/* * 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 <faith@redhat.com> * */ /** \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 <dmx-config.h> #endif #include "dmx.h" #include "dmxsync.h" #include "dmxstat.h" #include "dmxlog.h" #include <sys/time.h> static int dmxSyncInterval = 100; /* Default interval in milliseconds */ static OsTimerPtr dmxSyncTimer; static int dmxSyncPending; static void dmxDoSync(DMXScreenInfo *dmxScreen) { dmxScreen->needsSync = FALSE; if (!dmxScreen->beDisplay) return; /* FIXME: Is this correct behavior for sync stats? */ if (!dmxStatInterval) { XSync(dmxScreen->beDisplay, False); } else { struct timeval start, stop; gettimeofday(&start, 0); XSync(dmxScreen->beDisplay, False); gettimeofday(&stop, 0); dmxStatSync(dmxScreen, &stop, &start, dmxSyncPending); } } static CARD32 dmxSyncCallback(OsTimerPtr timer, CARD32 time, pointer arg) { int i; if (dmxSyncPending) { for (i = 0; i < dmxNumScreens; i++) { DMXScreenInfo *dmxScreen = &dmxScreens[i]; if (dmxScreen->needsSync) dmxDoSync(dmxScreen); } } dmxSyncPending = 0; return 0; /* Do not place on queue again */ } static void dmxSyncBlockHandler(pointer blockData, OSTimePtr pTimeout, pointer pReadMask) { TimerForce(dmxSyncTimer); } static void dmxSyncWakeupHandler(pointer blockData, int result, pointer pReadMask) { } /** 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) { RegisterBlockAndWakeupHandlers(dmxSyncBlockHandler, dmxSyncWakeupHandler, NULL); 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 && !dmxSyncPending) xfree(dmxSyncTimer); dmxSyncTimer = NULL; now = TRUE; dmxGeneration = serverGeneration; } /* Queue sync */ if (dmxScreen) { dmxScreen->needsSync = TRUE; ++dmxSyncPending; } /* Do sync or set time for later */ if (now || !dmxScreen) { if (!TimerForce(dmxSyncTimer)) dmxSyncCallback(NULL, 0, NULL); /* At this point, dmxSyncPending == 0 because * dmxSyncCallback must have been called. */ if (dmxSyncPending) dmxLog(dmxFatal, "dmxSync(%s,%d): dmxSyncPending = %d\n", dmxScreen ? dmxScreen->name : "", now, dmxSyncPending); } else { dmxScreen->needsSync = TRUE; if (dmxSyncPending == 1) dmxSyncTimer = 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); } }