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libhermit/usr/libgomp/time.c

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2015-09-12 17:10:09 +02:00
/* Copyright (C) 2015 RWTH Aachen University, Germany.
Contributed by Stefan Lankes <slankes@eonerc.rwth-aachen.de>.
Libgomp 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; either version 3, or (at your option)
any later version.
Libgomp 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.
Under Section 7 of GPL version 3, you are granted additional
permissions described in the GCC Runtime Library Exception, version
3.1, as published by the Free Software Foundation.
You should have received a copy of the GNU General Public License and
a copy of the GCC Runtime Library Exception along with this program;
see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
<http://www.gnu.org/licenses/>. */
/*
* This file contains system specific timer routines. It is expected that
* a system may well want to write special versions of each of these.
*/
#include "libgomp.h"
#include <unistd.h>
extern unsigned int get_cpufreq(void);
static unsigned long long start_tsc;
inline static unsigned long long rdtsc(void)
{
unsigned long lo, hi;
asm volatile ("rdtsc" : "=a"(lo), "=d"(hi) :: "memory");
return ((unsigned long long) hi << 32ULL | (unsigned long long) lo);
}
__attribute__((constructor)) static void timer_init()
{
start_tsc = rdtsc();
}
double
omp_get_wtime (void)
{
double ret;
ret = (double) (rdtsc() - start_tsc) / ((double) get_cpufreq() * 1000000.0);
//printf("CPU frequency: %d MHz\n", get_cpufreq());
return ret;
}
double
omp_get_wtick (void)
{
return 1.0 / ((double) get_cpufreq() * 1000000.0);
}
ialias (omp_get_wtime)
ialias (omp_get_wtick)