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/* Copyright (C) 2012-2016 Free Software Foundation, Inc.
This file is part of the UPC runtime Library.
Written by Gary Funck <gary@intrepid.com>
and Nenad Vukicevic <nenad@intrepid.com>
This file is part of GCC.
GCC 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.
GCC 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/>. */
/**
* @file gupcr_clock.c
* GUPC Clock routines.
*/
/**
* @addtogroup UPCCLOCK UPC Clock Functions
* @{
*/
#include "gupcr_config.h"
#include "gupcr_defs.h"
#include "gupcr_utils.h"
static double gupcr_clock_rez;
static double gupcr_clock_base;
#if HAVE_CLOCK_GETTIME
#if defined (CLOCK_MONOTONIC_RAW) && defined (CLOCK_MONOTONIC)
#define GUPCR_CLOCK_ID CLOCK_MONOTONIC_RAW
/* On some RHEL/CentOS systems, the timer resolution returned for
CLOCK_MONOTONIC_RAW is incorrect. Use CLOCK_MONOTONIC instead. */
#define GUPCR_CLOCK_REZ_ID CLOCK_MONOTONIC
#elif defined (CLOCK_MONOTONIC)
#define GUPCR_CLOCK_ID CLOCK_MONOTONIC
#define GUPCR_CLOCK_REZ_ID CLOCK_MONOTONIC
#else
#error missing system clock name definition.
#endif
double
gupcr_clock (void)
{
struct timespec ts;
double t;
gupcr_syscall (clock_gettime, (GUPCR_CLOCK_ID, &ts));
t = (double) ts.tv_sec + (double) ts.tv_nsec * 1.0e-9;
t -= gupcr_clock_base;
return t;
}
double
gupcr_clock_resolution (void)
{
return gupcr_clock_rez;
}
void
gupcr_clock_init (void)
{
struct timespec clock_rez;
gupcr_syscall (clock_getres, (GUPCR_CLOCK_REZ_ID, &clock_rez));
gupcr_assert (clock_rez.tv_sec == 0);
gupcr_clock_rez = clock_rez.tv_nsec * 1.0e-9;
gupcr_clock_base = gupcr_clock ();
}
#else /* Use gettimeofday(). */
double
gupcr_clock (void)
{
struct timeval tv;
double t;
gupcr_syscall (gettimeofday, (&tv, NULL));
t = (double) tv.tv_sec + (double) tv.tv_usec * 1.0e-6;
t -= gupcr_clock_base;
return t;
}
double
gupcr_clock_resolution (void)
{
return gupcr_clock_rez;
}
void
gupcr_clock_init (void)
{
int i;
gupcr_clock_base = gupcr_clock ();
gupcr_clock_rez = 1.0;
for (i = 1; i <= 10; ++i)
{
double t1, t2, diff;
t1 = gupcr_clock ();
do
{
t2 = gupcr_clock ();
}
while (t1 == t2);
diff = t2 - t1;
if (diff < gupcr_clock_rez)
gupcr_clock_rez = diff;
}
/* Round the clock resolution to some common values
if it is within range of one of them. */
if (gupcr_clock_rez > 0.9e-6 && gupcr_clock_rez < 1.1e-6)
gupcr_clock_rez = 1.0e-6;
else if (gupcr_clock_rez > 0.9e-3 && gupcr_clock_rez < 1.1e-3)
gupcr_clock_rez = 1.0e-3;
else if (gupcr_clock_rez > 0.9e-2 && gupcr_clock_rez < 1.1e-2)
gupcr_clock_rez = 1.0e-2;
else if (gupcr_clock_rez > 1.63e-2 && gupcr_clock_rez < 1.69e-2)
gupcr_clock_rez = 1.0 / 60.0;
else if (gupcr_clock_rez > 1.95e-2 && gupcr_clock_rez < 2.05e-2)
gupcr_clock_rez = 1.0 / 50.0;
}
#endif
/** @} */
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