jitterometer.h

Go to the documentation of this file.

#ifndef JITTEROMETER_H
#define JITTEROMETER_H
 
// Qt
#include <QVector>
#include <QFile>
 
// MythTV
#include "mythtvexp.h"
 
// Std
#include <sys/time.h>
 
/* Jitterometer usage. There are 2 ways to use this:
------------------------------------------------------------------
 
 1.  Every 100 iterations of the for loop, RecordCycleTime() will
     print a report about the mean time to execute the loop, and
     the jitter in the recorded times.
 
       my_jmeter = new Jitterometer("forloop", 100);
       for ( ) {
         ... some stuff ...
         my_jmeter->RecordCycleTime();
       }
 
-------------------------------------------------------------------
 
2.  Every 42 times Weird_Operation() is run, RecordEndTime() will
    print a report about the mean time to do a Weird_Operation(), and
    the jitter in the recorded times.
 
      beer = new Jitterometer("weird operation", 42);
      for( ) {
         ...
         beer->RecordStartTime();
         Weird_Operation();
         beer->RecordEndTime();
         ...
      }
*/
 
class MTV_PUBLIC Jitterometer
{
  public:
    explicit Jitterometer(QString nname, int ncycles = 0);
   ~Jitterometer();
 
    // Deleted functions should be public.
    Jitterometer(const Jitterometer &) = delete;            // not copyable
    Jitterometer &operator=(const Jitterometer &) = delete; // not copyable
 
    float GetLastFPS(void) const { return m_lastFps; }
    float GetLastSD(void) const { return m_lastSd;  }
    QString GetLastCPUStats(void) const { return m_lastCpuStats; }
    void SetNumCycles(int cycles);
    bool RecordCycleTime();
    void RecordStartTime();
    bool RecordEndTime();
    QString GetCPUStat(void);
 
 private:
    int                 m_count           {0};
    int                 m_numCycles;
    std::chrono::microseconds  m_starttime {-1us};
    QVector<std::chrono::microseconds> m_times; // array of cycle lengths
    float               m_lastFps         {0};
    float               m_lastSd          {0};
    QString             m_name;
    QFile              *m_cpuStat         {nullptr};
    unsigned long long *m_lastStats       {nullptr};
    QString             m_lastCpuStats;
};
 
#endif // JITTEROMETER_H