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/*
* 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 \a 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, void *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(void *blockData, void *timeout)
{
TimerForce(dmxSyncTimer);
}
static void
dmxSyncWakeupHandler(void *blockData, int result)
{
}
/** 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 \a 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)
free(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);
}
}
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