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 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 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