clockcore.c

Go to the documentation of this file.

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

#include "papi.h"

#include "clockcore.h"

#define NUM_ITERS  1000000

static char *func_name[] = {
    "PAPI_get_real_cyc",
    "PAPI_get_real_usec",
    "PAPI_get_virt_cyc",
    "PAPI_get_virt_usec"
};
static int CLOCK_ERROR = 0;

static int
clock_res_check( int flag, int quiet )
{
    if ( CLOCK_ERROR ) {
        return -1;
    }

    long long *elapsed_cyc, total_cyc = 0, uniq_cyc = 0, diff_cyc = 0;
    int i;
    double min, max, average, std, tmp;

    elapsed_cyc = ( long long * ) calloc( NUM_ITERS, sizeof ( long long ) );

    /* Real */
    switch ( flag ) {
    case 0:
        for ( i = 0; i < NUM_ITERS; i++ )
            elapsed_cyc[i] = ( long long ) PAPI_get_real_cyc(  );
        break;
    case 1:
        for ( i = 0; i < NUM_ITERS; i++ )
            elapsed_cyc[i] = ( long long ) PAPI_get_real_usec(  );
        break;
    case 2:
        for ( i = 0; i < NUM_ITERS; i++ )
            elapsed_cyc[i] = ( long long ) PAPI_get_virt_cyc(  );
        break;
    case 3:
        for ( i = 0; i < NUM_ITERS; i++ )
            elapsed_cyc[i] = ( long long ) PAPI_get_virt_usec(  );
        break;
    default:
        return -1;

    }

    min = max = ( double ) ( elapsed_cyc[1] - elapsed_cyc[0] );

    for ( i = 1; i < NUM_ITERS; i++ ) {
        if ( elapsed_cyc[i] - elapsed_cyc[i - 1] < 0 ) {
            CLOCK_ERROR = 1;
            fprintf(stderr,"Error! Negative elapsed time\n");
            free( elapsed_cyc );
            return -1;
        }

        diff_cyc = elapsed_cyc[i] - elapsed_cyc[i - 1];
        if ( min > diff_cyc )
            min = ( double ) diff_cyc;
        if ( max < diff_cyc )
            max = ( double ) diff_cyc;
        if ( diff_cyc != 0 )
            uniq_cyc++;
        total_cyc += diff_cyc;
    }

    average = ( double ) total_cyc / ( NUM_ITERS - 1 );
    std = 0;

    for ( i = 1; i < NUM_ITERS; i++ ) {
        tmp = ( double ) ( elapsed_cyc[i] - elapsed_cyc[i - 1] );
        tmp = tmp - average;
        std += tmp * tmp;
    }

    if ( !quiet ) {
        std = sqrt( std / ( NUM_ITERS - 2 ) );
        printf( "%s: min %.3lf  max %.3lf \n", func_name[flag], min, max );
        printf( "                   average %.3lf std %.3lf\n", average, std );

        if ( uniq_cyc == NUM_ITERS - 1 ) {
            printf( "%s : %7.3f   <%7.3f\n", func_name[flag],
                    ( double ) total_cyc / ( double ) ( NUM_ITERS ),
                    ( double ) total_cyc / ( double ) uniq_cyc );
        } else if ( uniq_cyc ) {
            printf( "%s : %7.3f    %7.3f\n", func_name[flag],
                    ( double ) total_cyc / ( double ) ( NUM_ITERS ),
                    ( double ) total_cyc / ( double ) uniq_cyc );
        } else {
            printf( "%s : %7.3f   >%7.3f\n", func_name[flag],
                    ( double ) total_cyc / ( double ) ( NUM_ITERS ),
                    ( double ) total_cyc );
        }
    }

    free( elapsed_cyc );

    return PAPI_OK;
}

int
clockcore( int quiet )
{
    /* check PAPI_get_real_cyc */
    clock_res_check( 0, quiet );
    /* check PAPI_get_real_usec */
    clock_res_check( 1, quiet );

    /* check PAPI_get_virt_cyc */
    /* Virtual */
    if ( PAPI_get_virt_cyc(  ) != -1 ) {
        clock_res_check( 2, quiet );
    } else {
        return CLOCKCORE_VIRT_CYC_FAIL;
    }

    /* check PAPI_get_virt_usec */
    if ( PAPI_get_virt_usec(  ) != -1 ) {
        clock_res_check( 3, quiet );
    } else {
        return CLOCKCORE_VIRT_USEC_FAIL;
    }

    return PAPI_OK;
}