/* -*- Mode: C; c-basic-offset:4 ; indent-tabs-mode:nil ; -*- */
/*
 *  (C) 2006 by Argonne National Laboratory.
 *      See COPYRIGHT in top-level directory.
 */

/*
 * Check that the timer produces monotone nondecreasing times and that
 * the Tick is reasonable
 */

#include "mpi.h"
#include <stdio.h>
#include "mpitest.h"

static int verbose = 0;

#define MAX_TIMER_TEST 5000

int main(int argc, char *argv[])
{
    double t1[MAX_TIMER_TEST], tick[MAX_TIMER_TEST], tickval;
    double minDiff, maxDiff, diff;
    int i, nZeros = 0;
    int errs = 0;

    MTest_Init(&argc, &argv);

    for (i = 0; i < MAX_TIMER_TEST; i++) {
        t1[i] = MPI_Wtime();
    }

    for (i = 0; i < MAX_TIMER_TEST; i++) {
        tick[i] = MPI_Wtick();
    }

    /* Look at the values */
    /* Look at the tick */
    tickval = MPI_Wtick();
    for (i = 0; i < MAX_TIMER_TEST; i++) {
        if (tickval != tick[i]) {
            fprintf(stderr, "Nonconstant value for MPI_Wtick: %e != %e\n", tickval, tick[i]);
            errs++;
        }
    }

    /* Look at the timer */
    minDiff = 1.e20;
    maxDiff = -1.0;
    nZeros = 0;
    for (i = 1; i < MAX_TIMER_TEST; i++) {
        diff = t1[i] - t1[i - 1];
        if (diff == 0.0)
            nZeros++;
        else if (diff < minDiff)
            minDiff = diff;
        if (diff > maxDiff)
            maxDiff = diff;
    }

    /* Are the time diff values and tick values consistent */
    if (verbose) {
        printf("Tick = %e, timer range = [%e,%e]\n", tickval, minDiff, maxDiff);
        if (nZeros)
            printf("Wtime difference was 0 %d times\n", nZeros);
    }

    MTest_Finalize(errs);

    return MTestReturnValue(errs);
}
