/* This code attempts to test the L2 Data Cache Missses */
/* performance counter PAPI_L2_DCM */
/* by Vince Weaver, vincent.weaver@maine.edu */
/* Due to prefetching it is hard to create a testcase short of */
/* just having random accesses. */
/* In addition, due to context switching the cache might be */
/* affected by other processes on a busy system. */
/* Other tests to attempt */
/* Repeatedly reading same cache line should give very small error */
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include "papi.h"
#include "papi_test.h"
#include "cache_helper.h"
#include "display_error.h"
#include "testcode.h"
/* How much should we allow? */
#define ALLOWED_ERROR 5.0
#define NUM_RUNS 100
#define ITERATIONS 1000000
int main(int argc, char **argv) {
int i;
int eventset=PAPI_NULL;
int num_runs=NUM_RUNS;
long long high,low,average,expected;
long long count,total;
int retval;
int l1_size,l2_size,l1_linesize,l2_linesize,l2_entries;
int arraysize;
int quiet,errors=0;
double error;
double *array;
double aSumm = 0.0;
quiet=tests_quiet(argc,argv);
if (!quiet) {
printf("Testing the PAPI_L2_DCM event\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);
}
retval=PAPI_create_eventset(&eventset);
if (retval!=PAPI_OK) {
test_fail( __FILE__, __LINE__, "PAPI_create_eventset", retval );
}
retval=PAPI_add_named_event(eventset,"PAPI_L2_DCM");
if (retval!=PAPI_OK) {
test_skip( __FILE__, __LINE__, "adding PAPI_L2_DCM", retval );
}
l1_size=get_cachesize(L1D_CACHE);
l1_linesize=get_linesize(L1D_CACHE);
l2_size=get_cachesize(L2_CACHE);
l2_linesize=get_linesize(L2_CACHE);
l2_entries=get_entries(L2_CACHE);
if (!quiet) {
printf("\tDetected %dk L1 DCache, %dB linesize\n",
l1_size/1024,l1_linesize);
printf("\tDetected %dk L2 DCache, %dB linesize, %d entries\n",
l2_size/1024,l2_linesize,l2_entries);
}
arraysize=(l2_size/sizeof(double))*8;
if (arraysize==0) {
if (!quiet) printf("Could not detect cache size\n");
test_skip(__FILE__,__LINE__,"Could not detect cache size",0);
}
if (!quiet) {
printf("\tAllocating %zu bytes of memory (%d doubles)\n",
arraysize*sizeof(double),arraysize);
}
array=calloc(arraysize,sizeof(double));
if (array==NULL) {
test_fail(__FILE__,__LINE__,"Can't allocate memory",0);
}
/******************/
/* Testing Writes */
/******************/
if (!quiet) {
printf("\nWrite Test: Writing an array of %d doubles %d random times:\n",
arraysize,ITERATIONS);
printf("\tPrefetch and shared nature of L2s make this hard.\n");
printf("\tExpected 7/8 of accesses to be miss.\n");
}
high=0; low=0; total=0;
for(i=0;i<num_runs;i++) {
PAPI_reset(eventset);
PAPI_start(eventset);
cache_random_write_test(array,arraysize,ITERATIONS);
retval=PAPI_stop(eventset,&count);
if (retval!=PAPI_OK) {
test_fail( __FILE__, __LINE__,
"reading PAPI_L2_DCM", retval );
}
if (count>high) high=count;
if ((low==0) || (count<low)) low=count;
total+=count;
}
average=(total/num_runs);
expected=(ITERATIONS*7)/8;
// expected=arraysize/(l1_linesize);
error=display_error(average,high,low,expected,quiet);
if ((error > ALLOWED_ERROR) || (error<-ALLOWED_ERROR)) {
if (!quiet) {
printf("Instruction count off by more "
"than %.2lf%%\n",ALLOWED_ERROR);
}
errors++;
}
if (!quiet) printf("\n");
/******************/
/* Testing Reads */
/******************/
if (!quiet) {
printf("\nRead Test: Summing %d random doubles from array "
"of size %d:\n",ITERATIONS,arraysize);
printf("\tExpected 7/8 of accesses to be miss.\n");
}
high=0; low=0; total=0;
for(i=0;i<num_runs;i++) {
PAPI_reset(eventset);
PAPI_start(eventset);
aSumm+=cache_random_read_test(array,arraysize,ITERATIONS);
retval=PAPI_stop(eventset,&count);
if (retval!=PAPI_OK) {
test_fail( __FILE__, __LINE__,
"reading PAPI_L2_DCM", retval );
}
if (count>high) high=count;
if ((low==0) || (count<low)) low=count;
total+=count;
}
average=(total/num_runs);
expected=(ITERATIONS*7)/8;
// expected=arraysize/(l1_linesize/sizeof(double));
error=display_error(average,high,low,expected,quiet);
if ((error > ALLOWED_ERROR) || (error<-ALLOWED_ERROR)) {
if (!quiet) {
printf("Instruction count off by more "
"than %.2lf%%\n",ALLOWED_ERROR);
}
errors++;
}
if (!quiet) {
printf("\n");
}
/* FIXME: Warn, as we fail on broadwell and more recent chips */
if (errors) {
test_warn( __FILE__, __LINE__, "Error too high", 1 );
}
test_pass(__FILE__);
return 0;
}