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glibc  2.9
ptclock_gettime.c
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00001 /* Copyright (C) 2001, 2004 Free Software Foundation, Inc.
00002    This file is part of the GNU C Library.
00003 
00004    The GNU C Library is free software; you can redistribute it and/or
00005    modify it under the terms of the GNU Lesser General Public License as
00006    published by the Free Software Foundation; either version 2.1 of the
00007    License, or (at your option) any later version.
00008 
00009    The GNU C Library is distributed in the hope that it will be useful,
00010    but WITHOUT ANY WARRANTY; without even the implied warranty of
00011    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00012    Lesser General Public License for more details.
00013 
00014    You should have received a copy of the GNU Lesser General Public
00015    License along with the GNU C Library; see the file COPYING.LIB.  If not,
00016    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
00017    Boston, MA 02111-1307, USA.  */
00018 
00019 #include <errno.h>
00020 #include <time.h>
00021 #include <libc-internal.h>
00022 #include "internals.h"
00023 #include "spinlock.h"
00024 
00025 
00026 #if HP_TIMING_AVAIL
00027 int
00028 __pthread_clock_gettime (clockid_t clock_id, hp_timing_t freq,
00029                       struct timespec *tp)
00030 {
00031   hp_timing_t tsc, cpuclock_offset;
00032   pthread_descr self = thread_self ();
00033   pthread_t thread = ((unsigned int) clock_id) >> CLOCK_IDFIELD_SIZE;
00034   const unsigned int mask = ~0U >> CLOCK_IDFIELD_SIZE;
00035 
00036   if (thread == 0 || (THREAD_GETMEM (self, p_tid) & mask) == thread)
00037     cpuclock_offset = THREAD_GETMEM (self, p_cpuclock_offset);
00038   else
00039     {
00040       pthread_descr th;
00041       pthread_handle handle = thread_handle (thread);
00042       __pthread_lock (&handle->h_lock, NULL);
00043       th = handle->h_descr;
00044       if (th == NULL || (th->p_tid & mask) != thread || th->p_terminated)
00045        {
00046          __pthread_unlock (&handle->h_lock);
00047          __set_errno (EINVAL);
00048          return -1;
00049        }
00050       cpuclock_offset = th->p_cpuclock_offset;
00051       __pthread_unlock (&handle->h_lock);
00052    }
00053 
00054   /* Get the current counter.  */
00055   HP_TIMING_NOW (tsc);
00056 
00057   /* Compute the offset since the start time of the process.  */
00058   tsc -= cpuclock_offset;
00059 
00060   /* Compute the seconds.  */
00061   tp->tv_sec = tsc / freq;
00062 
00063   /* And the nanoseconds.  This computation should be stable until
00064      we get machines with about 16GHz frequency.  */
00065   tp->tv_nsec = ((tsc % freq) * 1000000000ull) / freq;
00066 
00067   return 0;
00068 }
00069 #endif