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137 lines
3.5 KiB
C
137 lines
3.5 KiB
C
/* clock_gettime -- Get the current time from a POSIX clockid_t. Unix version.
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Copyright (C) 1999-2017 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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#include <errno.h>
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#include <stdint.h>
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#include <time.h>
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#include <sys/time.h>
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#include <libc-internal.h>
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#include <ldsodefs.h>
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#if HP_TIMING_AVAIL
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/* Clock frequency of the processor. We make it a 64-bit variable
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because some jokers are already playing with processors with more
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than 4GHz. */
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static hp_timing_t freq;
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/* This function is defined in the thread library. */
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extern int __pthread_clock_gettime (clockid_t clock_id, hp_timing_t freq,
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struct timespec *tp)
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__attribute__ ((__weak__));
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static int
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hp_timing_gettime (clockid_t clock_id, struct timespec *tp)
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{
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hp_timing_t tsc;
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if (__glibc_unlikely (freq == 0))
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{
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/* This can only happen if we haven't initialized the `freq'
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variable yet. Do this now. We don't have to protect this
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code against multiple execution since all of them should
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lead to the same result. */
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freq = __get_clockfreq ();
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if (__glibc_unlikely (freq == 0))
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/* Something went wrong. */
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return -1;
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}
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if (clock_id != CLOCK_PROCESS_CPUTIME_ID
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&& __pthread_clock_gettime != NULL)
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return __pthread_clock_gettime (clock_id, freq, tp);
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/* Get the current counter. */
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HP_TIMING_NOW (tsc);
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/* Compute the offset since the start time of the process. */
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tsc -= GL(dl_cpuclock_offset);
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/* Compute the seconds. */
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tp->tv_sec = tsc / freq;
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/* And the nanoseconds. This computation should be stable until
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we get machines with about 16GHz frequency. */
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tp->tv_nsec = ((tsc % freq) * UINT64_C (1000000000)) / freq;
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return 0;
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}
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#endif
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static inline int
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realtime_gettime (struct timespec *tp)
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{
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struct timeval tv;
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int retval = gettimeofday (&tv, NULL);
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if (retval == 0)
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/* Convert into `timespec'. */
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TIMEVAL_TO_TIMESPEC (&tv, tp);
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return retval;
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}
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/* Get current value of CLOCK and store it in TP. */
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int
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__clock_gettime (clockid_t clock_id, struct timespec *tp)
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{
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int retval = -1;
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switch (clock_id)
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{
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#ifdef SYSDEP_GETTIME
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SYSDEP_GETTIME;
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#endif
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#ifndef HANDLED_REALTIME
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case CLOCK_REALTIME:
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{
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struct timeval tv;
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retval = gettimeofday (&tv, NULL);
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if (retval == 0)
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TIMEVAL_TO_TIMESPEC (&tv, tp);
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}
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break;
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#endif
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default:
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#ifdef SYSDEP_GETTIME_CPU
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SYSDEP_GETTIME_CPU (clock_id, tp);
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#endif
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#if HP_TIMING_AVAIL
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if ((clock_id & ((1 << CLOCK_IDFIELD_SIZE) - 1))
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== CLOCK_THREAD_CPUTIME_ID)
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retval = hp_timing_gettime (clock_id, tp);
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else
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#endif
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__set_errno (EINVAL);
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break;
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#if HP_TIMING_AVAIL && !defined HANDLED_CPUTIME
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case CLOCK_PROCESS_CPUTIME_ID:
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retval = hp_timing_gettime (clock_id, tp);
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break;
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#endif
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}
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return retval;
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}
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weak_alias (__clock_gettime, clock_gettime)
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libc_hidden_def (__clock_gettime)
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