Permalink
Cannot retrieve contributors at this time
Name already in use
A tag already exists with the provided branch name. Many Git commands accept both tag and branch names, so creating this branch may cause unexpected behavior. Are you sure you want to create this branch?
glibc/sysdeps/unix/clock_gettime.c
Go to fileThis commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
136 lines (111 sloc)
3.54 KB
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
/* clock_gettime -- Get the current time from a POSIX clockid_t. Unix version. | |
Copyright (C) 1999-2013 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 (__builtin_expect (freq == 0, 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 (__builtin_expect (freq == 0, 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) | |
{ | |
#ifdef SYSDEP_GETTIME | |
SYSDEP_GETTIME; | |
#endif | |
#ifndef HANDLED_REALTIME | |
case CLOCK_REALTIME: | |
{ | |
struct timeval tv; | |
retval = gettimeofday (&tv, NULL); | |
if (retval == 0) | |
TIMEVAL_TO_TIMESPEC (&tv, tp); | |
} | |
break; | |
#endif | |
default: | |
#ifdef SYSDEP_GETTIME_CPU | |
SYSDEP_GETTIME_CPU (clock_id, tp); | |
#endif | |
#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 && !defined HANDLED_CPUTIME | |
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) |