TimeIt.h

/**************************************************************************
 * basf2 (Belle II Analysis Software Framework)                           *
 * Author: The Belle II Collaboration                                     *
 *                                                                        *
 * See git log for contributors and copyright holders.                    *
 * This file is licensed under LGPL-3.0, see LICENSE.md.                  *
 **************************************************************************/
#pragma once
 
#ifdef HAS_CALLGRIND
#include <valgrind/callgrind.h>
#endif
 
#include <framework/logging/Logger.h>
 
#include <vector>
#include <functional>
#include <chrono>
#include <numeric>
 
namespace Belle2 {
  namespace TrackFindingCDC {
 
    class TimeItResult {
    public:
      explicit TimeItResult(const std::vector<std::chrono::duration<double> >& timeSpans) :
        m_timeSpans(timeSpans)
      {}
 
      double getSeconds(size_t iExecution) const
      {
        return m_timeSpans.at(iExecution).count();
      }
 
      double getAverageSeconds() const
      {
        std::chrono::duration<double> sumTimeSpan =
          std::accumulate(m_timeSpans.begin(), m_timeSpans.end(), std::chrono::duration<double>());
 
        std::chrono::duration<double> avgTimeSpan = sumTimeSpan / m_timeSpans.size();
        return avgTimeSpan.count();
      }
 
      size_t getNExecutions() const
      { return m_timeSpans.size(); }
 
      void printSummary() const
      {
        B2INFO("First execution took " << getSeconds(0) << " seconds ");
        B2INFO("On average execution took " << getAverageSeconds() << " seconds " <<
               "in " << getNExecutions() << " executions.");
      }
 
    private:
      std::vector<std::chrono::duration<double> > m_timeSpans;
 
    };
 
    const std::function<void()> doNothing = []() {};
 
    template<class AFunction >
    TimeItResult
    timeIt(size_t nExecutions,
           bool activateCallgrind,
           const AFunction& function,
           const std::function<void()>& setUp = doNothing,
           const std::function<void()>& tearDown = doNothing)
    {
      using namespace std::chrono;
 
      std::vector<duration<double>> timeSpans;
      timeSpans.reserve(nExecutions);
 
      for (std::size_t iExecution = 0; iExecution < nExecutions; ++iExecution) {
        setUp();
 
        auto now = std::chrono::high_resolution_clock::now();
 
        if (activateCallgrind) {
#ifdef HAS_CALLGRIND
          CALLGRIND_START_INSTRUMENTATION;
#endif
        }
 
        function();
 
        if (activateCallgrind) {
#ifdef HAS_CALLGRIND
          CALLGRIND_STOP_INSTRUMENTATION;
#endif
        }
 
        auto later = std::chrono::high_resolution_clock::now();
 
        duration<double> timeSpan = duration_cast<duration<double> >(later - now);
        timeSpans.push_back(timeSpan);
        tearDown();
      }
      return TimeItResult(timeSpans);
    }
  }
}