ProcessTimer.h

//-----------------------------------------------------------------------------
//
// Module:       ProcessTimer.h
//
// Author:       Feng Xie -- xief@mcmaster.ca
//
// Discription:  Process timer.
//
// Change log:
//   09-06-08    Created.
//
//-----------------------------------------------------------------------------

#ifndef OMC_PROCESS_TIMER_H
#define OMC_PROCESS_TIMER_H

// fixme: set up a proper Makefile
#define HAVE_SYS_RESOURCE_H 1
#define HAVE_SYS_TIME_H 1

#ifdef HAVE_SYS_RESOURCE_H
#include <sys/resource.h>
#endif

#ifdef HAVE_SYS_TIME_H
#include <sys/time.h>
#endif

namespace omc 
{
  class ProcessTimer 
  {
  public:
    ProcessTimer() {}                // constructor
    
    ~ProcessTimer() {}               // destructor

    void start();                    // start the timer
    void stop();                     // end the timer
    
    double elapsed() const;          // elapsed time
    double elapsedUser() const;      // elapsed user time
    double elapsedSys() const;       // elapsed system time

  private:
#ifdef HAVE_SYS_RESOURCE_H
    struct rusage m_start;          
    struct rusage m_stop;
#endif
  };


  // Start the timer.
  inline void ProcessTimer::start() {
#ifdef HAVE_SYS_RESOURCE_H
    getrusage (RUSAGE_SELF, &m_start);
#endif
  }

  // Stop the timer.
  inline void ProcessTimer::stop() {
#ifdef HAVE_SYS_RESOURCE_H
    getrusage (RUSAGE_SELF,&m_stop);
#endif
  }
  
  // Compute the elapsed time: user time + system time.
  inline double ProcessTimer::elapsed() const {
#ifdef HAVE_SYS_RESOURCE_H
    return elapsedUser() + elapsedSys();
#else
    return 0.0;
#endif
  }

  // Compute the elapsed user time.
  inline double ProcessTimer::elapsedUser() const {
#ifdef HAVE_SYS_RESOURCE_H
    return double (m_stop.ru_utime.tv_sec * 10e6 +
                   m_stop.ru_utime.tv_usec -
                   m_start.ru_utime.tv_sec * 10e6 -
                   m_start.ru_utime.tv_usec) / 10e6;
#else
    return 0.0;
#endif
  }

  // Compute the elapsed system time.
  inline double ProcessTimer::elapsedSys() const {
#ifdef HAVE_SYS_RESOURCE_H
    return double (m_stop.ru_stime.tv_sec * 10e6 +
                   m_stop.ru_stime.tv_usec -
                   m_start.ru_stime.tv_sec * 10e6 -
                   m_start.ru_stime.tv_usec) / 10e6;
#else
    return 0.0;
#endif
  }
  
} // namespace omc

#endif // OMC_PROCESS_TIMER_H

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