timer.hh

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// -*- mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
// vi: set et ts=4 sw=4 sts=4:
/*
  This file is part of the Open Porous Media project (OPM).
 
  OPM is free software: you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation, either version 2 of the License, or
  (at your option) any later version.
 
  OPM is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.
 
  You should have received a copy of the GNU General Public License
  along with OPM.  If not, see <http://www.gnu.org/licenses/>.
 
  Consult the COPYING file in the top-level source directory of this
  module for the precise wording of the license and the list of
  copyright holders.
*/
#ifndef EWOMS_TIMER_HH
#define EWOMS_TIMER_HH
 
#include <chrono>
 
#if HAVE_MPI
#include <mpi.h>
#endif
 
namespace Opm {
class Timer
{
    struct TimeData
    {
        std::chrono::high_resolution_clock::time_point realtimeData;
        std::clock_t cputimeData;
    };
public:
    Timer()
    { halt(); }
 
    void start()
    {
        isStopped_ = false;
        measure_(startTime_);
    }
 
    double stop()
    {
        if (!isStopped_) {
            TimeData stopTime;
 
            measure_(stopTime);
 
            const auto& t1 = startTime_.realtimeData;
            const auto& t2 = stopTime.realtimeData;
            std::chrono::duration<double> dt =
                std::chrono::duration_cast<std::chrono::duration<double> >(t2 - t1);
 
            realTimeElapsed_ += dt.count();
            cpuTimeElapsed_ +=
                static_cast<double>(stopTime.cputimeData
                                    - startTime_.cputimeData)/CLOCKS_PER_SEC;
        }
 
        isStopped_ = true;
 
        return realTimeElapsed_;
    }
 
    void halt()
    {
        isStopped_ = true;
        cpuTimeElapsed_ = 0.0;
        realTimeElapsed_ = 0.0;
    }
 
    void reset()
    {
        cpuTimeElapsed_ = 0.0;
        realTimeElapsed_ = 0.0;
 
        measure_(startTime_);
    }
 
    double realTimeElapsed() const
    {
        if (isStopped_)
            return realTimeElapsed_;
 
        TimeData stopTime;
 
        measure_(stopTime);
 
        const auto& t1 = startTime_.realtimeData;
        const auto& t2 = stopTime.realtimeData;
        std::chrono::duration<double> dt =
            std::chrono::duration_cast<std::chrono::duration<double> >(t2 - t1);
 
        return realTimeElapsed_ + dt.count();
    }
 
    double elapsed() const
    { return realTimeElapsed(); }
 
    double cpuTimeElapsed() const
    {
        if (isStopped_)
            return cpuTimeElapsed_;
 
        TimeData stopTime;
 
        measure_(stopTime);
 
        const auto& t1 = startTime_.cputimeData;
        const auto& t2 = stopTime.cputimeData;
 
        return cpuTimeElapsed_ + static_cast<double>(t2 - t1)/CLOCKS_PER_SEC;
    }
 
    double globalCpuTimeElapsed() const
    {
        double val = cpuTimeElapsed();
        double globalVal = val;
 
#if HAVE_MPI
        MPI_Reduce(&val,
                   &globalVal,
                   /*count=*/1,
                   MPI_DOUBLE,
                   MPI_SUM,
                   /*rootRank=*/0,
                   MPI_COMM_WORLD);
#endif
 
        return globalVal;
    }
 
    Timer& operator+=(const Timer& other)
    {
        realTimeElapsed_ += other.realTimeElapsed();
        cpuTimeElapsed_ += other.cpuTimeElapsed();
 
        return *this;
    }
 
private:
    // measure the current time and put it into the object passed via
    // the argument.
    static void measure_(TimeData& timeData)
    {
        // Note: On Linux -- or rather fully POSIX compliant systems -- using
        // clock_gettime() would be more accurate for the CPU time.
        timeData.realtimeData = std::chrono::high_resolution_clock::now();
        timeData.cputimeData = std::clock();
    }
 
    bool isStopped_;
    double cpuTimeElapsed_;
    double realTimeElapsed_;
    TimeData startTime_;
};
} // namespace Opm
 
#endif