bench.c

/*
 * Copyright 2003 Niels Provos <provos@citi.umich.edu>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. 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.
 * 4. 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.
 *
 *
 * Mon 03/10/2003 - Modified by Davide Libenzi <davidel@xmailserver.org>
 *
 *     Added chain event propagation to improve the sensitivity of
 *     the measure respect to the event loop efficency.
 *
 *
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <sys/types.h>
#include <sys/stat.h>
#include <sys/time.h>
#ifdef WIN32
#include <windows.h>
#else
#include <sys/socket.h>
#include <signal.h>
#include <sys/resource.h>
#endif
#include <fcntl.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>

#include <event.h>
#include <evutil.h>


static int count, writes, fired;
static int *pipes;
static int num_pipes, num_active, num_writes;
static struct event *events;

static void
read_cb(int fd, short which, void *arg)
{
        long idx = (long) arg, widx = idx + 1;
        u_char ch;

        count += read(fd, &ch, sizeof(ch));
        if (writes) {
                if (widx >= num_pipes)
                        widx -= num_pipes;
                write(pipes[2 * widx + 1], "e", 1);
                writes--;
                fired++;
        }
}

static struct timeval *
run_once(void)
{
        int *cp, space;
        long i;
        static struct timeval ts, te;

        for (cp = pipes, i = 0; i < num_pipes; i++, cp += 2) {
                event_del(&events[i]);
                event_set(&events[i], cp[0], EV_READ | EV_PERSIST, read_cb, (void *) i);
                event_add(&events[i], NULL);
        }

        event_loop(EVLOOP_ONCE | EVLOOP_NONBLOCK);

        fired = 0;
        space = num_pipes / num_active;
        space = space * 2;
        for (i = 0; i < num_active; i++, fired++)
                write(pipes[i * space + 1], "e", 1);

        count = 0;
        writes = num_writes;
        { int xcount = 0;
        gettimeofday(&ts, NULL);
        do {
                event_loop(EVLOOP_ONCE | EVLOOP_NONBLOCK);
                xcount++;
        } while (count != fired);
        gettimeofday(&te, NULL);

        if (xcount != count) fprintf(stderr, "Xcount: %d, Rcount: %d\n", xcount, count);
        }

        evutil_timersub(&te, &ts, &te);

        return (&te);
}

int
main (int argc, char **argv)
{
#ifndef WIN32
        struct rlimit rl;
#endif
        int i, c;
        struct timeval *tv;
        int *cp;

        num_pipes = 100;
        num_active = 1;
        num_writes = num_pipes;
        while ((c = getopt(argc, argv, "n:a:w:")) != -1) {
                switch (c) {
                case 'n':
                        num_pipes = atoi(optarg);
                        break;
                case 'a':
                        num_active = atoi(optarg);
                        break;
                case 'w':
                        num_writes = atoi(optarg);
                        break;
                default:
                        fprintf(stderr, "Illegal argument \"%c\"\n", c);
                        exit(1);
                }
        }

#ifndef WIN32
        rl.rlim_cur = rl.rlim_max = num_pipes * 2 + 50;
        if (setrlimit(RLIMIT_NOFILE, &rl) == -1) {
                perror("setrlimit");
                exit(1);
        }
#endif

        events = calloc(num_pipes, sizeof(struct event));
        pipes = calloc(num_pipes * 2, sizeof(int));
        if (events == NULL || pipes == NULL) {
                perror("malloc");
                exit(1);
        }

        event_init();

        for (cp = pipes, i = 0; i < num_pipes; i++, cp += 2) {
#ifdef USE_PIPES
                if (pipe(cp) == -1) {
#else
                if (evutil_socketpair(AF_UNIX, SOCK_STREAM, 0, cp) == -1) {
#endif
                        perror("pipe");
                        exit(1);
                }
        }

        for (i = 0; i < 25; i++) {
                tv = run_once();
                if (tv == NULL)
                        exit(1);
                fprintf(stdout, "%ld\n",
                        tv->tv_sec * 1000000L + tv->tv_usec);
        }

        exit(0);
}