1 /* $NetBSD: select.c,v 1.2 2008/03/21 16:03:33 ad Exp $ */ 2 3 /*- 4 * Copyright (c)2008 YAMAMOTO Takashi, 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29 #define FD_SETSIZE 65536 30 #include <sys/select.h> 31 #include <sys/atomic.h> 32 33 #include <errno.h> 34 #include <fcntl.h> 35 #include <pthread.h> 36 #include <stdio.h> 37 #include <stdlib.h> 38 #include <string.h> 39 #include <unistd.h> 40 41 #define NPIPE 128 42 #define NTHREAD 64 43 #define VERBOSE 0 44 45 #if !defined(RANDOM_MAX) 46 #define RANDOM_MAX ((1UL << 31) - 1) 47 #endif 48 49 int fds[NPIPE][2]; 50 51 unsigned count; 52 53 pthread_barrier_t barrier; 54 55 static void 56 dowrite(void) 57 { 58 char buf[1]; 59 int fd; 60 int i; 61 62 i = random() % NPIPE; 63 fd = fds[i][1]; 64 #if VERBOSE 65 printf("[%p] write %d\n", (void *)pthread_self(), fd); 66 #endif 67 if (write(fd, buf, sizeof(buf)) == -1) { 68 perror("write"); 69 abort(); 70 } 71 } 72 73 static void * 74 f(void *dummy) 75 { 76 77 pthread_barrier_wait(&barrier); 78 79 for (;;) { 80 struct timeval to; 81 fd_set oset; 82 fd_set set; 83 int maxfd = -1; 84 int nfd = 0; 85 int ret; 86 int fd; 87 int i; 88 89 FD_ZERO(&set); 90 do { 91 for (i = 0; i < NPIPE; i++) { 92 fd = fds[i][0]; 93 if (fd > FD_SETSIZE) { 94 fprintf(stderr, 95 "fd(%d) > FD_SETSIZE(%d)\n", 96 fd, FD_SETSIZE); 97 abort(); 98 } 99 if (random() & 1) { 100 FD_SET(fd, &set); 101 if (fd > maxfd) { 102 maxfd = fd; 103 nfd++; 104 } 105 } 106 } 107 } while (nfd == 0); 108 memcpy(&oset, &set, sizeof(oset)); 109 memset(&to, 0, sizeof(to)); 110 to.tv_sec = random() % 10; 111 to.tv_usec = random() % 1000000; 112 #if VERBOSE 113 printf("[%p] select start to=%lu\n", (void *)pthread_self(), 114 (unsigned long)to.tv_sec); 115 #endif 116 ret = select(maxfd + 1, &set, NULL, NULL, &to); 117 #if VERBOSE 118 printf("[%p] select done ret=%d\n", 119 (void *)pthread_self(), ret); 120 #endif 121 if (ret == -1) { 122 perror("select"); 123 abort(); 124 } 125 if (ret > nfd) { 126 fprintf(stderr, "[%p] unexpected return value %d\n", 127 (void *)pthread_self(), ret); 128 abort(); 129 } 130 nfd = 0; 131 for (fd = 0; fd <= maxfd; fd++) { 132 if (FD_ISSET(fd, &set)) { 133 char buf[1]; 134 135 #if VERBOSE 136 printf("[%p] read %d\n", 137 (void *)pthread_self(), fd); 138 #endif 139 if (!FD_ISSET(fd, &oset)) { 140 fprintf(stderr, "[%p] unexpected\n", 141 (void *)pthread_self()); 142 abort(); 143 } 144 if (read(fd, buf, sizeof(buf)) == -1) { 145 if (errno != EAGAIN) { 146 perror("read"); 147 abort(); 148 } 149 } else { 150 dowrite(); 151 atomic_inc_uint(&count); 152 } 153 nfd++; 154 } 155 } 156 if (ret != nfd) { 157 fprintf(stderr, "[%p] ret(%d) != nfd(%d)\n", 158 (void *)pthread_self(), ret, nfd); 159 abort(); 160 } 161 } 162 } 163 164 int 165 main(int argc, char *argv[]) 166 { 167 pthread_t pt[NTHREAD]; 168 int i; 169 unsigned int secs; 170 171 secs = atoi(argv[1]); 172 173 for (i = 0; i < NPIPE; i++) { 174 if (pipe(fds[i])) { 175 perror("pipe"); 176 abort(); 177 } 178 if (fcntl(fds[i][0], F_SETFL, O_NONBLOCK) == -1) { 179 perror("fcntl"); 180 abort(); 181 } 182 } 183 pthread_barrier_init(&barrier, NULL, NTHREAD + 1); 184 for (i = 0; i < NTHREAD; i++) { 185 int error = pthread_create(&pt[i], NULL, f, NULL); 186 if (error) { 187 errno = error; 188 perror("pthread_create"); 189 abort(); 190 } 191 } 192 pthread_barrier_wait(&barrier); 193 dowrite(); 194 dowrite(); 195 dowrite(); 196 dowrite(); 197 198 sleep(secs); 199 printf("%u / %u = %lf\n", count, secs, (double)count / secs); 200 exit(EXIT_SUCCESS); 201 } 202