/*****************************************************************************

*  This example code shows how to use most of PAPI's High level functions    * 

*  to start,count,read and stop on an event set. We use two preset events    *

*  here:                                                                     *

*     PAPI_TOT_INS: Total instructions executed in a period of time		     *

*     PAPI_TOT_CYC: Total cpu cycles in a period of time		             *

******************************************************************************/ 

#include <stdio.h>

#include <stdlib.h>

#include "papi.h"

#define NUM_EVENTS 2

#define THRESHOLD 10000

#define ERROR_RETURN(retval) { fprintf(stderr, "Error %d %s:line %d: \n", retval,__FILE__,__LINE__);  exit(retval); }

/* stupid codes to be monitored */ 

void computation_mult()

{

   double tmp=1.0;

   int i=1;

   for( i = 1; i < THRESHOLD; i++ )

   {

      tmp = tmp*i;

   }

}

/* stupid codes to be monitored */ 

void computation_add()

{

   int tmp = 0;

   int i=0;

   for( i = 0; i < THRESHOLD; i++ )

   {

      tmp = tmp + i;

   }

}

int main()

{

   /*Declaring and initializing the event set with the presets*/

   int Events[2] = {PAPI_TOT_INS, PAPI_TOT_CYC};

   /*The length of the events array should be no longer than the 

     value returned by PAPI_num_counters.*/	

   /*declaring place holder for no of hardware counters */

   int num_hwcntrs = 0;

   int retval;

   char errstring[PAPI_MAX_STR_LEN];

   /*This is going to store our list of results*/

   long long values[NUM_EVENTS];

   /***************************************************************************

   *  This part initializes the library and compares the version number of the*

   * header file, to the version of the library, if these don't match then it *

   * is likely that PAPI won't work correctly.If there is an error, retval    *

   * keeps track of the version number.                                       *

   ***************************************************************************/

   if((retval = PAPI_library_init(PAPI_VER_CURRENT)) != PAPI_VER_CURRENT )

   {

      fprintf(stderr, "Error: %d %s\n",retval, errstring);

      exit(1);

   }

   /**************************************************************************

    * PAPI_num_counters returns the number of hardware counters the platform *

    * has or a negative number if there is an error                          *

    **************************************************************************/

   if ((num_hwcntrs = PAPI_num_counters()) < PAPI_OK)

   {

      printf("There are no counters available. \n");

      exit(1);

   }

   printf("There are %d counters in this system\n",num_hwcntrs);

   /**************************************************************************

    * PAPI_start_counters initializes the PAPI library (if necessary) and    *

    * starts counting the events named in the events array. This function    *

    * implicitly stops and initializes any counters running as a result of   *

    * a previous call to PAPI_start_counters.                                *

    **************************************************************************/

   if ( (retval = PAPI_start_counters(Events, NUM_EVENTS)) != PAPI_OK)

       ERROR_RETURN(retval);

   printf("\nCounter Started: \n");

   /* Your code goes here*/

   computation_add();

   /**********************************************************************

    * PAPI_read_counters reads the counter values into values array      *

    **********************************************************************/

   if ( (retval=PAPI_read_counters(values, NUM_EVENTS)) != PAPI_OK)

      ERROR_RETURN(retval);

   printf("Read successfully\n");

   printf("The total instructions executed for addition are %lld \n",values[0]);

   printf("The total cycles used are %lld \n", values[1] );

   printf("\nNow we try to use PAPI_accum to accumulate values\n"); 

   /* Do some computation here */

   computation_add();

   /************************************************************************

    * What PAPI_accum_counters does is it adds the running counter values  *

    * to what is in the values array. The hardware counters are reset and  *

    * left running after the call.                                         *

    ************************************************************************/

   if ( (retval=PAPI_accum_counters(values, NUM_EVENTS)) != PAPI_OK)

      ERROR_RETURN(retval);

   printf("We did an additional %d times addition!\n", THRESHOLD);

   printf("The total instructions executed for addition are %lld \n",

			values[0] );

   printf("The total cycles used are %lld \n", values[1] );

   /***********************************************************************

    * Stop counting events(this reads the counters as well as stops them  *

    ***********************************************************************/

   printf("\nNow we try to do some multiplications\n");

   computation_mult();

   /******************* PAPI_stop_counters **********************************/

   if ((retval=PAPI_stop_counters(values, NUM_EVENTS)) != PAPI_OK)

      ERROR_RETURN(retval);	

   printf("The total instruction executed for multiplication are %lld \n",

               values[0] );

   printf("The total cycles used are %lld \n", values[1] );

   exit(0);	

}