perftimer.h

网络流量采集及分析软件

/*! \file   PerfTimer.h

    Copyright 2003-2004 Fraunhofer Institute for Open Communication Systems (FOKUS),
                        Berlin, Germany

    This file is part of Network Measurement and Accounting System (NETMATE).

    NETMATE 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; either version 2 of the License, or
    (at your option) any later version.

    NETMATE 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 software; if not, write to the Free Software 
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

    Description:
    performance timing functions

    $Id: PerfTimer.h,v 1.1.1.1 2004/12/23 05:52:35 s_zander Exp $
*/

#ifndef _PERFTIMER_H_
#define _PERFTIMER_H_


#include "stdincpp.h"
#include "Logger.h"


/*! \short predefined identifiers for performance measurement slots */
enum perfSlots 
{ 
    slot1=0, 
    slot2, 
    slot3, 
    MS_MODULE, 
    MS_EXPORT, 
    MS_INSTALL,
    MAXPERFSLOTS 
};

/*! \short this struct stores a line of measured clock ticks */
struct tickDuration
{
    unsigned long long start; //!< start clock tick counter
    unsigned long long last;  //!< clock tick duration for last measurement
    unsigned long long sum;   //!< accumulated clock ticks
    int num;                  //!< number of measurements
};


//!   the PerfTimer class stores timestamps for performance measurments

class PerfTimer
{
  private:

    static PerfTimer *s_instance;

    Logger *log;
    int ch; //! logging channel number used by objects of this class

    //!< system clock speed in MHz
    double clockSpeed;

    //!< system clock speed in MHz
    unsigned int clockSpeed_int;

    //!< wasted CPU cycles per measurement
    unsigned int overhead;

    //!< table of performance measurement results
    tickDuration ticks[MAXPERFSLOTS];

    /*! \short   short read system clock speed from /proc/cpuinfo
        \returns system clock speed in MHz, -1.0 if not available
    */
    double readClockSpeed();

    //! construct and initialize a PerfTimer object
    PerfTimer();

  public:

    /*! \short   read system clock tick counter from cpu
        \returns number of CPU clock ticks since last reboot
    */
    static __inline__ unsigned long long readTSC()
    {
        unsigned long long x = 0;

#if (INTEL && PROFILING)
        __asm__ volatile (".byte 0x0f, 0x31" : "=A" (x));
#else
        x = 0;
#endif
        return x;
    }

    //! access the one and only PerfTimer instance
    static PerfTimer *getInstance();

    //! destroy a PerfTimer object
    ~PerfTimer();

    /*! \short   //!< get system clock speed in MHz
        \returns system clock speed in MHz, -1.0 if not available
    */
    double getClockSpeed() 
    { 
        return clockSpeed; 
    }

    /*! \short   start measurement for one slot
        \arg \c slot - number of measurement slot
    */
    void start( int slot );

    /*! \short   end measurement for one slot and record number of ticks
        \arg \c slot - number of measurement slot
    */
    void stop( int slot );

    /*! \short   account measurement with 'ticks' clock ticks for slot 'slot'
        \arg \c slot - number of measurement slot
        \arg \c ticks - number of CPU clock ticks from independant measurement
    */
    void account( int slot, unsigned long long ticks );

    /*! \short   calculate number of nsec taken for latest measurements for one specific slot
        \arg \c slot - number of measurement slot
    */
    unsigned long long latest( int slot );

    /*! \short   calculate average number of nsec taken for measurements for one slot
        \arg \c slot - number of measurement slot
    */
    unsigned long long avg( int slot );

    /*! \short   convert number of clock ticks into number of nanoseconds
        \arg \c runs  - number of measurements that accumulated the clock ticks
        \arg \c ticks - number of accumulated clock ticks
        \returns number of nanoseconds elapsed during one measurement on average

        warning: this function assumes the measurement overhead is still included
        in the number of clock ticks spent and subtracts runs*overhead !
    */
    static unsigned long long ticks2ns( unsigned int runs, unsigned long long ticks );
    static unsigned long long ticks2ns( unsigned long long ticks );

    //! dump a PerfTimer object
    void dump( ostream &os );
};


//! overload for <<, so that a PerfTimer object can be thrown into an ostream
ostream& operator<< ( ostream &os, PerfTimer &obj );


#endif // _PERFTIMER_H_