double MPID_Wtick( void )
{
MPIU_THREADSAFE_INIT_DECL(initTick);
static double tickval = -1.0;
double timediff; /* Keep compiler happy about timediff set before use*/
MPID_Time_t t1, t2;
int cnt;
int icnt;
if (initTick) {
MPIU_THREADSAFE_INIT_BLOCK_BEGIN(initTick);
tickval = 1.0e6;
for (icnt=0; icnt<10; icnt++) {
cnt = 1000;
MPID_Wtime( &t1 );
/* Make it abundently clear to the compiler that this block is
executed at least once. */
do {
MPID_Wtime( &t2 );
MPID_Wtime_diff( &t1, &t2, &timediff );
if (timediff > 0) break;
}
while (cnt--);
if (cnt && timediff > 0.0 && timediff < tickval) {
MPID_Wtime_diff( &t1, &t2, &tickval );
}
}
MPIU_THREADSAFE_INIT_CLEAR(initTick);
MPIU_THREADSAFE_INIT_BLOCK_END(initTick);
}
return tickval;
}
int MPID_Wtime_init( void )
{
MPID_Time_t t1, t2;
DWORD s1, s2;
double d;
int i;
MPID_Wtime(&t1);
MPID_Wtime(&t1);
/* time an interval using both timers */
s1 = GetTickCount();
MPID_Wtime(&t1);
/*Sleep(250);*/ /* Sleep causes power saving cpu's to stop which stops the counter */
while (GetTickCount() - s1 < 200)
{
for (i=2; i<1000; i++)
d = (double)i / (double)(i-1);
}
s2 = GetTickCount();
MPID_Wtime(&t2);
/* calculate the frequency of the assembly cycle counter */
MPID_Seconds_per_tick = ((double)(s2 - s1) / 1000.0) / (double)((__int64)(t2 - t1));
/*
printf("t2-t1 %10d\nsystime diff %d\nfrequency %g\n CPU MHz %g\n",
(int)(t2-t1), (int)(s2 - s1), MPID_Seconds_per_tick, MPID_Seconds_per_tick * 1.0e6);
*/
return 0;
}
FORT_DLL_SPEC double FORT_CALL mpi_wtime_ ( void ) {
double d; MPID_Time_t t;
MPID_Wtime( &t );
MPID_Wtime_todouble( &t, &d );
return d;
}
static double RLOG_timestamp(void)
{
double d;
MPID_Time_t t;
MPID_Wtime(&t);
MPID_Wtime_todouble(&t, &d);
return d;
}
int MPID_Wtime_init(void)
{
unsigned long long t1, t2;
struct timeval tv1, tv2;
double td1, td2;
gettimeofday(&tv1, NULL);
MPID_Wtime(&t1);
usleep(250000);
gettimeofday(&tv2, NULL);
MPID_Wtime(&t2);
td1 = tv1.tv_sec + tv1.tv_usec / 1000000.0;
td2 = tv2.tv_sec + tv2.tv_usec / 1000000.0;
MPID_Seconds_per_tick = (td2 - td1) / (double)(t2 - t1);
return 0;
}
/*@
MPI_Wtime - Returns an elapsed time on the calling processor
Return value:
Time in seconds since an arbitrary time in the past.
Notes:
This is intended to be a high-resolution, elapsed (or wall) clock.
See 'MPI_WTICK' to determine the resolution of 'MPI_WTIME'.
If the attribute 'MPI_WTIME_IS_GLOBAL' is defined and true, then the
value is synchronized across all processes in 'MPI_COMM_WORLD'.
Notes for Fortran:
This is a function, declared as 'DOUBLE PRECISION MPI_WTIME()' in Fortran.
.see also: MPI_Wtick, MPI_Comm_get_attr, MPI_Attr_get
@*/
double MPI_Wtime( void )
{
double d;
MPID_Time_t t;
MPID_MPI_STATE_DECL(MPID_STATE_MPI_WTIME);
MPIR_ERRTEST_INITIALIZED_ORDIE();
MPID_MPI_FUNC_ENTER(MPID_STATE_MPI_WTIME);
MPID_Wtime( &t );
MPID_Wtime_todouble( &t, &d );
MPID_MPI_FUNC_EXIT(MPID_STATE_MPI_WTIME);
return d;
}
