corysanin/tubestation
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Bug 1004923 part 8 - Add PRMJ_NowInit, call QueryPerformanceFrequency only once. r=njn

Browse Source
This commit is contained in:
Jan de Mooij
2014-05-05 10:33:29 +02:00
parent 58098c9345
commit 3fef6bff77
3 changed files with 45 additions and 40 deletions
Download Patch File Download Diff File Expand all files Collapse all files

69
js/src/prmjtime.cpp
View File

@@ -105,52 +105,52 @@ static CalibrationData calibration = { 0 };
static void
NowCalibrate()
{
if (calibration.freq == 0.0) {
// According to the documentation, QueryPerformanceFrequency will never
// return false or return a non-zero frequency on systems that run
// Windows XP or later.
LARGE_INTEGER liFreq;
DebugOnly<BOOL> res = QueryPerformanceFrequency(&liFreq);
MOZ_ASSERT(res);
calibration.freq = double(liFreq.QuadPart);
MOZ_ASSERT(calibration.freq > 0.0);
}
if (calibration.freq > 0.0) {
// By wrapping a timeBegin/EndPeriod pair of calls around this loop,
// the loop seems to take much less time (1 ms vs 15ms) on Vista.
timeBeginPeriod(1);
FILETIME ft, ftStart;
GetSystemTimeAsFileTime(&ftStart);
do {
GetSystemTimeAsFileTime(&ft);
} while (memcmp(&ftStart,&ft, sizeof(ft)) == 0);
timeEndPeriod(1);
MOZ_ASSERT(calibration.freq > 0);
LARGE_INTEGER now;
QueryPerformanceCounter(&now);
// By wrapping a timeBegin/EndPeriod pair of calls around this loop,
// the loop seems to take much less time (1 ms vs 15ms) on Vista.
timeBeginPeriod(1);
FILETIME ft, ftStart;
GetSystemTimeAsFileTime(&ftStart);
do {
GetSystemTimeAsFileTime(&ft);
} while (memcmp(&ftStart,&ft, sizeof(ft)) == 0);
timeEndPeriod(1);
calibration.offset = FileTimeToUnixMicroseconds(ft);
calibration.timer_offset = double(now.QuadPart);
LARGE_INTEGER now;
QueryPerformanceCounter(&now);
calibration.calibrated = true;
}
calibration.offset = FileTimeToUnixMicroseconds(ft);
calibration.timer_offset = double(now.QuadPart);
calibration.calibrated = true;
}
#define CALIBRATIONLOCK_SPINCOUNT 0
#define DATALOCK_SPINCOUNT 4096
#define LASTLOCK_SPINCOUNT 4096
#ifdef JS_THREADSAFE
static PRStatus
NowInit(void)
void
PRMJ_NowInit()
{
memset(&calibration, 0, sizeof(calibration));
NowCalibrate();
// According to the documentation, QueryPerformanceFrequency will never
// return false or return a non-zero frequency on systems that run
// Windows XP or later. Also, the frequency is fixed so we only have to
// query it once.
LARGE_INTEGER liFreq;
DebugOnly<BOOL> res = QueryPerformanceFrequency(&liFreq);
MOZ_ASSERT(res);
calibration.freq = double(liFreq.QuadPart);
MOZ_ASSERT(calibration.freq > 0.0);
#ifdef JS_THREADSAFE
InitializeCriticalSectionAndSpinCount(&calibration.calibration_lock, CALIBRATIONLOCK_SPINCOUNT);
InitializeCriticalSectionAndSpinCount(&calibration.data_lock, DATALOCK_SPINCOUNT);
return PR_SUCCESS;
#endif
}
#ifdef JS_THREADSAFE
void
PRMJ_NowShutdown()
{
@@ -163,8 +163,6 @@ PRMJ_NowShutdown()
#define MUTEX_UNLOCK(m) LeaveCriticalSection(m)
#define MUTEX_SETSPINCOUNT(m, c) SetCriticalSectionSpinCount((m),(c))
static PRCallOnceType calibrationOnce = { 0 };
#else
#define MUTEX_LOCK(m)
@@ -201,11 +199,6 @@ PRMJ_Now()
bool calibrated = false;
bool needsCalibration = false;
double cachedOffset = 0.0;
/* For non threadsafe platforms, NowInit is not necessary */
#ifdef JS_THREADSAFE
PR_CallOnce(&calibrationOnce, NowInit);
#endif
while (true) {
if (!calibration.calibrated || needsCalibration) {
MUTEX_LOCK(&calibration.calibration_lock);