diff options
Diffstat (limited to 'mysys/my_getsystime.c')
| -rw-r--r-- | mysys/my_getsystime.c | 205 |
1 files changed, 61 insertions, 144 deletions
diff --git a/mysys/my_getsystime.c b/mysys/my_getsystime.c index b692b18bfc7..b467c49c6e6 100644 --- a/mysys/my_getsystime.c +++ b/mysys/my_getsystime.c @@ -13,9 +13,6 @@ along with this program; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ -/* get time since epoc in 100 nanosec units */ -/* thus to get the current time we should use the system function - with the highest possible resolution */ /* TODO: in functions my_micro_time() and my_micro_time_and_time() there @@ -27,14 +24,33 @@ #ifdef __NETWARE__ #include <nks/time.h> +#elif defined(__WIN__) +static ulonglong query_performance_frequency, query_performance_offset; +#elif defined(HAVE_GETHRTIME) +static ulonglong gethrtime_offset; #endif +/* + get time since epoc in 100 nanosec units + + NOTE: + Thus to get the current time we should use the system function + with the highest possible resolution + + The value is not subject to resetting or drifting by way of adjtime() or + settimeofday(), and thus it is *NOT* appropriate for getting the current + timestamp. It can be used for calculating time intervals, though. + And it's good enough for UUID. +*/ + ulonglong my_getsystime() { #ifdef HAVE_CLOCK_GETTIME struct timespec tp; clock_gettime(CLOCK_REALTIME, &tp); return (ulonglong)tp.tv_sec*10000000+(ulonglong)tp.tv_nsec/100; +#elif defined(HAVE_GETHRTIME) + return gethrtime()/100-gethrtime_offset; #elif defined(__WIN__) LARGE_INTEGER t_cnt; if (query_performance_frequency) @@ -57,169 +73,70 @@ ulonglong my_getsystime() #endif } +/* Return current time in microseconds since epoch */ -/* - Return current time - - SYNOPSIS - my_time() - flags If MY_WME is set, write error if time call fails - -*/ - -time_t my_time(myf flags __attribute__((unused))) -{ - time_t t; -#ifdef HAVE_GETHRTIME - (void) my_micro_time_and_time(&t); - return t; -#else - /* The following loop is here beacuse time() may fail on some systems */ - while ((t= time(0)) == (time_t) -1) - { - if (flags & MY_WME) - fprintf(stderr, "%s: Warning: time() call failed\n", my_progname); - } - return t; -#endif -} - - -/* - Return time in micro seconds - - SYNOPSIS - my_micro_time() - - NOTES - This function is to be used to measure performance in micro seconds. - As it's not defined whats the start time for the clock, this function - us only useful to measure time between two moments. - - For windows platforms we need the frequency value of the CUP. This is - initalized in my_init.c through QueryPerformanceFrequency(). - - If Windows platform doesn't support QueryPerformanceFrequency() we will - obtain the time via GetClockCount, which only supports milliseconds. - - RETURN - Value in microseconds from some undefined point in time -*/ - -ulonglong my_micro_time() +my_hrtime_t my_hrtime() { + my_hrtime_t hrtime; #if defined(__WIN__) ulonglong newtime; GetSystemTimeAsFileTime((FILETIME*)&newtime); - return (newtime/10); + hrtime.val= newtime/10; #elif defined(HAVE_GETHRTIME) - return gethrtime()/1000; -#else - ulonglong newtime; struct timeval t; /* The following loop is here because gettimeofday may fail on some systems */ while (gettimeofday(&t, NULL) != 0) {} - newtime= (ulonglong)t.tv_sec * 1000000 + t.tv_usec; - return newtime; -#endif /* defined(__WIN__) */ + hrtime.val= t.tv_sec*1000000 + t.tv_usec; +#else + hrtime.val= my_getsystime()/10; +#endif + return hrtime; } - /* - Return time in seconds and timer in microseconds (not different start!) - - SYNOPSIS - my_micro_time_and_time() - time_arg Will be set to seconds since epoch (00:00:00 UTC, - January 1, 1970) + This function is basically equivalent to - NOTES - This function is to be useful when we need both the time and microtime. - For example in MySQL this is used to get the query time start of a query - and to measure the time of a query (for the slow query log) + *interval= my_getsystime()/10; + *timestamp= my_time(); - IMPLEMENTATION - Value of time is as in time() call. - Value of microtime is same as my_micro_time(), which may be totally - unrealated to time() - - RETURN - Value in microseconds from some undefined point in time + but it avoids calling OS time functions twice, if possible. */ - -#define DELTA_FOR_SECONDS LL(500000000) /* Half a second */ - -ulonglong my_micro_time_and_time(time_t *time_arg) +void my_diff_and_hrtime(my_timediff_t *interval, my_hrtime_t *timestamp) { -#if defined(__WIN__) - ulonglong newtime; - GetSystemTimeAsFileTime((FILETIME*)&newtime); - *time_arg= (time_t) ((newtime - OFFSET_TO_EPOCH) / 10000000); - return (newtime/10); -#elif defined(HAVE_GETHRTIME) - /* - Solaris has a very slow time() call. We optimize this by using the very - fast gethrtime() call and only calling time() every 1/2 second - */ - static hrtime_t prev_gethrtime= 0; - static time_t cur_time= 0; - hrtime_t cur_gethrtime; - - pthread_mutex_lock(&THR_LOCK_time); - cur_gethrtime= gethrtime(); - if ((cur_gethrtime - prev_gethrtime) > DELTA_FOR_SECONDS) - { - cur_time= time(0); - prev_gethrtime= cur_gethrtime; - } - *time_arg= cur_time; - pthread_mutex_unlock(&THR_LOCK_time); - return cur_gethrtime/1000; + interval->val= my_getsystime() / 10; +#if defined(__WIN__) || defined(HAVE_GETHRTIME) + timestamp->val= my_hrtime(); #else - ulonglong newtime; - struct timeval t; - /* - The following loop is here because gettimeofday may fail on some systems - */ - while (gettimeofday(&t, NULL) != 0) - {} - *time_arg= t.tv_sec; - newtime= (ulonglong)t.tv_sec * 1000000 + t.tv_usec; - return newtime; -#endif /* defined(__WIN__) */ + timestamp->val= interval->val; +#endif } - -/* - Returns current time - - SYNOPSIS - my_time_possible_from_micro() - microtime Value from very recent my_micro_time() - - NOTES - This function returns the current time. The microtime argument is only used - if my_micro_time() uses a function that can safely be converted to the - current time. - - RETURN - current time -*/ - -time_t my_time_possible_from_micro(ulonglong microtime __attribute__((unused))) +void my_time_init() { -#if defined(__WIN__) - time_t t; - while ((t= time(0)) == (time_t) -1) - {} - return t; +#ifdef __WIN__ +#define OFFSET_TO_EPOC ((__int64) 134774 * 24 * 60 * 60 * 1000 * 1000 * 10) + FILETIME ft; + LARGE_INTEGER li, t_cnt; + DBUG_ASSERT(sizeof(LARGE_INTEGER) == sizeof(query_performance_frequency)); + if (QueryPerformanceFrequency((LARGE_INTEGER *)&query_performance_frequency) == 0) + query_performance_frequency= 0; + else + { + GetSystemTimeAsFileTime(&ft); + li.LowPart= ft.dwLowDateTime; + li.HighPart= ft.dwHighDateTime; + query_performance_offset= li.QuadPart-OFFSET_TO_EPOC; + QueryPerformanceCounter(&t_cnt); + query_performance_offset-= (t_cnt.QuadPart / + query_performance_frequency * 10000000 + + t_cnt.QuadPart % + query_performance_frequency * 10000000 / + query_performance_frequency); + } #elif defined(HAVE_GETHRTIME) - return my_time(0); /* Cached time */ -#else - return (time_t) (microtime / 1000000); -#endif /* defined(__WIN__) */ + gethrtime_offset= gethrtime(); +#endif } - |