1/*
2 *
3 * sched-pipe.c
4 *
5 * pipe: Benchmark for pipe()
6 *
7 * Based on pipe-test-1m.c by Ingo Molnar <mingo@redhat.com>
8 *  http://people.redhat.com/mingo/cfs-scheduler/tools/pipe-test-1m.c
9 * Ported to perf by Hitoshi Mitake <mitake@dcl.info.waseda.ac.jp>
10 */
11#include "../perf.h"
12#include "../util/util.h"
13#include "../util/parse-options.h"
14#include "../builtin.h"
15#include "bench.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 <assert.h>
25#include <sys/time.h>
26#include <sys/types.h>
27#include <sys/syscall.h>
28
29#include <pthread.h>
30
31struct thread_data {
32	int			nr;
33	int			pipe_read;
34	int			pipe_write;
35	pthread_t		pthread;
36};
37
38#define LOOPS_DEFAULT 1000000
39static	int			loops = LOOPS_DEFAULT;
40
41/* Use processes by default: */
42static bool			threaded;
43
44static const struct option options[] = {
45	OPT_INTEGER('l', "loop",	&loops,		"Specify number of loops"),
46	OPT_BOOLEAN('T', "threaded",	&threaded,	"Specify threads/process based task setup"),
47	OPT_END()
48};
49
50static const char * const bench_sched_pipe_usage[] = {
51	"perf bench sched pipe <options>",
52	NULL
53};
54
55static void *worker_thread(void *__tdata)
56{
57	struct thread_data *td = __tdata;
58	int m = 0, i;
59	int ret;
60
61	for (i = 0; i < loops; i++) {
62		if (!td->nr) {
63			ret = read(td->pipe_read, &m, sizeof(int));
64			BUG_ON(ret != sizeof(int));
65			ret = write(td->pipe_write, &m, sizeof(int));
66			BUG_ON(ret != sizeof(int));
67		} else {
68			ret = write(td->pipe_write, &m, sizeof(int));
69			BUG_ON(ret != sizeof(int));
70			ret = read(td->pipe_read, &m, sizeof(int));
71			BUG_ON(ret != sizeof(int));
72		}
73	}
74
75	return NULL;
76}
77
78int bench_sched_pipe(int argc, const char **argv, const char *prefix __maybe_unused)
79{
80	struct thread_data threads[2], *td;
81	int pipe_1[2], pipe_2[2];
82	struct timeval start, stop, diff;
83	unsigned long long result_usec = 0;
84	int nr_threads = 2;
85	int t;
86
87	/*
88	 * why does "ret" exist?
89	 * discarding returned value of read(), write()
90	 * causes error in building environment for perf
91	 */
92	int __maybe_unused ret, wait_stat;
93	pid_t pid, retpid __maybe_unused;
94
95	argc = parse_options(argc, argv, options, bench_sched_pipe_usage, 0);
96
97	BUG_ON(pipe(pipe_1));
98	BUG_ON(pipe(pipe_2));
99
100	gettimeofday(&start, NULL);
101
102	for (t = 0; t < nr_threads; t++) {
103		td = threads + t;
104
105		td->nr = t;
106
107		if (t == 0) {
108			td->pipe_read = pipe_1[0];
109			td->pipe_write = pipe_2[1];
110		} else {
111			td->pipe_write = pipe_1[1];
112			td->pipe_read = pipe_2[0];
113		}
114	}
115
116
117	if (threaded) {
118
119		for (t = 0; t < nr_threads; t++) {
120			td = threads + t;
121
122			ret = pthread_create(&td->pthread, NULL, worker_thread, td);
123			BUG_ON(ret);
124		}
125
126		for (t = 0; t < nr_threads; t++) {
127			td = threads + t;
128
129			ret = pthread_join(td->pthread, NULL);
130			BUG_ON(ret);
131		}
132
133	} else {
134		pid = fork();
135		assert(pid >= 0);
136
137		if (!pid) {
138			worker_thread(threads + 0);
139			exit(0);
140		} else {
141			worker_thread(threads + 1);
142		}
143
144		retpid = waitpid(pid, &wait_stat, 0);
145		assert((retpid == pid) && WIFEXITED(wait_stat));
146	}
147
148	gettimeofday(&stop, NULL);
149	timersub(&stop, &start, &diff);
150
151	switch (bench_format) {
152	case BENCH_FORMAT_DEFAULT:
153		printf("# Executed %d pipe operations between two %s\n\n",
154			loops, threaded ? "threads" : "processes");
155
156		result_usec = diff.tv_sec * 1000000;
157		result_usec += diff.tv_usec;
158
159		printf(" %14s: %lu.%03lu [sec]\n\n", "Total time",
160		       diff.tv_sec,
161		       (unsigned long) (diff.tv_usec/1000));
162
163		printf(" %14lf usecs/op\n",
164		       (double)result_usec / (double)loops);
165		printf(" %14d ops/sec\n",
166		       (int)((double)loops /
167			     ((double)result_usec / (double)1000000)));
168		break;
169
170	case BENCH_FORMAT_SIMPLE:
171		printf("%lu.%03lu\n",
172		       diff.tv_sec,
173		       (unsigned long) (diff.tv_usec / 1000));
174		break;
175
176	default:
177		/* reaching here is something disaster */
178		fprintf(stderr, "Unknown format:%d\n", bench_format);
179		exit(1);
180		break;
181	}
182
183	return 0;
184}
185