1 /* $NetBSD: select.c,v 1.3 2011/11/02 16:49:12 yamt 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 #include <sys/time.h>
33
34 #include <assert.h>
35 #include <errno.h>
36 #include <fcntl.h>
37 #include <pthread.h>
38 #include <stdint.h>
39 #include <stdio.h>
40 #include <stdlib.h>
41 #include <string.h>
42 #include <unistd.h>
43
44 #define NPIPE 128
45 #define NTHREAD 64
46 #define NBALLS 5
47 #define VERBOSE 0
48
49 #if !defined(RANDOM_MAX)
50 #define RANDOM_MAX ((1UL << 31) - 1)
51 #endif
52
53 int fds[NPIPE][2];
54
55 volatile unsigned count;
56
57 pthread_barrier_t barrier;
58
59 static void
dowrite(void)60 dowrite(void)
61 {
62 char buf[1];
63 int fd;
64 int i;
65
66 i = random() % NPIPE;
67 fd = fds[i][1];
68 #if VERBOSE
69 printf("[%p] write %d\n", (void *)pthread_self(), fd);
70 #endif
71 if (write(fd, buf, sizeof(buf)) == -1) {
72 perror("write");
73 abort();
74 }
75 }
76
77 static void *
f(void * dummy)78 f(void *dummy)
79 {
80
81 pthread_barrier_wait(&barrier);
82
83 for (;;) {
84 struct timeval to;
85 fd_set oset;
86 fd_set set;
87 int maxfd = -1;
88 int nfd = 0;
89 int ret;
90 int fd;
91 int i;
92
93 FD_ZERO(&set);
94 do {
95 for (i = 0; i < NPIPE; i++) {
96 fd = fds[i][0];
97 if (fd > FD_SETSIZE) {
98 fprintf(stderr,
99 "fd(%d) > FD_SETSIZE(%d)\n",
100 fd, FD_SETSIZE);
101 abort();
102 }
103 if (random() & 1) {
104 assert(!FD_ISSET(fd, &set));
105 FD_SET(fd, &set);
106 nfd++;
107 if (fd > maxfd) {
108 maxfd = fd;
109 }
110 }
111 }
112 } while (nfd == 0);
113 memcpy(&oset, &set, sizeof(oset));
114 memset(&to, 0, sizeof(to));
115 to.tv_sec = random() % 10;
116 to.tv_usec = random() % 1000000;
117 #if VERBOSE
118 printf("[%p] select start to=%lu\n", (void *)pthread_self(),
119 (unsigned long)to.tv_sec);
120 #endif
121 ret = select(maxfd + 1, &set, NULL, NULL, &to);
122 #if VERBOSE
123 printf("[%p] select done ret=%d\n",
124 (void *)pthread_self(), ret);
125 #endif
126 if (ret == -1) {
127 perror("select");
128 abort();
129 }
130 if (ret > nfd) {
131 fprintf(stderr, "[%p] unexpected return value %d\n",
132 (void *)pthread_self(), ret);
133 abort();
134 }
135 if (ret > NBALLS) {
136 fprintf(stderr, "[%p] unexpected return value %d"
137 " > NBALLS\n",
138 (void *)pthread_self(), ret);
139 abort();
140 }
141 nfd = 0;
142 for (fd = 0; fd <= maxfd; fd++) {
143 if (FD_ISSET(fd, &set)) {
144 char buf[1];
145
146 #if VERBOSE
147 printf("[%p] read %d\n",
148 (void *)pthread_self(), fd);
149 #endif
150 if (!FD_ISSET(fd, &oset)) {
151 fprintf(stderr, "[%p] unexpected\n",
152 (void *)pthread_self());
153 abort();
154 }
155 if (read(fd, buf, sizeof(buf)) == -1) {
156 if (errno != EAGAIN) {
157 perror("read");
158 abort();
159 }
160 } else {
161 dowrite();
162 atomic_inc_uint(&count);
163 }
164 nfd++;
165 }
166 }
167 if (ret != nfd) {
168 fprintf(stderr, "[%p] ret(%d) != nfd(%d)\n",
169 (void *)pthread_self(), ret, nfd);
170 abort();
171 }
172 }
173 }
174
175 int
main(int argc,char * argv[])176 main(int argc, char *argv[])
177 {
178 pthread_t pt[NTHREAD];
179 int i;
180 unsigned int secs;
181 struct timeval start_tv;
182 struct timeval end_tv;
183 uint64_t usecs;
184 unsigned int result;
185
186 secs = atoi(argv[1]);
187
188 for (i = 0; i < NPIPE; i++) {
189 if (pipe(fds[i])) {
190 perror("pipe");
191 abort();
192 }
193 if (fcntl(fds[i][0], F_SETFL, O_NONBLOCK) == -1) {
194 perror("fcntl");
195 abort();
196 }
197 }
198 pthread_barrier_init(&barrier, NULL, NTHREAD + 1);
199 for (i = 0; i < NTHREAD; i++) {
200 int error = pthread_create(&pt[i], NULL, f, NULL);
201 if (error) {
202 errno = error;
203 perror("pthread_create");
204 abort();
205 }
206 }
207 pthread_barrier_wait(&barrier);
208 gettimeofday(&start_tv, NULL);
209 assert(count == 0);
210 for (i = 0; i < NBALLS; i++) {
211 dowrite();
212 }
213 sleep(secs);
214 gettimeofday(&end_tv, NULL);
215 result = count;
216 usecs = (end_tv.tv_sec - start_tv.tv_sec) * 1000000
217 + end_tv.tv_usec - start_tv.tv_usec;
218 printf("%u / %f = %f\n", result, (double)usecs / 1000000,
219 (double)result / usecs * 1000000);
220 exit(EXIT_SUCCESS);
221 }
222