diff options
Diffstat (limited to 'win/tclWinTime.c')
| -rw-r--r-- | win/tclWinTime.c | 1028 |
1 files changed, 910 insertions, 118 deletions
diff --git a/win/tclWinTime.c b/win/tclWinTime.c index b59f68d..7045c72 100644 --- a/win/tclWinTime.c +++ b/win/tclWinTime.c @@ -1,50 +1,146 @@ -/* +/* * tclWinTime.c -- * - * Contains Windows specific versions of Tcl functions that - * obtain time values from the operating system. - * - * Copyright 1995 by Sun Microsystems, Inc. + * Contains Windows specific versions of Tcl functions that obtain time + * values from the operating system. * - * See the file "license.terms" for information on usage and redistribution - * of this file, and for a DISCLAIMER OF ALL WARRANTIES. + * Copyright 1995-1998 by Sun Microsystems, Inc. * - * SCCS: @(#) tclWinTime.c 1.6 97/04/14 17:25:56 + * See the file "license.terms" for information on usage and redistribution of + * this file, and for a DISCLAIMER OF ALL WARRANTIES. */ #include "tclInt.h" -#include "tclPort.h" -#define SECSPERDAY (60L * 60L * 24L) -#define SECSPERYEAR (SECSPERDAY * 365L) -#define SECSPER4YEAR (SECSPERYEAR * 4L + SECSPERDAY) +#define SECSPERDAY (60L * 60L * 24L) +#define SECSPERYEAR (SECSPERDAY * 365L) +#define SECSPER4YEAR (SECSPERYEAR * 4L + SECSPERDAY) + +/* + * Number of samples over which to estimate the performance counter. + */ + +#define SAMPLES 64 /* - * The following arrays contain the day of year for the last day of - * each month, where index 1 is January. + * The following arrays contain the day of year for the last day of each + * month, where index 1 is January. */ -static int normalDays[] = { +static const int normalDays[] = { -1, 30, 58, 89, 119, 150, 180, 211, 242, 272, 303, 333, 364 }; -static int leapDays[] = { +static const int leapDays[] = { -1, 30, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365 }; +typedef struct ThreadSpecificData { + char tzName[64]; /* Time zone name */ + struct tm tm; /* time information */ +} ThreadSpecificData; +static Tcl_ThreadDataKey dataKey; + +/* + * Data for managing high-resolution timers. + */ + +typedef struct TimeInfo { + 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. */ + 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; + + /* + * Data used in developing the estimate of performance counter frequency + */ + + Tcl_WideUInt fileTimeSample[SAMPLES]; + /* Last 64 samples of system time. */ + Tcl_WideInt 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, + (HANDLE) NULL, + (HANDLE) NULL, + (HANDLE) NULL, +#ifdef HAVE_CAST_TO_UNION + (LARGE_INTEGER) (Tcl_WideInt) 0, + (ULARGE_INTEGER) (DWORDLONG) 0, + (LARGE_INTEGER) (Tcl_WideInt) 0, + (LARGE_INTEGER) (Tcl_WideInt) 0, +#else + 0, + 0, + 0, + 0, +#endif + { 0 }, + { 0 }, + 0 +}; + /* * Declarations for functions defined later in this file. */ -static struct tm * ComputeGMT _ANSI_ARGS_((const time_t *tp)); +static struct tm * ComputeGMT(const time_t *tp); +static void StopCalibration(ClientData clientData); +static DWORD WINAPI CalibrationThread(LPVOID arg); +static void UpdateTimeEachSecond(void); +static void ResetCounterSamples(Tcl_WideUInt fileTime, + Tcl_WideInt perfCounter, Tcl_WideInt perfFreq); +static Tcl_WideInt AccumulateSample(Tcl_WideInt perfCounter, + Tcl_WideUInt fileTime); +static void NativeScaleTime(Tcl_Time* timebuf, + ClientData clientData); +static void NativeGetTime(Tcl_Time* timebuf, + ClientData clientData); + +/* + * TIP #233 (Virtualized Time): Data for the time hooks, if any. + */ + +Tcl_GetTimeProc *tclGetTimeProcPtr = NativeGetTime; +Tcl_ScaleTimeProc *tclScaleTimeProcPtr = NativeScaleTime; +ClientData tclTimeClientData = NULL; /* *---------------------------------------------------------------------- * * TclpGetSeconds -- * - * This procedure returns the number of seconds from the epoch. - * On most Unix systems the epoch is Midnight Jan 1, 1970 GMT. + * 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. @@ -56,9 +152,12 @@ static struct tm * ComputeGMT _ANSI_ARGS_((const time_t *tp)); */ unsigned long -TclpGetSeconds() +TclpGetSeconds(void) { - return (unsigned long) time((time_t *) NULL); + Tcl_Time t; + + tclGetTimeProcPtr(&t, tclTimeClientData); /* Tcl_GetTime inlined. */ + return t.sec; } /* @@ -66,11 +165,10 @@ TclpGetSeconds() * * 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 - * dependant. + * 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 dependant. * * Results: * Number of clicks from some start time. @@ -82,94 +180,310 @@ TclpGetSeconds() */ unsigned long -TclpGetClicks() +TclpGetClicks(void) { - return GetTickCount(); + /* + * 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 */ + unsigned long retval; /* Value to return */ + + tclGetTimeProcPtr(&now, tclTimeClientData); /* Tcl_GetTime inlined */ + + retval = (now.sec * 1000000) + now.usec; + return retval; + } /* *---------------------------------------------------------------------- * - * TclpGetTimeZone -- + * Tcl_GetTime -- * - * Determines the current timezone. The method varies wildly - * between different Platform implementations, so its hidden in - * this function. + * Gets the current system time in seconds and microseconds since the + * beginning of the epoch: 00:00 UCT, January 1, 1970. * * Results: - * Minutes west of GMT. + * Returns the current time in timePtr. * * Side effects: - * None. + * 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. * *---------------------------------------------------------------------- */ -int -TclpGetTimeZone (currentTime) - unsigned long currentTime; +void +Tcl_GetTime( + Tcl_Time *timePtr) /* Location to store time information. */ { - int timeZone; - - tzset(); - timeZone = _timezone / 60; + tclGetTimeProcPtr(timePtr, tclTimeClientData); +} + +/* + *---------------------------------------------------------------------- + * + * 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. + * + *---------------------------------------------------------------------- + */ - return timeZone; +static void +NativeScaleTime( + Tcl_Time *timePtr, + ClientData clientData) +{ + /* + * Native scale is 1:1. Nothing is done. + */ } /* *---------------------------------------------------------------------- * - * TclpGetTime -- + * NativeGetTime -- * - * Gets the current system time in seconds and microseconds + * 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: - * None. + * 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 -TclpGetTime(timePtr) - Tcl_Time *timePtr; /* Location to store time information. */ +static void +NativeGetTime( + Tcl_Time *timePtr, + ClientData clientData) { - struct timeb t; + struct _timeb t; + int useFtime = 1; /* Flag == TRUE if we need to fall back on + * ftime rather than using the perf counter. */ + + /* + * 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.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 != (Tcl_WideInt)1193182 + * && timeInfo.nominalFreq.QuadPart != (Tcl_WideInt)3579545 + */ + && timeInfo.nominalFreq.QuadPart > (Tcl_WideInt) 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; + unsigned 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 */ + == systemInfo.dwNumberOfProcessors)) { + timeInfo.perfCounterAvailable = TRUE; + } else { + timeInfo.perfCounterAvailable = FALSE; + } + } +#endif /* above code is Win32 only */ + + /* + * If the performance counter is available, start a thread to + * calibrate it. + */ + + if (timeInfo.perfCounterAvailable) { + DWORD id; + + InitializeCriticalSection(&timeInfo.cs); + timeInfo.readyEvent = CreateEvent(NULL, FALSE, FALSE, NULL); + timeInfo.exitEvent = CreateEvent(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. + */ + + LARGE_INTEGER curCounter; + /* Current performance counter. */ + Tcl_WideInt curFileTime;/* Current estimated time, expressed as 100-ns + * ticks since the Windows epoch. */ + static LARGE_INTEGER posixEpoch; + /* Posix epoch expressed as 100-ns ticks since + * the windows epoch. */ + Tcl_WideInt usecSincePosixEpoch; + /* Current microseconds since Posix epoch. */ + + posixEpoch.LowPart = 0xD53E8000; + posixEpoch.HighPart = 0x019DB1DE; + + EnterCriticalSection(&timeInfo.cs); - ftime(&t); - timePtr->sec = t.time; - timePtr->usec = t.millitm * 1000; + QueryPerformanceCounter(&curCounter); + + /* + * 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 - timeInfo.perfCounterLastCall.QuadPart < + 11 * timeInfo.curCounterFreq.QuadPart / 10) { + curFileTime = timeInfo.fileTimeLastCall.QuadPart + + ((curCounter.QuadPart - timeInfo.perfCounterLastCall.QuadPart) + * 10000000 / timeInfo.curCounterFreq.QuadPart); + timeInfo.fileTimeLastCall.QuadPart = curFileTime; + timeInfo.perfCounterLastCall.QuadPart = curCounter.QuadPart; + usecSincePosixEpoch = (curFileTime - posixEpoch.QuadPart) / 10; + timePtr->sec = (long) (usecSincePosixEpoch / 1000000); + timePtr->usec = (unsigned long) (usecSincePosixEpoch % 1000000); + useFtime = 0; + } + + LeaveCriticalSection(&timeInfo.cs); + } + + if (useFtime) { + /* + * High resolution timer is not available. Just use ftime. + */ + + _ftime(&t); + timePtr->sec = (long)t.time; + timePtr->usec = t.millitm * 1000; + } } /* *---------------------------------------------------------------------- * - * TclpGetTZName -- + * StopCalibration -- * - * Gets the current timezone string. + * Turns off the calibration thread in preparation for exiting the + * process. * * Results: - * Returns a pointer to a static string, or NULL on failure. + * None. * * Side effects: - * None. + * Sets the 'exitEvent' event in the 'timeInfo' structure to ask the + * thread in question to exit, and waits for it to do so. * *---------------------------------------------------------------------- */ -char * -TclpGetTZName() +static void +StopCalibration( + ClientData unused) /* Client data is unused */ { - tzset(); - if (_daylight && _tzname[1] != NULL) { - return _tzname[1]; - } else { - return _tzname[0]; - } + 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); } /* @@ -177,9 +491,9 @@ TclpGetTZName() * * TclpGetDate -- * - * This function converts between seconds and struct tm. If - * useGMT is true, then the returned date will be in Greenwich - * Mean Time (GMT). Otherwise, it will be in the local time zone. + * This function converts between seconds and struct tm. If useGMT is + * true, then the returned date will be in Greenwich Mean Time (GMT). + * Otherwise, it will be in the local time zone. * * Results: * Returns a static tm structure. @@ -191,38 +505,55 @@ TclpGetTZName() */ struct tm * -TclpGetDate(tp, useGMT) - const time_t *tp; - int useGMT; +TclpGetDate( + const time_t *t, + int useGMT) { struct tm *tmPtr; - long time; + time_t time; if (!useGMT) { tzset(); /* - * If we are in the valid range, let the C run-time library - * handle it. Otherwise we need to fake it. Note that this - * algorithm ignores daylight savings time before the epoch. + * If we are in the valid range, let the C run-time library handle it. + * Otherwise we need to fake it. Note that this algorithm ignores + * daylight savings time before the epoch. */ - time = *tp - _timezone; - if (time >= 0) { - return localtime(tp); + /* + * Hm, Borland's localtime manages to return NULL under certain + * circumstances (e.g. wintime.test, test 1.2). Nobody tests for this, + * since 'localtime' isn't supposed to do this, possibly leading to + * crashes. + * + * Patch: We only call this function if we are at least one day into + * the epoch, else we handle it ourselves (like we do for times < 0). + * H. Giese, June 2003 + */ + +#ifdef __BORLANDC__ +#define LOCALTIME_VALIDITY_BOUNDARY SECSPERDAY +#else +#define LOCALTIME_VALIDITY_BOUNDARY 0 +#endif + + if (*t >= LOCALTIME_VALIDITY_BOUNDARY) { + return TclpLocaltime(t); } - + + time = *t - timezone; + /* * If we aren't near to overflowing the long, just add the bias and - * use the normal calculation. Otherwise we will need to adjust - * the result at the end. + * use the normal calculation. Otherwise we will need to adjust the + * result at the end. */ - if (*tp < (LONG_MAX - 2 * SECSPERDAY) - && *tp > (LONG_MIN + 2 * SECSPERDAY)) { + if (*t < (LONG_MAX - 2*SECSPERDAY) && *t > (LONG_MIN + 2*SECSPERDAY)) { tmPtr = ComputeGMT(&time); } else { - tmPtr = ComputeGMT(tp); + tmPtr = ComputeGMT(t); tzset(); @@ -231,13 +562,13 @@ TclpGetDate(tp, useGMT) * Propagate seconds overflow into minutes, hours and days. */ - time = tmPtr->tm_sec - _timezone; + time = tmPtr->tm_sec - timezone; tmPtr->tm_sec = (int)(time % 60); if (tmPtr->tm_sec < 0) { tmPtr->tm_sec += 60; time -= 60; } - + time = tmPtr->tm_min + time/60; tmPtr->tm_min = (int)(time % 60); if (tmPtr->tm_min < 0) { @@ -253,12 +584,12 @@ TclpGetDate(tp, useGMT) } time /= 24; - tmPtr->tm_mday += time; - tmPtr->tm_yday += time; - tmPtr->tm_wday = (tmPtr->tm_wday + time) % 7; + tmPtr->tm_mday += (int)time; + tmPtr->tm_yday += (int)time; + tmPtr->tm_wday = (tmPtr->tm_wday + (int)time) % 7; } } else { - tmPtr = ComputeGMT(tp); + tmPtr = ComputeGMT(t); } return tmPtr; } @@ -268,11 +599,11 @@ TclpGetDate(tp, useGMT) * * ComputeGMT -- * - * This function computes GMT given the number of seconds since - * the epoch (midnight Jan 1 1970). + * This function computes GMT given the number of seconds since the epoch + * (midnight Jan 1 1970). * * Results: - * Returns a statically allocated struct tm. + * Returns a (per thread) statically allocated struct tm. * * Side effects: * Updates the values of the static struct tm. @@ -281,20 +612,23 @@ TclpGetDate(tp, useGMT) */ static struct tm * -ComputeGMT(tp) - const time_t *tp; +ComputeGMT( + const time_t *tp) { - static struct tm tm; /* This should be allocated per thread.*/ + struct tm *tmPtr; long tmp, rem; int isLeap; - int *days; + const int *days; + ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey); + + tmPtr = &tsdPtr->tm; /* * Compute the 4 year span containing the specified time. */ - tmp = *tp / SECSPER4YEAR; - rem = *tp % SECSPER4YEAR; + tmp = (long)(*tp / SECSPER4YEAR); + rem = (long)(*tp % SECSPER4YEAR); /* * Correct for weird mod semantics so the remainder is always positive. @@ -306,9 +640,9 @@ ComputeGMT(tp) } /* - * Compute the year after 1900 by taking the 4 year span and adjusting - * for the remainder. This works because 2000 is a leap year, and - * 1900/2100 are out of the range. + * Compute the year after 1900 by taking the 4 year span and adjusting for + * the remainder. This works because 2000 is a leap year, and 1900/2100 + * are out of the range. */ tmp = (tmp * 4) + 70; @@ -327,47 +661,505 @@ ComputeGMT(tp) } } } - tm.tm_year = tmp; + tmPtr->tm_year = tmp; /* - * Compute the day of year and leave the seconds in the current day in - * the remainder. + * Compute the day of year and leave the seconds in the current day in the + * remainder. */ - tm.tm_yday = rem / SECSPERDAY; + tmPtr->tm_yday = rem / SECSPERDAY; rem %= SECSPERDAY; - + /* * Compute the time of day. */ - tm.tm_hour = rem / 3600; + tmPtr->tm_hour = rem / 3600; rem %= 3600; - tm.tm_min = rem / 60; - tm.tm_sec = rem % 60; + tmPtr->tm_min = rem / 60; + tmPtr->tm_sec = rem % 60; /* * Compute the month and day of month. */ days = (isLeap) ? leapDays : normalDays; - for (tmp = 1; days[tmp] < tm.tm_yday; tmp++) { + for (tmp = 1; days[tmp] < tmPtr->tm_yday; tmp++) { + /* empty body */ } - tm.tm_mon = --tmp; - tm.tm_mday = tm.tm_yday - days[tmp]; + tmPtr->tm_mon = --tmp; + tmPtr->tm_mday = tmPtr->tm_yday - days[tmp]; /* * Compute day of week. Epoch started on a Thursday. */ - tm.tm_wday = (*tp / SECSPERDAY) + 4; + tmPtr->tm_wday = (long)(*tp / SECSPERDAY) + 4; if ((*tp % SECSPERDAY) < 0) { - tm.tm_wday--; + tmPtr->tm_wday--; } - tm.tm_wday %= 7; - if (tm.tm_wday < 0) { - tm.tm_wday += 7; + tmPtr->tm_wday %= 7; + if (tmPtr->tm_wday < 0) { + tmPtr->tm_wday += 7; } - return &tm; + return tmPtr; } + +/* + *---------------------------------------------------------------------- + * + * 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( + LPVOID arg) +{ + 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; + + 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(); + } + + /* lint */ + 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. */ + LARGE_INTEGER curFileTime; /* File time at the time this callback was + * scheduled. */ + Tcl_WideInt estFreq; /* Estimated perf counter frequency. */ + Tcl_WideInt vt0; /* Tcl time right now. */ + Tcl_WideInt vt1; /* Tcl time one second from now. */ + Tcl_WideInt tdiff; /* Difference between system clock and Tcl + * time. */ + Tcl_WideInt driftFreq; /* Frequency needed to drift virtual time into + * step over 1 second. */ + + /* + * Sample performance counter and system time. + */ + + QueryPerformanceCounter(&curPerfCounter); + GetSystemTimeAsFileTime(&curSysTime); + curFileTime.LowPart = curSysTime.dwLowDateTime; + curFileTime.HighPart = curSysTime.dwHighDateTime; + + EnterCriticalSection(&timeInfo.cs); + + /* + * 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){ + LeaveCriticalSection(&timeInfo.cs); + 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, + (Tcl_WideUInt) 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 = 10000000 * (curPerfCounter.QuadPart + - timeInfo.perfCounterLastCall.QuadPart) + / timeInfo.curCounterFreq.QuadPart + + timeInfo.fileTimeLastCall.QuadPart; + vt1 = 20000000 + curFileTime.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) { + timeInfo.fileTimeLastCall.QuadPart = curFileTime.QuadPart; + timeInfo.curCounterFreq.QuadPart = estFreq; + } else { + driftFreq = estFreq * 20000000 / (vt1 - vt0); + + if (driftFreq > 1003*estFreq/1000) { + driftFreq = 1003*estFreq/1000; + } else if (driftFreq < 997*estFreq/1000) { + driftFreq = 997*estFreq/1000; + } + + timeInfo.fileTimeLastCall.QuadPart = vt0; + timeInfo.curCounterFreq.QuadPart = driftFreq; + } + + 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( + Tcl_WideUInt fileTime, /* Current file time */ + Tcl_WideInt perfCounter, /* Current performance counter */ + Tcl_WideInt 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 Tcl_WideInt +AccumulateSample( + Tcl_WideInt perfCounter, + Tcl_WideUInt fileTime) +{ + Tcl_WideUInt workFTSample; /* File time sample being removed from or + * added to the circular buffer. */ + Tcl_WideInt workPCSample; /* Performance counter sample being removed + * from or added to the circular buffer. */ + Tcl_WideUInt lastFTSample; /* Last file time sample recorded */ + Tcl_WideInt lastPCSample; /* Last performance counter sample recorded */ + Tcl_WideInt FTdiff; /* Difference between last FT and current */ + Tcl_WideInt PCdiff; /* Difference between last PC and current */ + Tcl_WideInt 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] = (Tcl_WideInt) fileTime; + + /* + * Advance the sample number. + */ + + if (++timeInfo.sampleNo >= SAMPLES) { + timeInfo.sampleNo = 0; + } + + return estFreq; + } +} + +/* + *---------------------------------------------------------------------- + * + * TclpGmtime -- + * + * Wrapper around the 'gmtime' library function to make it thread safe. + * + * Results: + * Returns a pointer to a 'struct tm' in thread-specific data. + * + * Side effects: + * Invokes gmtime or gmtime_r as appropriate. + * + *---------------------------------------------------------------------- + */ + +struct tm * +TclpGmtime( + const time_t *timePtr) /* Pointer to the number of seconds since the + * local system's epoch */ +{ + /* + * The MS implementation of gmtime is thread safe because it returns the + * time in a block of thread-local storage, and Windows does not provide a + * Posix gmtime_r function. + */ + + return gmtime(timePtr); +} + +/* + *---------------------------------------------------------------------- + * + * TclpLocaltime -- + * + * Wrapper around the 'localtime' library function to make it thread + * safe. + * + * Results: + * Returns a pointer to a 'struct tm' in thread-specific data. + * + * Side effects: + * Invokes localtime or localtime_r as appropriate. + * + *---------------------------------------------------------------------- + */ + +struct tm * +TclpLocaltime( + const time_t *timePtr) /* Pointer to the number of seconds since the + * local system's epoch */ +{ + /* + * The MS implementation of localtime is thread safe because it returns + * the time in a block of thread-local storage, and Windows does not + * provide a Posix localtime_r function. + */ + + return localtime(timePtr); +} + +/* + *---------------------------------------------------------------------- + * + * 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, + ClientData 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, + ClientData *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: + */ |