tools/perf/bench/sched-pipe.c

   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 }