a large amount of state at once. But we first apply all the changes to our GObject instances before emitting any signals. The result is that signals are always emitted in a moment when the cache is consistent. The unavoidable downside is that when you receive a property changed signal, possibly many other properties changed already and more signals are about to be emitted. - NMDeviceWifi no longer modifies the content of the cache from client side during poke_wireless_devices_with_rf_status(). The content of the cache should be determined by D-Bus alone and follow what NetworkManager service exposes. Local modifications should be avoided. - This aims to bring no API/ABI change, though it does of course bring various subtle changes in behavior. Those should be all for the better, but the goal is not to break any existing clients. This does change internal (albeit externally visible) API, like dropping NM_OBJECT_DBUS_OBJECT_MANAGER property and NMObject no longer implementing GInitableIface and GAsyncInitableIface. - Some uses of gdbus-codegen classes remain in NMVpnPluginOld, NMVpnServicePlugin and NMSecretAgentOld. These are independent of NMClient/NMObject and should be reworked separately. - While we no longer use generated classes from gdbus-codegen, we don't need more glue code than before. Also before we constructed NMPropertiesInfo and a had large amount of code to propagate properties from NMDBus* to NMObject. That got completely reworked, but did not fundamentally change. You still need about the same effort to create the NMLDBusMetaIface. Not using generated bindings did not make anything worse (which tells about the usefulness of generated code, at least in the way it was used). - NMLDBusMetaIface and other meta data is static and immutable. This avoids copying them around. Also, macros like NML_DBUS_META_PROPERTY_INIT_U() have compile time checks to ensure the property types matches. It's pretty hard to misuse them because it won't compile. - The meta data now explicitly encodes the expected D-Bus types and makes sure never to accept wrong data. That would only matter when the server (accidentally or intentionally) exposes unexpected types on D-Bus. I don't think that was previously ensured in all cases. For example, demarshal_generic() only cared about the GObject property type, it didn't know the expected D-Bus type. - Previously GDBusObjectManager would sometimes emit warnings (g_log()). Those probably indicated real bugs. In any case, it prevented us from running CI with G_DEBUG=fatal-warnings, because there would be just too many unrelated crashes. Now we log debug messages that can be enabled with "LIBNM_CLIENT_DEBUG=trace". Some of these messages can also be turned into g_warning()/g_critical() by setting LIBNM_CLIENT_DEBUG=warning,error. Together with G_DEBUG=fatal-warnings, this turns them into assertions. Note that such "assertion failures" might also happen because of a server bug (or change). Thus these are not common assertions that indicate a bug in libnm and are thus not armed unless explicitly requested. In our CI we should now always run with LIBNM_CLIENT_DEBUG=warning,error and G_DEBUG=fatal-warnings and to catch bugs. Note that currently NetworkManager has bugs in this regard, so enabling this will result in assertion failures. That should be fixed first. - Note that this changes the order in which we emit "notify:devices" and "device-added" signals. I think it makes the most sense to emit first "device-removed", then "notify:devices", and finally "device-added" signals. This changes behavior for commit 52ae28f6e5bf ('libnm: queue added/removed signals and suppress uninitialized notifications'), but I don't think that users should actually rely on the order. Still, the new order makes the most sense to me. - In NetworkManager, profiles can be invisible to the user by setting "connection.permissions". Such profiles would be hidden by NMClient's nm_client_get_connections() and their "connection-added"/"connection-removed" signals. Note that NMActiveConnection's nm_active_connection_get_connection() and NMDevice's nm_device_get_available_connections() still exposes such hidden NMRemoteConnection instances. This behavior was preserved. NUMBERS ------- I compared 3 versions of libnm. [1] 962297f9085d, current tip of nm-1-20 branch [2] 4fad8c7c642e, current master, immediate parent of this patch [3] this patch All tests were done on Fedora 31, x86_64, gcc 9.2.1-1.fc31. The libraries were build with $ ./contrib/fedora/rpm/build_clean.sh -g -w test -W debug Note that RPM build already stripped the library. --- N1) File size of libnm.so.0.1.0 in bytes. There currently seems to be a issue on Fedora 31 generating wrong ELF notes. Usually, libnm is smaller but in these tests it had large (and bogus) ELF notes. Anyway, the point is to show the relative sizes, so it doesn't matter). [1] 4075552 (102.7%) [2] 3969624 (100.0%) [3] 3705208 ( 93.3%) --- N2) `size /usr/lib64/libnm.so.0.1.0`: text data bss dec hex filename [1] 1314569 (102.0%) 69980 ( 94.8%) 10632 ( 80.4%) 1395181 (101.4%) 1549ed /usr/lib64/libnm.so.0.1.0 [2] 1288410 (100.0%) 73796 (100.0%) 13224 (100.0%) 1375430 (100.0%) 14fcc6 /usr/lib64/libnm.so.0.1.0 [3] 1229066 ( 95.4%) 65248 ( 88.4%) 13400 (101.3%) 1307714 ( 95.1%) 13f442 /usr/lib64/libnm.so.0.1.0 --- N3) Performance test with test-client.py. With checkout of [2], run ``` prepare_checkout() { rm -rf /tmp/nm-test && \ git checkout -B test 4fad8c7c642e && \ git clean -fdx && \ ./autogen.sh --prefix=/tmp/nm-test && \ make -j 5 install && \ make -j 5 check-local-clients-tests-test-client } prepare_test() { NM_TEST_REGENERATE=1 NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v } do_test() { for i in {1..10}; do NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v || return -1 done echo "done!" } prepare_checkout prepare_test time do_test ``` [1] real 2m14.497s (101.3%) user 5m26.651s (100.3%) sys 1m40.453s (101.4%) [2] real 2m12.800s (100.0%) user 5m25.619s (100.0%) sys 1m39.065s (100.0%) [3] real 1m54.915s ( 86.5%) user 4m18.585s ( 79.4%) sys 1m32.066s ( 92.9%) --- N4) Performance. Run NetworkManager from build [2] and setup a large number of profiles (551 profiles and 515 devices, mostly unrealized). This setup is already at the edge of what NetworkManager currently can handle. Of course, that is a different issue. Here we just check how long plain `nmcli` takes on the system. ``` do_cleanup() { for UUID in $(nmcli -g NAME,UUID connection show | sed -n 's/^xx-c-.*:\([^:]\+\)$/\1/p'); do nmcli connection delete uuid "$UUID" done for DEVICE in $(nmcli -g DEVICE device status | grep '^xx-i-'); do nmcli device delete "$DEVICE" done } do_setup() { do_cleanup for i in {1..30}; do nmcli connection add type bond autoconnect no con-name xx-c-bond-$i ifname xx-i-bond-$i ipv4.method disabled ipv6.method ignore for j in $(seq $i 30); do nmcli connection add type vlan autoconnect no con-name xx-c-vlan-$i-$j vlan.id $j ifname xx-i-vlan-$i-$j vlan.parent xx-i-bond-$i ipv4.method disabled ipv6.method ignore done done systemctl restart NetworkManager.service sleep 5 } do_test() { perf stat -r 50 -B nmcli 1>/dev/null } do_test ``` [1] Performance counter stats for 'nmcli' (50 runs): 456.33 msec task-clock:u # 1.093 CPUs utilized ( +- 0.44% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,900 page-faults:u # 0.013 M/sec ( +- 0.02% ) 1,408,675,453 cycles:u # 3.087 GHz ( +- 0.48% ) 1,594,741,060 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 368,744,018 branches:u # 808.061 M/sec ( +- 0.02% ) 4,566,058 branch-misses:u # 1.24% of all branches ( +- 0.76% ) 0.41761 +- 0.00282 seconds time elapsed ( +- 0.68% ) [2] Performance counter stats for 'nmcli' (50 runs): 477.99 msec task-clock:u # 1.088 CPUs utilized ( +- 0.36% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,948 page-faults:u # 0.012 M/sec ( +- 0.03% ) 1,471,133,482 cycles:u # 3.078 GHz ( +- 0.36% ) 1,655,275,369 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 382,595,152 branches:u # 800.433 M/sec ( +- 0.02% ) 4,746,070 branch-misses:u # 1.24% of all branches ( +- 0.49% ) 0.43923 +- 0.00242 seconds time elapsed ( +- 0.55% ) [3] Performance counter stats for 'nmcli' (50 runs): 352.36 msec task-clock:u # 1.027 CPUs utilized ( +- 0.32% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 4,790 page-faults:u # 0.014 M/sec ( +- 0.26% ) 1,092,341,186 cycles:u # 3.100 GHz ( +- 0.26% ) 1,209,045,283 instructions:u # 1.11 insn per cycle ( +- 0.02% ) 281,708,462 branches:u # 799.499 M/sec ( +- 0.01% ) 3,101,031 branch-misses:u # 1.10% of all branches ( +- 0.61% ) 0.34296 +- 0.00120 seconds time elapsed ( +- 0.35% ) --- N5) same setup as N4), but run `PAGER= /bin/time -v nmcli`: [1] Command being timed: "nmcli" User time (seconds): 0.42 System time (seconds): 0.04 Percent of CPU this job got: 107% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.43 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34456 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6128 Voluntary context switches: 1298 Involuntary context switches: 1106 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [2] Command being timed: "nmcli" User time (seconds): 0.44 System time (seconds): 0.04 Percent of CPU this job got: 108% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.44 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34452 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6169 Voluntary context switches: 1849 Involuntary context switches: 142 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [3] Command being timed: "nmcli" User time (seconds): 0.32 System time (seconds): 0.02 Percent of CPU this job got: 102% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.34 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 29196 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 5059 Voluntary context switches: 919 Involuntary context switches: 685 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 --- N6) same setup as N4), but run `nmcli monitor` and look at `ps aux` for the RSS size. USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND [1] me 1492900 21.0 0.2 461348 33248 pts/10 Sl+ 15:02 0:00 nmcli monitor [2] me 1490721 5.0 0.2 461496 33548 pts/10 Sl+ 15:00 0:00 nmcli monitor [3] me 1495801 16.5 0.1 459476 28692 pts/10 Sl+ 15:04 0:00 nmcli monitor
2019-10-30 11:42:58 +01:00
ret = _nm_client_dbus_call_sync (_nm_object_get_client (device),
cancellable,
libnm: refactor caching of D-Bus objects in NMClient No longer use GDBusObjectMangaerClient and gdbus-codegen generated classes for the NMClient cache. Instead, use GDBusConnection directly and a custom implementation (NMLDBusObject) for caching D-Bus' ObjectManager data. CHANGES ------- - This is a complete rework. I think the previous implementation was difficult to understand. There were unfixed bugs and nobody understood the code well enough to fix them. Maybe somebody out there understood the code, but I certainly did not. At least nobody provided patches to fix those issues. I do believe that this implementation is more straightforward and easier to understand. It removes a lot of layers of code. Whether this claim of simplicity is true, each reader must decide for himself/herself. Note that it is still fairly complex. - There was a lingering performance issue with large number of D-Bus objects. The patch tries hard that the implementation scales well. Of course, when we cache N objects that have N-to-M references to other, we still are fundamentally O(N*M) for runtime and memory consumption (with M being the number of references between objects). But each part should behave efficiently and well. - Play well with GMainContext. libnm code (NMClient) is generally not thread safe. However, it should work to use multiple instances in parallel, as long as each access to a NMClient is through the caller's GMainContext. This follows glib's style and effectively allows to use NMClient in a multi threaded scenario. This implies to stick to a main context upon construction and ensure that callbacks are only invoked when iterating that context. Also, NMClient itself shall never iterate the caller's context. This also means, libnm must never use g_idle_add() or g_timeout_add(), as those enqueue sources in the g_main_context_default() context. - Get ordering of messages right. All events are consistently enqueued in a GMainContext and processed strictly in order. For example, previously "nm-object.c" tried to combine signals and emit them on an idle handler. That is wrong, signals must be emitted in the right order and when they happen. Note that when using GInitable's synchronous initialization to initialize the NMClient instance, NMClient internally still operates fully asynchronously. In that case NMClient has an internal main context. - NMClient takes over most of the functionality. When using D-Bus' ObjectManager interface, one needs to handle basically the entire state of the D-Bus interface. That cannot be separated well into distinct parts, and even if you try, you just end up having closely related code in different source files. Spreading related code does not make it easier to understand, on the contrary. That means, NMClient is inherently complex as it contains most of the logic. I think that is not avoidable, but it's not as bad as it sounds. - NMClient processes D-Bus messages and state changes in separate steps. First NMClient unpacks the message (e.g. _dbus_handle_properties_changed()) and keeps track of the changed data. Then we update the GObject instances (_dbus_handle_obj_changed_dbus()) without emitting any signals yet. Finally, we emit all signals and notifications that were collected (_dbus_handle_changes_commit()). Note that for example during the initial GetManagedObjects() reply, NMClient receive a large amount of state at once. But we first apply all the changes to our GObject instances before emitting any signals. The result is that signals are always emitted in a moment when the cache is consistent. The unavoidable downside is that when you receive a property changed signal, possibly many other properties changed already and more signals are about to be emitted. - NMDeviceWifi no longer modifies the content of the cache from client side during poke_wireless_devices_with_rf_status(). The content of the cache should be determined by D-Bus alone and follow what NetworkManager service exposes. Local modifications should be avoided. - This aims to bring no API/ABI change, though it does of course bring various subtle changes in behavior. Those should be all for the better, but the goal is not to break any existing clients. This does change internal (albeit externally visible) API, like dropping NM_OBJECT_DBUS_OBJECT_MANAGER property and NMObject no longer implementing GInitableIface and GAsyncInitableIface. - Some uses of gdbus-codegen classes remain in NMVpnPluginOld, NMVpnServicePlugin and NMSecretAgentOld. These are independent of NMClient/NMObject and should be reworked separately. - While we no longer use generated classes from gdbus-codegen, we don't need more glue code than before. Also before we constructed NMPropertiesInfo and a had large amount of code to propagate properties from NMDBus* to NMObject. That got completely reworked, but did not fundamentally change. You still need about the same effort to create the NMLDBusMetaIface. Not using generated bindings did not make anything worse (which tells about the usefulness of generated code, at least in the way it was used). - NMLDBusMetaIface and other meta data is static and immutable. This avoids copying them around. Also, macros like NML_DBUS_META_PROPERTY_INIT_U() have compile time checks to ensure the property types matches. It's pretty hard to misuse them because it won't compile. - The meta data now explicitly encodes the expected D-Bus types and makes sure never to accept wrong data. That would only matter when the server (accidentally or intentionally) exposes unexpected types on D-Bus. I don't think that was previously ensured in all cases. For example, demarshal_generic() only cared about the GObject property type, it didn't know the expected D-Bus type. - Previously GDBusObjectManager would sometimes emit warnings (g_log()). Those probably indicated real bugs. In any case, it prevented us from running CI with G_DEBUG=fatal-warnings, because there would be just too many unrelated crashes. Now we log debug messages that can be enabled with "LIBNM_CLIENT_DEBUG=trace". Some of these messages can also be turned into g_warning()/g_critical() by setting LIBNM_CLIENT_DEBUG=warning,error. Together with G_DEBUG=fatal-warnings, this turns them into assertions. Note that such "assertion failures" might also happen because of a server bug (or change). Thus these are not common assertions that indicate a bug in libnm and are thus not armed unless explicitly requested. In our CI we should now always run with LIBNM_CLIENT_DEBUG=warning,error and G_DEBUG=fatal-warnings and to catch bugs. Note that currently NetworkManager has bugs in this regard, so enabling this will result in assertion failures. That should be fixed first. - Note that this changes the order in which we emit "notify:devices" and "device-added" signals. I think it makes the most sense to emit first "device-removed", then "notify:devices", and finally "device-added" signals. This changes behavior for commit 52ae28f6e5bf ('libnm: queue added/removed signals and suppress uninitialized notifications'), but I don't think that users should actually rely on the order. Still, the new order makes the most sense to me. - In NetworkManager, profiles can be invisible to the user by setting "connection.permissions". Such profiles would be hidden by NMClient's nm_client_get_connections() and their "connection-added"/"connection-removed" signals. Note that NMActiveConnection's nm_active_connection_get_connection() and NMDevice's nm_device_get_available_connections() still exposes such hidden NMRemoteConnection instances. This behavior was preserved. NUMBERS ------- I compared 3 versions of libnm. [1] 962297f9085d, current tip of nm-1-20 branch [2] 4fad8c7c642e, current master, immediate parent of this patch [3] this patch All tests were done on Fedora 31, x86_64, gcc 9.2.1-1.fc31. The libraries were build with $ ./contrib/fedora/rpm/build_clean.sh -g -w test -W debug Note that RPM build already stripped the library. --- N1) File size of libnm.so.0.1.0 in bytes. There currently seems to be a issue on Fedora 31 generating wrong ELF notes. Usually, libnm is smaller but in these tests it had large (and bogus) ELF notes. Anyway, the point is to show the relative sizes, so it doesn't matter). [1] 4075552 (102.7%) [2] 3969624 (100.0%) [3] 3705208 ( 93.3%) --- N2) `size /usr/lib64/libnm.so.0.1.0`: text data bss dec hex filename [1] 1314569 (102.0%) 69980 ( 94.8%) 10632 ( 80.4%) 1395181 (101.4%) 1549ed /usr/lib64/libnm.so.0.1.0 [2] 1288410 (100.0%) 73796 (100.0%) 13224 (100.0%) 1375430 (100.0%) 14fcc6 /usr/lib64/libnm.so.0.1.0 [3] 1229066 ( 95.4%) 65248 ( 88.4%) 13400 (101.3%) 1307714 ( 95.1%) 13f442 /usr/lib64/libnm.so.0.1.0 --- N3) Performance test with test-client.py. With checkout of [2], run ``` prepare_checkout() { rm -rf /tmp/nm-test && \ git checkout -B test 4fad8c7c642e && \ git clean -fdx && \ ./autogen.sh --prefix=/tmp/nm-test && \ make -j 5 install && \ make -j 5 check-local-clients-tests-test-client } prepare_test() { NM_TEST_REGENERATE=1 NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v } do_test() { for i in {1..10}; do NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v || return -1 done echo "done!" } prepare_checkout prepare_test time do_test ``` [1] real 2m14.497s (101.3%) user 5m26.651s (100.3%) sys 1m40.453s (101.4%) [2] real 2m12.800s (100.0%) user 5m25.619s (100.0%) sys 1m39.065s (100.0%) [3] real 1m54.915s ( 86.5%) user 4m18.585s ( 79.4%) sys 1m32.066s ( 92.9%) --- N4) Performance. Run NetworkManager from build [2] and setup a large number of profiles (551 profiles and 515 devices, mostly unrealized). This setup is already at the edge of what NetworkManager currently can handle. Of course, that is a different issue. Here we just check how long plain `nmcli` takes on the system. ``` do_cleanup() { for UUID in $(nmcli -g NAME,UUID connection show | sed -n 's/^xx-c-.*:\([^:]\+\)$/\1/p'); do nmcli connection delete uuid "$UUID" done for DEVICE in $(nmcli -g DEVICE device status | grep '^xx-i-'); do nmcli device delete "$DEVICE" done } do_setup() { do_cleanup for i in {1..30}; do nmcli connection add type bond autoconnect no con-name xx-c-bond-$i ifname xx-i-bond-$i ipv4.method disabled ipv6.method ignore for j in $(seq $i 30); do nmcli connection add type vlan autoconnect no con-name xx-c-vlan-$i-$j vlan.id $j ifname xx-i-vlan-$i-$j vlan.parent xx-i-bond-$i ipv4.method disabled ipv6.method ignore done done systemctl restart NetworkManager.service sleep 5 } do_test() { perf stat -r 50 -B nmcli 1>/dev/null } do_test ``` [1] Performance counter stats for 'nmcli' (50 runs): 456.33 msec task-clock:u # 1.093 CPUs utilized ( +- 0.44% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,900 page-faults:u # 0.013 M/sec ( +- 0.02% ) 1,408,675,453 cycles:u # 3.087 GHz ( +- 0.48% ) 1,594,741,060 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 368,744,018 branches:u # 808.061 M/sec ( +- 0.02% ) 4,566,058 branch-misses:u # 1.24% of all branches ( +- 0.76% ) 0.41761 +- 0.00282 seconds time elapsed ( +- 0.68% ) [2] Performance counter stats for 'nmcli' (50 runs): 477.99 msec task-clock:u # 1.088 CPUs utilized ( +- 0.36% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,948 page-faults:u # 0.012 M/sec ( +- 0.03% ) 1,471,133,482 cycles:u # 3.078 GHz ( +- 0.36% ) 1,655,275,369 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 382,595,152 branches:u # 800.433 M/sec ( +- 0.02% ) 4,746,070 branch-misses:u # 1.24% of all branches ( +- 0.49% ) 0.43923 +- 0.00242 seconds time elapsed ( +- 0.55% ) [3] Performance counter stats for 'nmcli' (50 runs): 352.36 msec task-clock:u # 1.027 CPUs utilized ( +- 0.32% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 4,790 page-faults:u # 0.014 M/sec ( +- 0.26% ) 1,092,341,186 cycles:u # 3.100 GHz ( +- 0.26% ) 1,209,045,283 instructions:u # 1.11 insn per cycle ( +- 0.02% ) 281,708,462 branches:u # 799.499 M/sec ( +- 0.01% ) 3,101,031 branch-misses:u # 1.10% of all branches ( +- 0.61% ) 0.34296 +- 0.00120 seconds time elapsed ( +- 0.35% ) --- N5) same setup as N4), but run `PAGER= /bin/time -v nmcli`: [1] Command being timed: "nmcli" User time (seconds): 0.42 System time (seconds): 0.04 Percent of CPU this job got: 107% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.43 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34456 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6128 Voluntary context switches: 1298 Involuntary context switches: 1106 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [2] Command being timed: "nmcli" User time (seconds): 0.44 System time (seconds): 0.04 Percent of CPU this job got: 108% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.44 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34452 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6169 Voluntary context switches: 1849 Involuntary context switches: 142 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [3] Command being timed: "nmcli" User time (seconds): 0.32 System time (seconds): 0.02 Percent of CPU this job got: 102% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.34 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 29196 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 5059 Voluntary context switches: 919 Involuntary context switches: 685 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 --- N6) same setup as N4), but run `nmcli monitor` and look at `ps aux` for the RSS size. USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND [1] me 1492900 21.0 0.2 461348 33248 pts/10 Sl+ 15:02 0:00 nmcli monitor [2] me 1490721 5.0 0.2 461496 33548 pts/10 Sl+ 15:00 0:00 nmcli monitor [3] me 1495801 16.5 0.1 459476 28692 pts/10 Sl+ 15:04 0:00 nmcli monitor
2019-10-30 11:42:58 +01:00
_nm_object_get_path (device),
NM_DBUS_INTERFACE_DEVICE,
"GetAppliedConnection",
g_variant_new ("(u)", flags),
G_VARIANT_TYPE ("(a{sa{sv}}t)"),
G_DBUS_CALL_FLAGS_NONE,
NM_DBUS_DEFAULT_TIMEOUT_MSEC,
TRUE,
error);
if (!ret)
return NULL;
g_variant_get (ret,
"(@a{sa{sv}}t)",
&v_connection,
&v_version_id);
connection = _nm_simple_connection_new_from_dbus (v_connection, NM_SETTING_PARSE_FLAGS_BEST_EFFORT, error);
if (!connection)
return NULL;
NM_SET_OUT (version_id, v_version_id);
return connection;
}
/**
* nm_device_get_applied_connection_async:
* @device: a #NMDevice
* @flags: the flags argument. Currently this value must always be zero.
* @cancellable: a #GCancellable, or %NULL
* @callback: callback to be called when the reapply operation completes
* @user_data: caller-specific data passed to @callback
*
* Asynchronously begins and gets the currently applied connection.
*
* Since: 1.2
**/
void
nm_device_get_applied_connection_async (NMDevice *device,
guint32 flags,
GCancellable *cancellable,
GAsyncReadyCallback callback,
gpointer user_data)
{
g_return_if_fail (NM_IS_DEVICE (device));
g_return_if_fail (!cancellable || G_IS_CANCELLABLE (cancellable));
libnm: refactor caching of D-Bus objects in NMClient No longer use GDBusObjectMangaerClient and gdbus-codegen generated classes for the NMClient cache. Instead, use GDBusConnection directly and a custom implementation (NMLDBusObject) for caching D-Bus' ObjectManager data. CHANGES ------- - This is a complete rework. I think the previous implementation was difficult to understand. There were unfixed bugs and nobody understood the code well enough to fix them. Maybe somebody out there understood the code, but I certainly did not. At least nobody provided patches to fix those issues. I do believe that this implementation is more straightforward and easier to understand. It removes a lot of layers of code. Whether this claim of simplicity is true, each reader must decide for himself/herself. Note that it is still fairly complex. - There was a lingering performance issue with large number of D-Bus objects. The patch tries hard that the implementation scales well. Of course, when we cache N objects that have N-to-M references to other, we still are fundamentally O(N*M) for runtime and memory consumption (with M being the number of references between objects). But each part should behave efficiently and well. - Play well with GMainContext. libnm code (NMClient) is generally not thread safe. However, it should work to use multiple instances in parallel, as long as each access to a NMClient is through the caller's GMainContext. This follows glib's style and effectively allows to use NMClient in a multi threaded scenario. This implies to stick to a main context upon construction and ensure that callbacks are only invoked when iterating that context. Also, NMClient itself shall never iterate the caller's context. This also means, libnm must never use g_idle_add() or g_timeout_add(), as those enqueue sources in the g_main_context_default() context. - Get ordering of messages right. All events are consistently enqueued in a GMainContext and processed strictly in order. For example, previously "nm-object.c" tried to combine signals and emit them on an idle handler. That is wrong, signals must be emitted in the right order and when they happen. Note that when using GInitable's synchronous initialization to initialize the NMClient instance, NMClient internally still operates fully asynchronously. In that case NMClient has an internal main context. - NMClient takes over most of the functionality. When using D-Bus' ObjectManager interface, one needs to handle basically the entire state of the D-Bus interface. That cannot be separated well into distinct parts, and even if you try, you just end up having closely related code in different source files. Spreading related code does not make it easier to understand, on the contrary. That means, NMClient is inherently complex as it contains most of the logic. I think that is not avoidable, but it's not as bad as it sounds. - NMClient processes D-Bus messages and state changes in separate steps. First NMClient unpacks the message (e.g. _dbus_handle_properties_changed()) and keeps track of the changed data. Then we update the GObject instances (_dbus_handle_obj_changed_dbus()) without emitting any signals yet. Finally, we emit all signals and notifications that were collected (_dbus_handle_changes_commit()). Note that for example during the initial GetManagedObjects() reply, NMClient receive a large amount of state at once. But we first apply all the changes to our GObject instances before emitting any signals. The result is that signals are always emitted in a moment when the cache is consistent. The unavoidable downside is that when you receive a property changed signal, possibly many other properties changed already and more signals are about to be emitted. - NMDeviceWifi no longer modifies the content of the cache from client side during poke_wireless_devices_with_rf_status(). The content of the cache should be determined by D-Bus alone and follow what NetworkManager service exposes. Local modifications should be avoided. - This aims to bring no API/ABI change, though it does of course bring various subtle changes in behavior. Those should be all for the better, but the goal is not to break any existing clients. This does change internal (albeit externally visible) API, like dropping NM_OBJECT_DBUS_OBJECT_MANAGER property and NMObject no longer implementing GInitableIface and GAsyncInitableIface. - Some uses of gdbus-codegen classes remain in NMVpnPluginOld, NMVpnServicePlugin and NMSecretAgentOld. These are independent of NMClient/NMObject and should be reworked separately. - While we no longer use generated classes from gdbus-codegen, we don't need more glue code than before. Also before we constructed NMPropertiesInfo and a had large amount of code to propagate properties from NMDBus* to NMObject. That got completely reworked, but did not fundamentally change. You still need about the same effort to create the NMLDBusMetaIface. Not using generated bindings did not make anything worse (which tells about the usefulness of generated code, at least in the way it was used). - NMLDBusMetaIface and other meta data is static and immutable. This avoids copying them around. Also, macros like NML_DBUS_META_PROPERTY_INIT_U() have compile time checks to ensure the property types matches. It's pretty hard to misuse them because it won't compile. - The meta data now explicitly encodes the expected D-Bus types and makes sure never to accept wrong data. That would only matter when the server (accidentally or intentionally) exposes unexpected types on D-Bus. I don't think that was previously ensured in all cases. For example, demarshal_generic() only cared about the GObject property type, it didn't know the expected D-Bus type. - Previously GDBusObjectManager would sometimes emit warnings (g_log()). Those probably indicated real bugs. In any case, it prevented us from running CI with G_DEBUG=fatal-warnings, because there would be just too many unrelated crashes. Now we log debug messages that can be enabled with "LIBNM_CLIENT_DEBUG=trace". Some of these messages can also be turned into g_warning()/g_critical() by setting LIBNM_CLIENT_DEBUG=warning,error. Together with G_DEBUG=fatal-warnings, this turns them into assertions. Note that such "assertion failures" might also happen because of a server bug (or change). Thus these are not common assertions that indicate a bug in libnm and are thus not armed unless explicitly requested. In our CI we should now always run with LIBNM_CLIENT_DEBUG=warning,error and G_DEBUG=fatal-warnings and to catch bugs. Note that currently NetworkManager has bugs in this regard, so enabling this will result in assertion failures. That should be fixed first. - Note that this changes the order in which we emit "notify:devices" and "device-added" signals. I think it makes the most sense to emit first "device-removed", then "notify:devices", and finally "device-added" signals. This changes behavior for commit 52ae28f6e5bf ('libnm: queue added/removed signals and suppress uninitialized notifications'), but I don't think that users should actually rely on the order. Still, the new order makes the most sense to me. - In NetworkManager, profiles can be invisible to the user by setting "connection.permissions". Such profiles would be hidden by NMClient's nm_client_get_connections() and their "connection-added"/"connection-removed" signals. Note that NMActiveConnection's nm_active_connection_get_connection() and NMDevice's nm_device_get_available_connections() still exposes such hidden NMRemoteConnection instances. This behavior was preserved. NUMBERS ------- I compared 3 versions of libnm. [1] 962297f9085d, current tip of nm-1-20 branch [2] 4fad8c7c642e, current master, immediate parent of this patch [3] this patch All tests were done on Fedora 31, x86_64, gcc 9.2.1-1.fc31. The libraries were build with $ ./contrib/fedora/rpm/build_clean.sh -g -w test -W debug Note that RPM build already stripped the library. --- N1) File size of libnm.so.0.1.0 in bytes. There currently seems to be a issue on Fedora 31 generating wrong ELF notes. Usually, libnm is smaller but in these tests it had large (and bogus) ELF notes. Anyway, the point is to show the relative sizes, so it doesn't matter). [1] 4075552 (102.7%) [2] 3969624 (100.0%) [3] 3705208 ( 93.3%) --- N2) `size /usr/lib64/libnm.so.0.1.0`: text data bss dec hex filename [1] 1314569 (102.0%) 69980 ( 94.8%) 10632 ( 80.4%) 1395181 (101.4%) 1549ed /usr/lib64/libnm.so.0.1.0 [2] 1288410 (100.0%) 73796 (100.0%) 13224 (100.0%) 1375430 (100.0%) 14fcc6 /usr/lib64/libnm.so.0.1.0 [3] 1229066 ( 95.4%) 65248 ( 88.4%) 13400 (101.3%) 1307714 ( 95.1%) 13f442 /usr/lib64/libnm.so.0.1.0 --- N3) Performance test with test-client.py. With checkout of [2], run ``` prepare_checkout() { rm -rf /tmp/nm-test && \ git checkout -B test 4fad8c7c642e && \ git clean -fdx && \ ./autogen.sh --prefix=/tmp/nm-test && \ make -j 5 install && \ make -j 5 check-local-clients-tests-test-client } prepare_test() { NM_TEST_REGENERATE=1 NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v } do_test() { for i in {1..10}; do NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v || return -1 done echo "done!" } prepare_checkout prepare_test time do_test ``` [1] real 2m14.497s (101.3%) user 5m26.651s (100.3%) sys 1m40.453s (101.4%) [2] real 2m12.800s (100.0%) user 5m25.619s (100.0%) sys 1m39.065s (100.0%) [3] real 1m54.915s ( 86.5%) user 4m18.585s ( 79.4%) sys 1m32.066s ( 92.9%) --- N4) Performance. Run NetworkManager from build [2] and setup a large number of profiles (551 profiles and 515 devices, mostly unrealized). This setup is already at the edge of what NetworkManager currently can handle. Of course, that is a different issue. Here we just check how long plain `nmcli` takes on the system. ``` do_cleanup() { for UUID in $(nmcli -g NAME,UUID connection show | sed -n 's/^xx-c-.*:\([^:]\+\)$/\1/p'); do nmcli connection delete uuid "$UUID" done for DEVICE in $(nmcli -g DEVICE device status | grep '^xx-i-'); do nmcli device delete "$DEVICE" done } do_setup() { do_cleanup for i in {1..30}; do nmcli connection add type bond autoconnect no con-name xx-c-bond-$i ifname xx-i-bond-$i ipv4.method disabled ipv6.method ignore for j in $(seq $i 30); do nmcli connection add type vlan autoconnect no con-name xx-c-vlan-$i-$j vlan.id $j ifname xx-i-vlan-$i-$j vlan.parent xx-i-bond-$i ipv4.method disabled ipv6.method ignore done done systemctl restart NetworkManager.service sleep 5 } do_test() { perf stat -r 50 -B nmcli 1>/dev/null } do_test ``` [1] Performance counter stats for 'nmcli' (50 runs): 456.33 msec task-clock:u # 1.093 CPUs utilized ( +- 0.44% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,900 page-faults:u # 0.013 M/sec ( +- 0.02% ) 1,408,675,453 cycles:u # 3.087 GHz ( +- 0.48% ) 1,594,741,060 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 368,744,018 branches:u # 808.061 M/sec ( +- 0.02% ) 4,566,058 branch-misses:u # 1.24% of all branches ( +- 0.76% ) 0.41761 +- 0.00282 seconds time elapsed ( +- 0.68% ) [2] Performance counter stats for 'nmcli' (50 runs): 477.99 msec task-clock:u # 1.088 CPUs utilized ( +- 0.36% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,948 page-faults:u # 0.012 M/sec ( +- 0.03% ) 1,471,133,482 cycles:u # 3.078 GHz ( +- 0.36% ) 1,655,275,369 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 382,595,152 branches:u # 800.433 M/sec ( +- 0.02% ) 4,746,070 branch-misses:u # 1.24% of all branches ( +- 0.49% ) 0.43923 +- 0.00242 seconds time elapsed ( +- 0.55% ) [3] Performance counter stats for 'nmcli' (50 runs): 352.36 msec task-clock:u # 1.027 CPUs utilized ( +- 0.32% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 4,790 page-faults:u # 0.014 M/sec ( +- 0.26% ) 1,092,341,186 cycles:u # 3.100 GHz ( +- 0.26% ) 1,209,045,283 instructions:u # 1.11 insn per cycle ( +- 0.02% ) 281,708,462 branches:u # 799.499 M/sec ( +- 0.01% ) 3,101,031 branch-misses:u # 1.10% of all branches ( +- 0.61% ) 0.34296 +- 0.00120 seconds time elapsed ( +- 0.35% ) --- N5) same setup as N4), but run `PAGER= /bin/time -v nmcli`: [1] Command being timed: "nmcli" User time (seconds): 0.42 System time (seconds): 0.04 Percent of CPU this job got: 107% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.43 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34456 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6128 Voluntary context switches: 1298 Involuntary context switches: 1106 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [2] Command being timed: "nmcli" User time (seconds): 0.44 System time (seconds): 0.04 Percent of CPU this job got: 108% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.44 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34452 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6169 Voluntary context switches: 1849 Involuntary context switches: 142 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [3] Command being timed: "nmcli" User time (seconds): 0.32 System time (seconds): 0.02 Percent of CPU this job got: 102% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.34 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 29196 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 5059 Voluntary context switches: 919 Involuntary context switches: 685 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 --- N6) same setup as N4), but run `nmcli monitor` and look at `ps aux` for the RSS size. USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND [1] me 1492900 21.0 0.2 461348 33248 pts/10 Sl+ 15:02 0:00 nmcli monitor [2] me 1490721 5.0 0.2 461496 33548 pts/10 Sl+ 15:00 0:00 nmcli monitor [3] me 1495801 16.5 0.1 459476 28692 pts/10 Sl+ 15:04 0:00 nmcli monitor
2019-10-30 11:42:58 +01:00
_nm_client_dbus_call (_nm_object_get_client (device),
device,
nm_device_get_applied_connection_async,
cancellable,
callback,
user_data,
libnm: refactor caching of D-Bus objects in NMClient No longer use GDBusObjectMangaerClient and gdbus-codegen generated classes for the NMClient cache. Instead, use GDBusConnection directly and a custom implementation (NMLDBusObject) for caching D-Bus' ObjectManager data. CHANGES ------- - This is a complete rework. I think the previous implementation was difficult to understand. There were unfixed bugs and nobody understood the code well enough to fix them. Maybe somebody out there understood the code, but I certainly did not. At least nobody provided patches to fix those issues. I do believe that this implementation is more straightforward and easier to understand. It removes a lot of layers of code. Whether this claim of simplicity is true, each reader must decide for himself/herself. Note that it is still fairly complex. - There was a lingering performance issue with large number of D-Bus objects. The patch tries hard that the implementation scales well. Of course, when we cache N objects that have N-to-M references to other, we still are fundamentally O(N*M) for runtime and memory consumption (with M being the number of references between objects). But each part should behave efficiently and well. - Play well with GMainContext. libnm code (NMClient) is generally not thread safe. However, it should work to use multiple instances in parallel, as long as each access to a NMClient is through the caller's GMainContext. This follows glib's style and effectively allows to use NMClient in a multi threaded scenario. This implies to stick to a main context upon construction and ensure that callbacks are only invoked when iterating that context. Also, NMClient itself shall never iterate the caller's context. This also means, libnm must never use g_idle_add() or g_timeout_add(), as those enqueue sources in the g_main_context_default() context. - Get ordering of messages right. All events are consistently enqueued in a GMainContext and processed strictly in order. For example, previously "nm-object.c" tried to combine signals and emit them on an idle handler. That is wrong, signals must be emitted in the right order and when they happen. Note that when using GInitable's synchronous initialization to initialize the NMClient instance, NMClient internally still operates fully asynchronously. In that case NMClient has an internal main context. - NMClient takes over most of the functionality. When using D-Bus' ObjectManager interface, one needs to handle basically the entire state of the D-Bus interface. That cannot be separated well into distinct parts, and even if you try, you just end up having closely related code in different source files. Spreading related code does not make it easier to understand, on the contrary. That means, NMClient is inherently complex as it contains most of the logic. I think that is not avoidable, but it's not as bad as it sounds. - NMClient processes D-Bus messages and state changes in separate steps. First NMClient unpacks the message (e.g. _dbus_handle_properties_changed()) and keeps track of the changed data. Then we update the GObject instances (_dbus_handle_obj_changed_dbus()) without emitting any signals yet. Finally, we emit all signals and notifications that were collected (_dbus_handle_changes_commit()). Note that for example during the initial GetManagedObjects() reply, NMClient receive a large amount of state at once. But we first apply all the changes to our GObject instances before emitting any signals. The result is that signals are always emitted in a moment when the cache is consistent. The unavoidable downside is that when you receive a property changed signal, possibly many other properties changed already and more signals are about to be emitted. - NMDeviceWifi no longer modifies the content of the cache from client side during poke_wireless_devices_with_rf_status(). The content of the cache should be determined by D-Bus alone and follow what NetworkManager service exposes. Local modifications should be avoided. - This aims to bring no API/ABI change, though it does of course bring various subtle changes in behavior. Those should be all for the better, but the goal is not to break any existing clients. This does change internal (albeit externally visible) API, like dropping NM_OBJECT_DBUS_OBJECT_MANAGER property and NMObject no longer implementing GInitableIface and GAsyncInitableIface. - Some uses of gdbus-codegen classes remain in NMVpnPluginOld, NMVpnServicePlugin and NMSecretAgentOld. These are independent of NMClient/NMObject and should be reworked separately. - While we no longer use generated classes from gdbus-codegen, we don't need more glue code than before. Also before we constructed NMPropertiesInfo and a had large amount of code to propagate properties from NMDBus* to NMObject. That got completely reworked, but did not fundamentally change. You still need about the same effort to create the NMLDBusMetaIface. Not using generated bindings did not make anything worse (which tells about the usefulness of generated code, at least in the way it was used). - NMLDBusMetaIface and other meta data is static and immutable. This avoids copying them around. Also, macros like NML_DBUS_META_PROPERTY_INIT_U() have compile time checks to ensure the property types matches. It's pretty hard to misuse them because it won't compile. - The meta data now explicitly encodes the expected D-Bus types and makes sure never to accept wrong data. That would only matter when the server (accidentally or intentionally) exposes unexpected types on D-Bus. I don't think that was previously ensured in all cases. For example, demarshal_generic() only cared about the GObject property type, it didn't know the expected D-Bus type. - Previously GDBusObjectManager would sometimes emit warnings (g_log()). Those probably indicated real bugs. In any case, it prevented us from running CI with G_DEBUG=fatal-warnings, because there would be just too many unrelated crashes. Now we log debug messages that can be enabled with "LIBNM_CLIENT_DEBUG=trace". Some of these messages can also be turned into g_warning()/g_critical() by setting LIBNM_CLIENT_DEBUG=warning,error. Together with G_DEBUG=fatal-warnings, this turns them into assertions. Note that such "assertion failures" might also happen because of a server bug (or change). Thus these are not common assertions that indicate a bug in libnm and are thus not armed unless explicitly requested. In our CI we should now always run with LIBNM_CLIENT_DEBUG=warning,error and G_DEBUG=fatal-warnings and to catch bugs. Note that currently NetworkManager has bugs in this regard, so enabling this will result in assertion failures. That should be fixed first. - Note that this changes the order in which we emit "notify:devices" and "device-added" signals. I think it makes the most sense to emit first "device-removed", then "notify:devices", and finally "device-added" signals. This changes behavior for commit 52ae28f6e5bf ('libnm: queue added/removed signals and suppress uninitialized notifications'), but I don't think that users should actually rely on the order. Still, the new order makes the most sense to me. - In NetworkManager, profiles can be invisible to the user by setting "connection.permissions". Such profiles would be hidden by NMClient's nm_client_get_connections() and their "connection-added"/"connection-removed" signals. Note that NMActiveConnection's nm_active_connection_get_connection() and NMDevice's nm_device_get_available_connections() still exposes such hidden NMRemoteConnection instances. This behavior was preserved. NUMBERS ------- I compared 3 versions of libnm. [1] 962297f9085d, current tip of nm-1-20 branch [2] 4fad8c7c642e, current master, immediate parent of this patch [3] this patch All tests were done on Fedora 31, x86_64, gcc 9.2.1-1.fc31. The libraries were build with $ ./contrib/fedora/rpm/build_clean.sh -g -w test -W debug Note that RPM build already stripped the library. --- N1) File size of libnm.so.0.1.0 in bytes. There currently seems to be a issue on Fedora 31 generating wrong ELF notes. Usually, libnm is smaller but in these tests it had large (and bogus) ELF notes. Anyway, the point is to show the relative sizes, so it doesn't matter). [1] 4075552 (102.7%) [2] 3969624 (100.0%) [3] 3705208 ( 93.3%) --- N2) `size /usr/lib64/libnm.so.0.1.0`: text data bss dec hex filename [1] 1314569 (102.0%) 69980 ( 94.8%) 10632 ( 80.4%) 1395181 (101.4%) 1549ed /usr/lib64/libnm.so.0.1.0 [2] 1288410 (100.0%) 73796 (100.0%) 13224 (100.0%) 1375430 (100.0%) 14fcc6 /usr/lib64/libnm.so.0.1.0 [3] 1229066 ( 95.4%) 65248 ( 88.4%) 13400 (101.3%) 1307714 ( 95.1%) 13f442 /usr/lib64/libnm.so.0.1.0 --- N3) Performance test with test-client.py. With checkout of [2], run ``` prepare_checkout() { rm -rf /tmp/nm-test && \ git checkout -B test 4fad8c7c642e && \ git clean -fdx && \ ./autogen.sh --prefix=/tmp/nm-test && \ make -j 5 install && \ make -j 5 check-local-clients-tests-test-client } prepare_test() { NM_TEST_REGENERATE=1 NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v } do_test() { for i in {1..10}; do NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v || return -1 done echo "done!" } prepare_checkout prepare_test time do_test ``` [1] real 2m14.497s (101.3%) user 5m26.651s (100.3%) sys 1m40.453s (101.4%) [2] real 2m12.800s (100.0%) user 5m25.619s (100.0%) sys 1m39.065s (100.0%) [3] real 1m54.915s ( 86.5%) user 4m18.585s ( 79.4%) sys 1m32.066s ( 92.9%) --- N4) Performance. Run NetworkManager from build [2] and setup a large number of profiles (551 profiles and 515 devices, mostly unrealized). This setup is already at the edge of what NetworkManager currently can handle. Of course, that is a different issue. Here we just check how long plain `nmcli` takes on the system. ``` do_cleanup() { for UUID in $(nmcli -g NAME,UUID connection show | sed -n 's/^xx-c-.*:\([^:]\+\)$/\1/p'); do nmcli connection delete uuid "$UUID" done for DEVICE in $(nmcli -g DEVICE device status | grep '^xx-i-'); do nmcli device delete "$DEVICE" done } do_setup() { do_cleanup for i in {1..30}; do nmcli connection add type bond autoconnect no con-name xx-c-bond-$i ifname xx-i-bond-$i ipv4.method disabled ipv6.method ignore for j in $(seq $i 30); do nmcli connection add type vlan autoconnect no con-name xx-c-vlan-$i-$j vlan.id $j ifname xx-i-vlan-$i-$j vlan.parent xx-i-bond-$i ipv4.method disabled ipv6.method ignore done done systemctl restart NetworkManager.service sleep 5 } do_test() { perf stat -r 50 -B nmcli 1>/dev/null } do_test ``` [1] Performance counter stats for 'nmcli' (50 runs): 456.33 msec task-clock:u # 1.093 CPUs utilized ( +- 0.44% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,900 page-faults:u # 0.013 M/sec ( +- 0.02% ) 1,408,675,453 cycles:u # 3.087 GHz ( +- 0.48% ) 1,594,741,060 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 368,744,018 branches:u # 808.061 M/sec ( +- 0.02% ) 4,566,058 branch-misses:u # 1.24% of all branches ( +- 0.76% ) 0.41761 +- 0.00282 seconds time elapsed ( +- 0.68% ) [2] Performance counter stats for 'nmcli' (50 runs): 477.99 msec task-clock:u # 1.088 CPUs utilized ( +- 0.36% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,948 page-faults:u # 0.012 M/sec ( +- 0.03% ) 1,471,133,482 cycles:u # 3.078 GHz ( +- 0.36% ) 1,655,275,369 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 382,595,152 branches:u # 800.433 M/sec ( +- 0.02% ) 4,746,070 branch-misses:u # 1.24% of all branches ( +- 0.49% ) 0.43923 +- 0.00242 seconds time elapsed ( +- 0.55% ) [3] Performance counter stats for 'nmcli' (50 runs): 352.36 msec task-clock:u # 1.027 CPUs utilized ( +- 0.32% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 4,790 page-faults:u # 0.014 M/sec ( +- 0.26% ) 1,092,341,186 cycles:u # 3.100 GHz ( +- 0.26% ) 1,209,045,283 instructions:u # 1.11 insn per cycle ( +- 0.02% ) 281,708,462 branches:u # 799.499 M/sec ( +- 0.01% ) 3,101,031 branch-misses:u # 1.10% of all branches ( +- 0.61% ) 0.34296 +- 0.00120 seconds time elapsed ( +- 0.35% ) --- N5) same setup as N4), but run `PAGER= /bin/time -v nmcli`: [1] Command being timed: "nmcli" User time (seconds): 0.42 System time (seconds): 0.04 Percent of CPU this job got: 107% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.43 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34456 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6128 Voluntary context switches: 1298 Involuntary context switches: 1106 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [2] Command being timed: "nmcli" User time (seconds): 0.44 System time (seconds): 0.04 Percent of CPU this job got: 108% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.44 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34452 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6169 Voluntary context switches: 1849 Involuntary context switches: 142 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [3] Command being timed: "nmcli" User time (seconds): 0.32 System time (seconds): 0.02 Percent of CPU this job got: 102% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.34 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 29196 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 5059 Voluntary context switches: 919 Involuntary context switches: 685 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 --- N6) same setup as N4), but run `nmcli monitor` and look at `ps aux` for the RSS size. USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND [1] me 1492900 21.0 0.2 461348 33248 pts/10 Sl+ 15:02 0:00 nmcli monitor [2] me 1490721 5.0 0.2 461496 33548 pts/10 Sl+ 15:00 0:00 nmcli monitor [3] me 1495801 16.5 0.1 459476 28692 pts/10 Sl+ 15:04 0:00 nmcli monitor
2019-10-30 11:42:58 +01:00
_nm_object_get_path (device),
NM_DBUS_INTERFACE_DEVICE,
"GetAppliedConnection",
g_variant_new ("(u)", flags),
G_VARIANT_TYPE ("(a{sa{sv}}t)"),
G_DBUS_CALL_FLAGS_NONE,
NM_DBUS_DEFAULT_TIMEOUT_MSEC,
nm_dbus_connection_call_finish_variant_strip_dbus_error_cb);
}
/**
* nm_device_get_applied_connection_finish:
* @device: a #NMDevice
* @result: the result passed to the #GAsyncReadyCallback
* @version_id: (out) (allow-none): the current version id of the applied
* connection.
* @error: location for a #GError, or %NULL
*
* Gets the result of a call to nm_device_get_applied_connection_async().
*
* Returns: (transfer full): a currently applied %NMConnection or %NULL in case
* of error.
*
* The connection is as received from D-Bus and might not validate according
* to nm_connection_verify().
*
* Since: 1.2
**/
NMConnection *
nm_device_get_applied_connection_finish (NMDevice *device,
GAsyncResult *result,
guint64 *version_id,
GError **error)
{
gs_unref_variant GVariant *ret = NULL;
gs_unref_variant GVariant *v_connection = NULL;
guint64 v_version_id;
NMConnection *connection;
g_return_val_if_fail (NM_IS_DEVICE (device), NULL);
g_return_val_if_fail (nm_g_task_is_valid (result, device, nm_device_get_applied_connection_async), NULL);
g_return_val_if_fail (!error || !*error, NULL);
ret = g_task_propagate_pointer (G_TASK (result), error);
if (!ret)
return NULL;
g_variant_get (ret,
"(@a{sa{sv}}t)",
&v_connection,
&v_version_id);
connection = _nm_simple_connection_new_from_dbus (v_connection, NM_SETTING_PARSE_FLAGS_BEST_EFFORT, error);
if (!connection)
return NULL;
NM_SET_OUT (version_id, v_version_id);
return connection;
}
/*****************************************************************************/
/**
* nm_device_disconnect:
* @device: a #NMDevice
* @cancellable: a #GCancellable, or %NULL
* @error: location for a #GError, or %NULL
*
* Disconnects the device if currently connected, and prevents the device from
* automatically connecting to networks until the next manual network connection
* request.
*
* Returns: %TRUE on success, %FALSE on error, in which case @error will be set.
libnm: deprecate synchronous/blocking API in libnm Note that D-Bus is fundamentally asynchronous. Doing blocking calls on top of D-Bus is odd, especially for libnm's NMClient. That is because NMClient essentially is a client-side cache of the objects from the D-Bus interface. This cache should be filled exclusively by (asynchronous) D-Bus events (PropertiesChanged). So, making a blocking D-Bus call means to wait for a response and return it, while queuing all messages that are received in the meantime. Basically there are three ways how a synchronous API on NMClient could behave: 1) the call just calls g_dbus_connection_call_sync(). This means that libnm sends a D-Bus request via GDBusConnection, and blockingly waits for the response. All D-Bus messages that get received in the meantime are queued in the GMainContext that belongs to NMClient. That means, none of these D-Bus events are processed until we iterate the GMainContext after the call returns. The effect is, that NMClient (and all cached objects in there) are unaffected by the D-Bus request. Most of the synchronous API calls in libnm are of this kind. The problem is that the strict ordering of D-Bus events gets violated. For some API this is not an immediate problem. Take for example nm_device_wifi_request_scan(). The call merely blockingly tells NetworkManager to start scanning, but since NetworkManager's D-Bus API does not directly expose any state that tells whether we are currently scanning, this out of order processing of the D-Bus request is a small issue. The problem is more obvious for nm_client_networking_set_enabled(). After calling it, NM_CLIENT_NETWORKING_ENABLED is still unaffected and unchanged, because the PropertiesChanged signal from D-Bus is not yet processed. This means, while you make such a blocking call, NMClient's state does not change. But usually you perform the synchronous call to change some state. In this form, the blocking call is not useful, because NMClient only changes the state after iterating the GMainContext, and not after the blocking call returns. 2) like 1), but after making the blocking g_dbus_connection_call_sync(), update the NMClient cache artificially. This is what nm_manager_check_connectivity() does, to "fix" bgo#784629. This also has the problem of out-of-order events, but it kinda solves the problem of not changing the state during the blocking call. But it does so by hacking the state of the cache. I think this is really wrong because the state should only be updated from the ordered stream of D-Bus messages (PropertiesChanged signal and similar). When libnm decides to modify the state, there may be already D-Bus messages queued that affect this very state. 3) instead of calling g_dbus_connection_call_sync(), use the asynchronous g_dbus_connection_call(). If we would use a sepaate GMainContext for all D-Bus related calls, we could ensure that while we block for the response, we iterate that internal main context. This might be nice, because all events are processed in order and after the blocking call returns, the NMClient state is up to date. The are problems however: current blocking API does not do this, so it's a significant change in behavior. Also, it might be unexpected to the user that during the blocking call the entire content of NMClient's cache might change and all pointers to the cache might be invalidated. Also, of course NMClient would invoke signals for all the changes that happen. Another problem is that this would be more effort to implement and it involves a small performance overhead for all D-Bus related calls (because we have to serialize all events in an internal GMainContext first and then invoke them on the caller's context). Also, if the users wants this behavior, they could implement it themself by running libnm in their own GMainContext. Note that libnm might have bugs to make that really working, but that should be fixed instead of adding such synchrnous API behavior. Read also [1], for why blocking calls are wrong. [1] https://smcv.pseudorandom.co.uk/2008/11/nonblocking/ So, all possible behaviors for synchronous API have severe behavioural issues. Mark all this API as deprecated. Also, this serves the purpose of identifying blocking D-Bus calls in libnm. Note that "deprecated" here does not really mean that the API is going to be removed. We don't break API. The user may: - continue to use this API. It's deprecated, awkward and discouraged, but if it works, by all means use it. - use asynchronous API. That's the only sensible way to use D-Bus. If libnm lacks a certain asynchronous counterpart, it should be added. - use GDBusConnection directly. There really isn't anything wrong with D-Bus or GDBusConnection. This deprecated API is just a wrapper around g_dbus_connection_call_sync(). You may call it directly without feeling dirty. --- The only other remainging API is the synchronous GInitable call for NMClient. That is an entirely separate beast and not particularly wrong (from an API point of view). Note that synchronous API in NMSecretAgentOld, NMVpnPluginOld and NMVpnServicePlugin as not deprecated here. These types are not part of the D-Bus cache and while they have similar issues, it's less severe because they have less state.
2019-09-04 13:58:43 +02:00
*
* Deprecated: 1.22: Use nm_device_disconnect_async() or GDBusConnection.
**/
gboolean
nm_device_disconnect (NMDevice *device,
GCancellable *cancellable,
GError **error)
{
g_return_val_if_fail (NM_IS_DEVICE (device), FALSE);
g_return_val_if_fail (!cancellable || G_IS_CANCELLABLE (cancellable), FALSE);
g_return_val_if_fail (!error || !*error, FALSE);
libnm: refactor caching of D-Bus objects in NMClient No longer use GDBusObjectMangaerClient and gdbus-codegen generated classes for the NMClient cache. Instead, use GDBusConnection directly and a custom implementation (NMLDBusObject) for caching D-Bus' ObjectManager data. CHANGES ------- - This is a complete rework. I think the previous implementation was difficult to understand. There were unfixed bugs and nobody understood the code well enough to fix them. Maybe somebody out there understood the code, but I certainly did not. At least nobody provided patches to fix those issues. I do believe that this implementation is more straightforward and easier to understand. It removes a lot of layers of code. Whether this claim of simplicity is true, each reader must decide for himself/herself. Note that it is still fairly complex. - There was a lingering performance issue with large number of D-Bus objects. The patch tries hard that the implementation scales well. Of course, when we cache N objects that have N-to-M references to other, we still are fundamentally O(N*M) for runtime and memory consumption (with M being the number of references between objects). But each part should behave efficiently and well. - Play well with GMainContext. libnm code (NMClient) is generally not thread safe. However, it should work to use multiple instances in parallel, as long as each access to a NMClient is through the caller's GMainContext. This follows glib's style and effectively allows to use NMClient in a multi threaded scenario. This implies to stick to a main context upon construction and ensure that callbacks are only invoked when iterating that context. Also, NMClient itself shall never iterate the caller's context. This also means, libnm must never use g_idle_add() or g_timeout_add(), as those enqueue sources in the g_main_context_default() context. - Get ordering of messages right. All events are consistently enqueued in a GMainContext and processed strictly in order. For example, previously "nm-object.c" tried to combine signals and emit them on an idle handler. That is wrong, signals must be emitted in the right order and when they happen. Note that when using GInitable's synchronous initialization to initialize the NMClient instance, NMClient internally still operates fully asynchronously. In that case NMClient has an internal main context. - NMClient takes over most of the functionality. When using D-Bus' ObjectManager interface, one needs to handle basically the entire state of the D-Bus interface. That cannot be separated well into distinct parts, and even if you try, you just end up having closely related code in different source files. Spreading related code does not make it easier to understand, on the contrary. That means, NMClient is inherently complex as it contains most of the logic. I think that is not avoidable, but it's not as bad as it sounds. - NMClient processes D-Bus messages and state changes in separate steps. First NMClient unpacks the message (e.g. _dbus_handle_properties_changed()) and keeps track of the changed data. Then we update the GObject instances (_dbus_handle_obj_changed_dbus()) without emitting any signals yet. Finally, we emit all signals and notifications that were collected (_dbus_handle_changes_commit()). Note that for example during the initial GetManagedObjects() reply, NMClient receive a large amount of state at once. But we first apply all the changes to our GObject instances before emitting any signals. The result is that signals are always emitted in a moment when the cache is consistent. The unavoidable downside is that when you receive a property changed signal, possibly many other properties changed already and more signals are about to be emitted. - NMDeviceWifi no longer modifies the content of the cache from client side during poke_wireless_devices_with_rf_status(). The content of the cache should be determined by D-Bus alone and follow what NetworkManager service exposes. Local modifications should be avoided. - This aims to bring no API/ABI change, though it does of course bring various subtle changes in behavior. Those should be all for the better, but the goal is not to break any existing clients. This does change internal (albeit externally visible) API, like dropping NM_OBJECT_DBUS_OBJECT_MANAGER property and NMObject no longer implementing GInitableIface and GAsyncInitableIface. - Some uses of gdbus-codegen classes remain in NMVpnPluginOld, NMVpnServicePlugin and NMSecretAgentOld. These are independent of NMClient/NMObject and should be reworked separately. - While we no longer use generated classes from gdbus-codegen, we don't need more glue code than before. Also before we constructed NMPropertiesInfo and a had large amount of code to propagate properties from NMDBus* to NMObject. That got completely reworked, but did not fundamentally change. You still need about the same effort to create the NMLDBusMetaIface. Not using generated bindings did not make anything worse (which tells about the usefulness of generated code, at least in the way it was used). - NMLDBusMetaIface and other meta data is static and immutable. This avoids copying them around. Also, macros like NML_DBUS_META_PROPERTY_INIT_U() have compile time checks to ensure the property types matches. It's pretty hard to misuse them because it won't compile. - The meta data now explicitly encodes the expected D-Bus types and makes sure never to accept wrong data. That would only matter when the server (accidentally or intentionally) exposes unexpected types on D-Bus. I don't think that was previously ensured in all cases. For example, demarshal_generic() only cared about the GObject property type, it didn't know the expected D-Bus type. - Previously GDBusObjectManager would sometimes emit warnings (g_log()). Those probably indicated real bugs. In any case, it prevented us from running CI with G_DEBUG=fatal-warnings, because there would be just too many unrelated crashes. Now we log debug messages that can be enabled with "LIBNM_CLIENT_DEBUG=trace". Some of these messages can also be turned into g_warning()/g_critical() by setting LIBNM_CLIENT_DEBUG=warning,error. Together with G_DEBUG=fatal-warnings, this turns them into assertions. Note that such "assertion failures" might also happen because of a server bug (or change). Thus these are not common assertions that indicate a bug in libnm and are thus not armed unless explicitly requested. In our CI we should now always run with LIBNM_CLIENT_DEBUG=warning,error and G_DEBUG=fatal-warnings and to catch bugs. Note that currently NetworkManager has bugs in this regard, so enabling this will result in assertion failures. That should be fixed first. - Note that this changes the order in which we emit "notify:devices" and "device-added" signals. I think it makes the most sense to emit first "device-removed", then "notify:devices", and finally "device-added" signals. This changes behavior for commit 52ae28f6e5bf ('libnm: queue added/removed signals and suppress uninitialized notifications'), but I don't think that users should actually rely on the order. Still, the new order makes the most sense to me. - In NetworkManager, profiles can be invisible to the user by setting "connection.permissions". Such profiles would be hidden by NMClient's nm_client_get_connections() and their "connection-added"/"connection-removed" signals. Note that NMActiveConnection's nm_active_connection_get_connection() and NMDevice's nm_device_get_available_connections() still exposes such hidden NMRemoteConnection instances. This behavior was preserved. NUMBERS ------- I compared 3 versions of libnm. [1] 962297f9085d, current tip of nm-1-20 branch [2] 4fad8c7c642e, current master, immediate parent of this patch [3] this patch All tests were done on Fedora 31, x86_64, gcc 9.2.1-1.fc31. The libraries were build with $ ./contrib/fedora/rpm/build_clean.sh -g -w test -W debug Note that RPM build already stripped the library. --- N1) File size of libnm.so.0.1.0 in bytes. There currently seems to be a issue on Fedora 31 generating wrong ELF notes. Usually, libnm is smaller but in these tests it had large (and bogus) ELF notes. Anyway, the point is to show the relative sizes, so it doesn't matter). [1] 4075552 (102.7%) [2] 3969624 (100.0%) [3] 3705208 ( 93.3%) --- N2) `size /usr/lib64/libnm.so.0.1.0`: text data bss dec hex filename [1] 1314569 (102.0%) 69980 ( 94.8%) 10632 ( 80.4%) 1395181 (101.4%) 1549ed /usr/lib64/libnm.so.0.1.0 [2] 1288410 (100.0%) 73796 (100.0%) 13224 (100.0%) 1375430 (100.0%) 14fcc6 /usr/lib64/libnm.so.0.1.0 [3] 1229066 ( 95.4%) 65248 ( 88.4%) 13400 (101.3%) 1307714 ( 95.1%) 13f442 /usr/lib64/libnm.so.0.1.0 --- N3) Performance test with test-client.py. With checkout of [2], run ``` prepare_checkout() { rm -rf /tmp/nm-test && \ git checkout -B test 4fad8c7c642e && \ git clean -fdx && \ ./autogen.sh --prefix=/tmp/nm-test && \ make -j 5 install && \ make -j 5 check-local-clients-tests-test-client } prepare_test() { NM_TEST_REGENERATE=1 NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v } do_test() { for i in {1..10}; do NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v || return -1 done echo "done!" } prepare_checkout prepare_test time do_test ``` [1] real 2m14.497s (101.3%) user 5m26.651s (100.3%) sys 1m40.453s (101.4%) [2] real 2m12.800s (100.0%) user 5m25.619s (100.0%) sys 1m39.065s (100.0%) [3] real 1m54.915s ( 86.5%) user 4m18.585s ( 79.4%) sys 1m32.066s ( 92.9%) --- N4) Performance. Run NetworkManager from build [2] and setup a large number of profiles (551 profiles and 515 devices, mostly unrealized). This setup is already at the edge of what NetworkManager currently can handle. Of course, that is a different issue. Here we just check how long plain `nmcli` takes on the system. ``` do_cleanup() { for UUID in $(nmcli -g NAME,UUID connection show | sed -n 's/^xx-c-.*:\([^:]\+\)$/\1/p'); do nmcli connection delete uuid "$UUID" done for DEVICE in $(nmcli -g DEVICE device status | grep '^xx-i-'); do nmcli device delete "$DEVICE" done } do_setup() { do_cleanup for i in {1..30}; do nmcli connection add type bond autoconnect no con-name xx-c-bond-$i ifname xx-i-bond-$i ipv4.method disabled ipv6.method ignore for j in $(seq $i 30); do nmcli connection add type vlan autoconnect no con-name xx-c-vlan-$i-$j vlan.id $j ifname xx-i-vlan-$i-$j vlan.parent xx-i-bond-$i ipv4.method disabled ipv6.method ignore done done systemctl restart NetworkManager.service sleep 5 } do_test() { perf stat -r 50 -B nmcli 1>/dev/null } do_test ``` [1] Performance counter stats for 'nmcli' (50 runs): 456.33 msec task-clock:u # 1.093 CPUs utilized ( +- 0.44% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,900 page-faults:u # 0.013 M/sec ( +- 0.02% ) 1,408,675,453 cycles:u # 3.087 GHz ( +- 0.48% ) 1,594,741,060 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 368,744,018 branches:u # 808.061 M/sec ( +- 0.02% ) 4,566,058 branch-misses:u # 1.24% of all branches ( +- 0.76% ) 0.41761 +- 0.00282 seconds time elapsed ( +- 0.68% ) [2] Performance counter stats for 'nmcli' (50 runs): 477.99 msec task-clock:u # 1.088 CPUs utilized ( +- 0.36% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,948 page-faults:u # 0.012 M/sec ( +- 0.03% ) 1,471,133,482 cycles:u # 3.078 GHz ( +- 0.36% ) 1,655,275,369 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 382,595,152 branches:u # 800.433 M/sec ( +- 0.02% ) 4,746,070 branch-misses:u # 1.24% of all branches ( +- 0.49% ) 0.43923 +- 0.00242 seconds time elapsed ( +- 0.55% ) [3] Performance counter stats for 'nmcli' (50 runs): 352.36 msec task-clock:u # 1.027 CPUs utilized ( +- 0.32% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 4,790 page-faults:u # 0.014 M/sec ( +- 0.26% ) 1,092,341,186 cycles:u # 3.100 GHz ( +- 0.26% ) 1,209,045,283 instructions:u # 1.11 insn per cycle ( +- 0.02% ) 281,708,462 branches:u # 799.499 M/sec ( +- 0.01% ) 3,101,031 branch-misses:u # 1.10% of all branches ( +- 0.61% ) 0.34296 +- 0.00120 seconds time elapsed ( +- 0.35% ) --- N5) same setup as N4), but run `PAGER= /bin/time -v nmcli`: [1] Command being timed: "nmcli" User time (seconds): 0.42 System time (seconds): 0.04 Percent of CPU this job got: 107% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.43 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34456 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6128 Voluntary context switches: 1298 Involuntary context switches: 1106 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [2] Command being timed: "nmcli" User time (seconds): 0.44 System time (seconds): 0.04 Percent of CPU this job got: 108% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.44 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34452 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6169 Voluntary context switches: 1849 Involuntary context switches: 142 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [3] Command being timed: "nmcli" User time (seconds): 0.32 System time (seconds): 0.02 Percent of CPU this job got: 102% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.34 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 29196 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 5059 Voluntary context switches: 919 Involuntary context switches: 685 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 --- N6) same setup as N4), but run `nmcli monitor` and look at `ps aux` for the RSS size. USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND [1] me 1492900 21.0 0.2 461348 33248 pts/10 Sl+ 15:02 0:00 nmcli monitor [2] me 1490721 5.0 0.2 461496 33548 pts/10 Sl+ 15:00 0:00 nmcli monitor [3] me 1495801 16.5 0.1 459476 28692 pts/10 Sl+ 15:04 0:00 nmcli monitor
2019-10-30 11:42:58 +01:00
return _nm_client_dbus_call_sync_void (_nm_object_get_client (device),
cancellable,
libnm: refactor caching of D-Bus objects in NMClient No longer use GDBusObjectMangaerClient and gdbus-codegen generated classes for the NMClient cache. Instead, use GDBusConnection directly and a custom implementation (NMLDBusObject) for caching D-Bus' ObjectManager data. CHANGES ------- - This is a complete rework. I think the previous implementation was difficult to understand. There were unfixed bugs and nobody understood the code well enough to fix them. Maybe somebody out there understood the code, but I certainly did not. At least nobody provided patches to fix those issues. I do believe that this implementation is more straightforward and easier to understand. It removes a lot of layers of code. Whether this claim of simplicity is true, each reader must decide for himself/herself. Note that it is still fairly complex. - There was a lingering performance issue with large number of D-Bus objects. The patch tries hard that the implementation scales well. Of course, when we cache N objects that have N-to-M references to other, we still are fundamentally O(N*M) for runtime and memory consumption (with M being the number of references between objects). But each part should behave efficiently and well. - Play well with GMainContext. libnm code (NMClient) is generally not thread safe. However, it should work to use multiple instances in parallel, as long as each access to a NMClient is through the caller's GMainContext. This follows glib's style and effectively allows to use NMClient in a multi threaded scenario. This implies to stick to a main context upon construction and ensure that callbacks are only invoked when iterating that context. Also, NMClient itself shall never iterate the caller's context. This also means, libnm must never use g_idle_add() or g_timeout_add(), as those enqueue sources in the g_main_context_default() context. - Get ordering of messages right. All events are consistently enqueued in a GMainContext and processed strictly in order. For example, previously "nm-object.c" tried to combine signals and emit them on an idle handler. That is wrong, signals must be emitted in the right order and when they happen. Note that when using GInitable's synchronous initialization to initialize the NMClient instance, NMClient internally still operates fully asynchronously. In that case NMClient has an internal main context. - NMClient takes over most of the functionality. When using D-Bus' ObjectManager interface, one needs to handle basically the entire state of the D-Bus interface. That cannot be separated well into distinct parts, and even if you try, you just end up having closely related code in different source files. Spreading related code does not make it easier to understand, on the contrary. That means, NMClient is inherently complex as it contains most of the logic. I think that is not avoidable, but it's not as bad as it sounds. - NMClient processes D-Bus messages and state changes in separate steps. First NMClient unpacks the message (e.g. _dbus_handle_properties_changed()) and keeps track of the changed data. Then we update the GObject instances (_dbus_handle_obj_changed_dbus()) without emitting any signals yet. Finally, we emit all signals and notifications that were collected (_dbus_handle_changes_commit()). Note that for example during the initial GetManagedObjects() reply, NMClient receive a large amount of state at once. But we first apply all the changes to our GObject instances before emitting any signals. The result is that signals are always emitted in a moment when the cache is consistent. The unavoidable downside is that when you receive a property changed signal, possibly many other properties changed already and more signals are about to be emitted. - NMDeviceWifi no longer modifies the content of the cache from client side during poke_wireless_devices_with_rf_status(). The content of the cache should be determined by D-Bus alone and follow what NetworkManager service exposes. Local modifications should be avoided. - This aims to bring no API/ABI change, though it does of course bring various subtle changes in behavior. Those should be all for the better, but the goal is not to break any existing clients. This does change internal (albeit externally visible) API, like dropping NM_OBJECT_DBUS_OBJECT_MANAGER property and NMObject no longer implementing GInitableIface and GAsyncInitableIface. - Some uses of gdbus-codegen classes remain in NMVpnPluginOld, NMVpnServicePlugin and NMSecretAgentOld. These are independent of NMClient/NMObject and should be reworked separately. - While we no longer use generated classes from gdbus-codegen, we don't need more glue code than before. Also before we constructed NMPropertiesInfo and a had large amount of code to propagate properties from NMDBus* to NMObject. That got completely reworked, but did not fundamentally change. You still need about the same effort to create the NMLDBusMetaIface. Not using generated bindings did not make anything worse (which tells about the usefulness of generated code, at least in the way it was used). - NMLDBusMetaIface and other meta data is static and immutable. This avoids copying them around. Also, macros like NML_DBUS_META_PROPERTY_INIT_U() have compile time checks to ensure the property types matches. It's pretty hard to misuse them because it won't compile. - The meta data now explicitly encodes the expected D-Bus types and makes sure never to accept wrong data. That would only matter when the server (accidentally or intentionally) exposes unexpected types on D-Bus. I don't think that was previously ensured in all cases. For example, demarshal_generic() only cared about the GObject property type, it didn't know the expected D-Bus type. - Previously GDBusObjectManager would sometimes emit warnings (g_log()). Those probably indicated real bugs. In any case, it prevented us from running CI with G_DEBUG=fatal-warnings, because there would be just too many unrelated crashes. Now we log debug messages that can be enabled with "LIBNM_CLIENT_DEBUG=trace". Some of these messages can also be turned into g_warning()/g_critical() by setting LIBNM_CLIENT_DEBUG=warning,error. Together with G_DEBUG=fatal-warnings, this turns them into assertions. Note that such "assertion failures" might also happen because of a server bug (or change). Thus these are not common assertions that indicate a bug in libnm and are thus not armed unless explicitly requested. In our CI we should now always run with LIBNM_CLIENT_DEBUG=warning,error and G_DEBUG=fatal-warnings and to catch bugs. Note that currently NetworkManager has bugs in this regard, so enabling this will result in assertion failures. That should be fixed first. - Note that this changes the order in which we emit "notify:devices" and "device-added" signals. I think it makes the most sense to emit first "device-removed", then "notify:devices", and finally "device-added" signals. This changes behavior for commit 52ae28f6e5bf ('libnm: queue added/removed signals and suppress uninitialized notifications'), but I don't think that users should actually rely on the order. Still, the new order makes the most sense to me. - In NetworkManager, profiles can be invisible to the user by setting "connection.permissions". Such profiles would be hidden by NMClient's nm_client_get_connections() and their "connection-added"/"connection-removed" signals. Note that NMActiveConnection's nm_active_connection_get_connection() and NMDevice's nm_device_get_available_connections() still exposes such hidden NMRemoteConnection instances. This behavior was preserved. NUMBERS ------- I compared 3 versions of libnm. [1] 962297f9085d, current tip of nm-1-20 branch [2] 4fad8c7c642e, current master, immediate parent of this patch [3] this patch All tests were done on Fedora 31, x86_64, gcc 9.2.1-1.fc31. The libraries were build with $ ./contrib/fedora/rpm/build_clean.sh -g -w test -W debug Note that RPM build already stripped the library. --- N1) File size of libnm.so.0.1.0 in bytes. There currently seems to be a issue on Fedora 31 generating wrong ELF notes. Usually, libnm is smaller but in these tests it had large (and bogus) ELF notes. Anyway, the point is to show the relative sizes, so it doesn't matter). [1] 4075552 (102.7%) [2] 3969624 (100.0%) [3] 3705208 ( 93.3%) --- N2) `size /usr/lib64/libnm.so.0.1.0`: text data bss dec hex filename [1] 1314569 (102.0%) 69980 ( 94.8%) 10632 ( 80.4%) 1395181 (101.4%) 1549ed /usr/lib64/libnm.so.0.1.0 [2] 1288410 (100.0%) 73796 (100.0%) 13224 (100.0%) 1375430 (100.0%) 14fcc6 /usr/lib64/libnm.so.0.1.0 [3] 1229066 ( 95.4%) 65248 ( 88.4%) 13400 (101.3%) 1307714 ( 95.1%) 13f442 /usr/lib64/libnm.so.0.1.0 --- N3) Performance test with test-client.py. With checkout of [2], run ``` prepare_checkout() { rm -rf /tmp/nm-test && \ git checkout -B test 4fad8c7c642e && \ git clean -fdx && \ ./autogen.sh --prefix=/tmp/nm-test && \ make -j 5 install && \ make -j 5 check-local-clients-tests-test-client } prepare_test() { NM_TEST_REGENERATE=1 NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v } do_test() { for i in {1..10}; do NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v || return -1 done echo "done!" } prepare_checkout prepare_test time do_test ``` [1] real 2m14.497s (101.3%) user 5m26.651s (100.3%) sys 1m40.453s (101.4%) [2] real 2m12.800s (100.0%) user 5m25.619s (100.0%) sys 1m39.065s (100.0%) [3] real 1m54.915s ( 86.5%) user 4m18.585s ( 79.4%) sys 1m32.066s ( 92.9%) --- N4) Performance. Run NetworkManager from build [2] and setup a large number of profiles (551 profiles and 515 devices, mostly unrealized). This setup is already at the edge of what NetworkManager currently can handle. Of course, that is a different issue. Here we just check how long plain `nmcli` takes on the system. ``` do_cleanup() { for UUID in $(nmcli -g NAME,UUID connection show | sed -n 's/^xx-c-.*:\([^:]\+\)$/\1/p'); do nmcli connection delete uuid "$UUID" done for DEVICE in $(nmcli -g DEVICE device status | grep '^xx-i-'); do nmcli device delete "$DEVICE" done } do_setup() { do_cleanup for i in {1..30}; do nmcli connection add type bond autoconnect no con-name xx-c-bond-$i ifname xx-i-bond-$i ipv4.method disabled ipv6.method ignore for j in $(seq $i 30); do nmcli connection add type vlan autoconnect no con-name xx-c-vlan-$i-$j vlan.id $j ifname xx-i-vlan-$i-$j vlan.parent xx-i-bond-$i ipv4.method disabled ipv6.method ignore done done systemctl restart NetworkManager.service sleep 5 } do_test() { perf stat -r 50 -B nmcli 1>/dev/null } do_test ``` [1] Performance counter stats for 'nmcli' (50 runs): 456.33 msec task-clock:u # 1.093 CPUs utilized ( +- 0.44% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,900 page-faults:u # 0.013 M/sec ( +- 0.02% ) 1,408,675,453 cycles:u # 3.087 GHz ( +- 0.48% ) 1,594,741,060 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 368,744,018 branches:u # 808.061 M/sec ( +- 0.02% ) 4,566,058 branch-misses:u # 1.24% of all branches ( +- 0.76% ) 0.41761 +- 0.00282 seconds time elapsed ( +- 0.68% ) [2] Performance counter stats for 'nmcli' (50 runs): 477.99 msec task-clock:u # 1.088 CPUs utilized ( +- 0.36% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,948 page-faults:u # 0.012 M/sec ( +- 0.03% ) 1,471,133,482 cycles:u # 3.078 GHz ( +- 0.36% ) 1,655,275,369 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 382,595,152 branches:u # 800.433 M/sec ( +- 0.02% ) 4,746,070 branch-misses:u # 1.24% of all branches ( +- 0.49% ) 0.43923 +- 0.00242 seconds time elapsed ( +- 0.55% ) [3] Performance counter stats for 'nmcli' (50 runs): 352.36 msec task-clock:u # 1.027 CPUs utilized ( +- 0.32% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 4,790 page-faults:u # 0.014 M/sec ( +- 0.26% ) 1,092,341,186 cycles:u # 3.100 GHz ( +- 0.26% ) 1,209,045,283 instructions:u # 1.11 insn per cycle ( +- 0.02% ) 281,708,462 branches:u # 799.499 M/sec ( +- 0.01% ) 3,101,031 branch-misses:u # 1.10% of all branches ( +- 0.61% ) 0.34296 +- 0.00120 seconds time elapsed ( +- 0.35% ) --- N5) same setup as N4), but run `PAGER= /bin/time -v nmcli`: [1] Command being timed: "nmcli" User time (seconds): 0.42 System time (seconds): 0.04 Percent of CPU this job got: 107% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.43 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34456 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6128 Voluntary context switches: 1298 Involuntary context switches: 1106 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [2] Command being timed: "nmcli" User time (seconds): 0.44 System time (seconds): 0.04 Percent of CPU this job got: 108% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.44 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34452 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6169 Voluntary context switches: 1849 Involuntary context switches: 142 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [3] Command being timed: "nmcli" User time (seconds): 0.32 System time (seconds): 0.02 Percent of CPU this job got: 102% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.34 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 29196 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 5059 Voluntary context switches: 919 Involuntary context switches: 685 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 --- N6) same setup as N4), but run `nmcli monitor` and look at `ps aux` for the RSS size. USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND [1] me 1492900 21.0 0.2 461348 33248 pts/10 Sl+ 15:02 0:00 nmcli monitor [2] me 1490721 5.0 0.2 461496 33548 pts/10 Sl+ 15:00 0:00 nmcli monitor [3] me 1495801 16.5 0.1 459476 28692 pts/10 Sl+ 15:04 0:00 nmcli monitor
2019-10-30 11:42:58 +01:00
_nm_object_get_path (device),
NM_DBUS_INTERFACE_DEVICE,
"Disconnect",
g_variant_new ("()"),
G_DBUS_CALL_FLAGS_NONE,
NM_DBUS_DEFAULT_TIMEOUT_MSEC,
TRUE,
error);
}
/**
* nm_device_disconnect_async:
* @device: a #NMDevice
* @cancellable: a #GCancellable, or %NULL
* @callback: callback to be called when the disconnect operation completes
* @user_data: caller-specific data passed to @callback
*
* Asynchronously begins disconnecting the device if currently connected, and
* prevents the device from automatically connecting to networks until the next
* manual network connection request.
**/
void
nm_device_disconnect_async (NMDevice *device,
GCancellable *cancellable,
GAsyncReadyCallback callback,
gpointer user_data)
{
g_return_if_fail (NM_IS_DEVICE (device));
g_return_if_fail (!cancellable || G_IS_CANCELLABLE (cancellable));
libnm: refactor caching of D-Bus objects in NMClient No longer use GDBusObjectMangaerClient and gdbus-codegen generated classes for the NMClient cache. Instead, use GDBusConnection directly and a custom implementation (NMLDBusObject) for caching D-Bus' ObjectManager data. CHANGES ------- - This is a complete rework. I think the previous implementation was difficult to understand. There were unfixed bugs and nobody understood the code well enough to fix them. Maybe somebody out there understood the code, but I certainly did not. At least nobody provided patches to fix those issues. I do believe that this implementation is more straightforward and easier to understand. It removes a lot of layers of code. Whether this claim of simplicity is true, each reader must decide for himself/herself. Note that it is still fairly complex. - There was a lingering performance issue with large number of D-Bus objects. The patch tries hard that the implementation scales well. Of course, when we cache N objects that have N-to-M references to other, we still are fundamentally O(N*M) for runtime and memory consumption (with M being the number of references between objects). But each part should behave efficiently and well. - Play well with GMainContext. libnm code (NMClient) is generally not thread safe. However, it should work to use multiple instances in parallel, as long as each access to a NMClient is through the caller's GMainContext. This follows glib's style and effectively allows to use NMClient in a multi threaded scenario. This implies to stick to a main context upon construction and ensure that callbacks are only invoked when iterating that context. Also, NMClient itself shall never iterate the caller's context. This also means, libnm must never use g_idle_add() or g_timeout_add(), as those enqueue sources in the g_main_context_default() context. - Get ordering of messages right. All events are consistently enqueued in a GMainContext and processed strictly in order. For example, previously "nm-object.c" tried to combine signals and emit them on an idle handler. That is wrong, signals must be emitted in the right order and when they happen. Note that when using GInitable's synchronous initialization to initialize the NMClient instance, NMClient internally still operates fully asynchronously. In that case NMClient has an internal main context. - NMClient takes over most of the functionality. When using D-Bus' ObjectManager interface, one needs to handle basically the entire state of the D-Bus interface. That cannot be separated well into distinct parts, and even if you try, you just end up having closely related code in different source files. Spreading related code does not make it easier to understand, on the contrary. That means, NMClient is inherently complex as it contains most of the logic. I think that is not avoidable, but it's not as bad as it sounds. - NMClient processes D-Bus messages and state changes in separate steps. First NMClient unpacks the message (e.g. _dbus_handle_properties_changed()) and keeps track of the changed data. Then we update the GObject instances (_dbus_handle_obj_changed_dbus()) without emitting any signals yet. Finally, we emit all signals and notifications that were collected (_dbus_handle_changes_commit()). Note that for example during the initial GetManagedObjects() reply, NMClient receive a large amount of state at once. But we first apply all the changes to our GObject instances before emitting any signals. The result is that signals are always emitted in a moment when the cache is consistent. The unavoidable downside is that when you receive a property changed signal, possibly many other properties changed already and more signals are about to be emitted. - NMDeviceWifi no longer modifies the content of the cache from client side during poke_wireless_devices_with_rf_status(). The content of the cache should be determined by D-Bus alone and follow what NetworkManager service exposes. Local modifications should be avoided. - This aims to bring no API/ABI change, though it does of course bring various subtle changes in behavior. Those should be all for the better, but the goal is not to break any existing clients. This does change internal (albeit externally visible) API, like dropping NM_OBJECT_DBUS_OBJECT_MANAGER property and NMObject no longer implementing GInitableIface and GAsyncInitableIface. - Some uses of gdbus-codegen classes remain in NMVpnPluginOld, NMVpnServicePlugin and NMSecretAgentOld. These are independent of NMClient/NMObject and should be reworked separately. - While we no longer use generated classes from gdbus-codegen, we don't need more glue code than before. Also before we constructed NMPropertiesInfo and a had large amount of code to propagate properties from NMDBus* to NMObject. That got completely reworked, but did not fundamentally change. You still need about the same effort to create the NMLDBusMetaIface. Not using generated bindings did not make anything worse (which tells about the usefulness of generated code, at least in the way it was used). - NMLDBusMetaIface and other meta data is static and immutable. This avoids copying them around. Also, macros like NML_DBUS_META_PROPERTY_INIT_U() have compile time checks to ensure the property types matches. It's pretty hard to misuse them because it won't compile. - The meta data now explicitly encodes the expected D-Bus types and makes sure never to accept wrong data. That would only matter when the server (accidentally or intentionally) exposes unexpected types on D-Bus. I don't think that was previously ensured in all cases. For example, demarshal_generic() only cared about the GObject property type, it didn't know the expected D-Bus type. - Previously GDBusObjectManager would sometimes emit warnings (g_log()). Those probably indicated real bugs. In any case, it prevented us from running CI with G_DEBUG=fatal-warnings, because there would be just too many unrelated crashes. Now we log debug messages that can be enabled with "LIBNM_CLIENT_DEBUG=trace". Some of these messages can also be turned into g_warning()/g_critical() by setting LIBNM_CLIENT_DEBUG=warning,error. Together with G_DEBUG=fatal-warnings, this turns them into assertions. Note that such "assertion failures" might also happen because of a server bug (or change). Thus these are not common assertions that indicate a bug in libnm and are thus not armed unless explicitly requested. In our CI we should now always run with LIBNM_CLIENT_DEBUG=warning,error and G_DEBUG=fatal-warnings and to catch bugs. Note that currently NetworkManager has bugs in this regard, so enabling this will result in assertion failures. That should be fixed first. - Note that this changes the order in which we emit "notify:devices" and "device-added" signals. I think it makes the most sense to emit first "device-removed", then "notify:devices", and finally "device-added" signals. This changes behavior for commit 52ae28f6e5bf ('libnm: queue added/removed signals and suppress uninitialized notifications'), but I don't think that users should actually rely on the order. Still, the new order makes the most sense to me. - In NetworkManager, profiles can be invisible to the user by setting "connection.permissions". Such profiles would be hidden by NMClient's nm_client_get_connections() and their "connection-added"/"connection-removed" signals. Note that NMActiveConnection's nm_active_connection_get_connection() and NMDevice's nm_device_get_available_connections() still exposes such hidden NMRemoteConnection instances. This behavior was preserved. NUMBERS ------- I compared 3 versions of libnm. [1] 962297f9085d, current tip of nm-1-20 branch [2] 4fad8c7c642e, current master, immediate parent of this patch [3] this patch All tests were done on Fedora 31, x86_64, gcc 9.2.1-1.fc31. The libraries were build with $ ./contrib/fedora/rpm/build_clean.sh -g -w test -W debug Note that RPM build already stripped the library. --- N1) File size of libnm.so.0.1.0 in bytes. There currently seems to be a issue on Fedora 31 generating wrong ELF notes. Usually, libnm is smaller but in these tests it had large (and bogus) ELF notes. Anyway, the point is to show the relative sizes, so it doesn't matter). [1] 4075552 (102.7%) [2] 3969624 (100.0%) [3] 3705208 ( 93.3%) --- N2) `size /usr/lib64/libnm.so.0.1.0`: text data bss dec hex filename [1] 1314569 (102.0%) 69980 ( 94.8%) 10632 ( 80.4%) 1395181 (101.4%) 1549ed /usr/lib64/libnm.so.0.1.0 [2] 1288410 (100.0%) 73796 (100.0%) 13224 (100.0%) 1375430 (100.0%) 14fcc6 /usr/lib64/libnm.so.0.1.0 [3] 1229066 ( 95.4%) 65248 ( 88.4%) 13400 (101.3%) 1307714 ( 95.1%) 13f442 /usr/lib64/libnm.so.0.1.0 --- N3) Performance test with test-client.py. With checkout of [2], run ``` prepare_checkout() { rm -rf /tmp/nm-test && \ git checkout -B test 4fad8c7c642e && \ git clean -fdx && \ ./autogen.sh --prefix=/tmp/nm-test && \ make -j 5 install && \ make -j 5 check-local-clients-tests-test-client } prepare_test() { NM_TEST_REGENERATE=1 NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v } do_test() { for i in {1..10}; do NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v || return -1 done echo "done!" } prepare_checkout prepare_test time do_test ``` [1] real 2m14.497s (101.3%) user 5m26.651s (100.3%) sys 1m40.453s (101.4%) [2] real 2m12.800s (100.0%) user 5m25.619s (100.0%) sys 1m39.065s (100.0%) [3] real 1m54.915s ( 86.5%) user 4m18.585s ( 79.4%) sys 1m32.066s ( 92.9%) --- N4) Performance. Run NetworkManager from build [2] and setup a large number of profiles (551 profiles and 515 devices, mostly unrealized). This setup is already at the edge of what NetworkManager currently can handle. Of course, that is a different issue. Here we just check how long plain `nmcli` takes on the system. ``` do_cleanup() { for UUID in $(nmcli -g NAME,UUID connection show | sed -n 's/^xx-c-.*:\([^:]\+\)$/\1/p'); do nmcli connection delete uuid "$UUID" done for DEVICE in $(nmcli -g DEVICE device status | grep '^xx-i-'); do nmcli device delete "$DEVICE" done } do_setup() { do_cleanup for i in {1..30}; do nmcli connection add type bond autoconnect no con-name xx-c-bond-$i ifname xx-i-bond-$i ipv4.method disabled ipv6.method ignore for j in $(seq $i 30); do nmcli connection add type vlan autoconnect no con-name xx-c-vlan-$i-$j vlan.id $j ifname xx-i-vlan-$i-$j vlan.parent xx-i-bond-$i ipv4.method disabled ipv6.method ignore done done systemctl restart NetworkManager.service sleep 5 } do_test() { perf stat -r 50 -B nmcli 1>/dev/null } do_test ``` [1] Performance counter stats for 'nmcli' (50 runs): 456.33 msec task-clock:u # 1.093 CPUs utilized ( +- 0.44% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,900 page-faults:u # 0.013 M/sec ( +- 0.02% ) 1,408,675,453 cycles:u # 3.087 GHz ( +- 0.48% ) 1,594,741,060 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 368,744,018 branches:u # 808.061 M/sec ( +- 0.02% ) 4,566,058 branch-misses:u # 1.24% of all branches ( +- 0.76% ) 0.41761 +- 0.00282 seconds time elapsed ( +- 0.68% ) [2] Performance counter stats for 'nmcli' (50 runs): 477.99 msec task-clock:u # 1.088 CPUs utilized ( +- 0.36% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,948 page-faults:u # 0.012 M/sec ( +- 0.03% ) 1,471,133,482 cycles:u # 3.078 GHz ( +- 0.36% ) 1,655,275,369 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 382,595,152 branches:u # 800.433 M/sec ( +- 0.02% ) 4,746,070 branch-misses:u # 1.24% of all branches ( +- 0.49% ) 0.43923 +- 0.00242 seconds time elapsed ( +- 0.55% ) [3] Performance counter stats for 'nmcli' (50 runs): 352.36 msec task-clock:u # 1.027 CPUs utilized ( +- 0.32% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 4,790 page-faults:u # 0.014 M/sec ( +- 0.26% ) 1,092,341,186 cycles:u # 3.100 GHz ( +- 0.26% ) 1,209,045,283 instructions:u # 1.11 insn per cycle ( +- 0.02% ) 281,708,462 branches:u # 799.499 M/sec ( +- 0.01% ) 3,101,031 branch-misses:u # 1.10% of all branches ( +- 0.61% ) 0.34296 +- 0.00120 seconds time elapsed ( +- 0.35% ) --- N5) same setup as N4), but run `PAGER= /bin/time -v nmcli`: [1] Command being timed: "nmcli" User time (seconds): 0.42 System time (seconds): 0.04 Percent of CPU this job got: 107% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.43 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34456 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6128 Voluntary context switches: 1298 Involuntary context switches: 1106 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [2] Command being timed: "nmcli" User time (seconds): 0.44 System time (seconds): 0.04 Percent of CPU this job got: 108% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.44 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34452 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6169 Voluntary context switches: 1849 Involuntary context switches: 142 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [3] Command being timed: "nmcli" User time (seconds): 0.32 System time (seconds): 0.02 Percent of CPU this job got: 102% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.34 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 29196 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 5059 Voluntary context switches: 919 Involuntary context switches: 685 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 --- N6) same setup as N4), but run `nmcli monitor` and look at `ps aux` for the RSS size. USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND [1] me 1492900 21.0 0.2 461348 33248 pts/10 Sl+ 15:02 0:00 nmcli monitor [2] me 1490721 5.0 0.2 461496 33548 pts/10 Sl+ 15:00 0:00 nmcli monitor [3] me 1495801 16.5 0.1 459476 28692 pts/10 Sl+ 15:04 0:00 nmcli monitor
2019-10-30 11:42:58 +01:00
_nm_client_dbus_call (_nm_object_get_client (device),
device,
nm_device_disconnect_async,
cancellable,
callback,
user_data,
libnm: refactor caching of D-Bus objects in NMClient No longer use GDBusObjectMangaerClient and gdbus-codegen generated classes for the NMClient cache. Instead, use GDBusConnection directly and a custom implementation (NMLDBusObject) for caching D-Bus' ObjectManager data. CHANGES ------- - This is a complete rework. I think the previous implementation was difficult to understand. There were unfixed bugs and nobody understood the code well enough to fix them. Maybe somebody out there understood the code, but I certainly did not. At least nobody provided patches to fix those issues. I do believe that this implementation is more straightforward and easier to understand. It removes a lot of layers of code. Whether this claim of simplicity is true, each reader must decide for himself/herself. Note that it is still fairly complex. - There was a lingering performance issue with large number of D-Bus objects. The patch tries hard that the implementation scales well. Of course, when we cache N objects that have N-to-M references to other, we still are fundamentally O(N*M) for runtime and memory consumption (with M being the number of references between objects). But each part should behave efficiently and well. - Play well with GMainContext. libnm code (NMClient) is generally not thread safe. However, it should work to use multiple instances in parallel, as long as each access to a NMClient is through the caller's GMainContext. This follows glib's style and effectively allows to use NMClient in a multi threaded scenario. This implies to stick to a main context upon construction and ensure that callbacks are only invoked when iterating that context. Also, NMClient itself shall never iterate the caller's context. This also means, libnm must never use g_idle_add() or g_timeout_add(), as those enqueue sources in the g_main_context_default() context. - Get ordering of messages right. All events are consistently enqueued in a GMainContext and processed strictly in order. For example, previously "nm-object.c" tried to combine signals and emit them on an idle handler. That is wrong, signals must be emitted in the right order and when they happen. Note that when using GInitable's synchronous initialization to initialize the NMClient instance, NMClient internally still operates fully asynchronously. In that case NMClient has an internal main context. - NMClient takes over most of the functionality. When using D-Bus' ObjectManager interface, one needs to handle basically the entire state of the D-Bus interface. That cannot be separated well into distinct parts, and even if you try, you just end up having closely related code in different source files. Spreading related code does not make it easier to understand, on the contrary. That means, NMClient is inherently complex as it contains most of the logic. I think that is not avoidable, but it's not as bad as it sounds. - NMClient processes D-Bus messages and state changes in separate steps. First NMClient unpacks the message (e.g. _dbus_handle_properties_changed()) and keeps track of the changed data. Then we update the GObject instances (_dbus_handle_obj_changed_dbus()) without emitting any signals yet. Finally, we emit all signals and notifications that were collected (_dbus_handle_changes_commit()). Note that for example during the initial GetManagedObjects() reply, NMClient receive a large amount of state at once. But we first apply all the changes to our GObject instances before emitting any signals. The result is that signals are always emitted in a moment when the cache is consistent. The unavoidable downside is that when you receive a property changed signal, possibly many other properties changed already and more signals are about to be emitted. - NMDeviceWifi no longer modifies the content of the cache from client side during poke_wireless_devices_with_rf_status(). The content of the cache should be determined by D-Bus alone and follow what NetworkManager service exposes. Local modifications should be avoided. - This aims to bring no API/ABI change, though it does of course bring various subtle changes in behavior. Those should be all for the better, but the goal is not to break any existing clients. This does change internal (albeit externally visible) API, like dropping NM_OBJECT_DBUS_OBJECT_MANAGER property and NMObject no longer implementing GInitableIface and GAsyncInitableIface. - Some uses of gdbus-codegen classes remain in NMVpnPluginOld, NMVpnServicePlugin and NMSecretAgentOld. These are independent of NMClient/NMObject and should be reworked separately. - While we no longer use generated classes from gdbus-codegen, we don't need more glue code than before. Also before we constructed NMPropertiesInfo and a had large amount of code to propagate properties from NMDBus* to NMObject. That got completely reworked, but did not fundamentally change. You still need about the same effort to create the NMLDBusMetaIface. Not using generated bindings did not make anything worse (which tells about the usefulness of generated code, at least in the way it was used). - NMLDBusMetaIface and other meta data is static and immutable. This avoids copying them around. Also, macros like NML_DBUS_META_PROPERTY_INIT_U() have compile time checks to ensure the property types matches. It's pretty hard to misuse them because it won't compile. - The meta data now explicitly encodes the expected D-Bus types and makes sure never to accept wrong data. That would only matter when the server (accidentally or intentionally) exposes unexpected types on D-Bus. I don't think that was previously ensured in all cases. For example, demarshal_generic() only cared about the GObject property type, it didn't know the expected D-Bus type. - Previously GDBusObjectManager would sometimes emit warnings (g_log()). Those probably indicated real bugs. In any case, it prevented us from running CI with G_DEBUG=fatal-warnings, because there would be just too many unrelated crashes. Now we log debug messages that can be enabled with "LIBNM_CLIENT_DEBUG=trace". Some of these messages can also be turned into g_warning()/g_critical() by setting LIBNM_CLIENT_DEBUG=warning,error. Together with G_DEBUG=fatal-warnings, this turns them into assertions. Note that such "assertion failures" might also happen because of a server bug (or change). Thus these are not common assertions that indicate a bug in libnm and are thus not armed unless explicitly requested. In our CI we should now always run with LIBNM_CLIENT_DEBUG=warning,error and G_DEBUG=fatal-warnings and to catch bugs. Note that currently NetworkManager has bugs in this regard, so enabling this will result in assertion failures. That should be fixed first. - Note that this changes the order in which we emit "notify:devices" and "device-added" signals. I think it makes the most sense to emit first "device-removed", then "notify:devices", and finally "device-added" signals. This changes behavior for commit 52ae28f6e5bf ('libnm: queue added/removed signals and suppress uninitialized notifications'), but I don't think that users should actually rely on the order. Still, the new order makes the most sense to me. - In NetworkManager, profiles can be invisible to the user by setting "connection.permissions". Such profiles would be hidden by NMClient's nm_client_get_connections() and their "connection-added"/"connection-removed" signals. Note that NMActiveConnection's nm_active_connection_get_connection() and NMDevice's nm_device_get_available_connections() still exposes such hidden NMRemoteConnection instances. This behavior was preserved. NUMBERS ------- I compared 3 versions of libnm. [1] 962297f9085d, current tip of nm-1-20 branch [2] 4fad8c7c642e, current master, immediate parent of this patch [3] this patch All tests were done on Fedora 31, x86_64, gcc 9.2.1-1.fc31. The libraries were build with $ ./contrib/fedora/rpm/build_clean.sh -g -w test -W debug Note that RPM build already stripped the library. --- N1) File size of libnm.so.0.1.0 in bytes. There currently seems to be a issue on Fedora 31 generating wrong ELF notes. Usually, libnm is smaller but in these tests it had large (and bogus) ELF notes. Anyway, the point is to show the relative sizes, so it doesn't matter). [1] 4075552 (102.7%) [2] 3969624 (100.0%) [3] 3705208 ( 93.3%) --- N2) `size /usr/lib64/libnm.so.0.1.0`: text data bss dec hex filename [1] 1314569 (102.0%) 69980 ( 94.8%) 10632 ( 80.4%) 1395181 (101.4%) 1549ed /usr/lib64/libnm.so.0.1.0 [2] 1288410 (100.0%) 73796 (100.0%) 13224 (100.0%) 1375430 (100.0%) 14fcc6 /usr/lib64/libnm.so.0.1.0 [3] 1229066 ( 95.4%) 65248 ( 88.4%) 13400 (101.3%) 1307714 ( 95.1%) 13f442 /usr/lib64/libnm.so.0.1.0 --- N3) Performance test with test-client.py. With checkout of [2], run ``` prepare_checkout() { rm -rf /tmp/nm-test && \ git checkout -B test 4fad8c7c642e && \ git clean -fdx && \ ./autogen.sh --prefix=/tmp/nm-test && \ make -j 5 install && \ make -j 5 check-local-clients-tests-test-client } prepare_test() { NM_TEST_REGENERATE=1 NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v } do_test() { for i in {1..10}; do NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v || return -1 done echo "done!" } prepare_checkout prepare_test time do_test ``` [1] real 2m14.497s (101.3%) user 5m26.651s (100.3%) sys 1m40.453s (101.4%) [2] real 2m12.800s (100.0%) user 5m25.619s (100.0%) sys 1m39.065s (100.0%) [3] real 1m54.915s ( 86.5%) user 4m18.585s ( 79.4%) sys 1m32.066s ( 92.9%) --- N4) Performance. Run NetworkManager from build [2] and setup a large number of profiles (551 profiles and 515 devices, mostly unrealized). This setup is already at the edge of what NetworkManager currently can handle. Of course, that is a different issue. Here we just check how long plain `nmcli` takes on the system. ``` do_cleanup() { for UUID in $(nmcli -g NAME,UUID connection show | sed -n 's/^xx-c-.*:\([^:]\+\)$/\1/p'); do nmcli connection delete uuid "$UUID" done for DEVICE in $(nmcli -g DEVICE device status | grep '^xx-i-'); do nmcli device delete "$DEVICE" done } do_setup() { do_cleanup for i in {1..30}; do nmcli connection add type bond autoconnect no con-name xx-c-bond-$i ifname xx-i-bond-$i ipv4.method disabled ipv6.method ignore for j in $(seq $i 30); do nmcli connection add type vlan autoconnect no con-name xx-c-vlan-$i-$j vlan.id $j ifname xx-i-vlan-$i-$j vlan.parent xx-i-bond-$i ipv4.method disabled ipv6.method ignore done done systemctl restart NetworkManager.service sleep 5 } do_test() { perf stat -r 50 -B nmcli 1>/dev/null } do_test ``` [1] Performance counter stats for 'nmcli' (50 runs): 456.33 msec task-clock:u # 1.093 CPUs utilized ( +- 0.44% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,900 page-faults:u # 0.013 M/sec ( +- 0.02% ) 1,408,675,453 cycles:u # 3.087 GHz ( +- 0.48% ) 1,594,741,060 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 368,744,018 branches:u # 808.061 M/sec ( +- 0.02% ) 4,566,058 branch-misses:u # 1.24% of all branches ( +- 0.76% ) 0.41761 +- 0.00282 seconds time elapsed ( +- 0.68% ) [2] Performance counter stats for 'nmcli' (50 runs): 477.99 msec task-clock:u # 1.088 CPUs utilized ( +- 0.36% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,948 page-faults:u # 0.012 M/sec ( +- 0.03% ) 1,471,133,482 cycles:u # 3.078 GHz ( +- 0.36% ) 1,655,275,369 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 382,595,152 branches:u # 800.433 M/sec ( +- 0.02% ) 4,746,070 branch-misses:u # 1.24% of all branches ( +- 0.49% ) 0.43923 +- 0.00242 seconds time elapsed ( +- 0.55% ) [3] Performance counter stats for 'nmcli' (50 runs): 352.36 msec task-clock:u # 1.027 CPUs utilized ( +- 0.32% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 4,790 page-faults:u # 0.014 M/sec ( +- 0.26% ) 1,092,341,186 cycles:u # 3.100 GHz ( +- 0.26% ) 1,209,045,283 instructions:u # 1.11 insn per cycle ( +- 0.02% ) 281,708,462 branches:u # 799.499 M/sec ( +- 0.01% ) 3,101,031 branch-misses:u # 1.10% of all branches ( +- 0.61% ) 0.34296 +- 0.00120 seconds time elapsed ( +- 0.35% ) --- N5) same setup as N4), but run `PAGER= /bin/time -v nmcli`: [1] Command being timed: "nmcli" User time (seconds): 0.42 System time (seconds): 0.04 Percent of CPU this job got: 107% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.43 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34456 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6128 Voluntary context switches: 1298 Involuntary context switches: 1106 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [2] Command being timed: "nmcli" User time (seconds): 0.44 System time (seconds): 0.04 Percent of CPU this job got: 108% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.44 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34452 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6169 Voluntary context switches: 1849 Involuntary context switches: 142 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [3] Command being timed: "nmcli" User time (seconds): 0.32 System time (seconds): 0.02 Percent of CPU this job got: 102% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.34 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 29196 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 5059 Voluntary context switches: 919 Involuntary context switches: 685 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 --- N6) same setup as N4), but run `nmcli monitor` and look at `ps aux` for the RSS size. USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND [1] me 1492900 21.0 0.2 461348 33248 pts/10 Sl+ 15:02 0:00 nmcli monitor [2] me 1490721 5.0 0.2 461496 33548 pts/10 Sl+ 15:00 0:00 nmcli monitor [3] me 1495801 16.5 0.1 459476 28692 pts/10 Sl+ 15:04 0:00 nmcli monitor
2019-10-30 11:42:58 +01:00
_nm_object_get_path (device),
NM_DBUS_INTERFACE_DEVICE,
"Disconnect",
g_variant_new ("()"),
G_VARIANT_TYPE ("()"),
G_DBUS_CALL_FLAGS_NONE,
NM_DBUS_DEFAULT_TIMEOUT_MSEC,
nm_dbus_connection_call_finish_void_strip_dbus_error_cb);
}
/**
* nm_device_disconnect_finish:
* @device: a #NMDevice
* @result: the result passed to the #GAsyncReadyCallback
* @error: location for a #GError, or %NULL
*
* Gets the result of a call to nm_device_disconnect_async().
*
* Returns: %TRUE on success, %FALSE on error, in which case @error
* will be set.
**/
gboolean
nm_device_disconnect_finish (NMDevice *device,
GAsyncResult *result,
GError **error)
{
g_return_val_if_fail (NM_IS_DEVICE (device), FALSE);
g_return_val_if_fail (nm_g_task_is_valid (result, device, nm_device_disconnect_async), FALSE);
return g_task_propagate_boolean (G_TASK (result), error);
}
/**
* nm_device_delete:
* @device: a #NMDevice
* @cancellable: a #GCancellable, or %NULL
* @error: location for a #GError, or %NULL
*
* Deletes the software device. Hardware devices can't be deleted.
*
* Returns: %TRUE on success, %FALSE on error, in which case @error
* will be set.
libnm: deprecate synchronous/blocking API in libnm Note that D-Bus is fundamentally asynchronous. Doing blocking calls on top of D-Bus is odd, especially for libnm's NMClient. That is because NMClient essentially is a client-side cache of the objects from the D-Bus interface. This cache should be filled exclusively by (asynchronous) D-Bus events (PropertiesChanged). So, making a blocking D-Bus call means to wait for a response and return it, while queuing all messages that are received in the meantime. Basically there are three ways how a synchronous API on NMClient could behave: 1) the call just calls g_dbus_connection_call_sync(). This means that libnm sends a D-Bus request via GDBusConnection, and blockingly waits for the response. All D-Bus messages that get received in the meantime are queued in the GMainContext that belongs to NMClient. That means, none of these D-Bus events are processed until we iterate the GMainContext after the call returns. The effect is, that NMClient (and all cached objects in there) are unaffected by the D-Bus request. Most of the synchronous API calls in libnm are of this kind. The problem is that the strict ordering of D-Bus events gets violated. For some API this is not an immediate problem. Take for example nm_device_wifi_request_scan(). The call merely blockingly tells NetworkManager to start scanning, but since NetworkManager's D-Bus API does not directly expose any state that tells whether we are currently scanning, this out of order processing of the D-Bus request is a small issue. The problem is more obvious for nm_client_networking_set_enabled(). After calling it, NM_CLIENT_NETWORKING_ENABLED is still unaffected and unchanged, because the PropertiesChanged signal from D-Bus is not yet processed. This means, while you make such a blocking call, NMClient's state does not change. But usually you perform the synchronous call to change some state. In this form, the blocking call is not useful, because NMClient only changes the state after iterating the GMainContext, and not after the blocking call returns. 2) like 1), but after making the blocking g_dbus_connection_call_sync(), update the NMClient cache artificially. This is what nm_manager_check_connectivity() does, to "fix" bgo#784629. This also has the problem of out-of-order events, but it kinda solves the problem of not changing the state during the blocking call. But it does so by hacking the state of the cache. I think this is really wrong because the state should only be updated from the ordered stream of D-Bus messages (PropertiesChanged signal and similar). When libnm decides to modify the state, there may be already D-Bus messages queued that affect this very state. 3) instead of calling g_dbus_connection_call_sync(), use the asynchronous g_dbus_connection_call(). If we would use a sepaate GMainContext for all D-Bus related calls, we could ensure that while we block for the response, we iterate that internal main context. This might be nice, because all events are processed in order and after the blocking call returns, the NMClient state is up to date. The are problems however: current blocking API does not do this, so it's a significant change in behavior. Also, it might be unexpected to the user that during the blocking call the entire content of NMClient's cache might change and all pointers to the cache might be invalidated. Also, of course NMClient would invoke signals for all the changes that happen. Another problem is that this would be more effort to implement and it involves a small performance overhead for all D-Bus related calls (because we have to serialize all events in an internal GMainContext first and then invoke them on the caller's context). Also, if the users wants this behavior, they could implement it themself by running libnm in their own GMainContext. Note that libnm might have bugs to make that really working, but that should be fixed instead of adding such synchrnous API behavior. Read also [1], for why blocking calls are wrong. [1] https://smcv.pseudorandom.co.uk/2008/11/nonblocking/ So, all possible behaviors for synchronous API have severe behavioural issues. Mark all this API as deprecated. Also, this serves the purpose of identifying blocking D-Bus calls in libnm. Note that "deprecated" here does not really mean that the API is going to be removed. We don't break API. The user may: - continue to use this API. It's deprecated, awkward and discouraged, but if it works, by all means use it. - use asynchronous API. That's the only sensible way to use D-Bus. If libnm lacks a certain asynchronous counterpart, it should be added. - use GDBusConnection directly. There really isn't anything wrong with D-Bus or GDBusConnection. This deprecated API is just a wrapper around g_dbus_connection_call_sync(). You may call it directly without feeling dirty. --- The only other remainging API is the synchronous GInitable call for NMClient. That is an entirely separate beast and not particularly wrong (from an API point of view). Note that synchronous API in NMSecretAgentOld, NMVpnPluginOld and NMVpnServicePlugin as not deprecated here. These types are not part of the D-Bus cache and while they have similar issues, it's less severe because they have less state.
2019-09-04 13:58:43 +02:00
*
* Deprecated: 1.22: Use nm_device_delete_async() or GDBusConnection.
**/
gboolean
nm_device_delete (NMDevice *device,
GCancellable *cancellable,
GError **error)
{
g_return_val_if_fail (NM_IS_DEVICE (device), FALSE);
g_return_val_if_fail (!cancellable || G_IS_CANCELLABLE (cancellable), FALSE);
g_return_val_if_fail (!error || !*error, FALSE);
libnm: refactor caching of D-Bus objects in NMClient No longer use GDBusObjectMangaerClient and gdbus-codegen generated classes for the NMClient cache. Instead, use GDBusConnection directly and a custom implementation (NMLDBusObject) for caching D-Bus' ObjectManager data. CHANGES ------- - This is a complete rework. I think the previous implementation was difficult to understand. There were unfixed bugs and nobody understood the code well enough to fix them. Maybe somebody out there understood the code, but I certainly did not. At least nobody provided patches to fix those issues. I do believe that this implementation is more straightforward and easier to understand. It removes a lot of layers of code. Whether this claim of simplicity is true, each reader must decide for himself/herself. Note that it is still fairly complex. - There was a lingering performance issue with large number of D-Bus objects. The patch tries hard that the implementation scales well. Of course, when we cache N objects that have N-to-M references to other, we still are fundamentally O(N*M) for runtime and memory consumption (with M being the number of references between objects). But each part should behave efficiently and well. - Play well with GMainContext. libnm code (NMClient) is generally not thread safe. However, it should work to use multiple instances in parallel, as long as each access to a NMClient is through the caller's GMainContext. This follows glib's style and effectively allows to use NMClient in a multi threaded scenario. This implies to stick to a main context upon construction and ensure that callbacks are only invoked when iterating that context. Also, NMClient itself shall never iterate the caller's context. This also means, libnm must never use g_idle_add() or g_timeout_add(), as those enqueue sources in the g_main_context_default() context. - Get ordering of messages right. All events are consistently enqueued in a GMainContext and processed strictly in order. For example, previously "nm-object.c" tried to combine signals and emit them on an idle handler. That is wrong, signals must be emitted in the right order and when they happen. Note that when using GInitable's synchronous initialization to initialize the NMClient instance, NMClient internally still operates fully asynchronously. In that case NMClient has an internal main context. - NMClient takes over most of the functionality. When using D-Bus' ObjectManager interface, one needs to handle basically the entire state of the D-Bus interface. That cannot be separated well into distinct parts, and even if you try, you just end up having closely related code in different source files. Spreading related code does not make it easier to understand, on the contrary. That means, NMClient is inherently complex as it contains most of the logic. I think that is not avoidable, but it's not as bad as it sounds. - NMClient processes D-Bus messages and state changes in separate steps. First NMClient unpacks the message (e.g. _dbus_handle_properties_changed()) and keeps track of the changed data. Then we update the GObject instances (_dbus_handle_obj_changed_dbus()) without emitting any signals yet. Finally, we emit all signals and notifications that were collected (_dbus_handle_changes_commit()). Note that for example during the initial GetManagedObjects() reply, NMClient receive a large amount of state at once. But we first apply all the changes to our GObject instances before emitting any signals. The result is that signals are always emitted in a moment when the cache is consistent. The unavoidable downside is that when you receive a property changed signal, possibly many other properties changed already and more signals are about to be emitted. - NMDeviceWifi no longer modifies the content of the cache from client side during poke_wireless_devices_with_rf_status(). The content of the cache should be determined by D-Bus alone and follow what NetworkManager service exposes. Local modifications should be avoided. - This aims to bring no API/ABI change, though it does of course bring various subtle changes in behavior. Those should be all for the better, but the goal is not to break any existing clients. This does change internal (albeit externally visible) API, like dropping NM_OBJECT_DBUS_OBJECT_MANAGER property and NMObject no longer implementing GInitableIface and GAsyncInitableIface. - Some uses of gdbus-codegen classes remain in NMVpnPluginOld, NMVpnServicePlugin and NMSecretAgentOld. These are independent of NMClient/NMObject and should be reworked separately. - While we no longer use generated classes from gdbus-codegen, we don't need more glue code than before. Also before we constructed NMPropertiesInfo and a had large amount of code to propagate properties from NMDBus* to NMObject. That got completely reworked, but did not fundamentally change. You still need about the same effort to create the NMLDBusMetaIface. Not using generated bindings did not make anything worse (which tells about the usefulness of generated code, at least in the way it was used). - NMLDBusMetaIface and other meta data is static and immutable. This avoids copying them around. Also, macros like NML_DBUS_META_PROPERTY_INIT_U() have compile time checks to ensure the property types matches. It's pretty hard to misuse them because it won't compile. - The meta data now explicitly encodes the expected D-Bus types and makes sure never to accept wrong data. That would only matter when the server (accidentally or intentionally) exposes unexpected types on D-Bus. I don't think that was previously ensured in all cases. For example, demarshal_generic() only cared about the GObject property type, it didn't know the expected D-Bus type. - Previously GDBusObjectManager would sometimes emit warnings (g_log()). Those probably indicated real bugs. In any case, it prevented us from running CI with G_DEBUG=fatal-warnings, because there would be just too many unrelated crashes. Now we log debug messages that can be enabled with "LIBNM_CLIENT_DEBUG=trace". Some of these messages can also be turned into g_warning()/g_critical() by setting LIBNM_CLIENT_DEBUG=warning,error. Together with G_DEBUG=fatal-warnings, this turns them into assertions. Note that such "assertion failures" might also happen because of a server bug (or change). Thus these are not common assertions that indicate a bug in libnm and are thus not armed unless explicitly requested. In our CI we should now always run with LIBNM_CLIENT_DEBUG=warning,error and G_DEBUG=fatal-warnings and to catch bugs. Note that currently NetworkManager has bugs in this regard, so enabling this will result in assertion failures. That should be fixed first. - Note that this changes the order in which we emit "notify:devices" and "device-added" signals. I think it makes the most sense to emit first "device-removed", then "notify:devices", and finally "device-added" signals. This changes behavior for commit 52ae28f6e5bf ('libnm: queue added/removed signals and suppress uninitialized notifications'), but I don't think that users should actually rely on the order. Still, the new order makes the most sense to me. - In NetworkManager, profiles can be invisible to the user by setting "connection.permissions". Such profiles would be hidden by NMClient's nm_client_get_connections() and their "connection-added"/"connection-removed" signals. Note that NMActiveConnection's nm_active_connection_get_connection() and NMDevice's nm_device_get_available_connections() still exposes such hidden NMRemoteConnection instances. This behavior was preserved. NUMBERS ------- I compared 3 versions of libnm. [1] 962297f9085d, current tip of nm-1-20 branch [2] 4fad8c7c642e, current master, immediate parent of this patch [3] this patch All tests were done on Fedora 31, x86_64, gcc 9.2.1-1.fc31. The libraries were build with $ ./contrib/fedora/rpm/build_clean.sh -g -w test -W debug Note that RPM build already stripped the library. --- N1) File size of libnm.so.0.1.0 in bytes. There currently seems to be a issue on Fedora 31 generating wrong ELF notes. Usually, libnm is smaller but in these tests it had large (and bogus) ELF notes. Anyway, the point is to show the relative sizes, so it doesn't matter). [1] 4075552 (102.7%) [2] 3969624 (100.0%) [3] 3705208 ( 93.3%) --- N2) `size /usr/lib64/libnm.so.0.1.0`: text data bss dec hex filename [1] 1314569 (102.0%) 69980 ( 94.8%) 10632 ( 80.4%) 1395181 (101.4%) 1549ed /usr/lib64/libnm.so.0.1.0 [2] 1288410 (100.0%) 73796 (100.0%) 13224 (100.0%) 1375430 (100.0%) 14fcc6 /usr/lib64/libnm.so.0.1.0 [3] 1229066 ( 95.4%) 65248 ( 88.4%) 13400 (101.3%) 1307714 ( 95.1%) 13f442 /usr/lib64/libnm.so.0.1.0 --- N3) Performance test with test-client.py. With checkout of [2], run ``` prepare_checkout() { rm -rf /tmp/nm-test && \ git checkout -B test 4fad8c7c642e && \ git clean -fdx && \ ./autogen.sh --prefix=/tmp/nm-test && \ make -j 5 install && \ make -j 5 check-local-clients-tests-test-client } prepare_test() { NM_TEST_REGENERATE=1 NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v } do_test() { for i in {1..10}; do NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v || return -1 done echo "done!" } prepare_checkout prepare_test time do_test ``` [1] real 2m14.497s (101.3%) user 5m26.651s (100.3%) sys 1m40.453s (101.4%) [2] real 2m12.800s (100.0%) user 5m25.619s (100.0%) sys 1m39.065s (100.0%) [3] real 1m54.915s ( 86.5%) user 4m18.585s ( 79.4%) sys 1m32.066s ( 92.9%) --- N4) Performance. Run NetworkManager from build [2] and setup a large number of profiles (551 profiles and 515 devices, mostly unrealized). This setup is already at the edge of what NetworkManager currently can handle. Of course, that is a different issue. Here we just check how long plain `nmcli` takes on the system. ``` do_cleanup() { for UUID in $(nmcli -g NAME,UUID connection show | sed -n 's/^xx-c-.*:\([^:]\+\)$/\1/p'); do nmcli connection delete uuid "$UUID" done for DEVICE in $(nmcli -g DEVICE device status | grep '^xx-i-'); do nmcli device delete "$DEVICE" done } do_setup() { do_cleanup for i in {1..30}; do nmcli connection add type bond autoconnect no con-name xx-c-bond-$i ifname xx-i-bond-$i ipv4.method disabled ipv6.method ignore for j in $(seq $i 30); do nmcli connection add type vlan autoconnect no con-name xx-c-vlan-$i-$j vlan.id $j ifname xx-i-vlan-$i-$j vlan.parent xx-i-bond-$i ipv4.method disabled ipv6.method ignore done done systemctl restart NetworkManager.service sleep 5 } do_test() { perf stat -r 50 -B nmcli 1>/dev/null } do_test ``` [1] Performance counter stats for 'nmcli' (50 runs): 456.33 msec task-clock:u # 1.093 CPUs utilized ( +- 0.44% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,900 page-faults:u # 0.013 M/sec ( +- 0.02% ) 1,408,675,453 cycles:u # 3.087 GHz ( +- 0.48% ) 1,594,741,060 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 368,744,018 branches:u # 808.061 M/sec ( +- 0.02% ) 4,566,058 branch-misses:u # 1.24% of all branches ( +- 0.76% ) 0.41761 +- 0.00282 seconds time elapsed ( +- 0.68% ) [2] Performance counter stats for 'nmcli' (50 runs): 477.99 msec task-clock:u # 1.088 CPUs utilized ( +- 0.36% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,948 page-faults:u # 0.012 M/sec ( +- 0.03% ) 1,471,133,482 cycles:u # 3.078 GHz ( +- 0.36% ) 1,655,275,369 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 382,595,152 branches:u # 800.433 M/sec ( +- 0.02% ) 4,746,070 branch-misses:u # 1.24% of all branches ( +- 0.49% ) 0.43923 +- 0.00242 seconds time elapsed ( +- 0.55% ) [3] Performance counter stats for 'nmcli' (50 runs): 352.36 msec task-clock:u # 1.027 CPUs utilized ( +- 0.32% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 4,790 page-faults:u # 0.014 M/sec ( +- 0.26% ) 1,092,341,186 cycles:u # 3.100 GHz ( +- 0.26% ) 1,209,045,283 instructions:u # 1.11 insn per cycle ( +- 0.02% ) 281,708,462 branches:u # 799.499 M/sec ( +- 0.01% ) 3,101,031 branch-misses:u # 1.10% of all branches ( +- 0.61% ) 0.34296 +- 0.00120 seconds time elapsed ( +- 0.35% ) --- N5) same setup as N4), but run `PAGER= /bin/time -v nmcli`: [1] Command being timed: "nmcli" User time (seconds): 0.42 System time (seconds): 0.04 Percent of CPU this job got: 107% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.43 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34456 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6128 Voluntary context switches: 1298 Involuntary context switches: 1106 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [2] Command being timed: "nmcli" User time (seconds): 0.44 System time (seconds): 0.04 Percent of CPU this job got: 108% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.44 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34452 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6169 Voluntary context switches: 1849 Involuntary context switches: 142 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [3] Command being timed: "nmcli" User time (seconds): 0.32 System time (seconds): 0.02 Percent of CPU this job got: 102% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.34 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 29196 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 5059 Voluntary context switches: 919 Involuntary context switches: 685 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 --- N6) same setup as N4), but run `nmcli monitor` and look at `ps aux` for the RSS size. USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND [1] me 1492900 21.0 0.2 461348 33248 pts/10 Sl+ 15:02 0:00 nmcli monitor [2] me 1490721 5.0 0.2 461496 33548 pts/10 Sl+ 15:00 0:00 nmcli monitor [3] me 1495801 16.5 0.1 459476 28692 pts/10 Sl+ 15:04 0:00 nmcli monitor
2019-10-30 11:42:58 +01:00
return _nm_client_dbus_call_sync_void (_nm_object_get_client (device),
cancellable,
libnm: refactor caching of D-Bus objects in NMClient No longer use GDBusObjectMangaerClient and gdbus-codegen generated classes for the NMClient cache. Instead, use GDBusConnection directly and a custom implementation (NMLDBusObject) for caching D-Bus' ObjectManager data. CHANGES ------- - This is a complete rework. I think the previous implementation was difficult to understand. There were unfixed bugs and nobody understood the code well enough to fix them. Maybe somebody out there understood the code, but I certainly did not. At least nobody provided patches to fix those issues. I do believe that this implementation is more straightforward and easier to understand. It removes a lot of layers of code. Whether this claim of simplicity is true, each reader must decide for himself/herself. Note that it is still fairly complex. - There was a lingering performance issue with large number of D-Bus objects. The patch tries hard that the implementation scales well. Of course, when we cache N objects that have N-to-M references to other, we still are fundamentally O(N*M) for runtime and memory consumption (with M being the number of references between objects). But each part should behave efficiently and well. - Play well with GMainContext. libnm code (NMClient) is generally not thread safe. However, it should work to use multiple instances in parallel, as long as each access to a NMClient is through the caller's GMainContext. This follows glib's style and effectively allows to use NMClient in a multi threaded scenario. This implies to stick to a main context upon construction and ensure that callbacks are only invoked when iterating that context. Also, NMClient itself shall never iterate the caller's context. This also means, libnm must never use g_idle_add() or g_timeout_add(), as those enqueue sources in the g_main_context_default() context. - Get ordering of messages right. All events are consistently enqueued in a GMainContext and processed strictly in order. For example, previously "nm-object.c" tried to combine signals and emit them on an idle handler. That is wrong, signals must be emitted in the right order and when they happen. Note that when using GInitable's synchronous initialization to initialize the NMClient instance, NMClient internally still operates fully asynchronously. In that case NMClient has an internal main context. - NMClient takes over most of the functionality. When using D-Bus' ObjectManager interface, one needs to handle basically the entire state of the D-Bus interface. That cannot be separated well into distinct parts, and even if you try, you just end up having closely related code in different source files. Spreading related code does not make it easier to understand, on the contrary. That means, NMClient is inherently complex as it contains most of the logic. I think that is not avoidable, but it's not as bad as it sounds. - NMClient processes D-Bus messages and state changes in separate steps. First NMClient unpacks the message (e.g. _dbus_handle_properties_changed()) and keeps track of the changed data. Then we update the GObject instances (_dbus_handle_obj_changed_dbus()) without emitting any signals yet. Finally, we emit all signals and notifications that were collected (_dbus_handle_changes_commit()). Note that for example during the initial GetManagedObjects() reply, NMClient receive a large amount of state at once. But we first apply all the changes to our GObject instances before emitting any signals. The result is that signals are always emitted in a moment when the cache is consistent. The unavoidable downside is that when you receive a property changed signal, possibly many other properties changed already and more signals are about to be emitted. - NMDeviceWifi no longer modifies the content of the cache from client side during poke_wireless_devices_with_rf_status(). The content of the cache should be determined by D-Bus alone and follow what NetworkManager service exposes. Local modifications should be avoided. - This aims to bring no API/ABI change, though it does of course bring various subtle changes in behavior. Those should be all for the better, but the goal is not to break any existing clients. This does change internal (albeit externally visible) API, like dropping NM_OBJECT_DBUS_OBJECT_MANAGER property and NMObject no longer implementing GInitableIface and GAsyncInitableIface. - Some uses of gdbus-codegen classes remain in NMVpnPluginOld, NMVpnServicePlugin and NMSecretAgentOld. These are independent of NMClient/NMObject and should be reworked separately. - While we no longer use generated classes from gdbus-codegen, we don't need more glue code than before. Also before we constructed NMPropertiesInfo and a had large amount of code to propagate properties from NMDBus* to NMObject. That got completely reworked, but did not fundamentally change. You still need about the same effort to create the NMLDBusMetaIface. Not using generated bindings did not make anything worse (which tells about the usefulness of generated code, at least in the way it was used). - NMLDBusMetaIface and other meta data is static and immutable. This avoids copying them around. Also, macros like NML_DBUS_META_PROPERTY_INIT_U() have compile time checks to ensure the property types matches. It's pretty hard to misuse them because it won't compile. - The meta data now explicitly encodes the expected D-Bus types and makes sure never to accept wrong data. That would only matter when the server (accidentally or intentionally) exposes unexpected types on D-Bus. I don't think that was previously ensured in all cases. For example, demarshal_generic() only cared about the GObject property type, it didn't know the expected D-Bus type. - Previously GDBusObjectManager would sometimes emit warnings (g_log()). Those probably indicated real bugs. In any case, it prevented us from running CI with G_DEBUG=fatal-warnings, because there would be just too many unrelated crashes. Now we log debug messages that can be enabled with "LIBNM_CLIENT_DEBUG=trace". Some of these messages can also be turned into g_warning()/g_critical() by setting LIBNM_CLIENT_DEBUG=warning,error. Together with G_DEBUG=fatal-warnings, this turns them into assertions. Note that such "assertion failures" might also happen because of a server bug (or change). Thus these are not common assertions that indicate a bug in libnm and are thus not armed unless explicitly requested. In our CI we should now always run with LIBNM_CLIENT_DEBUG=warning,error and G_DEBUG=fatal-warnings and to catch bugs. Note that currently NetworkManager has bugs in this regard, so enabling this will result in assertion failures. That should be fixed first. - Note that this changes the order in which we emit "notify:devices" and "device-added" signals. I think it makes the most sense to emit first "device-removed", then "notify:devices", and finally "device-added" signals. This changes behavior for commit 52ae28f6e5bf ('libnm: queue added/removed signals and suppress uninitialized notifications'), but I don't think that users should actually rely on the order. Still, the new order makes the most sense to me. - In NetworkManager, profiles can be invisible to the user by setting "connection.permissions". Such profiles would be hidden by NMClient's nm_client_get_connections() and their "connection-added"/"connection-removed" signals. Note that NMActiveConnection's nm_active_connection_get_connection() and NMDevice's nm_device_get_available_connections() still exposes such hidden NMRemoteConnection instances. This behavior was preserved. NUMBERS ------- I compared 3 versions of libnm. [1] 962297f9085d, current tip of nm-1-20 branch [2] 4fad8c7c642e, current master, immediate parent of this patch [3] this patch All tests were done on Fedora 31, x86_64, gcc 9.2.1-1.fc31. The libraries were build with $ ./contrib/fedora/rpm/build_clean.sh -g -w test -W debug Note that RPM build already stripped the library. --- N1) File size of libnm.so.0.1.0 in bytes. There currently seems to be a issue on Fedora 31 generating wrong ELF notes. Usually, libnm is smaller but in these tests it had large (and bogus) ELF notes. Anyway, the point is to show the relative sizes, so it doesn't matter). [1] 4075552 (102.7%) [2] 3969624 (100.0%) [3] 3705208 ( 93.3%) --- N2) `size /usr/lib64/libnm.so.0.1.0`: text data bss dec hex filename [1] 1314569 (102.0%) 69980 ( 94.8%) 10632 ( 80.4%) 1395181 (101.4%) 1549ed /usr/lib64/libnm.so.0.1.0 [2] 1288410 (100.0%) 73796 (100.0%) 13224 (100.0%) 1375430 (100.0%) 14fcc6 /usr/lib64/libnm.so.0.1.0 [3] 1229066 ( 95.4%) 65248 ( 88.4%) 13400 (101.3%) 1307714 ( 95.1%) 13f442 /usr/lib64/libnm.so.0.1.0 --- N3) Performance test with test-client.py. With checkout of [2], run ``` prepare_checkout() { rm -rf /tmp/nm-test && \ git checkout -B test 4fad8c7c642e && \ git clean -fdx && \ ./autogen.sh --prefix=/tmp/nm-test && \ make -j 5 install && \ make -j 5 check-local-clients-tests-test-client } prepare_test() { NM_TEST_REGENERATE=1 NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v } do_test() { for i in {1..10}; do NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v || return -1 done echo "done!" } prepare_checkout prepare_test time do_test ``` [1] real 2m14.497s (101.3%) user 5m26.651s (100.3%) sys 1m40.453s (101.4%) [2] real 2m12.800s (100.0%) user 5m25.619s (100.0%) sys 1m39.065s (100.0%) [3] real 1m54.915s ( 86.5%) user 4m18.585s ( 79.4%) sys 1m32.066s ( 92.9%) --- N4) Performance. Run NetworkManager from build [2] and setup a large number of profiles (551 profiles and 515 devices, mostly unrealized). This setup is already at the edge of what NetworkManager currently can handle. Of course, that is a different issue. Here we just check how long plain `nmcli` takes on the system. ``` do_cleanup() { for UUID in $(nmcli -g NAME,UUID connection show | sed -n 's/^xx-c-.*:\([^:]\+\)$/\1/p'); do nmcli connection delete uuid "$UUID" done for DEVICE in $(nmcli -g DEVICE device status | grep '^xx-i-'); do nmcli device delete "$DEVICE" done } do_setup() { do_cleanup for i in {1..30}; do nmcli connection add type bond autoconnect no con-name xx-c-bond-$i ifname xx-i-bond-$i ipv4.method disabled ipv6.method ignore for j in $(seq $i 30); do nmcli connection add type vlan autoconnect no con-name xx-c-vlan-$i-$j vlan.id $j ifname xx-i-vlan-$i-$j vlan.parent xx-i-bond-$i ipv4.method disabled ipv6.method ignore done done systemctl restart NetworkManager.service sleep 5 } do_test() { perf stat -r 50 -B nmcli 1>/dev/null } do_test ``` [1] Performance counter stats for 'nmcli' (50 runs): 456.33 msec task-clock:u # 1.093 CPUs utilized ( +- 0.44% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,900 page-faults:u # 0.013 M/sec ( +- 0.02% ) 1,408,675,453 cycles:u # 3.087 GHz ( +- 0.48% ) 1,594,741,060 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 368,744,018 branches:u # 808.061 M/sec ( +- 0.02% ) 4,566,058 branch-misses:u # 1.24% of all branches ( +- 0.76% ) 0.41761 +- 0.00282 seconds time elapsed ( +- 0.68% ) [2] Performance counter stats for 'nmcli' (50 runs): 477.99 msec task-clock:u # 1.088 CPUs utilized ( +- 0.36% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,948 page-faults:u # 0.012 M/sec ( +- 0.03% ) 1,471,133,482 cycles:u # 3.078 GHz ( +- 0.36% ) 1,655,275,369 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 382,595,152 branches:u # 800.433 M/sec ( +- 0.02% ) 4,746,070 branch-misses:u # 1.24% of all branches ( +- 0.49% ) 0.43923 +- 0.00242 seconds time elapsed ( +- 0.55% ) [3] Performance counter stats for 'nmcli' (50 runs): 352.36 msec task-clock:u # 1.027 CPUs utilized ( +- 0.32% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 4,790 page-faults:u # 0.014 M/sec ( +- 0.26% ) 1,092,341,186 cycles:u # 3.100 GHz ( +- 0.26% ) 1,209,045,283 instructions:u # 1.11 insn per cycle ( +- 0.02% ) 281,708,462 branches:u # 799.499 M/sec ( +- 0.01% ) 3,101,031 branch-misses:u # 1.10% of all branches ( +- 0.61% ) 0.34296 +- 0.00120 seconds time elapsed ( +- 0.35% ) --- N5) same setup as N4), but run `PAGER= /bin/time -v nmcli`: [1] Command being timed: "nmcli" User time (seconds): 0.42 System time (seconds): 0.04 Percent of CPU this job got: 107% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.43 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34456 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6128 Voluntary context switches: 1298 Involuntary context switches: 1106 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [2] Command being timed: "nmcli" User time (seconds): 0.44 System time (seconds): 0.04 Percent of CPU this job got: 108% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.44 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34452 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6169 Voluntary context switches: 1849 Involuntary context switches: 142 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [3] Command being timed: "nmcli" User time (seconds): 0.32 System time (seconds): 0.02 Percent of CPU this job got: 102% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.34 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 29196 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 5059 Voluntary context switches: 919 Involuntary context switches: 685 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 --- N6) same setup as N4), but run `nmcli monitor` and look at `ps aux` for the RSS size. USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND [1] me 1492900 21.0 0.2 461348 33248 pts/10 Sl+ 15:02 0:00 nmcli monitor [2] me 1490721 5.0 0.2 461496 33548 pts/10 Sl+ 15:00 0:00 nmcli monitor [3] me 1495801 16.5 0.1 459476 28692 pts/10 Sl+ 15:04 0:00 nmcli monitor
2019-10-30 11:42:58 +01:00
_nm_object_get_path (device),
NM_DBUS_INTERFACE_DEVICE,
"Delete",
g_variant_new ("()"),
G_DBUS_CALL_FLAGS_NONE,
NM_DBUS_DEFAULT_TIMEOUT_MSEC,
TRUE,
error);
}
/**
* nm_device_delete_async:
* @device: a #NMDevice
* @cancellable: a #GCancellable, or %NULL
* @callback: callback to be called when delete operation completes
* @user_data: caller-specific data passed to @callback
*
* Asynchronously begins deleting the software device. Hardware devices can't
* be deleted.
**/
void
nm_device_delete_async (NMDevice *device,
GCancellable *cancellable,
GAsyncReadyCallback callback,
gpointer user_data)
{
g_return_if_fail (NM_IS_DEVICE (device));
g_return_if_fail (!cancellable || G_IS_CANCELLABLE (cancellable));
libnm: refactor caching of D-Bus objects in NMClient No longer use GDBusObjectMangaerClient and gdbus-codegen generated classes for the NMClient cache. Instead, use GDBusConnection directly and a custom implementation (NMLDBusObject) for caching D-Bus' ObjectManager data. CHANGES ------- - This is a complete rework. I think the previous implementation was difficult to understand. There were unfixed bugs and nobody understood the code well enough to fix them. Maybe somebody out there understood the code, but I certainly did not. At least nobody provided patches to fix those issues. I do believe that this implementation is more straightforward and easier to understand. It removes a lot of layers of code. Whether this claim of simplicity is true, each reader must decide for himself/herself. Note that it is still fairly complex. - There was a lingering performance issue with large number of D-Bus objects. The patch tries hard that the implementation scales well. Of course, when we cache N objects that have N-to-M references to other, we still are fundamentally O(N*M) for runtime and memory consumption (with M being the number of references between objects). But each part should behave efficiently and well. - Play well with GMainContext. libnm code (NMClient) is generally not thread safe. However, it should work to use multiple instances in parallel, as long as each access to a NMClient is through the caller's GMainContext. This follows glib's style and effectively allows to use NMClient in a multi threaded scenario. This implies to stick to a main context upon construction and ensure that callbacks are only invoked when iterating that context. Also, NMClient itself shall never iterate the caller's context. This also means, libnm must never use g_idle_add() or g_timeout_add(), as those enqueue sources in the g_main_context_default() context. - Get ordering of messages right. All events are consistently enqueued in a GMainContext and processed strictly in order. For example, previously "nm-object.c" tried to combine signals and emit them on an idle handler. That is wrong, signals must be emitted in the right order and when they happen. Note that when using GInitable's synchronous initialization to initialize the NMClient instance, NMClient internally still operates fully asynchronously. In that case NMClient has an internal main context. - NMClient takes over most of the functionality. When using D-Bus' ObjectManager interface, one needs to handle basically the entire state of the D-Bus interface. That cannot be separated well into distinct parts, and even if you try, you just end up having closely related code in different source files. Spreading related code does not make it easier to understand, on the contrary. That means, NMClient is inherently complex as it contains most of the logic. I think that is not avoidable, but it's not as bad as it sounds. - NMClient processes D-Bus messages and state changes in separate steps. First NMClient unpacks the message (e.g. _dbus_handle_properties_changed()) and keeps track of the changed data. Then we update the GObject instances (_dbus_handle_obj_changed_dbus()) without emitting any signals yet. Finally, we emit all signals and notifications that were collected (_dbus_handle_changes_commit()). Note that for example during the initial GetManagedObjects() reply, NMClient receive a large amount of state at once. But we first apply all the changes to our GObject instances before emitting any signals. The result is that signals are always emitted in a moment when the cache is consistent. The unavoidable downside is that when you receive a property changed signal, possibly many other properties changed already and more signals are about to be emitted. - NMDeviceWifi no longer modifies the content of the cache from client side during poke_wireless_devices_with_rf_status(). The content of the cache should be determined by D-Bus alone and follow what NetworkManager service exposes. Local modifications should be avoided. - This aims to bring no API/ABI change, though it does of course bring various subtle changes in behavior. Those should be all for the better, but the goal is not to break any existing clients. This does change internal (albeit externally visible) API, like dropping NM_OBJECT_DBUS_OBJECT_MANAGER property and NMObject no longer implementing GInitableIface and GAsyncInitableIface. - Some uses of gdbus-codegen classes remain in NMVpnPluginOld, NMVpnServicePlugin and NMSecretAgentOld. These are independent of NMClient/NMObject and should be reworked separately. - While we no longer use generated classes from gdbus-codegen, we don't need more glue code than before. Also before we constructed NMPropertiesInfo and a had large amount of code to propagate properties from NMDBus* to NMObject. That got completely reworked, but did not fundamentally change. You still need about the same effort to create the NMLDBusMetaIface. Not using generated bindings did not make anything worse (which tells about the usefulness of generated code, at least in the way it was used). - NMLDBusMetaIface and other meta data is static and immutable. This avoids copying them around. Also, macros like NML_DBUS_META_PROPERTY_INIT_U() have compile time checks to ensure the property types matches. It's pretty hard to misuse them because it won't compile. - The meta data now explicitly encodes the expected D-Bus types and makes sure never to accept wrong data. That would only matter when the server (accidentally or intentionally) exposes unexpected types on D-Bus. I don't think that was previously ensured in all cases. For example, demarshal_generic() only cared about the GObject property type, it didn't know the expected D-Bus type. - Previously GDBusObjectManager would sometimes emit warnings (g_log()). Those probably indicated real bugs. In any case, it prevented us from running CI with G_DEBUG=fatal-warnings, because there would be just too many unrelated crashes. Now we log debug messages that can be enabled with "LIBNM_CLIENT_DEBUG=trace". Some of these messages can also be turned into g_warning()/g_critical() by setting LIBNM_CLIENT_DEBUG=warning,error. Together with G_DEBUG=fatal-warnings, this turns them into assertions. Note that such "assertion failures" might also happen because of a server bug (or change). Thus these are not common assertions that indicate a bug in libnm and are thus not armed unless explicitly requested. In our CI we should now always run with LIBNM_CLIENT_DEBUG=warning,error and G_DEBUG=fatal-warnings and to catch bugs. Note that currently NetworkManager has bugs in this regard, so enabling this will result in assertion failures. That should be fixed first. - Note that this changes the order in which we emit "notify:devices" and "device-added" signals. I think it makes the most sense to emit first "device-removed", then "notify:devices", and finally "device-added" signals. This changes behavior for commit 52ae28f6e5bf ('libnm: queue added/removed signals and suppress uninitialized notifications'), but I don't think that users should actually rely on the order. Still, the new order makes the most sense to me. - In NetworkManager, profiles can be invisible to the user by setting "connection.permissions". Such profiles would be hidden by NMClient's nm_client_get_connections() and their "connection-added"/"connection-removed" signals. Note that NMActiveConnection's nm_active_connection_get_connection() and NMDevice's nm_device_get_available_connections() still exposes such hidden NMRemoteConnection instances. This behavior was preserved. NUMBERS ------- I compared 3 versions of libnm. [1] 962297f9085d, current tip of nm-1-20 branch [2] 4fad8c7c642e, current master, immediate parent of this patch [3] this patch All tests were done on Fedora 31, x86_64, gcc 9.2.1-1.fc31. The libraries were build with $ ./contrib/fedora/rpm/build_clean.sh -g -w test -W debug Note that RPM build already stripped the library. --- N1) File size of libnm.so.0.1.0 in bytes. There currently seems to be a issue on Fedora 31 generating wrong ELF notes. Usually, libnm is smaller but in these tests it had large (and bogus) ELF notes. Anyway, the point is to show the relative sizes, so it doesn't matter). [1] 4075552 (102.7%) [2] 3969624 (100.0%) [3] 3705208 ( 93.3%) --- N2) `size /usr/lib64/libnm.so.0.1.0`: text data bss dec hex filename [1] 1314569 (102.0%) 69980 ( 94.8%) 10632 ( 80.4%) 1395181 (101.4%) 1549ed /usr/lib64/libnm.so.0.1.0 [2] 1288410 (100.0%) 73796 (100.0%) 13224 (100.0%) 1375430 (100.0%) 14fcc6 /usr/lib64/libnm.so.0.1.0 [3] 1229066 ( 95.4%) 65248 ( 88.4%) 13400 (101.3%) 1307714 ( 95.1%) 13f442 /usr/lib64/libnm.so.0.1.0 --- N3) Performance test with test-client.py. With checkout of [2], run ``` prepare_checkout() { rm -rf /tmp/nm-test && \ git checkout -B test 4fad8c7c642e && \ git clean -fdx && \ ./autogen.sh --prefix=/tmp/nm-test && \ make -j 5 install && \ make -j 5 check-local-clients-tests-test-client } prepare_test() { NM_TEST_REGENERATE=1 NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v } do_test() { for i in {1..10}; do NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v || return -1 done echo "done!" } prepare_checkout prepare_test time do_test ``` [1] real 2m14.497s (101.3%) user 5m26.651s (100.3%) sys 1m40.453s (101.4%) [2] real 2m12.800s (100.0%) user 5m25.619s (100.0%) sys 1m39.065s (100.0%) [3] real 1m54.915s ( 86.5%) user 4m18.585s ( 79.4%) sys 1m32.066s ( 92.9%) --- N4) Performance. Run NetworkManager from build [2] and setup a large number of profiles (551 profiles and 515 devices, mostly unrealized). This setup is already at the edge of what NetworkManager currently can handle. Of course, that is a different issue. Here we just check how long plain `nmcli` takes on the system. ``` do_cleanup() { for UUID in $(nmcli -g NAME,UUID connection show | sed -n 's/^xx-c-.*:\([^:]\+\)$/\1/p'); do nmcli connection delete uuid "$UUID" done for DEVICE in $(nmcli -g DEVICE device status | grep '^xx-i-'); do nmcli device delete "$DEVICE" done } do_setup() { do_cleanup for i in {1..30}; do nmcli connection add type bond autoconnect no con-name xx-c-bond-$i ifname xx-i-bond-$i ipv4.method disabled ipv6.method ignore for j in $(seq $i 30); do nmcli connection add type vlan autoconnect no con-name xx-c-vlan-$i-$j vlan.id $j ifname xx-i-vlan-$i-$j vlan.parent xx-i-bond-$i ipv4.method disabled ipv6.method ignore done done systemctl restart NetworkManager.service sleep 5 } do_test() { perf stat -r 50 -B nmcli 1>/dev/null } do_test ``` [1] Performance counter stats for 'nmcli' (50 runs): 456.33 msec task-clock:u # 1.093 CPUs utilized ( +- 0.44% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,900 page-faults:u # 0.013 M/sec ( +- 0.02% ) 1,408,675,453 cycles:u # 3.087 GHz ( +- 0.48% ) 1,594,741,060 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 368,744,018 branches:u # 808.061 M/sec ( +- 0.02% ) 4,566,058 branch-misses:u # 1.24% of all branches ( +- 0.76% ) 0.41761 +- 0.00282 seconds time elapsed ( +- 0.68% ) [2] Performance counter stats for 'nmcli' (50 runs): 477.99 msec task-clock:u # 1.088 CPUs utilized ( +- 0.36% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,948 page-faults:u # 0.012 M/sec ( +- 0.03% ) 1,471,133,482 cycles:u # 3.078 GHz ( +- 0.36% ) 1,655,275,369 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 382,595,152 branches:u # 800.433 M/sec ( +- 0.02% ) 4,746,070 branch-misses:u # 1.24% of all branches ( +- 0.49% ) 0.43923 +- 0.00242 seconds time elapsed ( +- 0.55% ) [3] Performance counter stats for 'nmcli' (50 runs): 352.36 msec task-clock:u # 1.027 CPUs utilized ( +- 0.32% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 4,790 page-faults:u # 0.014 M/sec ( +- 0.26% ) 1,092,341,186 cycles:u # 3.100 GHz ( +- 0.26% ) 1,209,045,283 instructions:u # 1.11 insn per cycle ( +- 0.02% ) 281,708,462 branches:u # 799.499 M/sec ( +- 0.01% ) 3,101,031 branch-misses:u # 1.10% of all branches ( +- 0.61% ) 0.34296 +- 0.00120 seconds time elapsed ( +- 0.35% ) --- N5) same setup as N4), but run `PAGER= /bin/time -v nmcli`: [1] Command being timed: "nmcli" User time (seconds): 0.42 System time (seconds): 0.04 Percent of CPU this job got: 107% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.43 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34456 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6128 Voluntary context switches: 1298 Involuntary context switches: 1106 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [2] Command being timed: "nmcli" User time (seconds): 0.44 System time (seconds): 0.04 Percent of CPU this job got: 108% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.44 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34452 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6169 Voluntary context switches: 1849 Involuntary context switches: 142 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [3] Command being timed: "nmcli" User time (seconds): 0.32 System time (seconds): 0.02 Percent of CPU this job got: 102% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.34 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 29196 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 5059 Voluntary context switches: 919 Involuntary context switches: 685 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 --- N6) same setup as N4), but run `nmcli monitor` and look at `ps aux` for the RSS size. USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND [1] me 1492900 21.0 0.2 461348 33248 pts/10 Sl+ 15:02 0:00 nmcli monitor [2] me 1490721 5.0 0.2 461496 33548 pts/10 Sl+ 15:00 0:00 nmcli monitor [3] me 1495801 16.5 0.1 459476 28692 pts/10 Sl+ 15:04 0:00 nmcli monitor
2019-10-30 11:42:58 +01:00
_nm_client_dbus_call (_nm_object_get_client (device),
device,
nm_device_delete_async,
cancellable,
callback,
user_data,
libnm: refactor caching of D-Bus objects in NMClient No longer use GDBusObjectMangaerClient and gdbus-codegen generated classes for the NMClient cache. Instead, use GDBusConnection directly and a custom implementation (NMLDBusObject) for caching D-Bus' ObjectManager data. CHANGES ------- - This is a complete rework. I think the previous implementation was difficult to understand. There were unfixed bugs and nobody understood the code well enough to fix them. Maybe somebody out there understood the code, but I certainly did not. At least nobody provided patches to fix those issues. I do believe that this implementation is more straightforward and easier to understand. It removes a lot of layers of code. Whether this claim of simplicity is true, each reader must decide for himself/herself. Note that it is still fairly complex. - There was a lingering performance issue with large number of D-Bus objects. The patch tries hard that the implementation scales well. Of course, when we cache N objects that have N-to-M references to other, we still are fundamentally O(N*M) for runtime and memory consumption (with M being the number of references between objects). But each part should behave efficiently and well. - Play well with GMainContext. libnm code (NMClient) is generally not thread safe. However, it should work to use multiple instances in parallel, as long as each access to a NMClient is through the caller's GMainContext. This follows glib's style and effectively allows to use NMClient in a multi threaded scenario. This implies to stick to a main context upon construction and ensure that callbacks are only invoked when iterating that context. Also, NMClient itself shall never iterate the caller's context. This also means, libnm must never use g_idle_add() or g_timeout_add(), as those enqueue sources in the g_main_context_default() context. - Get ordering of messages right. All events are consistently enqueued in a GMainContext and processed strictly in order. For example, previously "nm-object.c" tried to combine signals and emit them on an idle handler. That is wrong, signals must be emitted in the right order and when they happen. Note that when using GInitable's synchronous initialization to initialize the NMClient instance, NMClient internally still operates fully asynchronously. In that case NMClient has an internal main context. - NMClient takes over most of the functionality. When using D-Bus' ObjectManager interface, one needs to handle basically the entire state of the D-Bus interface. That cannot be separated well into distinct parts, and even if you try, you just end up having closely related code in different source files. Spreading related code does not make it easier to understand, on the contrary. That means, NMClient is inherently complex as it contains most of the logic. I think that is not avoidable, but it's not as bad as it sounds. - NMClient processes D-Bus messages and state changes in separate steps. First NMClient unpacks the message (e.g. _dbus_handle_properties_changed()) and keeps track of the changed data. Then we update the GObject instances (_dbus_handle_obj_changed_dbus()) without emitting any signals yet. Finally, we emit all signals and notifications that were collected (_dbus_handle_changes_commit()). Note that for example during the initial GetManagedObjects() reply, NMClient receive a large amount of state at once. But we first apply all the changes to our GObject instances before emitting any signals. The result is that signals are always emitted in a moment when the cache is consistent. The unavoidable downside is that when you receive a property changed signal, possibly many other properties changed already and more signals are about to be emitted. - NMDeviceWifi no longer modifies the content of the cache from client side during poke_wireless_devices_with_rf_status(). The content of the cache should be determined by D-Bus alone and follow what NetworkManager service exposes. Local modifications should be avoided. - This aims to bring no API/ABI change, though it does of course bring various subtle changes in behavior. Those should be all for the better, but the goal is not to break any existing clients. This does change internal (albeit externally visible) API, like dropping NM_OBJECT_DBUS_OBJECT_MANAGER property and NMObject no longer implementing GInitableIface and GAsyncInitableIface. - Some uses of gdbus-codegen classes remain in NMVpnPluginOld, NMVpnServicePlugin and NMSecretAgentOld. These are independent of NMClient/NMObject and should be reworked separately. - While we no longer use generated classes from gdbus-codegen, we don't need more glue code than before. Also before we constructed NMPropertiesInfo and a had large amount of code to propagate properties from NMDBus* to NMObject. That got completely reworked, but did not fundamentally change. You still need about the same effort to create the NMLDBusMetaIface. Not using generated bindings did not make anything worse (which tells about the usefulness of generated code, at least in the way it was used). - NMLDBusMetaIface and other meta data is static and immutable. This avoids copying them around. Also, macros like NML_DBUS_META_PROPERTY_INIT_U() have compile time checks to ensure the property types matches. It's pretty hard to misuse them because it won't compile. - The meta data now explicitly encodes the expected D-Bus types and makes sure never to accept wrong data. That would only matter when the server (accidentally or intentionally) exposes unexpected types on D-Bus. I don't think that was previously ensured in all cases. For example, demarshal_generic() only cared about the GObject property type, it didn't know the expected D-Bus type. - Previously GDBusObjectManager would sometimes emit warnings (g_log()). Those probably indicated real bugs. In any case, it prevented us from running CI with G_DEBUG=fatal-warnings, because there would be just too many unrelated crashes. Now we log debug messages that can be enabled with "LIBNM_CLIENT_DEBUG=trace". Some of these messages can also be turned into g_warning()/g_critical() by setting LIBNM_CLIENT_DEBUG=warning,error. Together with G_DEBUG=fatal-warnings, this turns them into assertions. Note that such "assertion failures" might also happen because of a server bug (or change). Thus these are not common assertions that indicate a bug in libnm and are thus not armed unless explicitly requested. In our CI we should now always run with LIBNM_CLIENT_DEBUG=warning,error and G_DEBUG=fatal-warnings and to catch bugs. Note that currently NetworkManager has bugs in this regard, so enabling this will result in assertion failures. That should be fixed first. - Note that this changes the order in which we emit "notify:devices" and "device-added" signals. I think it makes the most sense to emit first "device-removed", then "notify:devices", and finally "device-added" signals. This changes behavior for commit 52ae28f6e5bf ('libnm: queue added/removed signals and suppress uninitialized notifications'), but I don't think that users should actually rely on the order. Still, the new order makes the most sense to me. - In NetworkManager, profiles can be invisible to the user by setting "connection.permissions". Such profiles would be hidden by NMClient's nm_client_get_connections() and their "connection-added"/"connection-removed" signals. Note that NMActiveConnection's nm_active_connection_get_connection() and NMDevice's nm_device_get_available_connections() still exposes such hidden NMRemoteConnection instances. This behavior was preserved. NUMBERS ------- I compared 3 versions of libnm. [1] 962297f9085d, current tip of nm-1-20 branch [2] 4fad8c7c642e, current master, immediate parent of this patch [3] this patch All tests were done on Fedora 31, x86_64, gcc 9.2.1-1.fc31. The libraries were build with $ ./contrib/fedora/rpm/build_clean.sh -g -w test -W debug Note that RPM build already stripped the library. --- N1) File size of libnm.so.0.1.0 in bytes. There currently seems to be a issue on Fedora 31 generating wrong ELF notes. Usually, libnm is smaller but in these tests it had large (and bogus) ELF notes. Anyway, the point is to show the relative sizes, so it doesn't matter). [1] 4075552 (102.7%) [2] 3969624 (100.0%) [3] 3705208 ( 93.3%) --- N2) `size /usr/lib64/libnm.so.0.1.0`: text data bss dec hex filename [1] 1314569 (102.0%) 69980 ( 94.8%) 10632 ( 80.4%) 1395181 (101.4%) 1549ed /usr/lib64/libnm.so.0.1.0 [2] 1288410 (100.0%) 73796 (100.0%) 13224 (100.0%) 1375430 (100.0%) 14fcc6 /usr/lib64/libnm.so.0.1.0 [3] 1229066 ( 95.4%) 65248 ( 88.4%) 13400 (101.3%) 1307714 ( 95.1%) 13f442 /usr/lib64/libnm.so.0.1.0 --- N3) Performance test with test-client.py. With checkout of [2], run ``` prepare_checkout() { rm -rf /tmp/nm-test && \ git checkout -B test 4fad8c7c642e && \ git clean -fdx && \ ./autogen.sh --prefix=/tmp/nm-test && \ make -j 5 install && \ make -j 5 check-local-clients-tests-test-client } prepare_test() { NM_TEST_REGENERATE=1 NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v } do_test() { for i in {1..10}; do NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v || return -1 done echo "done!" } prepare_checkout prepare_test time do_test ``` [1] real 2m14.497s (101.3%) user 5m26.651s (100.3%) sys 1m40.453s (101.4%) [2] real 2m12.800s (100.0%) user 5m25.619s (100.0%) sys 1m39.065s (100.0%) [3] real 1m54.915s ( 86.5%) user 4m18.585s ( 79.4%) sys 1m32.066s ( 92.9%) --- N4) Performance. Run NetworkManager from build [2] and setup a large number of profiles (551 profiles and 515 devices, mostly unrealized). This setup is already at the edge of what NetworkManager currently can handle. Of course, that is a different issue. Here we just check how long plain `nmcli` takes on the system. ``` do_cleanup() { for UUID in $(nmcli -g NAME,UUID connection show | sed -n 's/^xx-c-.*:\([^:]\+\)$/\1/p'); do nmcli connection delete uuid "$UUID" done for DEVICE in $(nmcli -g DEVICE device status | grep '^xx-i-'); do nmcli device delete "$DEVICE" done } do_setup() { do_cleanup for i in {1..30}; do nmcli connection add type bond autoconnect no con-name xx-c-bond-$i ifname xx-i-bond-$i ipv4.method disabled ipv6.method ignore for j in $(seq $i 30); do nmcli connection add type vlan autoconnect no con-name xx-c-vlan-$i-$j vlan.id $j ifname xx-i-vlan-$i-$j vlan.parent xx-i-bond-$i ipv4.method disabled ipv6.method ignore done done systemctl restart NetworkManager.service sleep 5 } do_test() { perf stat -r 50 -B nmcli 1>/dev/null } do_test ``` [1] Performance counter stats for 'nmcli' (50 runs): 456.33 msec task-clock:u # 1.093 CPUs utilized ( +- 0.44% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,900 page-faults:u # 0.013 M/sec ( +- 0.02% ) 1,408,675,453 cycles:u # 3.087 GHz ( +- 0.48% ) 1,594,741,060 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 368,744,018 branches:u # 808.061 M/sec ( +- 0.02% ) 4,566,058 branch-misses:u # 1.24% of all branches ( +- 0.76% ) 0.41761 +- 0.00282 seconds time elapsed ( +- 0.68% ) [2] Performance counter stats for 'nmcli' (50 runs): 477.99 msec task-clock:u # 1.088 CPUs utilized ( +- 0.36% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 5,948 page-faults:u # 0.012 M/sec ( +- 0.03% ) 1,471,133,482 cycles:u # 3.078 GHz ( +- 0.36% ) 1,655,275,369 instructions:u # 1.13 insn per cycle ( +- 0.02% ) 382,595,152 branches:u # 800.433 M/sec ( +- 0.02% ) 4,746,070 branch-misses:u # 1.24% of all branches ( +- 0.49% ) 0.43923 +- 0.00242 seconds time elapsed ( +- 0.55% ) [3] Performance counter stats for 'nmcli' (50 runs): 352.36 msec task-clock:u # 1.027 CPUs utilized ( +- 0.32% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 4,790 page-faults:u # 0.014 M/sec ( +- 0.26% ) 1,092,341,186 cycles:u # 3.100 GHz ( +- 0.26% ) 1,209,045,283 instructions:u # 1.11 insn per cycle ( +- 0.02% ) 281,708,462 branches:u # 799.499 M/sec ( +- 0.01% ) 3,101,031 branch-misses:u # 1.10% of all branches ( +- 0.61% ) 0.34296 +- 0.00120 seconds time elapsed ( +- 0.35% ) --- N5) same setup as N4), but run `PAGER= /bin/time -v nmcli`: [1] Command being timed: "nmcli" User time (seconds): 0.42 System time (seconds): 0.04 Percent of CPU this job got: 107% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.43 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34456 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6128 Voluntary context switches: 1298 Involuntary context switches: 1106 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [2] Command being timed: "nmcli" User time (seconds): 0.44 System time (seconds): 0.04 Percent of CPU this job got: 108% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.44 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 34452 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 6169 Voluntary context switches: 1849 Involuntary context switches: 142 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 [3] Command being timed: "nmcli" User time (seconds): 0.32 System time (seconds): 0.02 Percent of CPU this job got: 102% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.34 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 29196 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 5059 Voluntary context switches: 919 Involuntary context switches: 685 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0 --- N6) same setup as N4), but run `nmcli monitor` and look at `ps aux` for the RSS size. USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND [1] me 1492900 21.0 0.2 461348 33248 pts/10 Sl+ 15:02 0:00 nmcli monitor [2] me 1490721 5.0 0.2 461496 33548 pts/10 Sl+ 15:00 0:00 nmcli monitor [3] me 1495801 16.5 0.1 459476 28692 pts/10 Sl+ 15:04 0:00 nmcli monitor
2019-10-30 11:42:58 +01:00
_nm_object_get_path (device),
NM_DBUS_INTERFACE_DEVICE,
"Delete",
g_variant_new ("()"),
G_VARIANT_TYPE ("()"),
G_DBUS_CALL_FLAGS_NONE,
NM_DBUS_DEFAULT_TIMEOUT_MSEC,
nm_dbus_connection_call_finish_void_strip_dbus_error_cb);
}
/**
* nm_device_delete_finish:
* @device: a #NMDevice
* @result: the result passed to the #GAsyncReadyCallback
* @error: location for a #GError, or %NULL
*
* Gets the result of a call to nm_device_delete_async().
*
* Returns: %TRUE on success, %FALSE on error, in which case @error
* will be set.
**/
gboolean
nm_device_delete_finish (NMDevice *device,
GAsyncResult *result,
GError **error)
{
g_return_val_if_fail (NM_IS_DEVICE (device), FALSE);
g_return_val_if_fail (nm_g_task_is_valid (result, device, nm_device_delete_async), FALSE);
return g_task_propagate_boolean (G_TASK (result), error);
}
/**
* nm_device_connection_valid:
* @device: an #NMDevice to validate @connection against
* @connection: an #NMConnection to validate against @device
*
* Validates a given connection for a given #NMDevice object and returns
* whether the connection may be activated with the device. For example if
* @device is a Wi-Fi device that supports only WEP encryption, the connection
* will only be valid if it is a Wi-Fi connection which describes a WEP or open
* network, and will not be valid if it describes a WPA network, or if it is
* an Ethernet, Bluetooth, WWAN, etc connection that is incompatible with the
* device.
*
* Returns: %TRUE if the connection may be activated with this device, %FALSE
* if is incompatible with the device's capabilities and characteristics.
**/
gboolean
nm_device_connection_valid (NMDevice *device, NMConnection *connection)
{
return nm_device_connection_compatible (device, connection, NULL);
}
static gboolean
connection_compatible (NMDevice *device, NMConnection *connection, GError **error)
{
const char *config_iface, *device_iface;
GError *local = NULL;
if (!nm_connection_verify (connection, &local)) {
g_set_error (error, NM_DEVICE_ERROR, NM_DEVICE_ERROR_INVALID_CONNECTION,
_("The connection was not valid: %s"), local->message);
g_error_free (local);
return FALSE;
}
config_iface = nm_connection_get_interface_name (connection);
device_iface = nm_device_get_iface (device);
if (config_iface && g_strcmp0 (config_iface, device_iface) != 0) {
g_set_error (error, NM_DEVICE_ERROR, NM_DEVICE_ERROR_INCOMPATIBLE_CONNECTION,
_("The interface names of the device and the connection didn't match."));
return FALSE;
}
return TRUE;
}
/**
* nm_device_connection_compatible:
* @device: an #NMDevice to validate @connection against
* @connection: an #NMConnection to validate against @device
* @error: return location for a #GError, or %NULL
*
* Validates a given connection for a given #NMDevice object and returns
* whether the connection may be activated with the device. For example if
* @device is a Wi-Fi device that supports only WEP encryption, the connection
* will only be valid if it is a Wi-Fi connection which describes a WEP or open
* network, and will not be valid if it describes a WPA network, or if it is
* an Ethernet, Bluetooth, WWAN, etc connection that is incompatible with the
* device.
*
* This function does the same as nm_device_connection_valid(), i.e. checking
* compatibility of the given device and connection. But, in addition, it sets
* GError when FALSE is returned.
*
* Returns: %TRUE if the connection may be activated with this device, %FALSE
* if is incompatible with the device's capabilities and characteristics.
**/
gboolean
nm_device_connection_compatible (NMDevice *device, NMConnection *connection, GError **error)
{
g_return_val_if_fail (NM_IS_DEVICE (device), FALSE);
g_return_val_if_fail (NM_IS_CONNECTION (connection), FALSE);
g_return_val_if_fail (error == NULL || *error == NULL, FALSE);
return NM_DEVICE_GET_CLASS (device)->connection_compatible (device, connection, error);
}
/**
* nm_device_filter_connections:
* @device: an #NMDevice to filter connections for
* @connections: (element-type NMConnection): an array of #NMConnections to filter
*
* Filters a given array of connections for a given #NMDevice object and returns
* connections which may be activated with the device. For example if @device
* is a Wi-Fi device that supports only WEP encryption, the returned array will
* contain any Wi-Fi connections in @connections that allow connection to
* unencrypted or WEP-enabled SSIDs. The returned array will not contain
* Ethernet, Bluetooth, Wi-Fi WPA connections, or any other connection that is
* incompatible with the device. To get the full list of connections see
* nm_client_get_connections().
*
* Returns: (transfer full) (element-type NMConnection): an array of
* #NMConnections that could be activated with the given @device. The array
* should be freed with g_ptr_array_unref() when it is no longer required.
**/
GPtrArray *
nm_device_filter_connections (NMDevice *device, const GPtrArray *connections)
{
GPtrArray *filtered;
int i;
filtered = g_ptr_array_new_with_free_func (g_object_unref);
for (i = 0; i < connections->len; i++) {
NMConnection *candidate = connections->pdata[i];
/* Connection applies to this device */
if (nm_device_connection_valid (device, candidate))
g_ptr_array_add (filtered, g_object_ref (candidate));
}
return filtered;
}
/**
* nm_device_get_setting_type:
* @device: an #NMDevice
*
* Gets the (primary) #NMSetting subtype associated with connections
* that can be used on @device.
*
* Returns: @device's associated #NMSetting type
*/
GType
nm_device_get_setting_type (NMDevice *device)
{
g_return_val_if_fail (NM_IS_DEVICE (device), G_TYPE_INVALID);
g_return_val_if_fail (NM_DEVICE_GET_CLASS (device)->get_setting_type != NULL, G_TYPE_INVALID);
return NM_DEVICE_GET_CLASS (device)->get_setting_type (device);
}
/*****************************************************************************/
static gboolean
NM_IS_LLDP_NEIGHBOR (const NMLldpNeighbor *self)
{
nm_assert ( !self
|| ( self->refcount > 0
&& self->attrs));
return self
&& self->refcount > 0;
}
/**
* nm_lldp_neighbor_new:
*
* Creates a new #NMLldpNeighbor object.
*
* Returns: (transfer full): the new #NMLldpNeighbor object.
*
* Since: 1.2
**/
NMLldpNeighbor *
nm_lldp_neighbor_new (void)
{
NMLldpNeighbor *neigh;
neigh = g_new0 (NMLldpNeighbor, 1);
neigh->refcount = 1;
neigh->attrs = g_hash_table_new_full (nm_str_hash, g_str_equal, g_free,
(GDestroyNotify) g_variant_unref);
return neigh;
}
static NMLldpNeighbor *
nm_lldp_neighbor_dup (NMLldpNeighbor *neighbor)
{
NMLldpNeighbor *copy;
GHashTableIter iter;
const char *key;
GVariant *value;
copy = nm_lldp_neighbor_new ();
g_hash_table_iter_init (&iter, neighbor->attrs);
while (g_hash_table_iter_next (&iter, (gpointer *) &key, (gpointer *) &value))
g_hash_table_insert (copy->attrs, g_strdup (key), g_variant_ref (value));
return copy;
}
/**
* nm_lldp_neighbor_ref:
* @neighbor: the #NMLldpNeighbor
*
* Increases the reference count of the object.
*
* Since: 1.2
**/
void
nm_lldp_neighbor_ref (NMLldpNeighbor *neighbor)
{
g_return_if_fail (NM_IS_LLDP_NEIGHBOR (neighbor));
neighbor->refcount++;
}
/**
* nm_lldp_neighbor_unref:
* @neighbor: the #NMLldpNeighbor
*
* Decreases the reference count of the object. If the reference count
* reaches zero, the object will be destroyed.
*
* Since: 1.2
**/
void
nm_lldp_neighbor_unref (NMLldpNeighbor *neighbor)
{
g_return_if_fail (NM_IS_LLDP_NEIGHBOR (neighbor));
if (--neighbor->refcount == 0) {
g_hash_table_unref (neighbor->attrs);
g_free (neighbor);
}
}
/**
* nm_lldp_neighbor_get_attr_names:
* @neighbor: the #NMLldpNeighbor
*
* Gets an array of attribute names available for @neighbor.
*
* Returns: (transfer full): a %NULL-terminated array of attribute names.
*
* Since: 1.2
**/
char **
nm_lldp_neighbor_get_attr_names (NMLldpNeighbor *neighbor)
{
GHashTableIter iter;
const char *key;
GPtrArray *names;
g_return_val_if_fail (NM_IS_LLDP_NEIGHBOR (neighbor), NULL);
names = g_ptr_array_new ();
g_hash_table_iter_init (&iter, neighbor->attrs);
while (g_hash_table_iter_next (&iter, (gpointer *) &key, NULL))
g_ptr_array_add (names, g_strdup (key));
g_ptr_array_add (names, NULL);
return (char **) g_ptr_array_free (names, FALSE);
}
/**
* nm_lldp_neighbor_get_attr_string_value:
* @neighbor: the #NMLldpNeighbor
* @name: the attribute name
* @out_value: (out) (allow-none) (transfer none): on return, the attribute value
*
* Gets the string value of attribute with name @name on @neighbor
*
* Returns: %TRUE if a string attribute with name @name was found, %FALSE otherwise
*
* Since: 1.2
**/
gboolean
nm_lldp_neighbor_get_attr_string_value (NMLldpNeighbor *neighbor, const char *name,
const char **out_value)
{
GVariant *variant;
g_return_val_if_fail (NM_IS_LLDP_NEIGHBOR (neighbor), FALSE);
g_return_val_if_fail (name && name[0], FALSE);
variant = g_hash_table_lookup (neighbor->attrs, name);
if (variant && g_variant_is_of_type (variant, G_VARIANT_TYPE_STRING)) {
if (out_value)
*out_value = g_variant_get_string (variant, NULL);
return TRUE;
} else
return FALSE;
}
/**
* nm_lldp_neighbor_get_attr_uint_value:
* @neighbor: the #NMLldpNeighbor
* @name: the attribute name
2015-10-16 15:20:45 +02:00
* @out_value: (out) (allow-none): on return, the attribute value
*
* Gets the uint value of attribute with name @name on @neighbor
*
* Returns: %TRUE if a uint attribute with name @name was found, %FALSE otherwise
*
* Since: 1.2
**/
gboolean
nm_lldp_neighbor_get_attr_uint_value (NMLldpNeighbor *neighbor, const char *name,
guint *out_value)
{
GVariant *variant;
g_return_val_if_fail (NM_IS_LLDP_NEIGHBOR (neighbor), FALSE);
g_return_val_if_fail (name && name[0], FALSE);
variant = g_hash_table_lookup (neighbor->attrs, name);
if (variant && g_variant_is_of_type (variant, G_VARIANT_TYPE_UINT32)) {
if (out_value)
*out_value = g_variant_get_uint32 (variant);
return TRUE;
} else
return FALSE;
}
/**
* nm_lldp_neighbor_get_attr_value:
* @neighbor: the #NMLldpNeighbor
* @name: the attribute name
*
* Gets the value (as a GVariant) of attribute with name @name on @neighbor
*
* Returns: (transfer none): the value or %NULL if the attribute with @name was
* not found.
*
* Since: 1.18
**/
GVariant *
nm_lldp_neighbor_get_attr_value (NMLldpNeighbor *neighbor, const char *name)
{
g_return_val_if_fail (NM_IS_LLDP_NEIGHBOR (neighbor), FALSE);
g_return_val_if_fail (name && name[0], FALSE);
return g_hash_table_lookup (neighbor->attrs, name);
}
/**
* nm_lldp_neighbor_get_attr_type:
* @neighbor: the #NMLldpNeighbor
* @name: the attribute name
*
* Get the type of an attribute.
*
* Returns: the #GVariantType of the attribute with name @name
*
* Since: 1.2
**/
const GVariantType *
nm_lldp_neighbor_get_attr_type (NMLldpNeighbor *neighbor, const char *name)
{
GVariant *variant;
g_return_val_if_fail (NM_IS_LLDP_NEIGHBOR (neighbor), NULL);
g_return_val_if_fail (name && name[0], NULL);
variant = g_hash_table_lookup (neighbor->attrs, name);
if (variant)
return g_variant_get_type (variant);
else
return NULL;
}