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 "../perf.h" 13 #include "../util/util.h" 14 #include <subcmd/parse-options.h> 15 #include "../builtin.h" 16 #include "bench.h" 17 18 #include <unistd.h> 19 #include <stdio.h> 20 #include <stdlib.h> 21 #include <signal.h> 22 #include <sys/wait.h> 23 #include <string.h> 24 #include <errno.h> 25 #include <assert.h> 26 #include <sys/time.h> 27 #include <sys/types.h> 28 #include <sys/syscall.h> 29 #include <linux/time64.h> 30 31 #include <pthread.h> 32 33 struct thread_data { 34 int nr; 35 int pipe_read; 36 int pipe_write; 37 pthread_t pthread; 38 }; 39 40 #define LOOPS_DEFAULT 1000000 41 static int loops = LOOPS_DEFAULT; 42 43 /* Use processes by default: */ 44 static bool threaded; 45 46 static const struct option options[] = { 47 OPT_INTEGER('l', "loop", &loops, "Specify number of loops"), 48 OPT_BOOLEAN('T', "threaded", &threaded, "Specify threads/process based task setup"), 49 OPT_END() 50 }; 51 52 static const char * const bench_sched_pipe_usage[] = { 53 "perf bench sched pipe <options>", 54 NULL 55 }; 56 57 static void *worker_thread(void *__tdata) 58 { 59 struct thread_data *td = __tdata; 60 int m = 0, i; 61 int ret; 62 63 for (i = 0; i < loops; i++) { 64 if (!td->nr) { 65 ret = read(td->pipe_read, &m, sizeof(int)); 66 BUG_ON(ret != sizeof(int)); 67 ret = write(td->pipe_write, &m, sizeof(int)); 68 BUG_ON(ret != sizeof(int)); 69 } else { 70 ret = write(td->pipe_write, &m, sizeof(int)); 71 BUG_ON(ret != sizeof(int)); 72 ret = read(td->pipe_read, &m, sizeof(int)); 73 BUG_ON(ret != sizeof(int)); 74 } 75 } 76 77 return NULL; 78 } 79 80 int bench_sched_pipe(int argc, const char **argv) 81 { 82 struct thread_data threads[2], *td; 83 int pipe_1[2], pipe_2[2]; 84 struct timeval start, stop, diff; 85 unsigned long long result_usec = 0; 86 int nr_threads = 2; 87 int t; 88 89 /* 90 * why does "ret" exist? 91 * discarding returned value of read(), write() 92 * causes error in building environment for perf 93 */ 94 int __maybe_unused ret, wait_stat; 95 pid_t pid, retpid __maybe_unused; 96 97 argc = parse_options(argc, argv, options, bench_sched_pipe_usage, 0); 98 99 BUG_ON(pipe(pipe_1)); 100 BUG_ON(pipe(pipe_2)); 101 102 gettimeofday(&start, NULL); 103 104 for (t = 0; t < nr_threads; t++) { 105 td = threads + t; 106 107 td->nr = t; 108 109 if (t == 0) { 110 td->pipe_read = pipe_1[0]; 111 td->pipe_write = pipe_2[1]; 112 } else { 113 td->pipe_write = pipe_1[1]; 114 td->pipe_read = pipe_2[0]; 115 } 116 } 117 118 119 if (threaded) { 120 121 for (t = 0; t < nr_threads; t++) { 122 td = threads + t; 123 124 ret = pthread_create(&td->pthread, NULL, worker_thread, td); 125 BUG_ON(ret); 126 } 127 128 for (t = 0; t < nr_threads; t++) { 129 td = threads + t; 130 131 ret = pthread_join(td->pthread, NULL); 132 BUG_ON(ret); 133 } 134 135 } else { 136 pid = fork(); 137 assert(pid >= 0); 138 139 if (!pid) { 140 worker_thread(threads + 0); 141 exit(0); 142 } else { 143 worker_thread(threads + 1); 144 } 145 146 retpid = waitpid(pid, &wait_stat, 0); 147 assert((retpid == pid) && WIFEXITED(wait_stat)); 148 } 149 150 gettimeofday(&stop, NULL); 151 timersub(&stop, &start, &diff); 152 153 switch (bench_format) { 154 case BENCH_FORMAT_DEFAULT: 155 printf("# Executed %d pipe operations between two %s\n\n", 156 loops, threaded ? "threads" : "processes"); 157 158 result_usec = diff.tv_sec * USEC_PER_SEC; 159 result_usec += diff.tv_usec; 160 161 printf(" %14s: %lu.%03lu [sec]\n\n", "Total time", 162 diff.tv_sec, 163 (unsigned long) (diff.tv_usec / USEC_PER_MSEC)); 164 165 printf(" %14lf usecs/op\n", 166 (double)result_usec / (double)loops); 167 printf(" %14d ops/sec\n", 168 (int)((double)loops / 169 ((double)result_usec / (double)USEC_PER_SEC))); 170 break; 171 172 case BENCH_FORMAT_SIMPLE: 173 printf("%lu.%03lu\n", 174 diff.tv_sec, 175 (unsigned long) (diff.tv_usec / USEC_PER_MSEC)); 176 break; 177 178 default: 179 /* reaching here is something disaster */ 180 fprintf(stderr, "Unknown format:%d\n", bench_format); 181 exit(1); 182 break; 183 } 184 185 return 0; 186 } 187