/* 
   Example C program to test the different event counters.  Before
   compiling ensure that the PAPI module has been loaded and the
   environment variables PAPI_INC and PAPI_LIB are set.  To compile
   issue the command:

   icc -I$PAPI_INC papi_event_test.c -L$PAPI_LIB -lpapi

   You can experiment with how the different counters interact by 
   changing the order of the Events variable.  Also, the number of 
   events that are actually counted is specified by the nevents variable
*/

#include <papi.h>
#include <stdio.h>
#define NUM_FLOPS 200000
#define NUM_EVENTS 20

int handle_error(int code, char *outstring)
{
  printf("Error in PAPI function call %s\n", outstring);
  char errmesg[PAPI_MAX_STR_LEN];
  PAPI_perror(code, errmesg, PAPI_MAX_STR_LEN);
  printf("PAPI Error %i: %s\n", code, errmesg);
  exit(1);
}

void dummy(void *array)
{

/* Confuse the compiler so as not to optimize
   away the flops in the calling routine    */
}

volatile double a = 0.5, b = 2.2;

void do_flops(int n)
{
   int i;
   double c = 0.11;

   for (i = 0; i < n; i++) {
     c += a * b;
   }
   dummy((void *) &c);
}

main()
{
  /* the events listed below are all of the available 
     events for a P4 using PAPI 3.0 */
  int Events[NUM_EVENTS] = {PAPI_FP_OPS     ,  
                            PAPI_TOT_CYC    ,
                            PAPI_TOT_INS    ,
                            PAPI_L2_DCM     ,
                            PAPI_FP_INS     ,
                            PAPI_BR_INS     ,
                            PAPI_L2_LDM     ,
                            PAPI_VEC_INS    ,
                            PAPI_RES_STL    ,
                            PAPI_TLB_DM     ,
                            PAPI_TLB_IM     ,
                            PAPI_TLB_TL     ,
                            PAPI_BR_TKN     ,
                            PAPI_BR_NTK     ,
                            PAPI_BR_MSP     ,
                            PAPI_BR_PRC     ,
                            PAPI_L1_LDM     ,
                            PAPI_L1_DCM     ,
                            PAPI_L1_DCA };
  long_long values[NUM_EVENTS];
          
  int code;
  int nevents;
  char in_string[80];

  char event_name[PAPI_MAX_STR_LEN];
  float rtime, ptime, mflips, mflops;
  long_long flpins;

  nevents = 4;
  printf("\nTrying %i events\n", nevents);

  /* Start counting events */

  if ((code=PAPI_start_counters(Events, nevents)) != PAPI_OK)
    handle_error(code, "start_counters");
  
  do_flops(NUM_FLOPS);
  
  /* Read the counters */
  
  if ((code=PAPI_read_counters(values, nevents)) != PAPI_OK)
    handle_error(code, "read_counters");
  
  printf("After reading the counters:\n");
  for(int j=0;j<nevents;j++)
    {
      PAPI_event_code_to_name(Events[j], event_name);
      printf("Event %s -> %lld\n", event_name, values[j]);
    }
  
  do_flops(NUM_FLOPS);
  
  /* Add the counters */
  
  if ((code=PAPI_accum_counters(values, nevents)) != PAPI_OK)
    handle_error(code, "accum_counters");
  
  printf("After accumulating the counters:\n");
  for(int j=0;j<nevents;j++)
    {
      PAPI_event_code_to_name(Events[j], event_name);
      printf("Event %s -> %lld\n", event_name, values[j]);
    }

  do_flops(NUM_FLOPS);
  
  /* Stop counting events */
  
  if ((code=PAPI_stop_counters(values, nevents)) != PAPI_OK)
    handle_error(code, "stop_counters");
  
  printf("After stopping the counters:\n");

  for(int j=0;j<nevents;j++)
    {
      PAPI_event_code_to_name(Events[j], event_name);
      printf("Event %s -> %lld\n", event_name, values[j]);
    }

  printf("\nTrying high-level PAPI_flops function\n");

  flpins = -1;
  if ((code=PAPI_flops(&rtime, &ptime, &flpins, &mflops)) != PAPI_OK)
    handle_error(code, "PAPI_flops 1");

  do_flops(NUM_FLOPS);
      
  if (PAPI_flops(&rtime, &ptime, &flpins, &mflops) != PAPI_OK)
    handle_error(code, "PAPI_flops 2");

  printf("First PAPI_flops:    %g %lld %g %g\n",mflops,flpins,rtime,ptime);
      
  do_flops(NUM_FLOPS);
      
  /* Add the counters */
      
  if ((code=PAPI_flops(&rtime, &ptime, &flpins, &mflops)) != PAPI_OK)
    handle_error(code, "PAPI_flops 3");

  printf("Second PAPI_flops:   %g %lld %g %g\n",mflops,flpins,rtime,ptime);
      
}