kc3-lang/angle/util/linux/LinuxTimer.cpp

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• Author : Corentin Wallez
  Date : 2015-05-21 15:26:15
  Hash : 5b2545bf
  Message : Correct LinuxTimer time calculations Changes to CLOCK_MONOTONIC as CLOCK_PROCESS_CPUTIME counts only user time and not kernel time. BUG=angleproject:892 Change-Id: I3d5aee26ee2bacd7449fdd7795ad8c2b289d7324 Reviewed-on: https://chromium-review.googlesource.com/272652 Reviewed-by: Jamie Madill <jmadill@chromium.org> Reviewed-by: Geoff Lang <geofflang@chromium.org> Tested-by: Corentin Wallez <cwallez@chromium.org>

• util/linux/LinuxTimer.cpp

• //
  // Copyright (c) 2015 The ANGLE Project Authors. All rights reserved.
  // Use of this source code is governed by a BSD-style license that can be
  // found in the LICENSE file.
  //
  
  // LinuxTimer.cpp: Implementation of a high precision timer class on Linux
  
  #include "linux/LinuxTimer.h"
  #include <iostream>
  
  LinuxTimer::LinuxTimer()
      : mRunning(false)
  {
  }
  
  void LinuxTimer::start()
  {
      clock_gettime(CLOCK_MONOTONIC, &mStartTime);
      mRunning = true;
  }
  
  void LinuxTimer::stop()
  {
      clock_gettime(CLOCK_MONOTONIC, &mStopTime);
      mRunning = false;
  }
  
  double LinuxTimer::getElapsedTime() const
  {
      struct timespec endTime;
      if (mRunning)
      {
          clock_gettime(CLOCK_MONOTONIC, &endTime);
      }
      else
      {
          endTime = mStopTime;
      }
  
      double startSeconds = mStartTime.tv_sec + (1.0 / 1000000000) * mStartTime.tv_nsec;
      double endSeconds = endTime.tv_sec + (1.0 / 1000000000) * endTime.tv_nsec;
      return endSeconds - startSeconds;
  }
  
  Timer *CreateTimer()
  {
      return new LinuxTimer();
  }