mariadb-columnstore-engine/utils/loggingcpp/stopwatch.h

/* Copyright (C) 2014 InfiniDB, Inc.

   This program 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; version 2 of
   the License.

   This program 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 this program; if not, write to the Free Software
   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
   MA 02110-1301, USA. */

//
// $Id$
//
// Timer class used to spit out times and percentages.  Temporarily lives in joblist.
// This is strictly a debugging utility class that accumulates times between .start() and
// .stop() calls for a particular string.  It can be useful in tdrivers.
//
// It outputs a report when finish() is called with
// the total times by string and their percentage of the total.  The total is tracked from
// the first time start() is called until finish() is called.  You should always match your
// start and stop calls up.
//
// This works fine as long as you don't use it with huge numbers of calls.  If you call start
// and stop too many times the overhead of the StopWatch class will start factoring in to your
// results.
//
// How to use:
//
// 	StopWatch timer;
// 	timer.start("Loop only");
// 	for(int i = 0; i < 6999075; i++)
// 	{
// 	}
// 	timer.stop("Loop only");
//
// 	timer.start("Loop Plus");
// 	for(int i = 0; i < 100000; i++)
// 	{
// 		timer.start("Inside loop");
// 		timer.stop("Inside loop");
// 	}
// 	timer.stop("Loop Plus");
// 	timer.finish();
//
// Produces this:
//
// Seconds  Percentage  Calls      Description
// 0.02865  9.377%      1          Loop only
// 0.27680  90.59%      1          Loop Plus
// 0.12138  39.72%      100000     Inside loop
//
// 0.30553  100  %      1          Total
//
// Note that you can have overlapping timers which will make your percentages add up to more than 100%.
#pragma once
#include <iostream>
#include <fstream>
#include <list>
#include <sstream>
#include <time.h>
#include <sys/time.h>
#include <vector>
#include <stdexcept>
#include <map>
#include <unistd.h>

namespace logging
{
class StopWatch
{
 public:
  void start(const std::string& message);
  bool stop(const std::string& message, const int limit);
  void stop(const std::string& message);
  void finish();

  bool isActive()
  {
    return fOpenCalls > 0;
  }
  StopWatch() : fStarted(false), fId(-1), fOpenCalls(0), fOutputToFile(false), fLogFile(""){};
  StopWatch(int id) : fStarted(false), fId(id), fOpenCalls(0), fOutputToFile(false), fLogFile(""){};
  StopWatch(const std::string& fileName)
   : fStarted(false), fId(-1), fOpenCalls(0), fOutputToFile(true), fLogFile(fileName)
  {
  }
  struct ::timeval fTvLast;
  int getId()
  {
    return fId;
  }

 private:
  class ProcessStats
  {
   public:
    std::string fProcess;
    struct timeval fTvProcessStarted;
    double fTotalSeconds;
    int64_t fStartCount;
    int64_t fStopCount;

    ProcessStats() : fProcess(""), fTotalSeconds(0.0), fStartCount(0), fStopCount(0){};

    void processStart()
    {
      gettimeofday(&fTvProcessStarted, 0);
      fStartCount++;
    }

    void processStop()
    {
      struct timeval tvStop;
      gettimeofday(&tvStop, 0);
      fStopCount++;
      fTotalSeconds += (tvStop.tv_sec + (tvStop.tv_usec / 1000000.0)) -
                       (fTvProcessStarted.tv_sec + (fTvProcessStarted.tv_usec / 1000000.0));
    }
  };

  struct timeval fTvStart;
  std::vector<ProcessStats> fProcessStats;
  bool fStarted;
  int fId;
  int fOpenCalls;
  bool fOutputToFile;
  std::string fLogFile;
};

}  // namespace logging