tools/perf/bench/futex-lock-pi.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2015 Davidlohr Bueso.
   4  */
   5
   6 /* For the CLR_() macros */
   7 #include <string.h>
   8 #include <pthread.h>
   9
  10 #include <signal.h>
  11 #include "../util/stat.h"
  12 #include <subcmd/parse-options.h>
  13 #include <linux/compiler.h>
  14 #include <linux/kernel.h>
  15 #include <errno.h>
  16 #include "bench.h"
  17 #include "futex.h"
  18 #include "cpumap.h"
  19
  20 #include <err.h>
  21 #include <stdlib.h>
  22 #include <sys/time.h>
  23
  24 struct worker {
  25         int tid;
  26         u_int32_t *futex;
  27         pthread_t thread;
  28         unsigned long ops;
  29 };
  30
  31 static u_int32_t global_futex = 0;
  32 static struct worker *worker;
  33 static unsigned int nsecs = 10;
  34 static bool silent = false, multi = false;
  35 static bool done = false, fshared = false;
  36 static unsigned int nthreads = 0;
  37 static int futex_flag = 0;
  38 static pthread_mutex_t thread_lock;
  39 static unsigned int threads_starting;
  40 static struct stats throughput_stats;
  41 static pthread_cond_t thread_parent, thread_worker;
  42
  43 static const struct option options[] = {
  44         OPT_UINTEGER('t', "threads",  &nthreads, "Specify amount of threads"),
  45         OPT_UINTEGER('r', "runtime", &nsecs,     "Specify runtime (in seconds)"),
  46         OPT_BOOLEAN( 'M', "multi",   &multi,     "Use multiple futexes"),
  47         OPT_BOOLEAN( 's', "silent",  &silent,    "Silent mode: do not display data/details"),
  48         OPT_BOOLEAN( 'S', "shared",  &fshared,   "Use shared futexes instead of private ones"),
  49         OPT_END()
  50 };
  51
  52 static const char * const bench_futex_lock_pi_usage[] = {
  53         "perf bench futex lock-pi <options>",
  54         NULL
  55 };
  56
  57 static void print_summary(void)
  58 {
  59         unsigned long avg = avg_stats(&throughput_stats);
  60         double stddev = stddev_stats(&throughput_stats);
  61
  62         printf("%sAveraged %ld operations/sec (+- %.2f%%), total secs = %d\n",
  63                !silent ? "\n" : "", avg, rel_stddev_stats(stddev, avg),
  64                (int)bench__runtime.tv_sec);
  65 }
  66
  67 static void toggle_done(int sig __maybe_unused,
  68                         siginfo_t *info __maybe_unused,
  69                         void *uc __maybe_unused)
  70 {
  71         /* inform all threads that we're done for the day */
  72         done = true;
  73         gettimeofday(&bench__end, NULL);
  74         timersub(&bench__end, &bench__start, &bench__runtime);
  75 }
  76
  77 static void *workerfn(void *arg)
  78 {
  79         struct worker *w = (struct worker *) arg;
  80         unsigned long ops = w->ops;
  81
  82         pthread_mutex_lock(&thread_lock);
  83         threads_starting--;
  84         if (!threads_starting)
  85                 pthread_cond_signal(&thread_parent);
  86         pthread_cond_wait(&thread_worker, &thread_lock);
  87         pthread_mutex_unlock(&thread_lock);
  88
  89         do {
  90                 int ret;
  91         again:
  92                 ret = futex_lock_pi(w->futex, NULL, futex_flag);
  93
  94                 if (ret) { /* handle lock acquisition */
  95                         if (!silent)
  96                                 warn("thread %d: Could not lock pi-lock for %p (%d)",
  97                                      w->tid, w->futex, ret);
  98                         if (done)
  99                                 break;
 100
 101                         goto again;
 102                 }
 103
 104                 usleep(1);
 105                 ret = futex_unlock_pi(w->futex, futex_flag);
 106                 if (ret && !silent)
 107                         warn("thread %d: Could not unlock pi-lock for %p (%d)",
 108                              w->tid, w->futex, ret);
 109                 ops++; /* account for thread's share of work */
 110         }  while (!done);
 111
 112         w->ops = ops;
 113         return NULL;
 114 }
 115
 116 static void create_threads(struct worker *w, pthread_attr_t thread_attr,
 117                            struct cpu_map *cpu)
 118 {
 119         cpu_set_t cpuset;
 120         unsigned int i;
 121
 122         threads_starting = nthreads;
 123
 124         for (i = 0; i < nthreads; i++) {
 125                 worker[i].tid = i;
 126
 127                 if (multi) {
 128                         worker[i].futex = calloc(1, sizeof(u_int32_t));
 129                         if (!worker[i].futex)
 130                                 err(EXIT_FAILURE, "calloc");
 131                 } else
 132                         worker[i].futex = &global_futex;
 133
 134                 CPU_ZERO(&cpuset);
 135                 CPU_SET(cpu->map[i % cpu->nr], &cpuset);
 136
 137                 if (pthread_attr_setaffinity_np(&thread_attr, sizeof(cpu_set_t), &cpuset))
 138                         err(EXIT_FAILURE, "pthread_attr_setaffinity_np");
 139
 140                 if (pthread_create(&w[i].thread, &thread_attr, workerfn, &worker[i]))
 141                         err(EXIT_FAILURE, "pthread_create");
 142         }
 143 }
 144
 145 int bench_futex_lock_pi(int argc, const char **argv)
 146 {
 147         int ret = 0;
 148         unsigned int i;
 149         struct sigaction act;
 150         pthread_attr_t thread_attr;
 151         struct cpu_map *cpu;
 152
 153         argc = parse_options(argc, argv, options, bench_futex_lock_pi_usage, 0);
 154         if (argc)
 155                 goto err;
 156
 157         cpu = cpu_map__new(NULL);
 158         if (!cpu)
 159                 err(EXIT_FAILURE, "calloc");
 160
 161         sigfillset(&act.sa_mask);
 162         act.sa_sigaction = toggle_done;
 163         sigaction(SIGINT, &act, NULL);
 164
 165         if (!nthreads)
 166                 nthreads = cpu->nr;
 167
 168         worker = calloc(nthreads, sizeof(*worker));
 169         if (!worker)
 170                 err(EXIT_FAILURE, "calloc");
 171
 172         if (!fshared)
 173                 futex_flag = FUTEX_PRIVATE_FLAG;
 174
 175         printf("Run summary [PID %d]: %d threads doing pi lock/unlock pairing for %d secs.\n\n",
 176                getpid(), nthreads, nsecs);
 177
 178         init_stats(&throughput_stats);
 179         pthread_mutex_init(&thread_lock, NULL);
 180         pthread_cond_init(&thread_parent, NULL);
 181         pthread_cond_init(&thread_worker, NULL);
 182
 183         threads_starting = nthreads;
 184         pthread_attr_init(&thread_attr);
 185         gettimeofday(&bench__start, NULL);
 186
 187         create_threads(worker, thread_attr, cpu);
 188         pthread_attr_destroy(&thread_attr);
 189
 190         pthread_mutex_lock(&thread_lock);
 191         while (threads_starting)
 192                 pthread_cond_wait(&thread_parent, &thread_lock);
 193         pthread_cond_broadcast(&thread_worker);
 194         pthread_mutex_unlock(&thread_lock);
 195
 196         sleep(nsecs);
 197         toggle_done(0, NULL, NULL);
 198
 199         for (i = 0; i < nthreads; i++) {
 200                 ret = pthread_join(worker[i].thread, NULL);
 201                 if (ret)
 202                         err(EXIT_FAILURE, "pthread_join");
 203         }
 204
 205         /* cleanup & report results */
 206         pthread_cond_destroy(&thread_parent);
 207         pthread_cond_destroy(&thread_worker);
 208         pthread_mutex_destroy(&thread_lock);
 209
 210         for (i = 0; i < nthreads; i++) {
 211                 unsigned long t = worker[i].ops / bench__runtime.tv_sec;
 212
 213                 update_stats(&throughput_stats, t);
 214                 if (!silent)
 215                         printf("[thread %3d] futex: %p [ %ld ops/sec ]\n",
 216                                worker[i].tid, worker[i].futex, t);
 217
 218                 if (multi)
 219                         free(worker[i].futex);
 220         }
 221
 222         print_summary();
 223
 224         free(worker);
 225         return ret;
 226 err:
 227         usage_with_options(bench_futex_lock_pi_usage, options);
 228         exit(EXIT_FAILURE);
 229 }