gold/timer.cc

   1 // timer.cc -- helper class for time accounting
   2
   3 // Copyright (C) 2009-2015 Free Software Foundation, Inc.
   4 // Written by Rafael Avila de Espindola <espindola@google.com>.
   5
   6 // This file is part of gold.
   7
   8 // This program is free software; you can redistribute it and/or modify
   9 // it under the terms of the GNU General Public License as published by
  10 // the Free Software Foundation; either version 3 of the License, or
  11 // (at your option) any later version.
  12
  13 // This program is distributed in the hope that it will be useful,
  14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 // GNU General Public License for more details.
  17
  18 // You should have received a copy of the GNU General Public License
  19 // along with this program; if not, write to the Free Software
  20 // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
  21 // MA 02110-1301, USA.
  22
  23 #include "gold.h"
  24
  25 #include <unistd.h>
  26
  27 #ifdef HAVE_TIMES
  28 #include <sys/times.h>
  29 #endif
  30
  31 #include "libiberty.h"
  32
  33 #include "timer.h"
  34
  35 namespace gold
  36 {
  37
  38 // Class Timer
  39
  40 Timer::Timer()
  41 {
  42   this->start_time_.wall = 0;
  43   this->start_time_.user = 0;
  44   this->start_time_.sys = 0;
  45 }
  46
  47 // Start counting the time.
  48 void
  49 Timer::start()
  50 {
  51   this->get_time(&this->start_time_);
  52 }
  53
  54 // Record the time used by pass N (0 <= N <= 2).
  55 void
  56 Timer::stamp(int n)
  57 {
  58   gold_assert(n >= 0 && n <= 2);
  59   TimeStats& thispass = this->pass_times_[n];
  60   this->get_time(&thispass);
  61 }
  62
  63 #if HAVE_SYSCONF && defined _SC_CLK_TCK
  64 # define TICKS_PER_SECOND sysconf (_SC_CLK_TCK) /* POSIX 1003.1-1996 */
  65 #else
  66 # ifdef CLK_TCK
  67 #  define TICKS_PER_SECOND CLK_TCK /* POSIX 1003.1-1988; obsolescent */
  68 # else
  69 #  ifdef HZ
  70 #   define TICKS_PER_SECOND HZ  /* traditional UNIX */
  71 #  else
  72 #   define TICKS_PER_SECOND 100 /* often the correct value */
  73 #  endif
  74 # endif
  75 #endif
  76
  77 // times returns statistics in clock_t units.  This variable will hold the
  78 // conversion factor to seconds.  We use a variable that is initialized once
  79 // because sysconf can be slow.
  80 static long ticks_per_sec;
  81 class Timer_init
  82 {
  83  public:
  84   Timer_init()
  85   {
  86     ticks_per_sec = TICKS_PER_SECOND;
  87   }
  88 };
  89 Timer_init timer_init;
  90
  91 // Write the current time information.
  92 void
  93 Timer::get_time(TimeStats *now)
  94 {
  95 #ifdef HAVE_TIMES
  96   tms t;
  97   now->wall = (times(&t) * 1000) / ticks_per_sec;
  98   now->user = (t.tms_utime * 1000) / ticks_per_sec;
  99   now->sys  = (t.tms_stime * 1000) / ticks_per_sec;
 100 #else
 101   now->wall = get_run_time() / 1000;
 102   now->user = 0;
 103   now->sys = 0;
 104 #endif
 105 }
 106
 107 // Return the stats since start was called.
 108 Timer::TimeStats
 109 Timer::get_elapsed_time()
 110 {
 111   TimeStats now;
 112   this->get_time(&now);
 113   TimeStats delta;
 114   delta.wall = now.wall - this->start_time_.wall;
 115   delta.user = now.user - this->start_time_.user;
 116   delta.sys = now.sys - this->start_time_.sys;
 117   return delta;
 118 }
 119
 120 // Return the stats for pass N (0 <= N <= 2).
 121 Timer::TimeStats
 122 Timer::get_pass_time(int n)
 123 {
 124   gold_assert(n >= 0 && n <= 2);
 125   TimeStats thispass = this->pass_times_[n];
 126   TimeStats& lastpass = n > 0 ? this->pass_times_[n-1] : this->start_time_;
 127   thispass.wall -= lastpass.wall;
 128   thispass.user -= lastpass.user;
 129   thispass.sys -= lastpass.sys;
 130   return thispass;
 131 }
 132
 133 }