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 */
12
13 #include "../perf.h"
14 #include "../util/util.h"
15 #include "../util/parse-options.h"
16 #include "../builtin.h"
17 #include "bench.h"
18
19 #include <unistd.h>
20 #include <stdio.h>
21 #include <stdlib.h>
22 #include <signal.h>
23 #include <sys/wait.h>
24 #include <linux/unistd.h>
25 #include <string.h>
26 #include <errno.h>
27 #include <assert.h>
28 #include <sys/time.h>
29 #include <sys/types.h>
30
31 #define LOOPS_DEFAULT 1000000
32 static int loops = LOOPS_DEFAULT;
33
34 static const struct option options[] = {
35 OPT_INTEGER('l', "loop", &loops,
36 "Specify number of loops"),
37 OPT_END()
38 };
39
40 static const char * const bench_sched_pipe_usage[] = {
41 "perf bench sched pipe <options>",
42 NULL
43 };
44
bench_sched_pipe(int argc,const char ** argv,const char * prefix __maybe_unused)45 int bench_sched_pipe(int argc, const char **argv,
46 const char *prefix __maybe_unused)
47 {
48 int pipe_1[2], pipe_2[2];
49 int m = 0, i;
50 struct timeval start, stop, diff;
51 unsigned long long result_usec = 0;
52
53 /*
54 * why does "ret" exist?
55 * discarding returned value of read(), write()
56 * causes error in building environment for perf
57 */
58 int __maybe_unused ret, wait_stat;
59 pid_t pid, retpid __maybe_unused;
60
61 argc = parse_options(argc, argv, options,
62 bench_sched_pipe_usage, 0);
63
64 BUG_ON(pipe(pipe_1));
65 BUG_ON(pipe(pipe_2));
66
67 pid = fork();
68 assert(pid >= 0);
69
70 gettimeofday(&start, NULL);
71
72 if (!pid) {
73 for (i = 0; i < loops; i++) {
74 ret = read(pipe_1[0], &m, sizeof(int));
75 ret = write(pipe_2[1], &m, sizeof(int));
76 }
77 } else {
78 for (i = 0; i < loops; i++) {
79 ret = write(pipe_1[1], &m, sizeof(int));
80 ret = read(pipe_2[0], &m, sizeof(int));
81 }
82 }
83
84 gettimeofday(&stop, NULL);
85 timersub(&stop, &start, &diff);
86
87 if (pid) {
88 retpid = waitpid(pid, &wait_stat, 0);
89 assert((retpid == pid) && WIFEXITED(wait_stat));
90 } else {
91 exit(0);
92 }
93
94 switch (bench_format) {
95 case BENCH_FORMAT_DEFAULT:
96 printf("# Executed %d pipe operations between two tasks\n\n",
97 loops);
98
99 result_usec = diff.tv_sec * 1000000;
100 result_usec += diff.tv_usec;
101
102 printf(" %14s: %lu.%03lu [sec]\n\n", "Total time",
103 diff.tv_sec,
104 (unsigned long) (diff.tv_usec/1000));
105
106 printf(" %14lf usecs/op\n",
107 (double)result_usec / (double)loops);
108 printf(" %14d ops/sec\n",
109 (int)((double)loops /
110 ((double)result_usec / (double)1000000)));
111 break;
112
113 case BENCH_FORMAT_SIMPLE:
114 printf("%lu.%03lu\n",
115 diff.tv_sec,
116 (unsigned long) (diff.tv_usec / 1000));
117 break;
118
119 default:
120 /* reaching here is something disaster */
121 fprintf(stderr, "Unknown format:%d\n", bench_format);
122 exit(1);
123 break;
124 }
125
126 return 0;
127 }
128