/*      $NetBSD: bench_cascade.c,v 1.1.1.3 2021/04/07 02:43:15 christos Exp $   */
/*
* Copyright 2007-2012 Niels Provos and Nick Mathewson
*
* 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.
*
*/

#include "event2/event-config.h"
#include <sys/cdefs.h>
__RCSID("$NetBSD: bench_cascade.c,v 1.1.1.3 2021/04/07 02:43:15 christos Exp $");

#include <sys/types.h>
#include <sys/stat.h>
#ifdef EVENT__HAVE_SYS_TIME_H
#include <sys/time.h>
#endif
#ifdef _WIN32
#define WIN32_LEAN_AND_MEAN
#include <windows.h>
#include <getopt.h>
#else /* _WIN32 */
#include <sys/socket.h>
#include <sys/resource.h>
#endif
#include <signal.h>
#include <fcntl.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#ifdef EVENT__HAVE_UNISTD_H
#include <unistd.h>
#endif
#include <errno.h>
#include <event.h>
#include <evutil.h>

/*
* This benchmark tests how quickly we can propagate a write down a chain
* of socket pairs.  We start by writing to the first socket pair and all
* events will fire subsequently until the last socket pair has been reached
* and the benchmark terminates.
*/

static int fired;
static evutil_socket_t *pipes;
static struct event *events;

static void
read_cb(evutil_socket_t fd, short which, void *arg)
{
       char ch;
       evutil_socket_t sock = (evutil_socket_t)(ev_intptr_t)arg;

       (void) recv(fd, &ch, sizeof(ch), 0);
       if (sock >= 0) {
               if (send(sock, "e", 1, 0) < 0)
                       perror("send");
       }
       fired++;
}

static struct timeval *
run_once(int num_pipes)
{
       int i;
       evutil_socket_t *cp;
       static struct timeval ts, te, tv_timeout;

       events = (struct event *)calloc(num_pipes, sizeof(struct event));
       pipes = (evutil_socket_t *)calloc(num_pipes * 2, sizeof(evutil_socket_t));

       if (events == NULL || pipes == NULL) {
               perror("malloc");
               exit(1);
       }

       for (cp = pipes, i = 0; i < num_pipes; i++, cp += 2) {
               if (evutil_socketpair(AF_UNIX, SOCK_STREAM, 0, cp) == -1) {
                       perror("socketpair");
                       exit(1);
               }
       }

       /* measurements includes event setup */
       evutil_gettimeofday(&ts, NULL);

       /* provide a default timeout for events */
       evutil_timerclear(&tv_timeout);
       tv_timeout.tv_sec = 60;

       for (cp = pipes, i = 0; i < num_pipes; i++, cp += 2) {
               evutil_socket_t fd = i < num_pipes - 1 ? cp[3] : -1;
               event_set(&events[i], cp[0], EV_READ, read_cb,
                   (void *)(ev_intptr_t)fd);
               event_add(&events[i], &tv_timeout);
       }

       fired = 0;

       /* kick everything off with a single write */
       if (send(pipes[1], "e", 1, 0) < 0)
               perror("send");

       event_dispatch();

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

       for (cp = pipes, i = 0; i < num_pipes; i++, cp += 2) {
               event_del(&events[i]);
               evutil_closesocket(cp[0]);
               evutil_closesocket(cp[1]);
       }

       free(pipes);
       free(events);

       return (&te);
}

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

       int num_pipes = 100;
#ifdef _WIN32
       WSADATA WSAData;
       WSAStartup(0x101, &WSAData);
#endif

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

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

       event_init();

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

#ifdef _WIN32
       WSACleanup();
#endif

       exit(0);
}