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/* Copyright (C) 2004 MySQL AB
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 of the License.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
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
exists some common code that should be merged into a function.
*/
#include "mysys_priv.h"
#include "my_static.h"
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;
#else
/* TODO: check for other possibilities for hi-res timestamping */
struct timeval tv;
gettimeofday(&tv,NULL);
return (ulonglong)tv.tv_sec*10000000+(ulonglong)tv.tv_usec*10;
#endif
}
/*
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()
{
#if 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(HAVE_GETHRTIME) */
}
/*
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)
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)
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
*/
#define DELTA_FOR_SECONDS LL(500000000) /* Half a second */
ulonglong my_micro_time_and_time(time_t *time_arg)
{
#if 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;
#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(HAVE_GETHRTIME) */
}
/*
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)))
{
#if defined(HAVE_GETHRTIME)
return my_time(0); /* Cached time */
#else
return (time_t) (microtime / 1000000);
#endif /* defined(HAVE_GETHRTIME) */
}
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