1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 *
4 * sched-pipe.c
5 *
6 * pipe: Benchmark for pipe()
7 *
8 * Based on pipe-test-1m.c by Ingo Molnar <mingo@redhat.com>
9 * http://people.redhat.com/mingo/cfs-scheduler/tools/pipe-test-1m.c
10 * Ported to perf by Hitoshi Mitake <mitake@dcl.info.waseda.ac.jp>
11 */
12 #include <subcmd/parse-options.h>
13 #include <api/fs/fs.h>
14 #include "bench.h"
15 #include "util/cgroup.h"
16
17 #include <unistd.h>
18 #include <stdio.h>
19 #include <stdlib.h>
20 #include <signal.h>
21 #include <sys/wait.h>
22 #include <string.h>
23 #include <errno.h>
24 #include <fcntl.h>
25 #include <assert.h>
26 #include <sys/epoll.h>
27 #include <sys/time.h>
28 #include <sys/types.h>
29 #include <sys/syscall.h>
30 #include <linux/time64.h>
31
32 #include <pthread.h>
33
34 struct thread_data {
35 int nr;
36 int pipe_read;
37 int pipe_write;
38 struct epoll_event epoll_ev;
39 int epoll_fd;
40 bool cgroup_failed;
41 pthread_t pthread;
42 };
43
44 #define LOOPS_DEFAULT 1000000
45 static int loops = LOOPS_DEFAULT;
46
47 /* Use processes by default: */
48 static bool threaded;
49
50 static bool nonblocking;
51 static char *cgrp_names[2];
52 static struct cgroup *cgrps[2];
53
parse_two_cgroups(const struct option * opt __maybe_unused,const char * str,int unset __maybe_unused)54 static int parse_two_cgroups(const struct option *opt __maybe_unused,
55 const char *str, int unset __maybe_unused)
56 {
57 char *p = strdup(str);
58 char *q;
59 int ret = -1;
60
61 if (p == NULL) {
62 fprintf(stderr, "memory allocation failure\n");
63 return -1;
64 }
65
66 q = strchr(p, ',');
67 if (q == NULL) {
68 fprintf(stderr, "it should have two cgroup names: %s\n", p);
69 goto out;
70 }
71 *q = '\0';
72
73 cgrp_names[0] = strdup(p);
74 cgrp_names[1] = strdup(q + 1);
75
76 if (cgrp_names[0] == NULL || cgrp_names[1] == NULL) {
77 fprintf(stderr, "memory allocation failure\n");
78 goto out;
79 }
80 ret = 0;
81
82 out:
83 free(p);
84 return ret;
85 }
86
87 static const struct option options[] = {
88 OPT_BOOLEAN('n', "nonblocking", &nonblocking, "Use non-blocking operations"),
89 OPT_INTEGER('l', "loop", &loops, "Specify number of loops"),
90 OPT_BOOLEAN('T', "threaded", &threaded, "Specify threads/process based task setup"),
91 OPT_CALLBACK('G', "cgroups", NULL, "SEND,RECV",
92 "Put sender and receivers in given cgroups",
93 parse_two_cgroups),
94 OPT_END()
95 };
96
97 static const char * const bench_sched_pipe_usage[] = {
98 "perf bench sched pipe <options>",
99 NULL
100 };
101
enter_cgroup(int nr)102 static int enter_cgroup(int nr)
103 {
104 char buf[32];
105 int fd, len, ret;
106 int saved_errno;
107 struct cgroup *cgrp;
108 pid_t pid;
109
110 if (cgrp_names[nr] == NULL)
111 return 0;
112
113 if (cgrps[nr] == NULL) {
114 cgrps[nr] = cgroup__new(cgrp_names[nr], /*do_open=*/true);
115 if (cgrps[nr] == NULL)
116 goto err;
117 }
118 cgrp = cgrps[nr];
119
120 if (threaded)
121 pid = syscall(__NR_gettid);
122 else
123 pid = getpid();
124
125 snprintf(buf, sizeof(buf), "%d\n", pid);
126 len = strlen(buf);
127
128 /* try cgroup v2 interface first */
129 if (threaded)
130 fd = openat(cgrp->fd, "cgroup.threads", O_WRONLY);
131 else
132 fd = openat(cgrp->fd, "cgroup.procs", O_WRONLY);
133
134 /* try cgroup v1 if failed */
135 if (fd < 0 && errno == ENOENT)
136 fd = openat(cgrp->fd, "tasks", O_WRONLY);
137
138 if (fd < 0)
139 goto err;
140
141 ret = write(fd, buf, len);
142 close(fd);
143
144 if (ret != len) {
145 printf("Cannot enter to cgroup: %s\n", cgrp->name);
146 return -1;
147 }
148 return 0;
149
150 err:
151 saved_errno = errno;
152 printf("Failed to open cgroup file in %s\n", cgrp_names[nr]);
153
154 if (saved_errno == ENOENT) {
155 char mnt[PATH_MAX];
156
157 if (cgroupfs_find_mountpoint(mnt, sizeof(mnt), "perf_event") == 0)
158 printf(" Hint: create the cgroup first, like 'mkdir %s/%s'\n",
159 mnt, cgrp_names[nr]);
160 } else if (saved_errno == EACCES && geteuid() > 0) {
161 printf(" Hint: try to run as root\n");
162 }
163
164 return -1;
165 }
166
exit_cgroup(int nr)167 static void exit_cgroup(int nr)
168 {
169 cgroup__put(cgrps[nr]);
170 free(cgrp_names[nr]);
171 }
172
read_pipe(struct thread_data * td)173 static inline int read_pipe(struct thread_data *td)
174 {
175 int ret, m;
176 retry:
177 if (nonblocking) {
178 ret = epoll_wait(td->epoll_fd, &td->epoll_ev, 1, -1);
179 if (ret < 0)
180 return ret;
181 }
182 ret = read(td->pipe_read, &m, sizeof(int));
183 if (nonblocking && ret < 0 && errno == EWOULDBLOCK)
184 goto retry;
185 return ret;
186 }
187
worker_thread(void * __tdata)188 static void *worker_thread(void *__tdata)
189 {
190 struct thread_data *td = __tdata;
191 int i, ret, m = 0;
192
193 ret = enter_cgroup(td->nr);
194 if (ret < 0) {
195 td->cgroup_failed = true;
196 return NULL;
197 }
198
199 if (nonblocking) {
200 td->epoll_ev.events = EPOLLIN;
201 td->epoll_fd = epoll_create(1);
202 BUG_ON(td->epoll_fd < 0);
203 BUG_ON(epoll_ctl(td->epoll_fd, EPOLL_CTL_ADD, td->pipe_read, &td->epoll_ev) < 0);
204 }
205
206 for (i = 0; i < loops; i++) {
207 ret = write(td->pipe_write, &m, sizeof(int));
208 BUG_ON(ret != sizeof(int));
209 ret = read_pipe(td);
210 BUG_ON(ret != sizeof(int));
211 }
212
213 return NULL;
214 }
215
bench_sched_pipe(int argc,const char ** argv)216 int bench_sched_pipe(int argc, const char **argv)
217 {
218 struct thread_data threads[2] = {};
219 struct thread_data *td;
220 int pipe_1[2], pipe_2[2];
221 struct timeval start, stop, diff;
222 unsigned long long result_usec = 0;
223 int nr_threads = 2;
224 int t;
225
226 /*
227 * why does "ret" exist?
228 * discarding returned value of read(), write()
229 * causes error in building environment for perf
230 */
231 int __maybe_unused ret, wait_stat, flags = 0;
232 pid_t pid, retpid __maybe_unused;
233
234 argc = parse_options(argc, argv, options, bench_sched_pipe_usage, 0);
235
236 if (nonblocking)
237 flags |= O_NONBLOCK;
238
239 BUG_ON(pipe2(pipe_1, flags));
240 BUG_ON(pipe2(pipe_2, flags));
241
242 gettimeofday(&start, NULL);
243
244 for (t = 0; t < nr_threads; t++) {
245 td = threads + t;
246
247 td->nr = t;
248
249 if (t == 0) {
250 td->pipe_read = pipe_1[0];
251 td->pipe_write = pipe_2[1];
252 } else {
253 td->pipe_write = pipe_1[1];
254 td->pipe_read = pipe_2[0];
255 }
256 }
257
258 if (threaded) {
259 for (t = 0; t < nr_threads; t++) {
260 td = threads + t;
261
262 ret = pthread_create(&td->pthread, NULL, worker_thread, td);
263 BUG_ON(ret);
264 }
265
266 for (t = 0; t < nr_threads; t++) {
267 td = threads + t;
268
269 ret = pthread_join(td->pthread, NULL);
270 BUG_ON(ret);
271 }
272 } else {
273 pid = fork();
274 assert(pid >= 0);
275
276 if (!pid) {
277 worker_thread(threads + 0);
278 exit(0);
279 } else {
280 worker_thread(threads + 1);
281 }
282
283 retpid = waitpid(pid, &wait_stat, 0);
284 assert((retpid == pid) && WIFEXITED(wait_stat));
285 }
286
287 gettimeofday(&stop, NULL);
288 timersub(&stop, &start, &diff);
289
290 exit_cgroup(0);
291 exit_cgroup(1);
292
293 if (threads[0].cgroup_failed || threads[1].cgroup_failed)
294 return 0;
295
296 switch (bench_format) {
297 case BENCH_FORMAT_DEFAULT:
298 printf("# Executed %d pipe operations between two %s\n\n",
299 loops, threaded ? "threads" : "processes");
300
301 result_usec = diff.tv_sec * USEC_PER_SEC;
302 result_usec += diff.tv_usec;
303
304 printf(" %14s: %lu.%03lu [sec]\n\n", "Total time",
305 (unsigned long) diff.tv_sec,
306 (unsigned long) (diff.tv_usec / USEC_PER_MSEC));
307
308 printf(" %14lf usecs/op\n",
309 (double)result_usec / (double)loops);
310 printf(" %14d ops/sec\n",
311 (int)((double)loops /
312 ((double)result_usec / (double)USEC_PER_SEC)));
313 break;
314
315 case BENCH_FORMAT_SIMPLE:
316 printf("%lu.%03lu\n",
317 (unsigned long) diff.tv_sec,
318 (unsigned long) (diff.tv_usec / USEC_PER_MSEC));
319 break;
320
321 default:
322 /* reaching here is something disaster */
323 fprintf(stderr, "Unknown format:%d\n", bench_format);
324 exit(1);
325 break;
326 }
327
328 return 0;
329 }
330