tools/perf/bench/sched-pipe.c

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