linuxthreads/ptclock_gettime.c

   1 /* Copyright (C) 2001, 2004 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public License as
   6    published by the Free Software Foundation; either version 2.1 of the
   7    License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  16    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  17    Boston, MA 02111-1307, USA.  */
  18
  19 #include <errno.h>
  20 #include <time.h>
  21 #include <libc-internal.h>
  22 #include "internals.h"
  23 #include "spinlock.h"
  24
  25
  26 #if HP_TIMING_AVAIL
  27 int
  28 __pthread_clock_gettime (clockid_t clock_id, hp_timing_t freq,
  29                          struct timespec *tp)
  30 {
  31   hp_timing_t tsc, cpuclock_offset;
  32   pthread_descr self = thread_self ();
  33   pthread_t thread = ((unsigned int) clock_id) >> CLOCK_IDFIELD_SIZE;
  34   const unsigned int mask = ~0U >> CLOCK_IDFIELD_SIZE;
  35
  36   if (thread == 0 || (THREAD_GETMEM (self, p_tid) & mask) == thread)
  37     cpuclock_offset = THREAD_GETMEM (self, p_cpuclock_offset);
  38   else
  39     {
  40       pthread_descr th;
  41       pthread_handle handle = thread_handle (thread);
  42       __pthread_lock (&handle->h_lock, NULL);
  43       th = handle->h_descr;
  44       if (th == NULL || (th->p_tid & mask) != thread || th->p_terminated)
  45         {
  46           __pthread_unlock (&handle->h_lock);
  47           __set_errno (EINVAL);
  48           return -1;
  49         }
  50       cpuclock_offset = th->p_cpuclock_offset;
  51       __pthread_unlock (&handle->h_lock);
  52    }
  53
  54   /* Get the current counter.  */
  55   HP_TIMING_NOW (tsc);
  56
  57   /* Compute the offset since the start time of the process.  */
  58   tsc -= cpuclock_offset;
  59
  60   /* Compute the seconds.  */
  61   tp->tv_sec = tsc / freq;
  62
  63   /* And the nanoseconds.  This computation should be stable until
  64      we get machines with about 16GHz frequency.  */
  65   tp->tv_nsec = ((tsc % freq) * 1000000000ull) / freq;
  66
  67   return 0;
  68 }
  69 #endif