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 <subcmd/parse-options.h>
  13 #include <api/fs/fs.h>
  14 #include "bench.h"
  15 #include "util/cgroup.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 <fcntl.h>
  25 #include <assert.h>
  26 #include <sys/epoll.h>
  27 #include <sys/time.h>
  28 #include <sys/types.h>
  29 #include <sys/syscall.h>
  30 #include <linux/time64.h>
  31
  32 #include <pthread.h>
  33
  34 struct thread_data {
  35         int                     nr;
  36         int                     pipe_read;
  37         int                     pipe_write;
  38         struct epoll_event      epoll_ev;
  39         int                     epoll_fd;
  40         bool                    cgroup_failed;
  41         pthread_t               pthread;
  42 };
  43
  44 #define LOOPS_DEFAULT 1000000
  45 static  int                     loops = LOOPS_DEFAULT;
  46
  47 /* Use processes by default: */
  48 static bool                     threaded;
  49
  50 static bool                     nonblocking;
  51 static char                     *cgrp_names[2];
  52 static struct cgroup            *cgrps[2];
  53
  54 static int parse_two_cgroups(const struct option *opt __maybe_unused,
  55                              const char *str, int unset __maybe_unused)
  56 {
  57         char *p = strdup(str);
  58         char *q;
  59         int ret = -1;
  60
  61         if (p == NULL) {
  62                 fprintf(stderr, "memory allocation failure\n");
  63                 return -1;
  64         }
  65
  66         q = strchr(p, ',');
  67         if (q == NULL) {
  68                 fprintf(stderr, "it should have two cgroup names: %s\n", p);
  69                 goto out;
  70         }
  71         *q = '\0';
  72
  73         cgrp_names[0] = strdup(p);
  74         cgrp_names[1] = strdup(q + 1);
  75
  76         if (cgrp_names[0] == NULL || cgrp_names[1] == NULL) {
  77                 fprintf(stderr, "memory allocation failure\n");
  78                 goto out;
  79         }
  80         ret = 0;
  81
  82 out:
  83         free(p);
  84         return ret;
  85 }
  86
  87 static const struct option options[] = {
  88         OPT_BOOLEAN('n', "nonblocking", &nonblocking,   "Use non-blocking operations"),
  89         OPT_INTEGER('l', "loop",        &loops,         "Specify number of loops"),
  90         OPT_BOOLEAN('T', "threaded",    &threaded,      "Specify threads/process based task setup"),
  91         OPT_CALLBACK('G', "cgroups", NULL, "SEND,RECV",
  92                      "Put sender and receivers in given cgroups",
  93                      parse_two_cgroups),
  94         OPT_END()
  95 };
  96
  97 static const char * const bench_sched_pipe_usage[] = {
  98         "perf bench sched pipe <options>",
  99         NULL
 100 };
 101
 102 static int enter_cgroup(int nr)
 103 {
 104         char buf[32];
 105         int fd, len, ret;
 106         int saved_errno;
 107         struct cgroup *cgrp;
 108         pid_t pid;
 109
 110         if (cgrp_names[nr] == NULL)
 111                 return 0;
 112
 113         if (cgrps[nr] == NULL) {
 114                 cgrps[nr] = cgroup__new(cgrp_names[nr], /*do_open=*/true);
 115                 if (cgrps[nr] == NULL)
 116                         goto err;
 117         }
 118         cgrp = cgrps[nr];
 119
 120         if (threaded)
 121                 pid = syscall(__NR_gettid);
 122         else
 123                 pid = getpid();
 124
 125         snprintf(buf, sizeof(buf), "%d\n", pid);
 126         len = strlen(buf);
 127
 128         /* try cgroup v2 interface first */
 129         if (threaded)
 130                 fd = openat(cgrp->fd, "cgroup.threads", O_WRONLY);
 131         else
 132                 fd = openat(cgrp->fd, "cgroup.procs", O_WRONLY);
 133
 134         /* try cgroup v1 if failed */
 135         if (fd < 0 && errno == ENOENT)
 136                 fd = openat(cgrp->fd, "tasks", O_WRONLY);
 137
 138         if (fd < 0)
 139                 goto err;
 140
 141         ret = write(fd, buf, len);
 142         close(fd);
 143
 144         if (ret != len) {
 145                 printf("Cannot enter to cgroup: %s\n", cgrp->name);
 146                 return -1;
 147         }
 148         return 0;
 149
 150 err:
 151         saved_errno = errno;
 152         printf("Failed to open cgroup file in %s\n", cgrp_names[nr]);
 153
 154         if (saved_errno == ENOENT) {
 155                 char mnt[PATH_MAX];
 156
 157                 if (cgroupfs_find_mountpoint(mnt, sizeof(mnt), "perf_event") == 0)
 158                         printf(" Hint: create the cgroup first, like 'mkdir %s/%s'\n",
 159                                mnt, cgrp_names[nr]);
 160         } else if (saved_errno == EACCES && geteuid() > 0) {
 161                 printf(" Hint: try to run as root\n");
 162         }
 163
 164         return -1;
 165 }
 166
 167 static void exit_cgroup(int nr)
 168 {
 169         cgroup__put(cgrps[nr]);
 170         free(cgrp_names[nr]);
 171 }
 172
 173 static inline int read_pipe(struct thread_data *td)
 174 {
 175         int ret, m;
 176 retry:
 177         if (nonblocking) {
 178                 ret = epoll_wait(td->epoll_fd, &td->epoll_ev, 1, -1);
 179                 if (ret < 0)
 180                         return ret;
 181         }
 182         ret = read(td->pipe_read, &m, sizeof(int));
 183         if (nonblocking && ret < 0 && errno == EWOULDBLOCK)
 184                 goto retry;
 185         return ret;
 186 }
 187
 188 static void *worker_thread(void *__tdata)
 189 {
 190         struct thread_data *td = __tdata;
 191         int i, ret, m = 0;
 192
 193         ret = enter_cgroup(td->nr);
 194         if (ret < 0) {
 195                 td->cgroup_failed = true;
 196                 return NULL;
 197         }
 198
 199         if (nonblocking) {
 200                 td->epoll_ev.events = EPOLLIN;
 201                 td->epoll_fd = epoll_create(1);
 202                 BUG_ON(td->epoll_fd < 0);
 203                 BUG_ON(epoll_ctl(td->epoll_fd, EPOLL_CTL_ADD, td->pipe_read, &td->epoll_ev) < 0);
 204         }
 205
 206         for (i = 0; i < loops; i++) {
 207                 if (!td->nr) {
 208                         ret = read_pipe(td);
 209                         BUG_ON(ret != sizeof(int));
 210                         ret = write(td->pipe_write, &m, sizeof(int));
 211                         BUG_ON(ret != sizeof(int));
 212                 } else {
 213                         ret = write(td->pipe_write, &m, sizeof(int));
 214                         BUG_ON(ret != sizeof(int));
 215                         ret = read_pipe(td);
 216                         BUG_ON(ret != sizeof(int));
 217                 }
 218         }
 219
 220         return NULL;
 221 }
 222
 223 int bench_sched_pipe(int argc, const char **argv)
 224 {
 225         struct thread_data threads[2] = {};
 226         struct thread_data *td;
 227         int pipe_1[2], pipe_2[2];
 228         struct timeval start, stop, diff;
 229         unsigned long long result_usec = 0;
 230         int nr_threads = 2;
 231         int t;
 232
 233         /*
 234          * why does "ret" exist?
 235          * discarding returned value of read(), write()
 236          * causes error in building environment for perf
 237          */
 238         int __maybe_unused ret, wait_stat, flags = 0;
 239         pid_t pid, retpid __maybe_unused;
 240
 241         argc = parse_options(argc, argv, options, bench_sched_pipe_usage, 0);
 242
 243         if (nonblocking)
 244                 flags |= O_NONBLOCK;
 245
 246         BUG_ON(pipe2(pipe_1, flags));
 247         BUG_ON(pipe2(pipe_2, flags));
 248
 249         gettimeofday(&start, NULL);
 250
 251         for (t = 0; t < nr_threads; t++) {
 252                 td = threads + t;
 253
 254                 td->nr = t;
 255
 256                 if (t == 0) {
 257                         td->pipe_read = pipe_1[0];
 258                         td->pipe_write = pipe_2[1];
 259                 } else {
 260                         td->pipe_write = pipe_1[1];
 261                         td->pipe_read = pipe_2[0];
 262                 }
 263         }
 264
 265         if (threaded) {
 266                 for (t = 0; t < nr_threads; t++) {
 267                         td = threads + t;
 268
 269                         ret = pthread_create(&td->pthread, NULL, worker_thread, td);
 270                         BUG_ON(ret);
 271                 }
 272
 273                 for (t = 0; t < nr_threads; t++) {
 274                         td = threads + t;
 275
 276                         ret = pthread_join(td->pthread, NULL);
 277                         BUG_ON(ret);
 278                 }
 279         } else {
 280                 pid = fork();
 281                 assert(pid >= 0);
 282
 283                 if (!pid) {
 284                         worker_thread(threads + 0);
 285                         exit(0);
 286                 } else {
 287                         worker_thread(threads + 1);
 288                 }
 289
 290                 retpid = waitpid(pid, &wait_stat, 0);
 291                 assert((retpid == pid) && WIFEXITED(wait_stat));
 292         }
 293
 294         gettimeofday(&stop, NULL);
 295         timersub(&stop, &start, &diff);
 296
 297         exit_cgroup(0);
 298         exit_cgroup(1);
 299
 300         if (threads[0].cgroup_failed || threads[1].cgroup_failed)
 301                 return 0;
 302
 303         switch (bench_format) {
 304         case BENCH_FORMAT_DEFAULT:
 305                 printf("# Executed %d pipe operations between two %s\n\n",
 306                         loops, threaded ? "threads" : "processes");
 307
 308                 result_usec = diff.tv_sec * USEC_PER_SEC;
 309                 result_usec += diff.tv_usec;
 310
 311                 printf(" %14s: %lu.%03lu [sec]\n\n", "Total time",
 312                        (unsigned long) diff.tv_sec,
 313                        (unsigned long) (diff.tv_usec / USEC_PER_MSEC));
 314
 315                 printf(" %14lf usecs/op\n",
 316                        (double)result_usec / (double)loops);
 317                 printf(" %14d ops/sec\n",
 318                        (int)((double)loops /
 319                              ((double)result_usec / (double)USEC_PER_SEC)));
 320                 break;
 321
 322         case BENCH_FORMAT_SIMPLE:
 323                 printf("%lu.%03lu\n",
 324                        (unsigned long) diff.tv_sec,
 325                        (unsigned long) (diff.tv_usec / USEC_PER_MSEC));
 326                 break;
 327
 328         default:
 329                 /* reaching here is something disaster */
 330                 fprintf(stderr, "Unknown format:%d\n", bench_format);
 331                 exit(1);
 332                 break;
 333         }
 334
 335         return 0;
 336 }