source: mainline/uspace/app/perf/ipc/ping_pong.c@ 02c6dcc

/*
 * Copyright (c) 2009 Jiri Svoboda
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <math.h>
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <ipc_test.h>
#include <async.h>
#include <errno.h>
#include "../perf.h"

#define MIN_DURATION_SECS  10
#define NUM_SAMPLES 10

static errno_t ping_pong_measure(ipc_test_t *test, uint64_t niter,
    uint64_t *rduration)
{
        struct timespec start;
        uint64_t count;

        getuptime(&start);

        for (count = 0; count < niter; count++) {
                errno_t retval = ipc_test_ping(test);

                if (retval != EOK) {
                        printf("Error sending ping message.\n");
                        return EIO;
                }
        }

        struct timespec now;
        getuptime(&now);

        *rduration = ts_sub_diff(&now, &start) / 1000;
        return EOK;
}

static void ping_pong_report(uint64_t niter, uint64_t duration)
{
        printf("Completed %" PRIu64 " round trips in %" PRIu64 " us",
            niter, duration);

        if (duration > 0) {
                printf(", %" PRIu64 " rt/s.\n", niter * 1000 * 1000 / duration);
        } else {
                printf(".\n");
        }
}

const char *bench_ping_pong(void)
{
        errno_t rc;
        uint64_t duration;
        uint64_t dsmp[NUM_SAMPLES];
        ipc_test_t *test;
        const char *msg;

        rc = ipc_test_create(&test);
        if (rc != EOK)
                return "Failed contacting IPC test server.";

        printf("Warm up and determine work size...\n");

        struct timespec start;
        getuptime(&start);

        uint64_t niter = 1;

        while (true) {
                rc = ping_pong_measure(test, niter, &duration);
                if (rc != EOK) {
                        msg = "Failed.";
                        goto error;
                }

                ping_pong_report(niter, duration);

                if (duration >= MIN_DURATION_SECS * 1000000)
                        break;

                niter *= 2;
        }

        printf("Measure %d samples...\n", NUM_SAMPLES);

        int i;

        for (i = 0; i < NUM_SAMPLES; i++) {
                rc = ping_pong_measure(test, niter, &dsmp[i]);
                if (rc != EOK) {
                        msg = "Failed.";
                        goto error;
                }

                ping_pong_report(niter, dsmp[i]);
        }

        double sum = 0.0;

        for (i = 0; i < NUM_SAMPLES; i++)
                sum += (double)niter / ((double)dsmp[i] / 1000000.0l);

        double avg = sum / NUM_SAMPLES;

        double qd = 0.0;
        double d;
        for (i = 0; i < NUM_SAMPLES; i++) {
                d = (double)niter / ((double)dsmp[i] / 1000000.0l) - avg;
                qd += d * d;
        }

        double stddev = qd / (NUM_SAMPLES - 1); // XXX sqrt

        printf("Average: %.0f rt/s Std.dev^2: %.0f rt/s Samples: %d\n",
            avg, stddev, NUM_SAMPLES);

        ipc_test_destroy(test);
        return NULL;
error:
        ipc_test_destroy(test);
        return msg;
}