PAPI_flips.c

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/*****************************************************************************
 * This example demonstrates the usage of the function PAPI_flips_rate which *
 * measures the number of floating point instructions executed and the       *
 * MegaFlip rate(defined as the number of floating point instructions per    *
 * microsecond). To use PAPI_flips_rate you need to have floating point      *
 * instructions events supported by the platform.                             *
 *****************************************************************************/
 
/*****************************************************************************
 * The first call to PAPI_flips_rate initializes the PAPI library, set up    *
 * the counters to monitor the floating point instructions event, and start  *
 * the counters. Subsequent calls will read the counters and return          *
 * real time, process time, floating point instructions, and the Mflips/s    *
 * rate since the latest call to PAPI_flips_rate.                              *
 *****************************************************************************/
 
 
 
#include <stdio.h>
#include <stdlib.h>
#include "papi.h"
 
int your_slow_code();
 
int main()
{ 
  float real_time, proc_time,mflips;
  long long flpins;
  float ireal_time, iproc_time, imflips;
  long long iflpins;
  int retval;
 
  /***********************************************************************
   * if PAPI_FP_INS is a derived event in your platform, then your       * 
   * platform must have at least three counters to support PAPI_flips,   *
   * because PAPI needs one counter to cycles. So in UltraSparcIII, even *
   * the platform supports PAPI_FP_INS, but UltraSparcIII only have two  *
   * available hardware counters and PAPI_FP_INS is a derived event in   *
   * this platform, so PAPI_flops returns an error.                      *
   ***********************************************************************/
 
  if((retval=PAPI_flips_rate(PAPI_FP_INS,&ireal_time,&iproc_time,&iflpins,&imflips)) < PAPI_OK)
  { 
    printf("Could not initialise PAPI_flips \n");
    printf("Your platform may not support floating point instruction event.\n");    printf("retval: %d\n", retval);
    exit(1);
  }
 
  your_slow_code();
 
  
  if((retval=PAPI_flips_rate(PAPI_FP_INS,&real_time, &proc_time, &flpins, &mflips))<PAPI_OK)
  {    
    printf("retval: %d\n", retval);
    exit(1);
  }
 
 
  printf("Real_time: %f Proc_time: %f flpins: %lld MFLIPS: %f\n", 
         real_time, proc_time,flpins,mflips);
 
  exit(0);
}
 
int your_slow_code()
{
  int i;
  double  tmp=1.1;
 
  for(i=1; i<2000; i++)
  { 
    tmp=(tmp+100)/i;
  }
  return 0;
}