/* This file attempts to test the predicted correctly branches	*/

/* performance event as counted by PAPI_BR_PRC			*/

/* Ideally this event should measure 				*/

/*	predicted correctly *conditional* branches		*/

/* If that's not available, then use total branches.		*/

/* by Vince Weaver, <vincent.weaver@maine.edu>			*/

#include <stdlib.h>

#include <stdio.h>

#include <unistd.h>

#include <string.h>

#include "papi.h"

#include "papi_test.h"

#include "display_error.h"

#include "testcode.h"

int main(int argc, char **argv) {

	int num_runs=100,i;

	int num_random_branches=500000;

	long long high=0,low=0,average=0,expected=1500000;

	long long expected_high,expected_low;

	long long count,total=0;

	int quiet=0,retval,ins_result;

	int total_eventset=PAPI_NULL,miss_eventset=PAPI_NULL;

	quiet=tests_quiet(argc,argv);

	if (!quiet) {

		printf("\nTesting the PAPI_BR_PRC event.\n\n");

		printf("This should measure predicted correctly conditional branches\n");

		printf("If such a counter is not available, it may report predicted correctly\n");

		printf("total branches instead.\n");

	}

	/* Init the PAPI library */

	retval = PAPI_library_init( PAPI_VER_CURRENT );

	if ( retval != PAPI_VER_CURRENT ) {

		test_fail( __FILE__, __LINE__, "PAPI_library_init", retval );

	}

	/* Create total eventset */

	retval=PAPI_create_eventset(&total_eventset);

	if (retval!=PAPI_OK) {

		test_fail( __FILE__, __LINE__, "PAPI_create_eventset", retval );

	}

	retval=PAPI_add_named_event(total_eventset,"PAPI_BR_CN");

	if (retval!=PAPI_OK) {

		if (!quiet) printf("Could not add PAPI_BR_CN\n");

		//test_skip( __FILE__, __LINE__, "adding PAPI_BR_CN", retval );

		retval=PAPI_add_named_event(total_eventset,"PAPI_BR_INS");

		if (retval!=PAPI_OK) {

			if (!quiet) printf("Could not add PAPI_BR_INS\n");

			test_skip( __FILE__, __LINE__, "adding PAPI_BR_INS", retval );

		}

	}

	/* Create correct eventset */

	retval=PAPI_create_eventset(&miss_eventset);

	if (retval!=PAPI_OK) {

		test_fail( __FILE__, __LINE__, "PAPI_create_eventset", retval );

	}

	retval=PAPI_add_named_event(miss_eventset,"PAPI_BR_PRC");

	if (retval!=PAPI_OK) {

		if (!quiet) printf("Could not add PAPI_BR_PRC\n");

		test_skip( __FILE__, __LINE__, "adding PAPI_BR_PRC", retval );

	}

	if (!quiet) {

		printf("\nPart 1: Testing that easy to predict loop has few misses\n");

		printf("Testing a loop with %lld branches (%d times):\n",

			expected,num_runs);

		printf("\tOn a simple loop like this, "

			"hit rate should be very high.\n");

	}

	for(i=0;i

		PAPI_reset(miss_eventset);

                PAPI_start(miss_eventset);

		ins_result=branches_testcode();

		retval=PAPI_stop(miss_eventset,&count);

		if (ins_result==CODE_UNIMPLEMENTED) {

			fprintf(stderr,"\tCode unimplemented\n");

			test_skip( __FILE__, __LINE__, "unimplemented", 0);

		}

		if (retval!=PAPI_OK) {

			test_fail( __FILE__, __LINE__,

				"reading PAPI_TOT_INS", retval );

		}

		if (count>high) high=count;

		if ((low==0) || (count

		total+=count;

	}

	average=(total/num_runs);

	if (!quiet) printf("\tAverage number of branch hits: %lld\n",average);

	if (average

		if (!quiet) printf("Branch miss rate too high\n");

		test_fail( __FILE__, __LINE__, "Error too high", 1 );

	}

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

	if (!quiet) {

		printf("\nPart 2\n");

	}

	high=0; low=0; total=0;

	for(i=0;i

		PAPI_reset(total_eventset);

                PAPI_start(total_eventset);

		ins_result=random_branches_testcode(num_random_branches,1);

		retval=PAPI_stop(total_eventset,&count);

		if (ins_result==CODE_UNIMPLEMENTED) {

			fprintf(stderr,"\tCode unimplemented\n");

			test_skip( __FILE__, __LINE__, "unimplemented", 0);

		}

		if (retval!=PAPI_OK) {

			test_fail( __FILE__, __LINE__,

				"reading PAPI_TOT_INS", retval );

		}

		if (count>high) high=count;

		if ((low==0) || (count

		total+=count;

	}

	average=total/num_runs;

	expected=average;

	if (!quiet) {

		printf("\nTesting a function that branches "

			"based on a random number\n");

		printf("   The loop has %lld conditional branches.\n",expected);

		printf("   %d are random branches.\n",num_random_branches);

	}

	high=0; low=0; total=0;

	for(i=0;i

		PAPI_reset(miss_eventset);

                PAPI_start(miss_eventset);

		ins_result=random_branches_testcode(num_random_branches,1);

		retval=PAPI_stop(miss_eventset,&count);

		if (ins_result==CODE_UNIMPLEMENTED) {

			fprintf(stderr,"\tCode unimplemented\n");

			test_skip( __FILE__, __LINE__, "unimplemented", 0);

		}

		if (retval!=PAPI_OK) {

			test_fail( __FILE__, __LINE__,

				"reading eventset", retval );

		}

		if (count>high) high=count;

		if ((low==0) || (count

		total+=count;

	}

	average=total/num_runs;

	expected_low=expected-((num_random_branches/4)*3);

	expected_high=expected-(num_random_branches/4);

	if (!quiet) {

		printf("\nOut of %lld branches, "

			"%lld were correctly predicted\n",expected,average);

		printf("Assuming a good random number generator and no "

			"freaky luck\n");

		printf("The mispredicts should be roughly "

			"between %lld and %lld\n",

			expected_low,expected_high);

	}

	if ( average < expected_low) {

		if (!quiet) printf("Branch hits too low\n");

		test_fail( __FILE__, __LINE__, "Error too low", 1 );

	}

	if (average > expected_high) {

		if (!quiet) printf("Branch hits too high\n");

		test_fail( __FILE__, __LINE__, "Error too high", 1 );

	}

	if (!quiet) printf("\n");

	test_pass( __FILE__ );

	PAPI_shutdown();

	return 0;

}