/* * Copyright 2002-2004 Red Hat Inc., Durham, North Carolina. * * All Rights Reserved. * * Permission is hereby granted, free of charge, to any person obtaining * a copy of this software and associated documentation files (the * "Software"), to deal in the Software without restriction, including * without limitation on the rights to use, copy, modify, merge, * publish, distribute, sublicense, and/or sell copies of the Software, * and to permit persons to whom the Software is furnished to do so, * subject to the following conditions: * * The above copyright notice and this permission notice (including the * next paragraph) shall be included in all copies or substantial * portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND * NON-INFRINGEMENT. IN NO EVENT SHALL RED HAT AND/OR THEIR SUPPLIERS * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE * SOFTWARE. */ /* * Authors: * Rickard E. (Rik) Faith * */ /** \file * * The DMX server code is written to call #dmxSync() whenever an XSync() * might be necessary. However, since XSync() requires a two way * communication with the other X server, eliminating unnecessary * XSync() calls is a key performance optimization. Support for this * optimization is provided here. Statistics about XSync() calls and * latency are gathered in #dmxstat.c. * * During the initial conversion from calling XSync() immediately to the * XSync() batching method implemented in this file, it was noted that, * out of more than 300 \a x11perf tests, 8 tests became more than 100 * times faster, with 68 more than 50X faster, 114 more than 10X faster, * and 181 more than 2X faster. */ #ifdef HAVE_DMX_CONFIG_H #include #endif #include "dmx.h" #include "dmxsync.h" #include "dmxstat.h" #include "dmxlog.h" #include "dmxextension.h" #include "dmxscrinit.h" #include static int dmxSyncInterval = 100; /* Default interval in milliseconds */ static OsTimerPtr dmxSyncTimer = NULL; static OsTimerPtr dmxActiveSyncTimer = NULL; static int dmxSyncPending = 0; static int dmxSyncRequest = 0; /* dispatch all pending back-end server responses */ void dmxDispatch (void) { int i; for (i = 0; i < dmxNumScreens; i++) if (dmxScreens[i].alive) dmxBEDispatch (screenInfo.screens[i]); } /* non-blocking wait for back-end server response. returns 0 when no more reponses can arrive */ int dmxWaitForResponse (void) { fd_set rfds; int nfd = 0; int i, ret = 0; FD_ZERO (&rfds); for (i = 0; i < dmxNumScreens; i++) { if (dmxScreens[i].alive) { xcb_flush (dmxScreens[i].connection); if (xcb_connection_has_error (dmxScreens[i].connection)) { dmxScreens[i].alive = FALSE; ret = -1; } else { FD_SET (dmxScreens[i].fd, &rfds); if (dmxScreens[i].fd > nfd) nfd = dmxScreens[i].fd; } } } if (ret == 0 && nfd) { do { ret = select (nfd + 1, &rfds, 0, 0, 0); } while (ret == -1 && errno == EINTR); /* screens with broken connections are detached in the block handler */ } return nfd; } static void dmxDoSync(DMXScreenInfo *dmxScreen) { dmxScreen->needsSync = FALSE; if (!dmxScreen->alive) return; /* FIXME: Is this correct behavior for sync stats? */ if (dmxScreen->sync.sequence) return; dmxScreen->sync = xcb_get_input_focus (dmxScreen->connection); dmxAddRequest (&dmxScreen->request, dmxScreenSyncReply, dmxScreen->sync.sequence, 0); dmxSyncRequest++; } static CARD32 dmxSyncCallback(OsTimerPtr timer, CARD32 time, pointer arg) { int i; /* make sure TimerFree is not called from while waiting for pending replies */ dmxActiveSyncTimer = NULL; /* wait for all pending sync replies */ do { dmxDispatch (); } while (dmxSyncRequest && dmxWaitForResponse ()); if (dmxSyncPending) { for (i = 0; i < dmxNumScreens; i++) if (dmxScreens[i].needsSync) dmxDoSync (&dmxScreens[i]); dmxSyncPending = 0; if (dmxSyncRequest) { dmxActiveSyncTimer = timer; return dmxSyncInterval; } } return 0; /* Do not place on queue again */ } /** Request the XSync() batching optimization with the specified \a * interval (in mS). If the \a interval is 0, 100mS is used. If the \a * interval is less than 0, then the XSync() batching optimization is * not requested (e.g., so the -syncbatch -1 command line option can * turn off the default 100mS XSync() batching). * * Note that the parameter to this routine is a string, since it will * usually be called from #ddxProcessArgument in #dmxinit.c */ void dmxSyncActivate(const char *interval) { dmxSyncInterval = (interval ? atoi(interval) : 100); if (dmxSyncInterval < 0) dmxSyncInterval = 0; } /** Initialize the XSync() batching optimization, but only if * #dmxSyncActivate was last called with a non-negative value. */ void dmxSyncInit(void) { if (dmxSyncInterval) { dmxLog(dmxInfo, "XSync batching with %d ms interval\n", dmxSyncInterval); } else { dmxLog(dmxInfo, "XSync batching disabled\n"); } } /** Request an XSync() to the display used by \a dmxScreen. If \a now * is TRUE, call XSync() immediately instead of waiting for the next * XSync() batching point. Note that if XSync() batching was deselected * with #dmxSyncActivate() before #dmxSyncInit() was called, then no * XSync() batching is performed and this function always calles XSync() * immediately. * * (Note that this function uses TimerSet but works correctly in the * face of a server generation. See the source for details.) * * If \a dmxScreen is \a NULL, then all pending syncs will be flushed * immediately. */ void dmxSync(DMXScreenInfo *dmxScreen, Bool now) { static unsigned long dmxGeneration = 0; if (dmxSyncInterval) { if (dmxGeneration != serverGeneration) { /* Server generation does a TimerInit, which frees all * timers. So, at this point dmxSyncTimer is either: * 1) NULL, iff dmxGeneration == 0, * 2) freed, if it was on a queue (dmxSyncPending != 0), or * 3) allocated, if it wasn't on a queue (dmxSyncPending == 0) */ if (dmxSyncTimer && !dmxActiveSyncTimer) xfree(dmxSyncTimer); dmxSyncTimer = NULL; now = FALSE; dmxGeneration = serverGeneration; } /* Queue sync */ if (dmxScreen) { if (now && dmxScreen->inDispatch) { dmxLog (dmxWarning, "Immediate sync from within back-end dispatch\n"); free (xcb_get_input_focus_reply (dmxScreen->connection, xcb_get_input_focus (dmxScreen->connection), NULL)); return; } dmxScreen->needsSync = TRUE; ++dmxSyncPending; } /* Do sync or set time for later */ if (now || !dmxScreen) { if (dmxActiveSyncTimer) { TimerCancel (dmxActiveSyncTimer); dmxActiveSyncTimer = NULL; } while (dmxSyncRequest || dmxSyncPending) dmxSyncCallback (NULL, 0, NULL); } else if (!dmxActiveSyncTimer) { dmxActiveSyncTimer = TimerSet (dmxSyncTimer, 0, dmxSyncInterval, dmxSyncCallback, NULL); } } else { /* If dmxSyncInterval is not being used, * then all the backends are already * up-to-date. */ if (dmxScreen) { dmxDoSync (dmxScreen); dmxSyncCallback (NULL, 0, NULL); } } } /* error or reply doesn't matter, all we need is some response from the back-end server */ void dmxScreenSyncReply (ScreenPtr pScreen, unsigned int sequence, xcb_generic_reply_t *reply, xcb_generic_error_t *error, void *data) { DMXScreenInfo *dmxScreen = &dmxScreens[pScreen->myNum]; if (dmxScreen->sync.sequence) { dmxScreen->sync.sequence = 0; dmxSyncRequest--; if (dmxSyncRequest == 0 && dmxSyncPending == 0 && dmxActiveSyncTimer) { TimerCancel (dmxActiveSyncTimer); dmxActiveSyncTimer = NULL; } } }