attach_cpu.c

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/*
 * This test case creates an event set and attaches it to a cpu.  This causes only activity
 * on that cpu to get counted.  The test case then starts the event set does a little work and
 * then stops the event set.  It then prints out the event, count and cpu number which was used
 * during the test case.
 *
 * Since this test case does not try to force its own execution to the cpu which it is using to
 * count events, it is fairly normal to get zero counts printed at the end of the test.  But every
 * now and then it will count the cpu where the test case is running and then the counts will be non-zero.
 *
 * The test case allows the user to specify which cpu should be counted by providing an argument to the
 * test case (ie: ./attach_cpu 3).  Sometimes by trying different cpu numbers with the test case, you
 * can find the cpu used to run the test (because counts will look like cycle counts).
 *
 */

#include <stdio.h>
#include <stdlib.h>

#include "papi.h"
#include "papi_test.h"

#include "do_loops.h"

int
main( int argc, char **argv )
{
    int num_tests=1;
    int num_events=1;
    int retval;
    int cpu_num = 1;
    int EventSet1 = PAPI_NULL;
    long long **values;
    char event_name[PAPI_MAX_STR_LEN] = "PAPI_TOT_CYC";
    PAPI_option_t opts;
    int quiet;

    /* Set TESTS_QUIET variable */
    quiet=tests_quiet( argc, argv );

    // user can provide cpu number on which to count events as arg 1
    if (argc > 1) {
        retval = atoi(argv[1]);
        if (retval >= 0) {
            cpu_num = retval;
        }
    }

    retval = PAPI_library_init( PAPI_VER_CURRENT );
    if ( retval != PAPI_VER_CURRENT )
        test_fail( __FILE__, __LINE__, "PAPI_library_init", retval );

    retval = PAPI_create_eventset(&EventSet1);
    if ( retval != PAPI_OK )
        test_fail( __FILE__, __LINE__, "PAPI_attach", retval );

    // Force event set to be associated with component 0 (perf_events component provides all core events)
    retval = PAPI_assign_eventset_component( EventSet1, 0 );
    if ( retval != PAPI_OK )
        test_fail( __FILE__, __LINE__, "PAPI_assign_eventset_component", retval );

    // Attach this event set to cpu 1
    opts.cpu.eventset = EventSet1;
    opts.cpu.cpu_num = cpu_num;

    retval = PAPI_set_opt( PAPI_CPU_ATTACH, &opts );
    if ( retval != PAPI_OK ) {
        if (!quiet) printf("Can't PAPI_CPU_ATTACH: %s\n",
                PAPI_strerror(retval));
        test_skip( __FILE__, __LINE__, "PAPI_set_opt", retval );
    }

    retval = PAPI_add_named_event(EventSet1, event_name);
    if ( retval != PAPI_OK ) {
        if (!quiet) printf("Trouble adding event %s\n",event_name);
        test_skip( __FILE__, __LINE__, "PAPI_add_named_event", retval );
    }

    // get space for counter values (this needs to do this call because it malloc's space that test_pass and friends free)
    values = allocate_test_space( num_tests, num_events);

    retval = PAPI_start( EventSet1 );
    if ( retval != PAPI_OK ) {
        test_fail( __FILE__, __LINE__, "PAPI_start", retval );
    }

    // do some work
    do_flops(NUM_FLOPS);

    retval = PAPI_stop( EventSet1, values[0] );
    if ( retval != PAPI_OK )
        test_fail( __FILE__, __LINE__, "PAPI_stop", retval );

    if (!quiet) printf ("Event: %s: %8lld on Cpu: %d\n", event_name, values[0][0], cpu_num);

    PAPI_shutdown( );

    test_pass( __FILE__ );

    return 0;

}