/* $NetBSD: select.c,v 1.3 2011/11/02 16:49:12 yamt Exp $ */
/*-
* Copyright (c)2008 YAMAMOTO Takashi,
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``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 OR CONTRIBUTORS 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.
*/
#define FD_SETSIZE 65536
#include <sys/select.h>
#include <sys/atomic.h>
#include <sys/time.h>
#include <assert.h>
#include <errno.h>
#include <fcntl.h>
#include <pthread.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#define NPIPE 128
#define NTHREAD 64
#define NBALLS 5
#define VERBOSE 0
#if !defined(RANDOM_MAX)
#define RANDOM_MAX ((1UL << 31) - 1)
#endif
int fds[NPIPE][2];
volatile unsigned count;
pthread_barrier_t barrier;
static void
dowrite(void)
{
char buf[1];
int fd;
int i;
i = random() % NPIPE;
fd = fds[i][1];
#if VERBOSE
printf("[%p] write %d\n", (void *)pthread_self(), fd);
#endif
if (write(fd, buf, sizeof(buf)) == -1) {
perror("write");
abort();
}
}
static void *
f(void *dummy)
{
pthread_barrier_wait(&barrier);
for (;;) {
struct timeval to;
fd_set oset;
fd_set set;
int maxfd = -1;
int nfd = 0;
int ret;
int fd;
int i;
FD_ZERO(&set);
do {
for (i = 0; i < NPIPE; i++) {
fd = fds[i][0];
if (fd > FD_SETSIZE) {
fprintf(stderr,
"fd(%d) > FD_SETSIZE(%d)\n",
fd, FD_SETSIZE);
abort();
}
if (random() & 1) {
assert(!FD_ISSET(fd, &set));
FD_SET(fd, &set);
nfd++;
if (fd > maxfd) {
maxfd = fd;
}
}
}
} while (nfd == 0);
memcpy(&oset, &set, sizeof(oset));
memset(&to, 0, sizeof(to));
to.tv_sec = random() % 10;
to.tv_usec = random() % 1000000;
#if VERBOSE
printf("[%p] select start to=%lu\n", (void *)pthread_self(),
(unsigned long)to.tv_sec);
#endif
ret = select(maxfd + 1, &set, NULL, NULL, &to);
#if VERBOSE
printf("[%p] select done ret=%d\n",
(void *)pthread_self(), ret);
#endif
if (ret == -1) {
perror("select");
abort();
}
if (ret > nfd) {
fprintf(stderr, "[%p] unexpected return value %d\n",
(void *)pthread_self(), ret);
abort();
}
if (ret > NBALLS) {
fprintf(stderr, "[%p] unexpected return value %d"
" > NBALLS\n",
(void *)pthread_self(), ret);
abort();
}
nfd = 0;
for (fd = 0; fd <= maxfd; fd++) {
if (FD_ISSET(fd, &set)) {
char buf[1];
#if VERBOSE
printf("[%p] read %d\n",
(void *)pthread_self(), fd);
#endif
if (!FD_ISSET(fd, &oset)) {
fprintf(stderr, "[%p] unexpected\n",
(void *)pthread_self());
abort();
}
if (read(fd, buf, sizeof(buf)) == -1) {
if (errno != EAGAIN) {
perror("read");
abort();
}
} else {
dowrite();
atomic_inc_uint(&count);
}
nfd++;
}
}
if (ret != nfd) {
fprintf(stderr, "[%p] ret(%d) != nfd(%d)\n",
(void *)pthread_self(), ret, nfd);
abort();
}
}
}
int
main(int argc, char *argv[])
{
pthread_t pt[NTHREAD];
int i;
unsigned int secs;
struct timeval start_tv;
struct timeval end_tv;
uint64_t usecs;
unsigned int result;
secs = atoi(argv[1]);
for (i = 0; i < NPIPE; i++) {
if (pipe(fds[i])) {
perror("pipe");
abort();
}
if (fcntl(fds[i][0], F_SETFL, O_NONBLOCK) == -1) {
perror("fcntl");
abort();
}
}
pthread_barrier_init(&barrier, NULL, NTHREAD + 1);
for (i = 0; i < NTHREAD; i++) {
int error = pthread_create(&pt[i], NULL, f, NULL);
if (error) {
errno = error;
perror("pthread_create");
abort();
}
}
pthread_barrier_wait(&barrier);
gettimeofday(&start_tv, NULL);
assert(count == 0);
for (i = 0; i < NBALLS; i++) {
dowrite();
}
sleep(secs);
gettimeofday(&end_tv, NULL);
result = count;
usecs = (end_tv.tv_sec - start_tv.tv_sec) * 1000000
+ end_tv.tv_usec - start_tv.tv_usec;
printf("%u / %f = %f\n", result, (double)usecs / 1000000,
(double)result / usecs * 1000000);
exit(EXIT_SUCCESS);
}
