paraSysTimer.h

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/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
/*                                                                           */
/*          This file is part of the program and software framework          */
/*                    UG --- Ubquity Generator Framework                     */
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/*  Copyright Written by Yuji Shinano <shinano@zib.de>,                      */
/*            Copyright (C) 2021-2026 by Zuse Institute Berlin,              */
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/* modify it under the terms of the GNU Lesser General Public License        */
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/**@file    paraSysTimer.h
 * @brief   System timer.
 * @author  Yuji Shinano
 *
 *
 *
 */
 
/*---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8----+----9----+----0----+----1----+----2*/
 
 
#ifndef __PARA_SYS_TIMER_H__
#define __PARA_SYS_TIMER_H__
 
//-------------------
// include files
//-------------------
#include <chrono>
#include "paraTimer.h"
 
namespace UG
{
 
///
/// Class ParaSysTimer
///
/// Wall-clock timing uses std::chrono::steady_clock (monotonic, high
/// resolution). Process CPU user/system time uses getrusage() where available.
///
/// (Historically the real-time path was implemented with times()/HZ under a
/// SYSV code path. On Linux times() reports in units of sysconf(_SC_CLK_TCK)
/// (100), but TICKS was defined as the kernel HZ, so the elapsed wall time was
/// scaled by the wrong constant -- a ~600 s run was measured as ~14 s, which in
/// turn made the "limits/time" derived from it far too large. Using std::chrono
/// removes the platform-specific tick arithmetic entirely.)
///
class ParaSysTimer : public ParaTimer {
 
   std::chrono::steady_clock::time_point startPoint;   ///< real time at start()
   std::chrono::steady_clock::time_point stopPoint;    ///< real time at stop()
   double uTimeStart;   ///< process user   CPU seconds at start()
   double uTimeStop;    ///< process user   CPU seconds at stop()
   double sTimeStart;   ///< process system CPU seconds at start()
   double sTimeStop;    ///< process system CPU seconds at stop()
 
public:
 
   ///
   /// default constructor
   ///
   ParaSysTimer(
         )
         : startPoint(), stopPoint(),
           uTimeStart(0.0), uTimeStop(0.0), sTimeStart(0.0), sTimeStop(0.0)
   {
   }
 
   ///
   /// destructor
   ///
   ~ParaSysTimer(
         )
   {
   }
 
   ///
   /// initialize timer
   ///
   void init(
         ParaComm* paraComm     ///< communicator used
         )
   {
      start();
   }
 
   ///
   /// get elapsed time
   /// @return elapsed time
   ///
   double getElapsedTime(
         )
   {
      return getRTimeInterval();
   }
 
   ///
   /// start timer
   ///
   void    start(
         void
         );
 
   ///
   /// stop timer
   ///
   void    stop(
         void
         );
 
   ///
   /// get start time
   /// @return start time
   ///
   double  getStartTime(
         void
         );
 
   ///
   /// get elapsed time from start time
   /// @return elapsed time
   ///
   double  getRTimeInterval(
         void
         );
 
   ///
   /// get real time between start timne and stop time
   /// @return real time
   ///
   double  getRTime(
         void
         );
 
   ///
   /// get user time between start timne and stop time
   /// @return user time
   ///
   double  getUTime(
         void
         );
 
   ///
   /// get system time between start timne and stop time
   /// @return system time
   ///
   double  getSTime(
         void
         );
 
};
 
}
 
#endif  // __PARA_SYS_TIMER_H__