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