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/mutex.h"
  12 #include "../util/stat.h"
  13 #include <subcmd/parse-options.h>
  14 #include <linux/compiler.h>
  15 #include <linux/kernel.h>
  16 #include <linux/zalloc.h>
  17 #include <errno.h>
  18 #include <perf/cpumap.h>
  19 #include "bench.h"
  20 #include "futex.h"
  21
  22 #include <err.h>
  23 #include <stdlib.h>
  24 #include <sys/time.h>
  25 #include <sys/mman.h>
  26
  27 struct worker {
  28         int tid;
  29         u_int32_t *futex;
  30         pthread_t thread;
  31         unsigned long ops;
  32 };
  33
  34 static u_int32_t global_futex = 0;
  35 static struct worker *worker;
  36 static bool done = false;
  37 static int futex_flag = 0;
  38 static struct mutex thread_lock;
  39 static unsigned int threads_starting;
  40 static struct stats throughput_stats;
  41 static struct cond thread_parent, thread_worker;
  42
  43 static struct bench_futex_parameters params = {
  44         .runtime  = 10,
  45 };
  46
  47 static const struct option options[] = {
  48         OPT_UINTEGER('t', "threads", &params.nthreads, "Specify amount of threads"),
  49         OPT_UINTEGER('r', "runtime", &params.runtime, "Specify runtime (in seconds)"),
  50         OPT_BOOLEAN( 'M', "multi",   &params.multi, "Use multiple futexes"),
  51         OPT_BOOLEAN( 's', "silent",  &params.silent, "Silent mode: do not display data/details"),
  52         OPT_BOOLEAN( 'S', "shared",  &params.fshared, "Use shared futexes instead of private ones"),
  53         OPT_BOOLEAN( 'm', "mlockall", &params.mlockall, "Lock all current and future memory"),
  54         OPT_END()
  55 };
  56
  57 static const char * const bench_futex_lock_pi_usage[] = {
  58         "perf bench futex lock-pi <options>",
  59         NULL
  60 };
  61
  62 static void print_summary(void)
  63 {
  64         unsigned long avg = avg_stats(&throughput_stats);
  65         double stddev = stddev_stats(&throughput_stats);
  66
  67         printf("%sAveraged %ld operations/sec (+- %.2f%%), total secs = %d\n",
  68                !params.silent ? "\n" : "", avg, rel_stddev_stats(stddev, avg),
  69                (int)bench__runtime.tv_sec);
  70 }
  71
  72 static void toggle_done(int sig __maybe_unused,
  73                         siginfo_t *info __maybe_unused,
  74                         void *uc __maybe_unused)
  75 {
  76         /* inform all threads that we're done for the day */
  77         done = true;
  78         gettimeofday(&bench__end, NULL);
  79         timersub(&bench__end, &bench__start, &bench__runtime);
  80 }
  81
  82 static void *workerfn(void *arg)
  83 {
  84         struct worker *w = (struct worker *) arg;
  85         unsigned long ops = w->ops;
  86
  87         mutex_lock(&thread_lock);
  88         threads_starting--;
  89         if (!threads_starting)
  90                 cond_signal(&thread_parent);
  91         cond_wait(&thread_worker, &thread_lock);
  92         mutex_unlock(&thread_lock);
  93
  94         do {
  95                 int ret;
  96         again:
  97                 ret = futex_lock_pi(w->futex, NULL, futex_flag);
  98
  99                 if (ret) { /* handle lock acquisition */
 100                         if (!params.silent)
 101                                 warn("thread %d: Could not lock pi-lock for %p (%d)",
 102                                      w->tid, w->futex, ret);
 103                         if (done)
 104                                 break;
 105
 106                         goto again;
 107                 }
 108
 109                 usleep(1);
 110                 ret = futex_unlock_pi(w->futex, futex_flag);
 111                 if (ret && !params.silent)
 112                         warn("thread %d: Could not unlock pi-lock for %p (%d)",
 113                              w->tid, w->futex, ret);
 114                 ops++; /* account for thread's share of work */
 115         }  while (!done);
 116
 117         w->ops = ops;
 118         return NULL;
 119 }
 120
 121 static void create_threads(struct worker *w, pthread_attr_t thread_attr,
 122                            struct perf_cpu_map *cpu)
 123 {
 124         cpu_set_t *cpuset;
 125         unsigned int i;
 126         int nrcpus =  perf_cpu_map__nr(cpu);
 127         size_t size;
 128
 129         threads_starting = params.nthreads;
 130
 131         cpuset = CPU_ALLOC(nrcpus);
 132         BUG_ON(!cpuset);
 133         size = CPU_ALLOC_SIZE(nrcpus);
 134
 135         for (i = 0; i < params.nthreads; i++) {
 136                 worker[i].tid = i;
 137
 138                 if (params.multi) {
 139                         worker[i].futex = calloc(1, sizeof(u_int32_t));
 140                         if (!worker[i].futex)
 141                                 err(EXIT_FAILURE, "calloc");
 142                 } else
 143                         worker[i].futex = &global_futex;
 144
 145                 CPU_ZERO_S(size, cpuset);
 146                 CPU_SET_S(perf_cpu_map__cpu(cpu, i % perf_cpu_map__nr(cpu)).cpu, size, cpuset);
 147
 148                 if (pthread_attr_setaffinity_np(&thread_attr, size, cpuset)) {
 149                         CPU_FREE(cpuset);
 150                         err(EXIT_FAILURE, "pthread_attr_setaffinity_np");
 151                 }
 152
 153                 if (pthread_create(&w[i].thread, &thread_attr, workerfn, &worker[i])) {
 154                         CPU_FREE(cpuset);
 155                         err(EXIT_FAILURE, "pthread_create");
 156                 }
 157         }
 158         CPU_FREE(cpuset);
 159 }
 160
 161 int bench_futex_lock_pi(int argc, const char **argv)
 162 {
 163         int ret = 0;
 164         unsigned int i;
 165         struct sigaction act;
 166         pthread_attr_t thread_attr;
 167         struct perf_cpu_map *cpu;
 168
 169         argc = parse_options(argc, argv, options, bench_futex_lock_pi_usage, 0);
 170         if (argc)
 171                 goto err;
 172
 173         cpu = perf_cpu_map__new(NULL);
 174         if (!cpu)
 175                 err(EXIT_FAILURE, "calloc");
 176
 177         memset(&act, 0, sizeof(act));
 178         sigfillset(&act.sa_mask);
 179         act.sa_sigaction = toggle_done;
 180         sigaction(SIGINT, &act, NULL);
 181
 182         if (params.mlockall) {
 183                 if (mlockall(MCL_CURRENT | MCL_FUTURE))
 184                         err(EXIT_FAILURE, "mlockall");
 185         }
 186
 187         if (!params.nthreads)
 188                 params.nthreads = perf_cpu_map__nr(cpu);
 189
 190         worker = calloc(params.nthreads, sizeof(*worker));
 191         if (!worker)
 192                 err(EXIT_FAILURE, "calloc");
 193
 194         if (!params.fshared)
 195                 futex_flag = FUTEX_PRIVATE_FLAG;
 196
 197         printf("Run summary [PID %d]: %d threads doing pi lock/unlock pairing for %d secs.\n\n",
 198                getpid(), params.nthreads, params.runtime);
 199
 200         init_stats(&throughput_stats);
 201         mutex_init(&thread_lock);
 202         cond_init(&thread_parent);
 203         cond_init(&thread_worker);
 204
 205         threads_starting = params.nthreads;
 206         pthread_attr_init(&thread_attr);
 207         gettimeofday(&bench__start, NULL);
 208
 209         create_threads(worker, thread_attr, cpu);
 210         pthread_attr_destroy(&thread_attr);
 211
 212         mutex_lock(&thread_lock);
 213         while (threads_starting)
 214                 cond_wait(&thread_parent, &thread_lock);
 215         cond_broadcast(&thread_worker);
 216         mutex_unlock(&thread_lock);
 217
 218         sleep(params.runtime);
 219         toggle_done(0, NULL, NULL);
 220
 221         for (i = 0; i < params.nthreads; i++) {
 222                 ret = pthread_join(worker[i].thread, NULL);
 223                 if (ret)
 224                         err(EXIT_FAILURE, "pthread_join");
 225         }
 226
 227         /* cleanup & report results */
 228         cond_destroy(&thread_parent);
 229         cond_destroy(&thread_worker);
 230         mutex_destroy(&thread_lock);
 231
 232         for (i = 0; i < params.nthreads; i++) {
 233                 unsigned long t = bench__runtime.tv_sec > 0 ?
 234                         worker[i].ops / bench__runtime.tv_sec : 0;
 235
 236                 update_stats(&throughput_stats, t);
 237                 if (!params.silent)
 238                         printf("[thread %3d] futex: %p [ %ld ops/sec ]\n",
 239                                worker[i].tid, worker[i].futex, t);
 240
 241                 if (params.multi)
 242                         zfree(&worker[i].futex);
 243         }
 244
 245         print_summary();
 246
 247         free(worker);
 248         perf_cpu_map__put(cpu);
 249         return ret;
 250 err:
 251         usage_with_options(bench_futex_lock_pi_usage, options);
 252         exit(EXIT_FAILURE);
 253 }