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

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