libgfortran/intrinsics/cpu_time.c

   1 /* Implementation of the CPU_TIME intrinsic.
   2    Copyright (C) 2003 Free Software Foundation, Inc.
   3
   4 This file is part of the GNU Fortran 95 runtime library (libgfortran).
   5
   6 Libgfortran is free software; you can redistribute it and/or
   7 modify it under the terms of the GNU General Public
   8 License as published by the Free Software Foundation; either
   9 version 2 of the License, or (at your option) any later version.
  10
  11 In addition to the permissions in the GNU General Public License, the
  12 Free Software Foundation gives you unlimited permission to link the
  13 compiled version of this file into combinations with other programs,
  14 and to distribute those combinations without any restriction coming
  15 from the use of this file.  (The General Public License restrictions
  16 do apply in other respects; for example, they cover modification of
  17 the file, and distribution when not linked into a combine
  18 executable.)
  19
  20 Libgfortran is distributed in the hope that it will be useful,
  21 but WITHOUT ANY WARRANTY; without even the implied warranty of
  22 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  23 GNU General Public License for more details.
  24
  25 You should have received a copy of the GNU General Public
  26 License along with libgfortran; see the file COPYING.  If not,
  27 write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  28 Boston, MA 02111-1307, USA.  */
  29
  30 #include "config.h"
  31 #include <sys/types.h>
  32 #include "libgfortran.h"
  33
  34 #ifdef HAVE_UNISTD_H
  35 #include <unistd.h>
  36 #endif
  37
  38 /* The CPU_TIME intrinsic to "compare different algorithms on the same
  39    computer or discover which parts are the most expensive", so we
  40    need a way to get the CPU time with the finest resolution possible.
  41    We can only be accurate up to microseconds.
  42
  43    As usual with UNIX systems, unfortunately no single way is
  44    available for all systems.  */
  45
  46 #ifdef TIME_WITH_SYS_TIME
  47 #  include <sys/time.h>
  48 #  include <time.h>
  49 #else
  50 #  if HAVE_SYS_TIME_H
  51 #    include <sys/time.h>
  52 #  else
  53 #    ifdef HAVE_TIME_H
  54 #      include <time.h>
  55 #    endif
  56 #  endif
  57 #endif
  58
  59 /* The most accurate way to get the CPU time is getrusage ().
  60    If we have times(), that's good enough, too.  */
  61 #if defined (HAVE_GETRUSAGE) && defined (HAVE_SYS_RESOURCE_H)
  62 #  include <sys/resource.h>
  63 #else
  64 /* For times(), we _must_ know the number of clock ticks per second.  */
  65 #  if defined (HAVE_TIMES) && (defined (HZ) || defined (_SC_CLK_TCK) || defined (CLK_TCK))
  66 #    ifdef HAVE_SYS_PARAM_H
  67 #      include <sys/param.h>
  68 #    endif
  69 #    include <sys/times.h>
  70 #    ifndef HZ
  71 #      if defined _SC_CLK_TCK
  72 #        define HZ  sysconf(_SC_CLK_TCK)
  73 #      else
  74 #        define HZ  CLK_TCK
  75 #      endif
  76 #    endif
  77 #  endif  /* HAVE_TIMES etc.  */
  78 #endif  /* HAVE_GETRUSAGE && HAVE_SYS_RESOURCE_H  */
  79
  80 #if defined (__GNUC__) && (__GNUC__ >= 3)
  81 #  define ATTRIBUTE_ALWAYS_INLINE __attribute__ ((__always_inline__))
  82 #else
  83 #  define ATTRIBUTE_ALWAYS_INLINE
  84 #endif
  85
  86 static inline void __cpu_time_1 (long *, long *) ATTRIBUTE_ALWAYS_INLINE;
  87
  88 /* Helper function for the actual implementation of the CPU_TIME
  89    intrnsic.  Returns a CPU time in microseconds or -1 if no CPU time
  90    could be computed.  */
  91 static inline void
  92 __cpu_time_1 (long *sec, long *usec)
  93 {
  94 #if defined (HAVE_GETRUSAGE) && defined (HAVE_SYS_RESOURCE_H)
  95   struct rusage usage;
  96   getrusage (0, &usage);
  97   *sec = usage.ru_utime.tv_sec + usage.ru_stime.tv_sec;
  98   *usec = usage.ru_utime.tv_usec + usage.ru_stime.tv_usec;
  99 #else /* ! HAVE_GETRUSAGE || ! HAVE_SYS_RESOURCE_H  */
 100 #ifdef HAVE_TIMES
 101   struct tms buf;
 102   times (&buf);
 103   *sec = 0;
 104   *usec = (buf.tms_utime + buf.tms_stime) * (1000000 / HZ);
 105 #else /* ! HAVE_TIMES */
 106   /* We have nothing to go on.  Return -1.  */
 107   *sec = -1;
 108   *usec = 0;
 109 #endif  /* HAVE_TIMES */
 110 #endif  /* HAVE_GETRUSAGE */
 111 }
 112
 113 extern void cpu_time_4 (GFC_REAL_4 *);
 114 iexport_proto(cpu_time_4);
 115
 116 void cpu_time_4 (GFC_REAL_4 *time)
 117 {
 118   long sec, usec;
 119   __cpu_time_1 (&sec, &usec);
 120   *time = sec + usec * (GFC_REAL_4)1.e-6;
 121 }
 122 iexport(cpu_time_4);
 123
 124 extern void cpu_time_8 (GFC_REAL_8 *);
 125 export_proto(cpu_time_8);
 126
 127 void cpu_time_8 (GFC_REAL_8 *time)
 128 {
 129   long sec, usec;
 130   __cpu_time_1 (&sec, &usec);
 131   *time = sec + usec * (GFC_REAL_8)1.e-6;
 132 }
 133
 134 extern void second_sub (GFC_REAL_4 *);
 135 export_proto(second_sub);
 136
 137 void
 138 second_sub (GFC_REAL_4 *s)
 139 {
 140   cpu_time_4 (s);
 141 }
 142
 143 extern GFC_REAL_4 second (void);
 144 export_proto(second);
 145
 146 GFC_REAL_4
 147 second (void)
 148 {
 149   GFC_REAL_4 s;
 150   cpu_time_4 (&s);
 151   return s;
 152 }