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