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/* clock_gettime -- Get the current time from a POSIX clockid_t. Unix version.
Copyright (C) 1999-2019 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#include <errno.h>
#include <stdint.h>
#include <time.h>
#include <sys/time.h>
#include <libc-internal.h>
#include <ldsodefs.h>
#if HP_TIMING_AVAIL
/* Clock frequency of the processor. We make it a 64-bit variable
because some jokers are already playing with processors with more
than 4GHz. */
static hp_timing_t freq;
/* This function is defined in the thread library. */
extern int __pthread_clock_gettime (clockid_t clock_id, hp_timing_t freq,
struct timespec *tp)
__attribute__ ((__weak__));
static int
hp_timing_gettime (clockid_t clock_id, struct timespec *tp)
{
hp_timing_t tsc;
if (__glibc_unlikely (freq == 0))
{
/* This can only happen if we haven't initialized the `freq'
variable yet. Do this now. We don't have to protect this
code against multiple execution since all of them should
lead to the same result. */
freq = __get_clockfreq ();
if (__glibc_unlikely (freq == 0))
/* Something went wrong. */
return -1;
}
if (clock_id != CLOCK_PROCESS_CPUTIME_ID
&& __pthread_clock_gettime != NULL)
return __pthread_clock_gettime (clock_id, freq, tp);
/* Get the current counter. */
HP_TIMING_NOW (tsc);
/* Compute the offset since the start time of the process. */
tsc -= GL(dl_cpuclock_offset);
/* Compute the seconds. */
tp->tv_sec = tsc / freq;
/* And the nanoseconds. This computation should be stable until
we get machines with about 16GHz frequency. */
tp->tv_nsec = ((tsc % freq) * UINT64_C (1000000000)) / freq;
return 0;
}
#endif
static inline int
realtime_gettime (struct timespec *tp)
{
struct timeval tv;
int retval = __gettimeofday (&tv, NULL);
if (retval == 0)
/* Convert into `timespec'. */
TIMEVAL_TO_TIMESPEC (&tv, tp);
return retval;
}
/* Get current value of CLOCK and store it in TP. */
int
__clock_gettime (clockid_t clock_id, struct timespec *tp)
{
int retval = -1;
switch (clock_id)
{
case CLOCK_REALTIME:
{
struct timeval tv;
retval = __gettimeofday (&tv, NULL);
if (retval == 0)
TIMEVAL_TO_TIMESPEC (&tv, tp);
}
break;
default:
#if HP_TIMING_AVAIL
if ((clock_id & ((1 << CLOCK_IDFIELD_SIZE) - 1))
== CLOCK_THREAD_CPUTIME_ID)
retval = hp_timing_gettime (clock_id, tp);
else
#endif
__set_errno (EINVAL);
break;
#if HP_TIMING_AVAIL
case CLOCK_PROCESS_CPUTIME_ID:
retval = hp_timing_gettime (clock_id, tp);
break;
#endif
}
return retval;
}
weak_alias (__clock_gettime, clock_gettime)
libc_hidden_def (__clock_gettime)
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