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 "bench.h"
14
15 #include <unistd.h>
16 #include <stdio.h>
17 #include <stdlib.h>
18 #include <signal.h>
19 #include <sys/wait.h>
20 #include <string.h>
21 #include <errno.h>
22 #include <assert.h>
23 #include <sys/time.h>
24 #include <sys/types.h>
25 #include <sys/syscall.h>
26 #include <linux/time64.h>
27
28 #include <pthread.h>
29
30 struct thread_data {
31 int nr;
32 int pipe_read;
33 int pipe_write;
34 pthread_t pthread;
35 };
36
37 #define LOOPS_DEFAULT 1000000
38 static int loops = LOOPS_DEFAULT;
39
40 /* Use processes by default: */
41 static bool threaded;
42
43 static const struct option options[] = {
44 OPT_INTEGER('l', "loop", &loops, "Specify number of loops"),
45 OPT_BOOLEAN('T', "threaded", &threaded, "Specify threads/process based task setup"),
46 OPT_END()
47 };
48
49 static const char * const bench_sched_pipe_usage[] = {
50 "perf bench sched pipe <options>",
51 NULL
52 };
53
worker_thread(void * __tdata)54 static void *worker_thread(void *__tdata)
55 {
56 struct thread_data *td = __tdata;
57 int m = 0, i;
58 int ret;
59
60 for (i = 0; i < loops; i++) {
61 if (!td->nr) {
62 ret = read(td->pipe_read, &m, sizeof(int));
63 BUG_ON(ret != sizeof(int));
64 ret = write(td->pipe_write, &m, sizeof(int));
65 BUG_ON(ret != sizeof(int));
66 } else {
67 ret = write(td->pipe_write, &m, sizeof(int));
68 BUG_ON(ret != sizeof(int));
69 ret = read(td->pipe_read, &m, sizeof(int));
70 BUG_ON(ret != sizeof(int));
71 }
72 }
73
74 return NULL;
75 }
76
bench_sched_pipe(int argc,const char ** argv)77 int bench_sched_pipe(int argc, const char **argv)
78 {
79 struct thread_data threads[2], *td;
80 int pipe_1[2], pipe_2[2];
81 struct timeval start, stop, diff;
82 unsigned long long result_usec = 0;
83 int nr_threads = 2;
84 int t;
85
86 /*
87 * why does "ret" exist?
88 * discarding returned value of read(), write()
89 * causes error in building environment for perf
90 */
91 int __maybe_unused ret, wait_stat;
92 pid_t pid, retpid __maybe_unused;
93
94 argc = parse_options(argc, argv, options, bench_sched_pipe_usage, 0);
95
96 BUG_ON(pipe(pipe_1));
97 BUG_ON(pipe(pipe_2));
98
99 gettimeofday(&start, NULL);
100
101 for (t = 0; t < nr_threads; t++) {
102 td = threads + t;
103
104 td->nr = t;
105
106 if (t == 0) {
107 td->pipe_read = pipe_1[0];
108 td->pipe_write = pipe_2[1];
109 } else {
110 td->pipe_write = pipe_1[1];
111 td->pipe_read = pipe_2[0];
112 }
113 }
114
115
116 if (threaded) {
117
118 for (t = 0; t < nr_threads; t++) {
119 td = threads + t;
120
121 ret = pthread_create(&td->pthread, NULL, worker_thread, td);
122 BUG_ON(ret);
123 }
124
125 for (t = 0; t < nr_threads; t++) {
126 td = threads + t;
127
128 ret = pthread_join(td->pthread, NULL);
129 BUG_ON(ret);
130 }
131
132 } else {
133 pid = fork();
134 assert(pid >= 0);
135
136 if (!pid) {
137 worker_thread(threads + 0);
138 exit(0);
139 } else {
140 worker_thread(threads + 1);
141 }
142
143 retpid = waitpid(pid, &wait_stat, 0);
144 assert((retpid == pid) && WIFEXITED(wait_stat));
145 }
146
147 gettimeofday(&stop, NULL);
148 timersub(&stop, &start, &diff);
149
150 switch (bench_format) {
151 case BENCH_FORMAT_DEFAULT:
152 printf("# Executed %d pipe operations between two %s\n\n",
153 loops, threaded ? "threads" : "processes");
154
155 result_usec = diff.tv_sec * USEC_PER_SEC;
156 result_usec += diff.tv_usec;
157
158 printf(" %14s: %lu.%03lu [sec]\n\n", "Total time",
159 (unsigned long) diff.tv_sec,
160 (unsigned long) (diff.tv_usec / USEC_PER_MSEC));
161
162 printf(" %14lf usecs/op\n",
163 (double)result_usec / (double)loops);
164 printf(" %14d ops/sec\n",
165 (int)((double)loops /
166 ((double)result_usec / (double)USEC_PER_SEC)));
167 break;
168
169 case BENCH_FORMAT_SIMPLE:
170 printf("%lu.%03lu\n",
171 (unsigned long) diff.tv_sec,
172 (unsigned long) (diff.tv_usec / USEC_PER_MSEC));
173 break;
174
175 default:
176 /* reaching here is something disaster */
177 fprintf(stderr, "Unknown format:%d\n", bench_format);
178 exit(1);
179 break;
180 }
181
182 return 0;
183 }
184