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