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systemclock: use preformance counters on windows

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Based on clock implementation by Håvard Graff <havard.graff@tandberg.com>

Try to get the time on windows using the performance counters. These have a much
higher resolution and accuracy than the regular getcurrenttime(). Be careful to
fall back to regular getcurrenttime() or posix clocks when performance counters
are not available.
This commit is contained in:
Wim Taymans 2009-08-28 17:02:30 +02:00
parent 7c054f5f53
commit e54e5eb9bb
1 changed files with 63 additions and 19 deletions
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82
gst/gstsystemclock.c
View file

@ -46,6 +46,12 @@
#include <errno.h>
#ifdef G_OS_WIN32
# define WIN32_LEAN_AND_MEAN /* prevents from including too many things */
# include <windows.h> /* QueryPerformance* stuff */
# undef WIN32_LEAN_AND_MEAN
#endif /* G_OS_WIN32 */
/* Define this to get some extra debug about jitter from each clock_wait */
#undef WAIT_DEBUGGING
@ -55,6 +61,11 @@ struct _GstSystemClockPrivate
GstPoll *timer;
gint wakeup_count; /* the number of entries with a pending wakeup */
gboolean async_wakeup; /* if the wakeup was because of a async list change */
#ifdef G_OS_WIN32
LARGE_INTEGER start;
LARGE_INTEGER frequency;
#endif /* G_OS_WIN32 */
};
#define GST_SYSTEM_CLOCK_GET_PRIVATE(obj) \
@ -155,6 +166,14 @@ gst_system_clock_init (GstSystemClock * clock)
clock->priv->clock_type = DEFAULT_CLOCK_TYPE;
clock->priv->timer = gst_poll_new_timer ();
#ifdef G_OS_WIN32
QueryPerformanceFrequency (&clock->priv->frequency);
/* can be 0 if the hardware does not have hardware support */
if (clock->priv->frequency.QuadPart != 0)
/* we take a base time so that time starts from 0 to ease debugging */
QueryPerformanceCounter (&clock->priv->start);
#endif /* G_OS_WIN32 */
#if 0
/* Uncomment this to start the async clock thread straight away */
GST_OBJECT_LOCK (clock);
@ -459,42 +478,67 @@ clock_type_to_posix_id (GstClockType clock_type)
static GstClockTime
gst_system_clock_get_internal_time (GstClock * clock)
{
#ifdef HAVE_POSIX_TIMERS
GstSystemClock *sysclock = GST_SYSTEM_CLOCK_CAST (clock);
clockid_t ptype;
struct timespec ts;
#ifdef G_OS_WIN32
if (clock->priv->frequency.QuadPart != 0) {
GstSystemClock *sysclock = GST_SYSTEM_CLOCK_CAST (clock);
LARGE_INTEGER now;
ptype = clock_type_to_posix_id (sysclock->priv->clock_type);
/* we prefer the highly accurate performance counters on windows */
QueryPerformanceCounter (&now);
if (G_UNLIKELY (clock_gettime (ptype, &ts)))
return GST_CLOCK_TIME_NONE;
return gst_util_uint64_scale (now.QuadPart - sysclock->priv->start.QuadPart,
GST_SECOND, sysclock->priv->frequency.QuadPart);
} else
#endif /* G_OS_WIN32 */
#if !defined HAVE_POSIX_TIMERS
{
GTimeVal timeval;
return GST_TIMESPEC_TO_TIME (ts);
g_get_current_time (&timeval);
return GST_TIMEVAL_TO_TIME (timeval);
}
#else
GTimeVal timeval;
{
GstSystemClock *sysclock = GST_SYSTEM_CLOCK_CAST (clock);
clockid_t ptype;
struct timespec ts;
g_get_current_time (&timeval);
ptype = clock_type_to_posix_id (sysclock->priv->clock_type);
return GST_TIMEVAL_TO_TIME (timeval);
if (G_UNLIKELY (clock_gettime (ptype, &ts)))
return GST_CLOCK_TIME_NONE;
return GST_TIMESPEC_TO_TIME (ts);
}
#endif
}
static guint64
gst_system_clock_get_resolution (GstClock * clock)
{
#ifdef G_OS_WIN32
if (clock->priv->frequency.QuadPart != 0) {
return GST_SECOND / sysclock->priv->frequency.QuadPart;
} else
#endif /* G_OS_WIN32 */
#ifdef HAVE_POSIX_TIMERS
GstSystemClock *sysclock = GST_SYSTEM_CLOCK_CAST (clock);
clockid_t ptype;
struct timespec ts;
{
GstSystemClock *sysclock = GST_SYSTEM_CLOCK_CAST (clock);
clockid_t ptype;
struct timespec ts;
ptype = clock_type_to_posix_id (sysclock->priv->clock_type);
ptype = clock_type_to_posix_id (sysclock->priv->clock_type);
if (G_UNLIKELY (clock_getres (ptype, &ts)))
return GST_CLOCK_TIME_NONE;
if (G_UNLIKELY (clock_getres (ptype, &ts)))
return GST_CLOCK_TIME_NONE;
return GST_TIMESPEC_TO_TIME (ts);
return GST_TIMESPEC_TO_TIME (ts);
}
#else
return 1 * GST_USECOND;
{
return 1 * GST_USECOND;
}
#endif
}