sysdeps/generic/hp-timing.h

   1 /* High precision, low overhead timing functions.  Generic version.
   2    Copyright (C) 1998, 2000 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4    Contributed by Ulrich Drepper <drepper@cygnus.com>, 1998.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library; if not, write to the Free
  18    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  19    02111-1307 USA.  */
  20
  21 #ifndef _HP_TIMING_H
  22 #define _HP_TIMING_H    1
  23
  24
  25 /* There are no generic definitions for the times.  We could write something
  26    using the `gettimeofday' system call where available but the overhead of
  27    the system call might be too high.
  28
  29    In case a platform supports timers in the hardware the following macros
  30    and types must be defined:
  31
  32    - HP_TIMING_AVAIL: test for availability.
  33
  34    - HP_TIMING_INLINE: this macro is non-zero if the functionality is not
  35      implemented using function calls but instead uses some inlined code
  36      which might simply consist of a few assembler instructions.  We have to
  37      know this since we might want to use the macros here in places where we
  38      cannot make function calls.
  39
  40    - hp_timing_t: This is the type for variables used to store the time
  41      values.
  42
  43    - HP_TIMING_ZERO: clear `hp_timing_t' object.
  44
  45    - HP_TIMING_NOW: place timestamp for current time in variable given as
  46      parameter.
  47
  48    - HP_TIMING_DIFF_INIT: do whatever is necessary to be able to use the
  49      HP_TIMING_DIFF macro.
  50
  51    - HP_TIMING_DIFF: compute difference between two times and store it
  52      in a third.  Source and destination might overlap.
  53
  54    - HP_TIMING_ACCUM: add time difference to another variable.  This might
  55      be a bit more complicated to implement for some platforms as the
  56      operation should be thread-safe and 64bit arithmetic on 32bit platforms
  57      is not.
  58
  59    - HP_TIMING_ACCUM_NT: this is the variant for situations where we know
  60      there are no threads involved.
  61
  62    - HP_TIMING_PRINT: write decimal representation of the timing value into
  63      the given string.  This operation need not be inline even though
  64      HP_TIMING_INLINE is specified.
  65
  66 */
  67
  68 /* Provide dummy definitions.  */
  69 #define HP_TIMING_AVAIL         (0)
  70 #define HP_TIMING_INLINE        (0)
  71 typedef int hp_timing_t;
  72 #define HP_TIMING_ZERO(Var)
  73 #define HP_TIMING_NOW(var)
  74 #define HP_TIMING_DIFF_INIT()
  75 #define HP_TIMING_DIFF(Diff, Start, End)
  76 #define HP_TIMING_ACCUM(Sum, Diff)
  77 #define HP_TIMING_ACCUM_NT(Sum, Diff)
  78 #define HP_TIMING_PRINT(Buf, Len, Val)
  79
  80 /* Since this implementation is not available we tell the user about it.  */
  81 #define HP_TIMING_NONAVAIL      1
  82
  83 #endif  /* hp-timing.h */