[vlc-commits] commit: Win32: always use the performance timers (fix #3918) ( Rémi Denis-Courmont )
git at videolan.org
git at videolan.org
Mon Aug 2 19:45:02 CEST 2010
vlc | branch: master | Rémi Denis-Courmont <remi at remlab.net> | Mon Aug 2 20:43:19 2010 +0300| [ef61df309612786ed316534908978a2a9340e154] | committer: Rémi Denis-Courmont
Win32: always use the performance timers (fix #3918)
They may be inconsistent on broken multi-processor hardware. But the
system tick count is causing worse problems with power saving features.
> http://git.videolan.org/gitweb.cgi/vlc.git/?a=commit;h=ef61df309612786ed316534908978a2a9340e154
---
src/misc/mtime.c | 110 ++++-------------------------------------------------
1 files changed, 9 insertions(+), 101 deletions(-)
diff --git a/src/misc/mtime.c b/src/misc/mtime.c
index b85c7ef..940505d 100644
--- a/src/misc/mtime.c
+++ b/src/misc/mtime.c
@@ -221,112 +221,20 @@ mtime_t mdate( void )
/* Convert to microseconds */
res = date / 1000;
+
#elif defined( WIN32 ) || defined( UNDER_CE )
/* We don't need the real date, just the value of a high precision timer */
- static mtime_t freq = INT64_C(-1);
+ LARGE_INTEGER counter, freq;
+ if (!QueryPerformanceCounter (&counter)
+ || !QueryPerformanceFrequency (&freq))
+ abort();
- if( freq == INT64_C(-1) )
- {
- /* Extract from the Tcl source code:
- * (http://www.cs.man.ac.uk/fellowsd-bin/TIP/7.html)
- *
- * Some hardware abstraction layers use the CPU clock
- * in place of the real-time clock as a performance counter
- * reference. This results in:
- * - inconsistent results among the processors on
- * multi-processor systems.
- * - unpredictable changes in performance counter frequency
- * on "gearshift" processors such as Transmeta and
- * SpeedStep.
- * There seems to be no way to test whether the performance
- * counter is reliable, but a useful heuristic is that
- * if its frequency is 1.193182 MHz or 3.579545 MHz, it's
- * derived from a colorburst crystal and is therefore
- * the RTC rather than the TSC. If it's anything else, we
- * presume that the performance counter is unreliable.
- */
- LARGE_INTEGER buf;
-
- freq = ( QueryPerformanceFrequency( &buf ) &&
- (buf.QuadPart == INT64_C(1193182) || buf.QuadPart == INT64_C(3579545) ) )
- ? buf.QuadPart : 0;
-
-#if defined( WIN32 )
- /* on windows 2000, XP and Vista detect if there are two
- cores there - that makes QueryPerformanceFrequency in
- any case not trustable?
- (may also be true, for single cores with adaptive
- CPU frequency and active power management?)
- */
- HINSTANCE h_Kernel32 = LoadLibrary(_T("kernel32.dll"));
- if(h_Kernel32)
- {
- void WINAPI (*pf_GetSystemInfo)(LPSYSTEM_INFO);
- pf_GetSystemInfo = (void WINAPI (*)(LPSYSTEM_INFO))
- GetProcAddress(h_Kernel32, _T("GetSystemInfo"));
- if(pf_GetSystemInfo)
- {
- SYSTEM_INFO system_info;
- pf_GetSystemInfo(&system_info);
- if(system_info.dwNumberOfProcessors > 1)
- freq = 0;
- }
- FreeLibrary(h_Kernel32);
- }
-#endif
- }
+ /* Convert to from (1/freq) to microsecond resolution */
+ /* We need to split the division to avoid 63-bits overflow */
+ lldiv_t d = lldiv (counter.QuadPart, freq.QuadPart);
- if( freq != 0 )
- {
- LARGE_INTEGER counter;
- QueryPerformanceCounter (&counter);
-
- /* Convert to from (1/freq) to microsecond resolution */
- /* We need to split the division to avoid 63-bits overflow */
- lldiv_t d = lldiv (counter.QuadPart, freq);
+ res = (d.quot * 1000000) + ((d.rem * 1000000) / freq.QuadPart);
- res = (d.quot * 1000000) + ((d.rem * 1000000) / freq);
- }
- else
- {
- /* Fallback on timeGetTime() which has a millisecond resolution
- * (actually, best case is about 5 ms resolution)
- * timeGetTime() only returns a DWORD thus will wrap after
- * about 49.7 days so we try to detect the wrapping. */
-
- static CRITICAL_SECTION date_lock;
- static mtime_t i_previous_time = INT64_C(-1);
- static int i_wrap_counts = -1;
-
- if( i_wrap_counts == -1 )
- {
- /* Initialization */
-#if defined( WIN32 )
- i_previous_time = INT64_C(1000) * timeGetTime();
-#else
- i_previous_time = INT64_C(1000) * GetTickCount();
-#endif
- InitializeCriticalSection( &date_lock );
- i_wrap_counts = 0;
- }
-
- EnterCriticalSection( &date_lock );
-#if defined( WIN32 )
- res = INT64_C(1000) *
- (i_wrap_counts * INT64_C(0x100000000) + timeGetTime());
-#else
- res = INT64_C(1000) *
- (i_wrap_counts * INT64_C(0x100000000) + GetTickCount());
-#endif
- if( i_previous_time > res )
- {
- /* Counter wrapped */
- i_wrap_counts++;
- res += INT64_C(0x100000000) * 1000;
- }
- i_previous_time = res;
- LeaveCriticalSection( &date_lock );
- }
#elif defined(USE_APPLE_MACH)
/* The version that should be used, if it was cancelable */
pthread_once(&mtime_timebase_info_once, mtime_init_timebase);
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