gold/timer.cc

   1 // timer.cc -- helper class for time accounting
   2
   3 // Copyright 2009, 2010 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 #ifdef HAVE_TIMES
  26 #include <sys/times.h>
  27 #endif
  28
  29 #include "libiberty.h"
  30
  31 #include "timer.h"
  32
  33 namespace gold
  34 {
  35
  36 // Class Timer
  37
  38 Timer::Timer()
  39 {
  40   this->start_time_.wall = 0;
  41   this->start_time_.user = 0;
  42   this->start_time_.sys = 0;
  43 }
  44
  45 // Start counting the time.
  46 void
  47 Timer::start()
  48 {
  49   this->get_time(&this->start_time_);
  50 }
  51
  52 // Record the time used by pass N (0 <= N <= 2).
  53 void
  54 Timer::stamp(int n)
  55 {
  56   gold_assert(n >= 0 && n <= 2);
  57   TimeStats& thispass = this->pass_times_[n];
  58   this->get_time(&thispass);
  59 }
  60
  61 #if HAVE_SYSCONF && defined _SC_CLK_TCK
  62 # define TICKS_PER_SECOND sysconf (_SC_CLK_TCK) /* POSIX 1003.1-1996 */
  63 #else
  64 # ifdef CLK_TCK
  65 #  define TICKS_PER_SECOND CLK_TCK /* POSIX 1003.1-1988; obsolescent */
  66 # else
  67 #  ifdef HZ
  68 #   define TICKS_PER_SECOND HZ  /* traditional UNIX */
  69 #  else
  70 #   define TICKS_PER_SECOND 100 /* often the correct value */
  71 #  endif
  72 # endif
  73 #endif
  74
  75 // times returns statistics in clock_t units.  This variable will hold the
  76 // conversion factor to seconds.  We use a variable that is initialized once
  77 // because sysconf can be slow.
  78 static long ticks_per_sec;
  79 class Timer_init
  80 {
  81  public:
  82   Timer_init()
  83   {
  84     ticks_per_sec = TICKS_PER_SECOND;
  85   }
  86 };
  87 Timer_init timer_init;
  88
  89 // Write the current time information.
  90 void
  91 Timer::get_time(TimeStats *now)
  92 {
  93 #ifdef HAVE_TIMES
  94   tms t;
  95   now->wall = (times(&t) * 1000) / ticks_per_sec;
  96   now->user = (t.tms_utime * 1000) / ticks_per_sec;
  97   now->sys  = (t.tms_stime * 1000) / ticks_per_sec;
  98 #else
  99   now->wall = get_run_time() / 1000;
 100   now->user = 0;
 101   now->sys = 0;
 102 #endif
 103 }
 104
 105 // Return the stats since start was called.
 106 Timer::TimeStats
 107 Timer::get_elapsed_time()
 108 {
 109   TimeStats now;
 110   this->get_time(&now);
 111   TimeStats delta;
 112   delta.wall = now.wall - this->start_time_.wall;
 113   delta.user = now.user - this->start_time_.user;
 114   delta.sys = now.sys - this->start_time_.sys;
 115   return delta;
 116 }
 117
 118 // Return the stats for pass N (0 <= N <= 2).
 119 Timer::TimeStats
 120 Timer::get_pass_time(int n)
 121 {
 122   gold_assert(n >= 0 && n <= 2);
 123   TimeStats thispass = this->pass_times_[n];
 124   TimeStats& lastpass = n > 0 ? this->pass_times_[n-1] : this->start_time_;
 125   thispass.wall -= lastpass.wall;
 126   thispass.user -= lastpass.user;
 127   thispass.sys -= lastpass.sys;
 128   return thispass;
 129 }
 130
 131 }