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

* This example shows how to use PAPI_add_event, PAPI_start, PAPI_read,       *

*  PAPI_stop and PAPI_remove_event.                                          *

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

#include <stdio.h>

#include <stdlib.h>

#include "papi.h" /* This needs to be included every time you use PAPI */

#define NUM_EVENTS 2

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

int main()

{

   int EventSet = PAPI_NULL;

   int tmp, i;

   /*must be initialized to PAPI_NULL before calling PAPI_create_event*/

   long long values[NUM_EVENTS];

   /*This is where we store the values we read from the eventset */

   /* We use number to keep track of the number of events in the EventSet */ 

   int retval, number;

   char errstring[PAPI_MAX_STR_LEN];

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

   *  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 )

      ERROR_RETURN(retval);

   /* Creating the eventset */              

   if ( (retval = PAPI_create_eventset(&EventSet)) != PAPI_OK)

      ERROR_RETURN(retval);

   /* Add Total Instructions Executed to the EventSet */

   if ( (retval = PAPI_add_event(EventSet, PAPI_TOT_INS)) != PAPI_OK)

      ERROR_RETURN(retval);

   /* Add Total Cycles event to the EventSet */

   if ( (retval = PAPI_add_event(EventSet, PAPI_TOT_CYC)) != PAPI_OK)

      ERROR_RETURN(retval);

   /* get the number of events in the event set */

   number = 0;

   if ( (retval = PAPI_list_events(EventSet, NULL, &number)) != PAPI_OK)

      ERROR_RETURN(retval);

   printf("There are %d events in the event set\n", number);

   /* Start counting */

   if ( (retval = PAPI_start(EventSet)) != PAPI_OK)

      ERROR_RETURN(retval);

   /* you can replace your code here */

   tmp=0;

   for (i = 0; i < 2000000; i++)

   {

      tmp = i + tmp;

   }

   /* read the counter values and store them in the values array */

   if ( (retval=PAPI_read(EventSet, values)) != PAPI_OK)

      ERROR_RETURN(retval);

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

   printf("The total cycles executed for the first loop are %lld \n",values[1]);

   /* our slow code again */

   tmp=0;

   for (i = 0; i < 2000000; i++)

   {

      tmp = i + tmp;

   }

   /* Stop counting and store the values into the array */

   if ( (retval = PAPI_stop(EventSet, values)) != PAPI_OK)

      ERROR_RETURN(retval);

   printf("Total instructions executed are %lld \n", values[0] );

   printf("Total cycles executed are %lld \n",values[1]);

   /* Remove event: We are going to take the PAPI_TOT_INS from the eventset */

   if( (retval = PAPI_remove_event(EventSet, PAPI_TOT_INS)) != PAPI_OK)

      ERROR_RETURN(retval);

   printf("Removing PAPI_TOT_INS from the eventset\n"); 

   /* Now we list how many events are left on the event set */

   number = 0;

   if ((retval=PAPI_list_events(EventSet, NULL, &number))!= PAPI_OK)

      ERROR_RETURN(retval);

   printf("There is only %d event left in the eventset now\n", number);

   /* free the resources used by PAPI */

   PAPI_shutdown();

   exit(0);

}