Commit graph

433 commits

Author SHA1 Message Date
Tapani Pälli
41c5bf3836 disk cache: move path creation back to constructor
This patch moves disk cache path and index creation back to the
constructor which matches previous behavior. We still allow create
to succeed without path so that cache can be used with callback
functionality.

Fixes: c95d3ed091 "disk cache: create cache even if path creation fails"
Signed-off-by: Tapani Pälli <tapani.palli@intel.com>
Reviewed-by: Timothy Arceri <tarceri@itsqueeze.com>
2018-02-09 11:33:25 +02:00
Tapani Pälli
ae00ef2702 disk cache: add callback functionality
v2: add disk_cache_has_key, disk_cache_put_key support
    using blob cache (Nicolai, Jordan)

v3: rename set_cb as put_cb to match existing naming (Timothy)

Signed-off-by: Tapani Pälli <tapani.palli@intel.com>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>
Reviewed-by: Emil Velikov <emil.velikov@collabora.com>
2018-02-07 14:45:34 +02:00
Tapani Pälli
6a651b6b77 disk cache: initialize cache path and index only when used
This patch makes disk_cache initialize path and index lazily so
that we can utilize disk_cache without a path using callback
functionality introduced by next patch.

v2: unmap mmap and destroy queue only if index_mmap exists

Signed-off-by: Tapani Pälli <tapani.palli@intel.com>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>
Reviewed-by: Emil Velikov <emil.velikov@collabora.com>
2018-02-07 14:45:34 +02:00
Vlad Golovkin
d919ff0f27 util: remove redundant check for the __clang__ macro
Clang defines __GNUC__ macro, so one doesn't need to check __clang__
macro in this particular case.

v2: added comment as per Brian Paul's suggestion

Reviewed-by: Brian Paul <brianp@vmware.com>
2018-02-06 15:23:26 -07:00
Stephan Gerhold
02e2009b92 util/build-id: Fix address comparison for binaries with LOAD vaddr > 0
build_id_find_nhdr_for_addr() fails to find the build-id if the first LOAD
segment has a virtual address other than 0x0.

For most shared libraries, the first LOAD segment has vaddr=0x0:

    Type           Offset   VirtAddr   PhysAddr   FileSiz MemSiz  Flg Align
    LOAD           0x000000 0x00000000 0x00000000 0x2d2e26 0x2d2e26 R E 0x1000
    LOAD           0x2d2e54 0x002d3e54 0x002d3e54 0x2e248 0x2f148 RW  0x1000

However, compiling the Intel Vulkan driver as 32-bit binary on Android produces
the following ELF header with vaddr=0x8000 instead:

    Type           Offset   VirtAddr   PhysAddr   FileSiz MemSiz  Flg Align
    PHDR           0x000034 0x00008034 0x00008034 0x00100 0x00100 R   0x4
    LOAD           0x000000 0x00008000 0x00008000 0x224a04 0x224a04 R E 0x1000
    LOAD           0x225710 0x0022e710 0x0022e710 0x25988 0x27364 RW  0x1000

build_id_find_nhdr_callback() compares the address of dli_fbase from dladdr()
and dlpi_addr from dl_iterate_phdr(). With vaddr > 0, these point to a
different memory address, e.g.:

    dli_fbase=0xd8395000 (offset 0x8000)
    dlpi_addr=0xd838d000

At least on glibc and bionic (Android) dli_fbase refers to the address where
the shared object is mapped into the process space, whereas dlpi_addr is just
the base address for the vaddrs declared in the ELF header.

To compare them correctly, we need to calculate the start of the mapping
by adding the vaddr of the first LOAD segment to the base address.

Note: musl users will need the following patch.
https://git.musl-libc.org/cgit/musl/commit/?id=b3ae7beabb9f0c219bb8a8b63567a01c6530c1ac

Cc: Chad Versace <chadversary@chromium.org>
Cc: <mesa-stable@lists.freedesktop.org>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=104642
Fixes: 5c98d38 "util: Query build-id by symbol address, not library name"
Reviewed-by: Emil Velikov <emil.velikov@collabora.com>
Reviewed-by: Tapani Pälli <tapani.palli@intel.com>
2018-02-05 14:26:33 +00:00
Dylan Baker
5781c3d1db meson: correctly set SYSCONFDIR for loading dirrc
Fixes: d1992255bb ("meson: Add build Intel "anv" vulkan driver")
Reported-by: Marc Dietrich <marvin24@gmx.de>
Signed-off-by: Dylan Baker <dylan.c.baker@intel.com>
Reviewed-by: Eric Engestrom <eric.engestrom@imgtec.com>
2018-01-24 13:10:32 -08:00
Samuel Thibault
9131e6d3c2 u_thread: Use pthread_setname_np on linux only.
pthread_setname_np was added in glibc 2.12 for the Linux port only, other
ports do not necessarily have it.

Signed-off-by: Jose Fonseca <jfonseca@vmware.com>
2018-01-22 21:12:41 +00:00
Dylan Baker
436ed65d38 autotools: include meson build files in tarball
This adds the meson.build, meson_options.txt, and a few scripts that are
used exclusively by the meson build.

v2: - Remove accidentally included changes needed to test make dist with
      LLVM > 3.9

Signed-off-by: Dylan Baker <dylan.c.baker@intel.com>
Acked-by: Eric Engestrom <eric@engestrom.ch>
Reviewed-by: Emil Velikov <emil.velikov@collabora.com>
2018-01-19 16:30:51 -08:00
Brian Paul
2f14146200 util: include string.h in u_dynarray.h
To get memset() prototype.

Reviewed-by: Nicolai Hähnle <nicolai.haehnle@amd.com>
2018-01-17 11:17:56 -07:00
Brian Paul
484ac243f6 mesa: include compiler.h in disk_cache.c
Instead of indirect inclusion to get CPU_TO_LE32() macro.

Reviewed-by: Nicolai Hähnle <nicolai.haehnle@amd.com>
2018-01-17 11:17:56 -07:00
Grazvydas Ignotas
6acf22a179 util: use faster zlib's CRC32 implementaion
zlib provides a faster slice-by-4 CRC32 implementation than the
traditional single byte lookup one used by mesa. As most supported
platforms now link zlib unconditionally, we can easily use it.

Improvement for a 1MB buffer (avg MB/s, n=100, zlib 1.2.8):

  i5-6600K                    C2D E4500
mesa zlib                    mesa zlib
 443 1443 225% +/- 2.1%       403 1175 191% +/- 0.9%

It has been verified the calculation results stay the same after this
change.

Signed-off-by: Grazvydas Ignotas <notasas@gmail.com>
Reviewed-by: Eric Engestrom <eric.engestrom@imgtec.com>
Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
2018-01-14 19:10:33 +02:00
Grazvydas Ignotas
b7347cc313 util/crc32: don't drop the const qualifier
Signed-off-by: Grazvydas Ignotas <notasas@gmail.com>
Reviewed-by: Eric Engestrom <eric.engestrom@imgtec.com>
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
2018-01-14 18:47:50 +02:00
Roland Scheidegger
85377dc55c util: fix NORETURN for msvc, add HAVE_FUNC_ATTRIBUTE_NORETURN to c99_compat.h
We've seen some problems internally due to macro redefinition.
Fix this by adding HAVE_FUNC_ATTRIBUTE_NORETURN to c99_compat.h,
and defining it for msvc.
And avoid redefinition just in case.

Reviewed-by: Brian Paul <brianp@vmware.com>
Reviewed-by: Jose Fonseca <jfonseca@vmware.com>
2018-01-12 02:52:10 +01:00
Dylan Baker
4ccb981673 meson: Use consistent style for tests
Don't use intermediate variables, use consistent whitespace.

Acked-by: Eric Engestrom <eric.engestrom@imgtec.com>
Signed-off-by: Dylan Baker <dylan.c.baker@intel.com>
2018-01-11 15:40:02 -08:00
Igor Gnatenko
23ce168048 link mesautil with pthreads
../../src/util/.libs/libmesautil.a(libmesautil_la-u_queue.o): In function `u_thread_setname':
/builddir/build/BUILD/mesa-17.3.1/src/util/../../src/util/u_thread.h:66: undefined reference to `pthread_setname_np'
../../src/util/.libs/libmesautil.a(libmesautil_la-u_queue.o): In function `thrd_join':
/builddir/build/BUILD/mesa-17.3.1/src/util/../../include/c11/threads_posix.h:336: undefined reference to `pthread_join'
../../src/util/.libs/libmesautil.a(libmesautil_la-u_queue.o): In function `u_thread_create':
/builddir/build/BUILD/mesa-17.3.1/src/util/../../src/util/u_thread.h:48: undefined reference to `pthread_sigmask'
../../src/util/.libs/libmesautil.a(libmesautil_la-u_queue.o): In function `thrd_create':
/builddir/build/BUILD/mesa-17.3.1/src/util/../../include/c11/threads_posix.h:296: undefined reference to `pthread_create'
../../src/util/.libs/libmesautil.a(libmesautil_la-u_queue.o): In function `u_thread_create':
/builddir/build/BUILD/mesa-17.3.1/src/util/../../src/util/u_thread.h:50: undefined reference to `pthread_sigmask'
/builddir/build/BUILD/mesa-17.3.1/src/util/../../src/util/u_thread.h:50: undefined reference to `pthread_sigmask'
../../src/util/.libs/libmesautil.a(libmesautil_la-u_queue.o): In function `call_once':
/builddir/build/BUILD/mesa-17.3.1/src/util/../../include/c11/threads_posix.h:96: undefined reference to `pthread_once'
../../src/util/.libs/libmesautil.a(libmesautil_la-u_queue.o): In function `u_thread_get_time_nano':
/builddir/build/BUILD/mesa-17.3.1/src/util/../../src/util/u_thread.h:84: undefined reference to `pthread_getcpuclockid'
collect2: error: ld returned 1 exit status

Reviewed-by: Adam Jackson <ajax@redhat.com>
Signed-off-by: Igor Gnatenko <ignatenko@redhat.com>
2018-01-08 11:40:02 -05:00
Mario Kleiner
67674ad0dc dri/common: Add option to allow exposure of 10 bpc color configs. (v2)
Some clients may not like RGB10X2 and RGB10A2 fbconfigs and
visuals. Add a new driconf option 'allow_rgb10_configs' to
allow per application enable/disable.

The option defaults to enabled.

v2: Rename expose_rgb10_configs to allow_rgb10_configs,
    as suggested by Emil. Add comment to option parsing,
    to make sure it stays before the ->InitScreen().

Signed-off-by: Mario Kleiner <mario.kleiner.de@gmail.com>
Reviewed-by: Tapani Pälli <tapani.palli@intel.com>
Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Signed-off-by: Marek Olšák <marek.olsak@amd.com>
2018-01-03 22:57:56 +01:00
Rob Herring
28234c5bf8 Android: util: fix locale generation in options.h
The parameters to gen_xmlpool.py are wrong and cause the following
warnings:

Warning: language 'out/target/product/linaro_x86_64/gen/STATIC_LIBRARIES/libmesa_util_intermediates/xmlpool/es/LC_MESSAGES/options.mo' not found.
Warning: language 'out/target/product/linaro_x86_64/gen/STATIC_LIBRARIES/libmesa_util_intermediates/xmlpool/nl/LC_MESSAGES/options.mo' not found.
Warning: language 'out/target/product/linaro_x86_64/gen/STATIC_LIBRARIES/libmesa_util_intermediates/xmlpool/fr/LC_MESSAGES/options.mo' not found.
Warning: language 'out/target/product/linaro_x86_64/gen/STATIC_LIBRARIES/libmesa_util_intermediates/xmlpool/sv/LC_MESSAGES/options.mo' not found.
Warning: language 'external/mesa3d/src/util/xmlpool/t_options.h' not found.
Warning: language 'out/target/product/linaro_x86_64/gen/STATIC_LIBRARIES/libmesa_util_intermediates/xmlpool' not found.
Warning: language 'de' not found.
Warning: language 'es' not found.
Warning: language 'nl' not found.
Warning: language 'fr' not found.
Warning: language 'sv' not found.

The result is English is the only language in options.h. Use "$<"
instead of "$^" because we only need the first dependency (the script),
not all dependencies.

Signed-off-by: Rob Herring <robh@kernel.org>
2018-01-03 09:49:08 -06:00
Tapani Pälli
fcfb423646 drirc: set allow_glsl_cross_stage_interpolation_mismatch for more games
Signed-off-by: Tapani Pälli <tapani.palli@intel.com>
Suggested-by: Darius Spitznagel <d.spitznagel@goodbytez.de>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=104288
Acked-by: Kenneth Graunke <kenneth@whitecape.org>
2017-12-20 09:43:42 +02:00
Emil Velikov
5d03a68640 util: scons: wire up the sha1 test
Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>
Reviewed-by: Andres Gomez <agomez@igalia.com>
2017-12-15 19:01:12 +00:00
Marek Olšák
8a821fa91c drirc: whitelist glthread for Mount and Blade Warband again 2017-12-11 19:11:12 +01:00
Eric Engestrom
4cba39331d meson: add dep_thread to every lib that includes threads.h
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=104141
Signed-off-by: Eric Engestrom <eric.engestrom@imgtec.com>
Reviewed-by: Dylan Baker <dylan@pnwbakers.com>
2017-12-07 17:29:42 +00:00
Vadym Shovkoplias
b2490a326c util/disk_cache: Remove unneeded free() on always null string
At this point dc_job->cache_item_metadata.keys always equals
NULL, so call to free() is useless

Fixes: b86ecea344 ("util/disk_cache: write cache item metadata to disk")
Signed-off-by: Vadym Shovkoplias <vadym.shovkoplias@globallogic.com>
Reviewed-by: Eric Engestrom <eric.engestrom@imgtec.com>
2017-12-07 11:50:41 +00:00
Jason Ekstrand
0c49aa0624 util: Add a NORETURN macro
Reviewed-by: Tapani Pälli <tapani.palli@intel.com>
Reviewed-by: Ian Romanick <idr@freedesktop.org>
2017-12-04 09:21:09 -08:00
Tapani Pälli
faccbaf3fa mesa: add AllowGLSLCrossStageInterpolationMismatch workaround
This fixes issues seen with certain versions of Unreal Engine 4 editor
and games built with that using GLSL 4.30.

v2: add driinfo_gallium change (Emil Velikov)

Signed-off-by: Tapani Pälli <tapani.palli@intel.com>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=97852
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=103801
Acked-by: Andres Gomez <agomez@igalia.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
2017-11-30 11:43:10 +02:00
Jon Turney
2c62ccb10a util: Also include endian.h on cygwin
If u_endian.h can't determine the endianess, the default behaviour in sha1.c
is to build for big-endian

Signed-off-by: Jon Turney <jon.turney@dronecode.org.uk>
Reviewed-by: Matt Turner <mattst88@gmail.com>
2017-11-29 14:04:40 +00:00
Eric Engestrom
44fbbd6fd0 util: add mesa-sha1 test to meson
Fixes: 513d7ffa23 "util: Add a SHA1 unit test program"
Signed-off-by: Eric Engestrom <eric.engestrom@imgtec.com>
Reviewed-by: Matt Turner <mattst88@gmail.com>
2017-11-28 11:06:04 +00:00
Matt Turner
676761252b util: Just give up and define PIPE_ARCH_LITTLE_ENDIAN on MSVC
MSVC doesn't support #warning?! Getting really tired of this.
2017-11-25 16:46:00 -08:00
Matt Turner
b8cbad624b util: Use preprocessor correctly
Fixes: 6a353479a7 ("util: Assume little endian in the absence of
                      platform-specific handling")
2017-11-25 15:57:37 -08:00
Matt Turner
c690a7a8cd util: Fix disk_cache index calculation on big endian
The cache-test test program attempts to create a collision (using key_a
and key_a_collide) by making the first two bytes identical. The idea is
fine -- the shader cache wants to use the first four characters of a
SHA1 hex digest as the index.

The following program

        unsigned char array[4] = {1, 2, 3, 4};
        int *ptr = (int *)array;

        for (int i = 0; i < 4; i++) {
            printf("%02x", array[i]);
        }
        printf("\n");

        printf("%08x\n", *ptr);

prints

   01020304
   04030201

on little endian, and

   01020304
   01020304

on big endian.

On big endian platforms reading the character array back as an int (as
is done in disk_cache.c) does not yield the same results as reading the
byte array.

To get the first four characters of the SHA1 hex digest when we mask
with CACHE_INDEX_KEY_MASK, we need to byte swap the int on big endian
platforms.

Bugzilla: https://bugs.freedesktop.org/103668
Bugzilla: https://bugs.gentoo.org/637060
Bugzilla: https://bugs.gentoo.org/636326
Fixes: 87ab26b2ab ("glsl: Add initial functions to implement an
                      on-disk cache")
Reviewed-by: Emil Velikov <emil.velikov@collabora.com>
2017-11-25 12:30:46 -08:00
Matt Turner
513d7ffa23 util: Add a SHA1 unit test program
Reviewed-by: Emil Velikov <emil.velikov@collabora.com>
2017-11-25 12:30:46 -08:00
Matt Turner
532674303a util: Fix SHA1 implementation on big endian
The code defines a macro blk0(i) based on the preprocessor condition
BYTE_ORDER == LITTLE_ENDIAN. If true, blk0(i) is defined as a byte swap
operation. Unfortunately, if the preprocessor macros used in the test
are no defined, then the comparison becomes 0 == 0 and it evaluates as
true.

Fixes: d1efa09d34 ("util: import sha1 implementation from OpenBSD")
Reviewed-by: Emil Velikov <emil.velikov@collabora.com>
2017-11-25 12:30:46 -08:00
Matt Turner
6a353479a7 util: Assume little endian in the absence of platform-specific handling 2017-11-25 12:30:46 -08:00
Nicolai Hähnle
81aabb20f3 util/u_queue: really use futex-based fences
The relevant define changed in the final revision of the simple mutex
patch.

Reviewed-by: Marek Olšák <marek.olsak@amd.com>
2017-11-20 18:15:53 +01:00
Nicolai Hähnle
a6e8311723 util/u_queue: fix timeout handling in util_queue_fence_wait_timeout
Fixes: e3a8013de8 ("util/u_queue: add util_queue_fence_wait_timeout")
Reviewed-by: Marek Olšák <marek.olsak@amd.com>
2017-11-20 18:15:49 +01:00
Gert Wollny
0b984188f9 src/util/simple_mtx.h: Fix two -Wunused-param warnings.
Decorate the parameters accordingly with "UNUSED" or "MAYBE_UNUSED" (for
the param that is used in debug mode, but not in release mode).

v2: move UNUSED decoration in front of parameter declaration

Signed-off-by: Gert Wollny <gw.fossdev@gmail.com>
Reviewed-by: Brian Paul <brianp@vmware.com> (v1)
2017-11-17 09:27:57 -07:00
Brian Paul
fe81e1f975 util: add new ASSERT_BITFIELD_SIZE() macro (v3)
For checking that bitfields are large enough to hold the largest
expected value.

v2: move into existing util/macros.h header where STATIC_ASSERT() lives.
v3: add MAYBE_UNUSED to variable declaration

Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
2017-11-16 20:35:17 -07:00
Jon Turney
764f1e4d45 util: include unistd.h, which may be required for usleep prototype
This seems to be dropped in 222a2fb9 "util: move os_time.[ch] to src/util"

../../../src/util/os_time.c: In function ‘os_time_sleep’:
../../../src/util/os_time.c:104:4: error: implicit declaration of function ‘usleep’ [-Werror=implicit-function-declaration]

Signed-off-by: Jon Turney <jon.turney@dronecode.org.uk>
Reviewed-by: Nicolai Hähnle <nicolai.haehnle@amd.com>
2017-11-10 18:20:35 +00:00
Nicolai Hähnle
e7972b8943 util/u_thread: fix compilation on Mac OS
Apparently, it doesn't have pthread barriers.

p_config.h (which was originally used to guard this code) uses the
__APPLE__ macro to detect Mac OS.

Fixes: f0d3a4de75 ("util: move pipe_barrier into src/util and rename to util_barrier")
Cc: Roland Scheidegger <sroland@vmware.com>
Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Reviewed-by: Brian Paul <brianp@vmware.com>
2017-11-10 16:37:54 +01:00
Nicolai Hähnle
f53570a7a6 util/u_queue: handle OS_TIMEOUT_INFINITE in util_queue_fence_wait_timeout
Fixes e.g. piglit/bin/bufferstorage-persistent read -auto

Fixes: e6dbc804a8 ("winsys/amdgpu: handle cs_add_fence_dependency for deferred/unsubmitted fences")
Reviewed-by: Marek Olšák <marek.olsak@amd.com>
2017-11-10 16:37:47 +01:00
Nicolai Hähnle
e3a8013de8 util/u_queue: add util_queue_fence_wait_timeout
v2:
- style fixes
- fix missing timeout handling in futex path

Reviewed-by: Marek Olšák <marek.olsak@amd.com>
2017-11-09 13:58:10 +01:00
Nicolai Hähnle
222a2fb998 util: move os_time.[ch] to src/util
Reviewed-by: Marek Olšák <marek.olsak@amd.com>
2017-11-09 11:57:21 +01:00
Nicolai Hähnle
185061aef4 u_queue: add util_queue_finish for waiting for previously added jobs
Schedule one job for every thread, and wait on a barrier inside the job
execution function.

v2: avoid alloca (fixes Windows build error)

Reviewed-by: Marek Olšák <marek.olsak@amd.com> (v1)
2017-11-09 11:53:19 +01:00
Nicolai Hähnle
f0d3a4de75 util: move pipe_barrier into src/util and rename to util_barrier
The #if guard is probably not 100% equivalent to the previous PIPE_OS
check, but if anything it should be an over-approximation (are there
pthread implementations without barriers?), so people will get either
a good implementation or compile errors that are easy to fix.

Reviewed-by: Marek Olšák <marek.olsak@amd.com>
2017-11-09 11:53:19 +01:00
Nicolai Hähnle
d1ff082637 u_queue: add a futex-based implementation of fences
Fences are now 4 bytes instead of 96 bytes (on my 64-bit system).

Signaling a fence is a single atomic operation in the fast case plus a
syscall in the slow case.

Testing if a fence is signaled is the same as before (a simple comparison),
but waiting on a fence is now no more expensive than just testing it in
the fast (already signaled) case.

v2:
- style fixes
- use p_atomic_xxx macros with the right barriers

Acked-by: Marek Olšák <marek.olsak@amd.com>
2017-11-09 11:37:39 +01:00
Nicolai Hähnle
574c59d4f9 u_queue: add util_queue_fence_reset
Reviewed-by: Marek Olšák <marek.olsak@amd.com>
2017-11-09 11:37:39 +01:00
Nicolai Hähnle
1b9d5ece55 u_queue: export util_queue_fence_signal
Reviewed-by: Marek Olšák <marek.olsak@amd.com>
2017-11-09 11:37:38 +01:00
Nicolai Hähnle
b20f955bc1 u_queue: group fence functions together
Reviewed-by: Marek Olšák <marek.olsak@amd.com>
2017-11-09 11:37:38 +01:00
Nicolai Hähnle
0a7f17cf5b util/u_atomic: add p_atomic_xchg
The closest to it in the old-style gcc builtins is __sync_lock_test_and_set,
however, that is only guaranteed to work with values 0 and 1 and only
provides an acquire barrier. I also don't know about other OSes, so we
provide a simple & stupid emulation via p_atomic_cmpxchg.

Reviewed-by: Marek Olšák <marek.olsak@amd.com>
2017-11-09 11:37:30 +01:00
Nicolai Hähnle
b4b2a951c8 util: move futex helpers into futex.h
v2: style fixes

Reviewed-by: Marek Olšák <marek.olsak@amd.com> (v1)
2017-11-09 11:37:22 +01:00
Timothy Arceri
f98a2768ca mesa: Add new fast mtx_t mutex type for basic use cases
While modern pthread mutexes are very fast, they still incur a call to an
external DSO and overhead of the generality and features of pthread mutexes.
Most mutexes in mesa only needs lock/unlock, and the idea here is that we can
inline the atomic operation and make the fast case just two intructions.
Mutexes are subtle and finicky to implement, so we carefully copy the
implementation from Ulrich Dreppers well-written and well-reviewed paper:

  "Futexes Are Tricky"
  http://www.akkadia.org/drepper/futex.pdf

We implement "mutex3", which gives us a mutex that has no syscalls on
uncontended lock or unlock.  Further, the uncontended case boils down to a
cmpxchg and an untaken branch and the uncontended unlock is just a locked decr
and an untaken branch.  We use __builtin_expect() to indicate that contention
is unlikely so that gcc will put the contention code out of the main code
flow.

A fast mutex only supports lock/unlock, can't be recursive or used with
condition variables.  We keep the pthread mutex implementation around as
for the few places where we use condition variables or recursive locking.
For platforms or compilers where futex and atomics aren't available,
simple_mtx_t falls back to the pthread mutex.

The pthread mutex lock/unlock overhead shows up on benchmarks for CPU bound
applications.  Most CPU bound cases are helped and some of our internal
bind_buffer_object heavy benchmarks gain up to 10%.

Signed-off-by: Kristian Høgsberg <krh@bitplanet.net>
Signed-off-by: Timothy Arceri <tarceri@itsqueeze.com>
Reviewed-by: Nicolai Hähnle <nicolai.haehnle@amd.com>
2017-11-09 12:07:48 +11:00