/* * tclWinTime.c -- * * Contains Windows specific versions of Tcl functions that obtain time * values from the operating system. * * Copyright © 1995-1998 Sun Microsystems, Inc. * * See the file "license.terms" for information on usage and redistribution of * this file, and for a DISCLAIMER OF ALL WARRANTIES. */ #include "tclInt.h" /* * Number of samples over which to estimate the performance counter. */ #define SAMPLES 64 /* * Data for managing high-resolution timers. */ typedef struct { CRITICAL_SECTION cs; /* Mutex guarding this structure. */ int initialized; /* Flag == 1 if this structure is * initialized. */ int perfCounterAvailable; /* Flag == 1 if the hardware has a performance * counter. */ DWORD calibrationInterv; /* Calibration interval in seconds (start 1 * sec) */ HANDLE calibrationThread; /* Handle to the thread that keeps the virtual * clock calibrated. */ HANDLE readyEvent; /* System event used to trigger the requesting * thread when the clock calibration procedure * is initialized for the first time. */ HANDLE exitEvent; /* Event to signal out of an exit handler to * tell the calibration loop to terminate. */ LARGE_INTEGER nominalFreq; /* Nominal frequency of the system performance * counter, that is, the value returned from * QueryPerformanceFrequency. */ /* * The following values are used for calculating virtual time. Virtual * time is always equal to: * lastFileTime + (current perf counter - lastCounter) * * 10000000 / curCounterFreq * and lastFileTime and lastCounter are updated any time that virtual time * is returned to a caller. */ ULARGE_INTEGER fileTimeLastCall; LARGE_INTEGER perfCounterLastCall; LARGE_INTEGER curCounterFreq; LARGE_INTEGER posixEpoch; /* Posix epoch expressed as 100-ns ticks since * the windows epoch. */ /* * Data used in developing the estimate of performance counter frequency */ unsigned long long fileTimeSample[SAMPLES]; /* Last 64 samples of system time. */ long long perfCounterSample[SAMPLES]; /* Last 64 samples of performance counter. */ int sampleNo; /* Current sample number. */ } TimeInfo; static TimeInfo timeInfo = { { NULL, 0, 0, NULL, NULL, 0 }, 0, 0, 1, (HANDLE) NULL, (HANDLE) NULL, (HANDLE) NULL, #if defined(HAVE_CAST_TO_UNION) && !defined(__cplusplus) (LARGE_INTEGER) (long long) 0, (ULARGE_INTEGER) (DWORDLONG) 0, (LARGE_INTEGER) (long long) 0, (LARGE_INTEGER) (long long) 0, (LARGE_INTEGER) (long long) 0, #else {0, 0}, {0, 0}, {0, 0}, {0, 0}, {0, 0}, #endif { 0 }, { 0 }, 0 }; /* * Scale to convert wide click values from the TclpGetWideClicks native * resolution to microsecond resolution and back. */ static struct { int initialized; /* 1 if initialized, 0 otherwise */ int perfCounter; /* 1 if performance counter usable for wide * clicks */ double microsecsScale; /* Denominator scale between clock / microsecs */ } wideClick = {0, 0, 0.0}; /* * Declarations for functions defined later in this file. */ static void StopCalibration(void *clientData); static DWORD WINAPI CalibrationThread(LPVOID arg); static void UpdateTimeEachSecond(void); static void ResetCounterSamples(unsigned long long fileTime, long long perfCounter, long long perfFreq); static long long AccumulateSample(long long perfCounter, unsigned long long fileTime); static void NativeScaleTime(Tcl_Time* timebuf, void *clientData); static long long NativeGetMicroseconds(void); static void NativeGetTime(Tcl_Time* timebuf, void *clientData); /* * TIP #233 (Virtualized Time): Data for the time hooks, if any. */ Tcl_GetTimeProc *tclGetTimeProcPtr = NativeGetTime; Tcl_ScaleTimeProc *tclScaleTimeProcPtr = NativeScaleTime; void *tclTimeClientData = NULL; /* * Inlined version of Tcl_GetTime. */ static inline void GetTime( Tcl_Time *timePtr) { tclGetTimeProcPtr(timePtr, tclTimeClientData); } static inline int IsTimeNative(void) { return tclGetTimeProcPtr == NativeGetTime; } /* *---------------------------------------------------------------------- * * TclpGetSeconds -- * * This procedure returns the number of seconds from the epoch. On most * Unix systems the epoch is Midnight Jan 1, 1970 GMT. * * Results: * Number of seconds from the epoch. * * Side effects: * None. * *---------------------------------------------------------------------- */ unsigned long long TclpGetSeconds(void) { long long usecSincePosixEpoch; /* * Try to use high resolution timer */ if (IsTimeNative() && (usecSincePosixEpoch = NativeGetMicroseconds())) { return usecSincePosixEpoch / 1000000; } else { Tcl_Time t; GetTime(&t); return (unsigned long long)(unsigned long) t.sec; } } /* *---------------------------------------------------------------------- * * TclpGetClicks -- * * This procedure returns a value that represents the highest resolution * clock available on the system. There are no guarantees on what the * resolution will be. In Tcl we will call this value a "click". The * start time is also system dependent. * * Results: * Number of clicks from some start time. * * Side effects: * None. * *---------------------------------------------------------------------- */ unsigned long long TclpGetClicks(void) { long long usecSincePosixEpoch; /* * Try to use high resolution timer. */ if (IsTimeNative() && (usecSincePosixEpoch = NativeGetMicroseconds())) { return (Tcl_WideUInt) usecSincePosixEpoch; } else { /* * Use the Tcl_GetTime abstraction to get the time in microseconds, as * nearly as we can, and return it. */ Tcl_Time now; /* Current Tcl time */ GetTime(&now); return ((unsigned long long)(now.sec)*1000000ULL) + (unsigned long long)(now.usec); } } /* *---------------------------------------------------------------------- * * TclpGetWideClicks -- * * This procedure returns a WideInt value that represents the highest * resolution clock in microseconds available on the system. * * Results: * Number of microseconds (from some start time). * * Side effects: * This should be used for time-delta resp. for measurement purposes * only, because on some platforms can return microseconds from some * start time (not from the epoch). * *---------------------------------------------------------------------- */ long long TclpGetWideClicks(void) { LARGE_INTEGER curCounter; if (!wideClick.initialized) { LARGE_INTEGER perfCounterFreq; /* * The frequency of the performance counter is fixed at system boot and * is consistent across all processors. Therefore, the frequency need * only be queried upon application initialization. */ if (QueryPerformanceFrequency(&perfCounterFreq)) { wideClick.perfCounter = 1; wideClick.microsecsScale = 1000000.0 / perfCounterFreq.QuadPart; } else { /* fallback using microseconds */ wideClick.perfCounter = 0; wideClick.microsecsScale = 1; } wideClick.initialized = 1; } if (wideClick.perfCounter) { if (QueryPerformanceCounter(&curCounter)) { return (long long)curCounter.QuadPart; } /* fallback using microseconds */ wideClick.perfCounter = 0; wideClick.microsecsScale = 1; return TclpGetMicroseconds(); } else { return TclpGetMicroseconds(); } } /* *---------------------------------------------------------------------- * * TclpWideClickInMicrosec -- * * This procedure return scale to convert wide click values from the * TclpGetWideClicks native resolution to microsecond resolution * and back. * * Results: * 1 click in microseconds as double. * * Side effects: * None. * *---------------------------------------------------------------------- */ double TclpWideClickInMicrosec(void) { if (!wideClick.initialized) { (void) TclpGetWideClicks(); /* initialize */ } return wideClick.microsecsScale; } /* *---------------------------------------------------------------------- * * TclpGetMicroseconds -- * * This procedure returns a WideInt value that represents the highest * resolution clock in microseconds available on the system. * * Results: * Number of microseconds (from the epoch). * * Side effects: * None. * *---------------------------------------------------------------------- */ long long TclpGetMicroseconds(void) { long long usecSincePosixEpoch; /* * Try to use high resolution timer. */ if (IsTimeNative() && (usecSincePosixEpoch = NativeGetMicroseconds())) { return usecSincePosixEpoch; } else { /* * Use the Tcl_GetTime abstraction to get the time in microseconds, as * nearly as we can, and return it. */ Tcl_Time now; GetTime(&now); return (((long long) now.sec) * 1000000) + now.usec; } } /* *---------------------------------------------------------------------- * * Tcl_GetTime -- * * Gets the current system time in seconds and microseconds since the * beginning of the epoch: 00:00 UCT, January 1, 1970. * * Results: * Returns the current time in timePtr. * * Side effects: * On the first call, initializes a set of static variables to keep track * of the base value of the performance counter, the corresponding wall * clock (obtained through ftime) and the frequency of the performance * counter. Also spins a thread whose function is to wake up periodically * and monitor these values, adjusting them as necessary to correct for * drift in the performance counter's oscillator. * *---------------------------------------------------------------------- */ void Tcl_GetTime( Tcl_Time *timePtr) /* Location to store time information. */ { long long usecSincePosixEpoch; /* * Try to use high resolution timer. */ if (IsTimeNative() && (usecSincePosixEpoch = NativeGetMicroseconds())) { timePtr->sec = (long) (usecSincePosixEpoch / 1000000); timePtr->usec = (unsigned long) (usecSincePosixEpoch % 1000000); } else { GetTime(timePtr); } } /* *---------------------------------------------------------------------- * * NativeScaleTime -- * * TIP #233: Scale from virtual time to the real-time. For native scaling * the relationship is 1:1 and nothing has to be done. * * Results: * Scales the time in timePtr. * * Side effects: * See above. * *---------------------------------------------------------------------- */ static void NativeScaleTime( TCL_UNUSED(Tcl_Time *), TCL_UNUSED(void *)) { /* * Native scale is 1:1. Nothing is done. */ } /* *---------------------------------------------------------------------- * * IsPerfCounterAvailable -- * * Tests whether the performance counter is available, which is a gnarly * problem on 32-bit systems. Also retrieves the nominal frequency of the * performance counter. * * Results: * 1 if the counter is available, 0 if not. * * Side effects: * Updates fields of the timeInfo global. Make sure you hold the lock * before calling this. * *---------------------------------------------------------------------- */ static inline int IsPerfCounterAvailable(void) { timeInfo.perfCounterAvailable = QueryPerformanceFrequency(&timeInfo.nominalFreq); /* * 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. * * A sloppier but serviceable heuristic is that the RTC crystal is * normally less than 15 MHz while the TSC crystal is virtually assured to * be greater than 100 MHz. Since Win98SE appears to fiddle with the * definition of the perf counter frequency (perhaps in an attempt to * calibrate the clock?), we use the latter rule rather than an exact * match. * * We also assume (perhaps questionably) that the vendors have gotten * their act together on Win64, so bypass all this rubbish on that * platform. */ #if !defined(_WIN64) if (timeInfo.perfCounterAvailable && /* * The following lines would do an exact match on crystal * frequency: * * timeInfo.nominalFreq.QuadPart != (long long) 1193182 && * timeInfo.nominalFreq.QuadPart != (long long) 3579545 && */ timeInfo.nominalFreq.QuadPart > (long long) 15000000) { /* * As an exception, if every logical processor on the system is on the * same chip, we use the performance counter anyway, presuming that * everyone's TSC is locked to the same oscillator. */ SYSTEM_INFO systemInfo; int regs[4]; GetSystemInfo(&systemInfo); if (TclWinCPUID(0, regs) == TCL_OK && regs[1] == 0x756E6547 /* "Genu" */ && regs[3] == 0x49656E69 /* "ineI" */ && regs[2] == 0x6C65746E /* "ntel" */ && TclWinCPUID(1, regs) == TCL_OK && ((regs[0]&0x00000F00) == 0x00000F00 /* Pentium 4 */ || ((regs[0] & 0x00F00000) /* Extended family */ && (regs[3] & 0x10000000))) /* Hyperthread */ && (((regs[1]&0x00FF0000) >> 16)/* CPU count */ == (int)systemInfo.dwNumberOfProcessors)) { timeInfo.perfCounterAvailable = TRUE; } else { timeInfo.perfCounterAvailable = FALSE; } } #endif /* above code is Win32 only */ return timeInfo.perfCounterAvailable; } /* *---------------------------------------------------------------------- * * NativeGetMicroseconds -- * * Gets the current system time in microseconds since the beginning * of the epoch: 00:00 UCT, January 1, 1970. * * Results: * Returns the wide integer with number of microseconds from the epoch, or * 0 if high resolution timer is not available. * * Side effects: * On the first call, initializes a set of static variables to keep track * of the base value of the performance counter, the corresponding wall * clock (obtained through ftime) and the frequency of the performance * counter. Also spins a thread whose function is to wake up periodically * and monitor these values, adjusting them as necessary to correct for * drift in the performance counter's oscillator. * *---------------------------------------------------------------------- */ static inline long long NativeCalc100NsTicks( ULONGLONG fileTimeLastCall, LONGLONG perfCounterLastCall, LONGLONG curCounterFreq, LONGLONG curCounter) { return fileTimeLastCall + ((curCounter - perfCounterLastCall) * 10000000 / curCounterFreq); } static long long NativeGetMicroseconds(void) { /* * Initialize static storage on the first trip through. * * Note: Outer check for 'initialized' is a performance win since it * avoids an extra mutex lock in the common case. */ if (!timeInfo.initialized) { TclpInitLock(); if (!timeInfo.initialized) { timeInfo.posixEpoch.LowPart = 0xD53E8000; timeInfo.posixEpoch.HighPart = 0x019DB1DE; /* * If the performance counter is available, start a thread to * calibrate it. */ if (IsPerfCounterAvailable()) { DWORD id; InitializeCriticalSection(&timeInfo.cs); timeInfo.readyEvent = CreateEventW(NULL, FALSE, FALSE, NULL); timeInfo.exitEvent = CreateEventW(NULL, FALSE, FALSE, NULL); timeInfo.calibrationThread = CreateThread(NULL, 256, CalibrationThread, (LPVOID) NULL, 0, &id); SetThreadPriority(timeInfo.calibrationThread, THREAD_PRIORITY_HIGHEST); /* * Wait for the thread just launched to start running, and * create an exit handler that kills it so that it doesn't * outlive unloading tclXX.dll */ WaitForSingleObject(timeInfo.readyEvent, INFINITE); CloseHandle(timeInfo.readyEvent); Tcl_CreateExitHandler(StopCalibration, NULL); } timeInfo.initialized = TRUE; } TclpInitUnlock(); } if (timeInfo.perfCounterAvailable && timeInfo.curCounterFreq.QuadPart!=0) { /* * Query the performance counter and use it to calculate the current * time. */ ULONGLONG fileTimeLastCall; LONGLONG perfCounterLastCall, curCounterFreq; /* Copy with current data of calibration * cycle. */ LARGE_INTEGER curCounter; /* Current performance counter. */ QueryPerformanceCounter(&curCounter); /* * Hold time section locked as short as possible */ EnterCriticalSection(&timeInfo.cs); fileTimeLastCall = timeInfo.fileTimeLastCall.QuadPart; perfCounterLastCall = timeInfo.perfCounterLastCall.QuadPart; curCounterFreq = timeInfo.curCounterFreq.QuadPart; LeaveCriticalSection(&timeInfo.cs); /* * If calibration cycle occurred after we get curCounter */ if (curCounter.QuadPart <= perfCounterLastCall) { /* * Calibrated file-time is saved from posix in 100-ns ticks */ return fileTimeLastCall / 10; } /* * If it appears to be more than 1.1 seconds since the last trip * through the calibration loop, the performance counter may have * jumped forward. (See MSDN Knowledge Base article Q274323 for a * description of the hardware problem that makes this test * necessary.) If the counter jumps, we don't want to use it directly. * Instead, we must return system time. Eventually, the calibration * loop should recover. */ if (curCounter.QuadPart - perfCounterLastCall < 11 * curCounterFreq * timeInfo.calibrationInterv / 10) { /* * Calibrated file-time is saved from posix in 100-ns ticks. */ return NativeCalc100NsTicks(fileTimeLastCall, perfCounterLastCall, curCounterFreq, curCounter.QuadPart) / 10; } } /* * High resolution timer is not available. */ return 0; } /* *---------------------------------------------------------------------- * * NativeGetTime -- * * TIP #233: Gets the current system time in seconds and microseconds * since the beginning of the epoch: 00:00 UCT, January 1, 1970. * * Results: * Returns the current time in timePtr. * * Side effects: * See NativeGetMicroseconds for more information. * *---------------------------------------------------------------------- */ static void NativeGetTime( Tcl_Time *timePtr, TCL_UNUSED(void *)) { long long usecSincePosixEpoch; /* * Try to use high resolution timer. */ usecSincePosixEpoch = NativeGetMicroseconds(); if (usecSincePosixEpoch) { timePtr->sec = (long) (usecSincePosixEpoch / 1000000); timePtr->usec = (unsigned long) (usecSincePosixEpoch % 1000000); } else { /* * High resolution timer is not available. Just use ftime. */ struct _timeb t; _ftime(&t); timePtr->sec = (long) t.time; timePtr->usec = t.millitm * 1000; } } /* *---------------------------------------------------------------------- * * StopCalibration -- * * Turns off the calibration thread in preparation for exiting the * process. * * Results: * None. * * Side effects: * Sets the 'exitEvent' event in the 'timeInfo' structure to ask the * thread in question to exit, and waits for it to do so. * *---------------------------------------------------------------------- */ void TclWinResetTimerResolution(void); static void StopCalibration( TCL_UNUSED(void *)) { SetEvent(timeInfo.exitEvent); /* * If Tcl_Finalize was called from DllMain, the calibration thread is in a * paused state so we need to timeout and continue. */ WaitForSingleObject(timeInfo.calibrationThread, 100); CloseHandle(timeInfo.exitEvent); CloseHandle(timeInfo.calibrationThread); } /* *---------------------------------------------------------------------- * * CalibrationThread -- * * Thread that manages calibration of the hi-resolution time derived from * the performance counter, to keep it synchronized with the system * clock. * * Parameters: * arg - Client data from the CreateThread call. This parameter points to * the static TimeInfo structure. * * Return value: * None. This thread embeds an infinite loop. * * Side effects: * At an interval of 1s, this thread performs virtual time discipline. * * Note: When this thread is entered, TclpInitLock has been called to * safeguard the static storage. There is therefore no synchronization in the * body of this procedure. * *---------------------------------------------------------------------- */ static DWORD WINAPI CalibrationThread( TCL_UNUSED(LPVOID)) { FILETIME curFileTime; DWORD waitResult; /* * Get initial system time and performance counter. */ GetSystemTimeAsFileTime(&curFileTime); QueryPerformanceCounter(&timeInfo.perfCounterLastCall); QueryPerformanceFrequency(&timeInfo.curCounterFreq); timeInfo.fileTimeLastCall.LowPart = curFileTime.dwLowDateTime; timeInfo.fileTimeLastCall.HighPart = curFileTime.dwHighDateTime; /* * Calibrated file-time will be saved from posix in 100-ns ticks. */ timeInfo.fileTimeLastCall.QuadPart -= timeInfo.posixEpoch.QuadPart; ResetCounterSamples(timeInfo.fileTimeLastCall.QuadPart, timeInfo.perfCounterLastCall.QuadPart, timeInfo.curCounterFreq.QuadPart); /* * Wake up the calling thread. When it wakes up, it will release the * initialization lock. */ SetEvent(timeInfo.readyEvent); /* * Run the calibration once a second. */ while (timeInfo.perfCounterAvailable) { /* * If the exitEvent is set, break out of the loop. */ waitResult = WaitForSingleObjectEx(timeInfo.exitEvent, 1000, FALSE); if (waitResult == WAIT_OBJECT_0) { break; } UpdateTimeEachSecond(); } return (DWORD) 0; } /* *---------------------------------------------------------------------- * * UpdateTimeEachSecond -- * * Callback from the waitable timer in the clock calibration thread that * updates system time. * * Parameters: * info - Pointer to the static TimeInfo structure * * Results: * None. * * Side effects: * Performs virtual time calibration discipline. * *---------------------------------------------------------------------- */ static void UpdateTimeEachSecond(void) { LARGE_INTEGER curPerfCounter; /* Current value returned from * QueryPerformanceCounter. */ FILETIME curSysTime; /* Current system time. */ static LARGE_INTEGER lastFileTime; /* File time of the previous calibration */ LARGE_INTEGER curFileTime; /* File time at the time this callback was * scheduled. */ long long estFreq; /* Estimated perf counter frequency. */ long long vt0; /* Tcl time right now. */ long long vt1; /* Tcl time one second from now. */ long long tdiff; /* Difference between system clock and Tcl * time. */ long long driftFreq; /* Frequency needed to drift virtual time into * step over 1 second. */ /* * Sample performance counter and system time (from posix epoch). */ GetSystemTimeAsFileTime(&curSysTime); curFileTime.LowPart = curSysTime.dwLowDateTime; curFileTime.HighPart = curSysTime.dwHighDateTime; curFileTime.QuadPart -= timeInfo.posixEpoch.QuadPart; /* * If calibration still not needed (check for possible time switch) */ if (curFileTime.QuadPart > lastFileTime.QuadPart && curFileTime.QuadPart < lastFileTime.QuadPart + (timeInfo.calibrationInterv * 10000000)) { /* * Look again in next one second. */ return; } QueryPerformanceCounter(&curPerfCounter); lastFileTime.QuadPart = curFileTime.QuadPart; /* * We devide by timeInfo.curCounterFreq.QuadPart in several places. That * value should always be positive on a correctly functioning system. But * it is good to be defensive about such matters. So if something goes * wrong and the value does goes to zero, we clear the * timeInfo.perfCounterAvailable in order to cause the calibration thread * to shut itself down, then return without additional processing. */ if (timeInfo.curCounterFreq.QuadPart == 0){ timeInfo.perfCounterAvailable = 0; return; } /* * Several things may have gone wrong here that have to be checked for. * (1) The performance counter may have jumped. * (2) The system clock may have been reset. * * In either case, we'll need to reinitialize the circular buffer with * samples relative to the current system time and the NOMINAL performance * frequency (not the actual, because the actual has probably run slow in * the first case). Our estimated frequency will be the nominal frequency. * * Store the current sample into the circular buffer of samples, and * estimate the performance counter frequency. */ estFreq = AccumulateSample(curPerfCounter.QuadPart, (unsigned long long) curFileTime.QuadPart); /* * We want to adjust things so that time appears to be continuous. * Virtual file time, right now, is * * vt0 = 10000000 * (curPerfCounter - perfCounterLastCall) * / curCounterFreq * + fileTimeLastCall * * Ideally, we would like to drift the clock into place over a period of 2 * sec, so that virtual time 2 sec from now will be * * vt1 = 20000000 + curFileTime * * The frequency that we need to use to drift the counter back into place * is estFreq * 20000000 / (vt1 - vt0) */ vt0 = NativeCalc100NsTicks(timeInfo.fileTimeLastCall.QuadPart, timeInfo.perfCounterLastCall.QuadPart, timeInfo.curCounterFreq.QuadPart, curPerfCounter.QuadPart); /* * If we've gotten more than a second away from system time, then drifting * the clock is going to be pretty hopeless. Just let it jump. Otherwise, * compute the drift frequency and fill in everything. */ tdiff = vt0 - curFileTime.QuadPart; if (tdiff > 10000000 || tdiff < -10000000) { /* * Jump to current system time, use curent estimated frequency. */ vt0 = curFileTime.QuadPart; } else { /* * Calculate new frequency and estimate drift to the next second. */ vt1 = 20000000 + curFileTime.QuadPart; driftFreq = (estFreq * 20000000 / (vt1 - vt0)); /* * Avoid too large drifts (only half of the current difference), that * allows also be more accurate (aspire to the smallest tdiff), so * then we can prolong calibration interval by tdiff < 100000 */ driftFreq = timeInfo.curCounterFreq.QuadPart + (driftFreq - timeInfo.curCounterFreq.QuadPart) / 2; /* * Average between estimated, 2 current and 5 drifted frequencies, * (do the soft drifting as possible) */ estFreq = (estFreq + 2 * timeInfo.curCounterFreq.QuadPart + 5 * driftFreq) / 8; } /* * Avoid too large discrepancy from nominal frequency. */ if (estFreq > 1003 * timeInfo.nominalFreq.QuadPart / 1000) { estFreq = 1003 * timeInfo.nominalFreq.QuadPart / 1000; vt0 = curFileTime.QuadPart; } else if (estFreq < 997 * timeInfo.nominalFreq.QuadPart / 1000) { estFreq = 997 * timeInfo.nominalFreq.QuadPart / 1000; vt0 = curFileTime.QuadPart; } else if (vt0 != curFileTime.QuadPart) { /* * Be sure the clock ticks never backwards (avoid it by negative * drifting). Just compare native time (in 100-ns) before and * hereafter using new calibrated values) and do a small adjustment * (short time freeze). */ LARGE_INTEGER newPerfCounter; long long nt0, nt1; QueryPerformanceCounter(&newPerfCounter); nt0 = NativeCalc100NsTicks(timeInfo.fileTimeLastCall.QuadPart, timeInfo.perfCounterLastCall.QuadPart, timeInfo.curCounterFreq.QuadPart, newPerfCounter.QuadPart); nt1 = NativeCalc100NsTicks(vt0, curPerfCounter.QuadPart, estFreq, newPerfCounter.QuadPart); if (nt0 > nt1) { /* * Drifted backwards, try to compensate with new base. * * First adjust with a micro jump (short frozen time is * acceptable). */ vt0 += nt0 - nt1; /* * If drift unavoidable (e. g. we had a time switch), then reset * it. */ vt1 = vt0 - curFileTime.QuadPart; if (vt1 > 10000000 || vt1 < -10000000) { /* * Larger jump resp. shift relative new file-time. */ vt0 = curFileTime.QuadPart; } } } /* * In lock commit new values to timeInfo (hold lock as short as possible) */ EnterCriticalSection(&timeInfo.cs); /* * Grow calibration interval up to 10 seconds (if still precise enough) */ if (tdiff < -100000 || tdiff > 100000) { /* * Too long drift. Reset calibration interval to 1000 second. */ timeInfo.calibrationInterv = 1; } else if (timeInfo.calibrationInterv < 10) { timeInfo.calibrationInterv++; } timeInfo.fileTimeLastCall.QuadPart = vt0; timeInfo.curCounterFreq.QuadPart = estFreq; timeInfo.perfCounterLastCall.QuadPart = curPerfCounter.QuadPart; LeaveCriticalSection(&timeInfo.cs); } /* *---------------------------------------------------------------------- * * ResetCounterSamples -- * * Fills the sample arrays in 'timeInfo' with dummy values that will * yield the current performance counter and frequency. * * Results: * None. * * Side effects: * The array of samples is filled in so that it appears that there are * SAMPLES samples at one-second intervals, separated by precisely the * given frequency. * *---------------------------------------------------------------------- */ static void ResetCounterSamples( unsigned long long fileTime,/* Current file time */ long long perfCounter, /* Current performance counter */ long long perfFreq) /* Target performance frequency */ { int i; for (i = SAMPLES - 1 ; i >= 0 ; --i) { timeInfo.perfCounterSample[i] = perfCounter; timeInfo.fileTimeSample[i] = fileTime; perfCounter -= perfFreq; fileTime -= 10000000; } timeInfo.sampleNo = 0; } /* *---------------------------------------------------------------------- * * AccumulateSample -- * * Updates the circular buffer of performance counter and system time * samples with a new data point. * * Results: * None. * * Side effects: * The new data point replaces the oldest point in the circular buffer, * and the descriptive statistics are updated to accumulate the new * point. * * Several things may have gone wrong here that have to be checked for. * (1) The performance counter may have jumped. * (2) The system clock may have been reset. * * In either case, we'll need to reinitialize the circular buffer with samples * relative to the current system time and the NOMINAL performance frequency * (not the actual, because the actual has probably run slow in the first * case). */ static long long AccumulateSample( long long perfCounter, unsigned long long fileTime) { unsigned long long workFTSample; /* File time sample being removed from or * added to the circular buffer. */ long long workPCSample; /* Performance counter sample being removed * from or added to the circular buffer. */ unsigned long long lastFTSample; /* Last file time sample recorded */ long long lastPCSample; /* Last performance counter sample recorded */ long long FTdiff; /* Difference between last FT and current */ long long PCdiff; /* Difference between last PC and current */ long long estFreq; /* Estimated performance counter frequency */ /* * Test for jumps and reset the samples if we have one. */ if (timeInfo.sampleNo == 0) { lastPCSample = timeInfo.perfCounterSample[timeInfo.sampleNo + SAMPLES - 1]; lastFTSample = timeInfo.fileTimeSample[timeInfo.sampleNo + SAMPLES - 1]; } else { lastPCSample = timeInfo.perfCounterSample[timeInfo.sampleNo - 1]; lastFTSample = timeInfo.fileTimeSample[timeInfo.sampleNo - 1]; } PCdiff = perfCounter - lastPCSample; FTdiff = fileTime - lastFTSample; if (PCdiff < timeInfo.nominalFreq.QuadPart * 9 / 10 || PCdiff > timeInfo.nominalFreq.QuadPart * 11 / 10 || FTdiff < 9000000 || FTdiff > 11000000) { ResetCounterSamples(fileTime, perfCounter, timeInfo.nominalFreq.QuadPart); return timeInfo.nominalFreq.QuadPart; } else { /* * Estimate the frequency. */ workPCSample = timeInfo.perfCounterSample[timeInfo.sampleNo]; workFTSample = timeInfo.fileTimeSample[timeInfo.sampleNo]; estFreq = 10000000 * (perfCounter - workPCSample) / (fileTime - workFTSample); timeInfo.perfCounterSample[timeInfo.sampleNo] = perfCounter; timeInfo.fileTimeSample[timeInfo.sampleNo] = (long long) fileTime; /* * Advance the sample number. */ if (++timeInfo.sampleNo >= SAMPLES) { timeInfo.sampleNo = 0; } return estFreq; } } /* *---------------------------------------------------------------------- * * Tcl_SetTimeProc -- * * TIP #233 (Virtualized Time): Registers two handlers for the * virtualization of Tcl's access to time information. * * Results: * None. * * Side effects: * Remembers the handlers, alters core behaviour. * *---------------------------------------------------------------------- */ void Tcl_SetTimeProc( Tcl_GetTimeProc *getProc, Tcl_ScaleTimeProc *scaleProc, void *clientData) { tclGetTimeProcPtr = getProc; tclScaleTimeProcPtr = scaleProc; tclTimeClientData = clientData; } /* *---------------------------------------------------------------------- * * Tcl_QueryTimeProc -- * * TIP #233 (Virtualized Time): Query which time handlers are registered. * * Results: * None. * * Side effects: * None. * *---------------------------------------------------------------------- */ void Tcl_QueryTimeProc( Tcl_GetTimeProc **getProc, Tcl_ScaleTimeProc **scaleProc, void **clientData) { if (getProc) { *getProc = tclGetTimeProcPtr; } if (scaleProc) { *scaleProc = tclScaleTimeProcPtr; } if (clientData) { *clientData = tclTimeClientData; } } /* * Local Variables: * mode: c * c-basic-offset: 4 * fill-column: 78 * End: */