text: /*
   * Copyright 2003-2007 Niels Provos <provos@citi.umich.edu>
   * 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.
   *
   *
   * 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.
   *
   *
   */
  
  #include "event2/event-config.h"
  
  #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>
  #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>
  #ifdef _EVENT_HAVE_UNISTD_H
  #include <unistd.h>
  #endif
  #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(evutil_socket_t fd, short which, void *arg)
  {
  	long idx = (long) arg, widx = idx + 1;
  	u_char ch;
  
  	count += recv(fd, (char*)&ch, sizeof(ch), 0);
  	if (writes) {
  		if (widx >= num_pipes)
  			widx -= num_pipes;
  		send(pipes[2 * widx + 1], "e", 1, 0);
  		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) {
  		if (event_initialized(&events[i]))
  			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++)
  		send(pipes[i * space + 1], "e", 1, 0);
  
  	count = 0;
  	writes = num_writes;
  	{ int xcount = 0;
  	evutil_gettimeofday(&ts, NULL);
  	do {
  		event_loop(EVLOOP_ONCE | EVLOOP_NONBLOCK);
  		xcount++;
  	} while (count != fired);
  	evutil_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;
  
  #ifdef WIN32
  	WSADATA WSAData;
  	WSAStartup(0x101, &WSAData);
  #endif
  	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);
  }
  