Added experimental code to handle QueryPerformanceCounter leaping bug on Win32
git-svn-id: https://svn.pjsip.org/repos/pjproject/trunk@396 74dad513-b988-da41-8d7b-12977e46ad98
This commit is contained in:
Benny Prijono
parent
393e5f310b
commit
e2eea447d0
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@ -17,9 +17,23 @@
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#include <pj/os.h>
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#include <pj/assert.h>
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#include <pj/errno.h>
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#include <pj/log.h>
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#include <windows.h>
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#define THIS_FILE "os_timestamp_win32.c"
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#if 1
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# define TRACE_(x) PJ_LOG(3,x)
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#else
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# define TRACE_(x) ;
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#endif
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/////////////////////////////////////////////////////////////////////////////
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#if defined(PJ_TIMESTAMP_USE_RDTSC) && PJ_TIMESTAMP_USE_RDTSC!=0 && \
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defined(PJ_M_I386) && PJ_M_I386 != 0 && \
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defined(PJ_HAS_PENTIUM) && PJ_HAS_PENTIUM!=0 && \
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@ -94,9 +108,164 @@ PJ_DEF(pj_status_t) pj_get_timestamp_freq(pj_timestamp *freq)
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return PJ_SUCCESS;
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}
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/////////////////////////////////////////////////////////////////////////////
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#elif defined(PJ_TIMESTAMP_WIN32_USE_SAFE_QPC) && \
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PJ_TIMESTAMP_WIN32_USE_SAFE_QPC!=0
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/* Use safe QueryPerformanceCounter.
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* This implementation has some protection against bug in KB Q274323:
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* Performance counter value may unexpectedly leap forward
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* http://support.microsoft.com/default.aspx?scid=KB;EN-US;Q274323
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*
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* THIS SHOULD NOT BE USED YET AS IT DOESN'T HANDLE SYSTEM TIME
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* CHANGE.
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*/
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static pj_timestamp g_ts_freq;
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static pj_timestamp g_ts_base;
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static pj_int64_t g_time_base;
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PJ_DEF(pj_status_t) pj_get_timestamp(pj_timestamp *ts)
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{
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enum { MAX_RETRY = 10 };
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unsigned i;
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/* pj_get_timestamp_freq() must have been called before.
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* This is done when application called pj_init().
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*/
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pj_assert(g_ts_freq.u64 != 0);
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/* Retry QueryPerformanceCounter() until we're sure that the
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* value returned makes sense.
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*/
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i = 0;
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do {
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LARGE_INTEGER val;
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pj_int64_t counter64, time64, diff;
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pj_time_val time_now;
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/* Retrieve the counter */
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if (!QueryPerformanceCounter(&val))
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return PJ_RETURN_OS_ERROR(GetLastError());
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/* Regardless of the goodness of the value, we should put
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* the counter here, because normally application wouldn't
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* check the error result of this function.
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*/
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ts->u64 = val.QuadPart;
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/* Retrieve time */
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pj_gettimeofday(&time_now);
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/* Get the counter elapsed time in miliseconds */
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counter64 = (val.QuadPart - g_ts_base.u64) * 1000 / g_ts_freq.u64;
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/* Get the time elapsed in miliseconds.
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* We don't want to use PJ_TIME_VAL_MSEC() since it's using
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* 32bit calculation, which limits the maximum elapsed time
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* to around 49 days only.
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*/
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time64 = time_now.sec;
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time64 = time64 * 1000 + time_now.msec;
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//time64 = GetTickCount();
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/* It's good if the difference between two clocks are within
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* some compile time constant (default: 20ms, which to allow
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* context switch happen between QueryPerformanceCounter and
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* pj_gettimeofday()).
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*/
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diff = (time64 - g_time_base) - counter64;
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if (diff >= -20 && diff <= 20) {
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/* It's good */
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return PJ_SUCCESS;
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}
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++i;
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} while (i < MAX_RETRY);
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TRACE_((THIS_FILE, "QueryPerformanceCounter returned bad value"));
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return PJ_ETIMEDOUT;
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}
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static pj_status_t init_performance_counter(void)
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{
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LARGE_INTEGER val;
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pj_time_val time_base;
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pj_status_t status;
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/* Get the frequency */
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if (!QueryPerformanceFrequency(&val))
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return PJ_RETURN_OS_ERROR(GetLastError());
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g_ts_freq.u64 = val.QuadPart;
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/* Get the base timestamp */
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if (!QueryPerformanceCounter(&val))
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return PJ_RETURN_OS_ERROR(GetLastError());
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g_ts_base.u64 = val.QuadPart;
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/* Get the base time */
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status = pj_gettimeofday(&time_base);
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if (status != PJ_SUCCESS)
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return status;
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/* Convert time base to 64bit value in msec */
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g_time_base = time_base.sec;
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g_time_base = g_time_base * 1000 + time_base.msec;
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//g_time_base = GetTickCount();
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return PJ_SUCCESS;
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}
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PJ_DEF(pj_status_t) pj_get_timestamp_freq(pj_timestamp *freq)
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{
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if (g_ts_freq.u64 == 0) {
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enum { MAX_REPEAT = 10 };
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unsigned i;
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pj_status_t status;
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/* Make unellegant compiler happy */
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status = 0;
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/* Repeat initializing performance counter until we're sure
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* the base timing is correct. It is possible that the system
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* returns bad counter during this initialization!
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*/
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for (i=0; i<MAX_REPEAT; ++i) {
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pj_timestamp dummy;
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/* Init base time */
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status = init_performance_counter();
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if (status != PJ_SUCCESS)
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return status;
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/* Try the base time */
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status = pj_get_timestamp(&dummy);
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if (status == PJ_SUCCESS)
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break;
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}
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if (status != PJ_SUCCESS)
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return status;
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}
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freq->u64 = g_ts_freq.u64;
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return PJ_SUCCESS;
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}
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/////////////////////////////////////////////////////////////////////////////
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#else
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/*
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* Use QueryPerformanceCounter and QueryPerformanceFrequency.
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* This should be the default implementation to be used on Windows.
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*/
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PJ_DEF(pj_status_t) pj_get_timestamp(pj_timestamp *ts)
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{
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@ -120,5 +289,6 @@ PJ_DEF(pj_status_t) pj_get_timestamp_freq(pj_timestamp *freq)
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return PJ_SUCCESS;
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}
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#endif /* PJ_TIMESTAMP_USE_RDTSC */
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