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 <linux/zalloc.h>
  16 #include <errno.h>
  17 #include <perf/cpumap.h>
  18 #include "bench.h"
  19 #include "futex.h"
  20
  21 #include <err.h>
  22 #include <stdlib.h>
  23 #include <sys/time.h>
  24 #include <sys/mman.h>
  25
  26 struct worker {
  27         int tid;
  28         u_int32_t *futex;
  29         pthread_t thread;
  30         unsigned long ops;
  31 };
  32
  33 static u_int32_t global_futex = 0;
  34 static struct worker *worker;
  35 static bool done = false;
  36 static int futex_flag = 0;
  37 static pthread_mutex_t thread_lock;
  38 static unsigned int threads_starting;
  39 static struct stats throughput_stats;
  40 static pthread_cond_t thread_parent, thread_worker;
  41
  42 static struct bench_futex_parameters params = {
  43         .runtime  = 10,
  44 };
  45
  46 static const struct option options[] = {
  47         OPT_UINTEGER('t', "threads", &params.nthreads, "Specify amount of threads"),
  48         OPT_UINTEGER('r', "runtime", &params.runtime, "Specify runtime (in seconds)"),
  49         OPT_BOOLEAN( 'M', "multi",   &params.multi, "Use multiple futexes"),
  50         OPT_BOOLEAN( 's', "silent",  &params.silent, "Silent mode: do not display data/details"),
  51         OPT_BOOLEAN( 'S', "shared",  &params.fshared, "Use shared futexes instead of private ones"),
  52         OPT_BOOLEAN( 'm', "mlockall", &params.mlockall, "Lock all current and future memory"),
  53         OPT_END()
  54 };
  55
  56 static const char * const bench_futex_lock_pi_usage[] = {
  57         "perf bench futex lock-pi <options>",
  58         NULL
  59 };
  60
  61 static void print_summary(void)
  62 {
  63         unsigned long avg = avg_stats(&throughput_stats);
  64         double stddev = stddev_stats(&throughput_stats);
  65
  66         printf("%sAveraged %ld operations/sec (+- %.2f%%), total secs = %d\n",
  67                !params.silent ? "\n" : "", avg, rel_stddev_stats(stddev, avg),
  68                (int)bench__runtime.tv_sec);
  69 }
  70
  71 static void toggle_done(int sig __maybe_unused,
  72                         siginfo_t *info __maybe_unused,
  73                         void *uc __maybe_unused)
  74 {
  75         /* inform all threads that we're done for the day */
  76         done = true;
  77         gettimeofday(&bench__end, NULL);
  78         timersub(&bench__end, &bench__start, &bench__runtime);
  79 }
  80
  81 static void *workerfn(void *arg)
  82 {
  83         struct worker *w = (struct worker *) arg;
  84         unsigned long ops = w->ops;
  85
  86         pthread_mutex_lock(&thread_lock);
  87         threads_starting--;
  88         if (!threads_starting)
  89                 pthread_cond_signal(&thread_parent);
  90         pthread_cond_wait(&thread_worker, &thread_lock);
  91         pthread_mutex_unlock(&thread_lock);
  92
  93         do {
  94                 int ret;
  95         again:
  96                 ret = futex_lock_pi(w->futex, NULL, futex_flag);
  97
  98                 if (ret) { /* handle lock acquisition */
  99                         if (!params.silent)
 100                                 warn("thread %d: Could not lock pi-lock for %p (%d)",
 101                                      w->tid, w->futex, ret);
 102                         if (done)
 103                                 break;
 104
 105                         goto again;
 106                 }
 107
 108                 usleep(1);
 109                 ret = futex_unlock_pi(w->futex, futex_flag);
 110                 if (ret && !params.silent)
 111                         warn("thread %d: Could not unlock pi-lock for %p (%d)",
 112                              w->tid, w->futex, ret);
 113                 ops++; /* account for thread's share of work */
 114         }  while (!done);
 115
 116         w->ops = ops;
 117         return NULL;
 118 }
 119
 120 static void create_threads(struct worker *w, pthread_attr_t thread_attr,
 121                            struct perf_cpu_map *cpu)
 122 {
 123         cpu_set_t cpuset;
 124         unsigned int i;
 125
 126         threads_starting = params.nthreads;
 127
 128         for (i = 0; i < params.nthreads; i++) {
 129                 worker[i].tid = i;
 130
 131                 if (params.multi) {
 132                         worker[i].futex = calloc(1, sizeof(u_int32_t));
 133                         if (!worker[i].futex)
 134                                 err(EXIT_FAILURE, "calloc");
 135                 } else
 136                         worker[i].futex = &global_futex;
 137
 138                 CPU_ZERO(&cpuset);
 139                 CPU_SET(perf_cpu_map__cpu(cpu, i % perf_cpu_map__nr(cpu)).cpu, &cpuset);
 140
 141                 if (pthread_attr_setaffinity_np(&thread_attr, sizeof(cpu_set_t), &cpuset))
 142                         err(EXIT_FAILURE, "pthread_attr_setaffinity_np");
 143
 144                 if (pthread_create(&w[i].thread, &thread_attr, workerfn, &worker[i]))
 145                         err(EXIT_FAILURE, "pthread_create");
 146         }
 147 }
 148
 149 int bench_futex_lock_pi(int argc, const char **argv)
 150 {
 151         int ret = 0;
 152         unsigned int i;
 153         struct sigaction act;
 154         pthread_attr_t thread_attr;
 155         struct perf_cpu_map *cpu;
 156
 157         argc = parse_options(argc, argv, options, bench_futex_lock_pi_usage, 0);
 158         if (argc)
 159                 goto err;
 160
 161         cpu = perf_cpu_map__new(NULL);
 162         if (!cpu)
 163                 err(EXIT_FAILURE, "calloc");
 164
 165         memset(&act, 0, sizeof(act));
 166         sigfillset(&act.sa_mask);
 167         act.sa_sigaction = toggle_done;
 168         sigaction(SIGINT, &act, NULL);
 169
 170         if (params.mlockall) {
 171                 if (mlockall(MCL_CURRENT | MCL_FUTURE))
 172                         err(EXIT_FAILURE, "mlockall");
 173         }
 174
 175         if (!params.nthreads)
 176                 params.nthreads = cpu->nr;
 177
 178         worker = calloc(params.nthreads, sizeof(*worker));
 179         if (!worker)
 180                 err(EXIT_FAILURE, "calloc");
 181
 182         if (!params.fshared)
 183                 futex_flag = FUTEX_PRIVATE_FLAG;
 184
 185         printf("Run summary [PID %d]: %d threads doing pi lock/unlock pairing for %d secs.\n\n",
 186                getpid(), params.nthreads, params.runtime);
 187
 188         init_stats(&throughput_stats);
 189         pthread_mutex_init(&thread_lock, NULL);
 190         pthread_cond_init(&thread_parent, NULL);
 191         pthread_cond_init(&thread_worker, NULL);
 192
 193         threads_starting = params.nthreads;
 194         pthread_attr_init(&thread_attr);
 195         gettimeofday(&bench__start, NULL);
 196
 197         create_threads(worker, thread_attr, cpu);
 198         pthread_attr_destroy(&thread_attr);
 199
 200         pthread_mutex_lock(&thread_lock);
 201         while (threads_starting)
 202                 pthread_cond_wait(&thread_parent, &thread_lock);
 203         pthread_cond_broadcast(&thread_worker);
 204         pthread_mutex_unlock(&thread_lock);
 205
 206         sleep(params.runtime);
 207         toggle_done(0, NULL, NULL);
 208
 209         for (i = 0; i < params.nthreads; i++) {
 210                 ret = pthread_join(worker[i].thread, NULL);
 211                 if (ret)
 212                         err(EXIT_FAILURE, "pthread_join");
 213         }
 214
 215         /* cleanup & report results */
 216         pthread_cond_destroy(&thread_parent);
 217         pthread_cond_destroy(&thread_worker);
 218         pthread_mutex_destroy(&thread_lock);
 219
 220         for (i = 0; i < params.nthreads; i++) {
 221                 unsigned long t = bench__runtime.tv_sec > 0 ?
 222                         worker[i].ops / bench__runtime.tv_sec : 0;
 223
 224                 update_stats(&throughput_stats, t);
 225                 if (!params.silent)
 226                         printf("[thread %3d] futex: %p [ %ld ops/sec ]\n",
 227                                worker[i].tid, worker[i].futex, t);
 228
 229                 if (params.multi)
 230                         zfree(&worker[i].futex);
 231         }
 232
 233         print_summary();
 234
 235         free(worker);
 236         perf_cpu_map__put(cpu);
 237         return ret;
 238 err:
 239         usage_with_options(bench_futex_lock_pi_usage, options);
 240         exit(EXIT_FAILURE);
 241 }