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

 * This is a simple low level function demonstration on using PAPI_add_events *

 * to add an array of events to a created eventset, we are going to use these *

 * events to monitor a set of instructions, start the counters, read the      *

 * counters and then cleanup the eventset when done. In this example we use   *

 * the presets PAPI_TOT_INS and PAPI_TOT_CYC. PAPI_add_events,PAPI_start,     *

 * PAPI_stop, PAPI_clean_eventset, PAPI_destroy_eventset and                  *

 * PAPI_create_eventset all return PAPI_OK(which is 0) when succesful.        *

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

#include <stdio.h>

#include <stdlib.h>

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

#define NUM_EVENT 2

#define THRESHOLD 100000

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

int main(){

	int i,retval,tmp;

    int EventSet = PAPI_NULL;

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

    int event_codes[NUM_EVENT]={PAPI_TOT_INS,PAPI_TOT_CYC}; 

    char errstring[PAPI_MAX_STR_LEN];

    long long values[NUM_EVENT];

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

   * 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: %s\n", errstring);

    	exit(1);

    }

  	/* Creating event set   */

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

		ERROR_RETURN(retval);

  	/* Add the array of events PAPI_TOT_INS and PAPI_TOT_CYC to the eventset*/

	if ((retval=PAPI_add_events(EventSet, event_codes, NUM_EVENT)) != PAPI_OK)

		ERROR_RETURN(retval);

	/* Start counting */

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

		ERROR_RETURN(retval);

    /*** this is where your computation goes *********/

	for(i=0;i<1000;i++)

    {

    	tmp = tmp+i;

    }  

    /* Stop counting, this reads from the counter as well as stop it. */

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

		ERROR_RETURN(retval);

	printf("\nThe total instructions executed are %lld, total cycles %lld\n",

            values[0],values[1]);

	if ( (retval=PAPI_remove_events(EventSet,event_codes, NUM_EVENT))!=PAPI_OK)

		ERROR_RETURN(retval);

    /* Free all memory and data structures, EventSet must be empty. */

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

		ERROR_RETURN(retval);

    /* free the resources used by PAPI */

    PAPI_shutdown();

    exit(0);

}