~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

TOMOYO Linux Cross Reference
Linux/tools/perf/bench/futex-requeue.c

Version: ~ [ linux-5.3-rc5 ] ~ [ linux-5.2.9 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.67 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.139 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.189 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.189 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.140 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.72 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-3.9.11 ] ~ [ linux-3.8.13 ] ~ [ linux-3.7.10 ] ~ [ linux-3.6.11 ] ~ [ linux-3.5.7 ] ~ [ linux-3.4.113 ] ~ [ linux-3.3.8 ] ~ [ linux-3.2.102 ] ~ [ linux-3.1.10 ] ~ [ linux-3.0.101 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  1 /*
  2  * Copyright (C) 2013  Davidlohr Bueso <davidlohr@hp.com>
  3  *
  4  * futex-requeue: Block a bunch of threads on futex1 and requeue them
  5  *                on futex2, N at a time.
  6  *
  7  * This program is particularly useful to measure the latency of nthread
  8  * requeues without waking up any tasks -- thus mimicking a regular futex_wait.
  9  */
 10 
 11 #include "../perf.h"
 12 #include "../util/util.h"
 13 #include "../util/stat.h"
 14 #include "../util/parse-options.h"
 15 #include "../util/header.h"
 16 #include "bench.h"
 17 #include "futex.h"
 18 
 19 #include <err.h>
 20 #include <stdlib.h>
 21 #include <sys/time.h>
 22 #include <pthread.h>
 23 
 24 static u_int32_t futex1 = 0, futex2 = 0;
 25 
 26 /*
 27  * How many tasks to requeue at a time.
 28  * Default to 1 in order to make the kernel work more.
 29  */
 30 static unsigned int nrequeue = 1;
 31 
 32 static pthread_t *worker;
 33 static bool done = false, silent = false, fshared = false;
 34 static pthread_mutex_t thread_lock;
 35 static pthread_cond_t thread_parent, thread_worker;
 36 static struct stats requeuetime_stats, requeued_stats;
 37 static unsigned int ncpus, threads_starting, nthreads = 0;
 38 static int futex_flag = 0;
 39 
 40 static const struct option options[] = {
 41         OPT_UINTEGER('t', "threads",  &nthreads, "Specify amount of threads"),
 42         OPT_UINTEGER('q', "nrequeue", &nrequeue, "Specify amount of threads to requeue at once"),
 43         OPT_BOOLEAN( 's', "silent",   &silent,   "Silent mode: do not display data/details"),
 44         OPT_BOOLEAN( 'S', "shared",   &fshared,  "Use shared futexes instead of private ones"),
 45         OPT_END()
 46 };
 47 
 48 static const char * const bench_futex_requeue_usage[] = {
 49         "perf bench futex requeue <options>",
 50         NULL
 51 };
 52 
 53 static void print_summary(void)
 54 {
 55         double requeuetime_avg = avg_stats(&requeuetime_stats);
 56         double requeuetime_stddev = stddev_stats(&requeuetime_stats);
 57         unsigned int requeued_avg = avg_stats(&requeued_stats);
 58 
 59         printf("Requeued %d of %d threads in %.4f ms (+-%.2f%%)\n",
 60                requeued_avg,
 61                nthreads,
 62                requeuetime_avg/1e3,
 63                rel_stddev_stats(requeuetime_stddev, requeuetime_avg));
 64 }
 65 
 66 static void *workerfn(void *arg __maybe_unused)
 67 {
 68         pthread_mutex_lock(&thread_lock);
 69         threads_starting--;
 70         if (!threads_starting)
 71                 pthread_cond_signal(&thread_parent);
 72         pthread_cond_wait(&thread_worker, &thread_lock);
 73         pthread_mutex_unlock(&thread_lock);
 74 
 75         futex_wait(&futex1, 0, NULL, futex_flag);
 76         return NULL;
 77 }
 78 
 79 static void block_threads(pthread_t *w,
 80                           pthread_attr_t thread_attr)
 81 {
 82         cpu_set_t cpu;
 83         unsigned int i;
 84 
 85         threads_starting = nthreads;
 86 
 87         /* create and block all threads */
 88         for (i = 0; i < nthreads; i++) {
 89                 CPU_ZERO(&cpu);
 90                 CPU_SET(i % ncpus, &cpu);
 91 
 92                 if (pthread_attr_setaffinity_np(&thread_attr, sizeof(cpu_set_t), &cpu))
 93                         err(EXIT_FAILURE, "pthread_attr_setaffinity_np");
 94 
 95                 if (pthread_create(&w[i], &thread_attr, workerfn, NULL))
 96                         err(EXIT_FAILURE, "pthread_create");
 97         }
 98 }
 99 
100 static void toggle_done(int sig __maybe_unused,
101                         siginfo_t *info __maybe_unused,
102                         void *uc __maybe_unused)
103 {
104         done = true;
105 }
106 
107 int bench_futex_requeue(int argc, const char **argv,
108                         const char *prefix __maybe_unused)
109 {
110         int ret = 0;
111         unsigned int i, j;
112         struct sigaction act;
113         pthread_attr_t thread_attr;
114 
115         argc = parse_options(argc, argv, options, bench_futex_requeue_usage, 0);
116         if (argc)
117                 goto err;
118 
119         ncpus = sysconf(_SC_NPROCESSORS_ONLN);
120 
121         sigfillset(&act.sa_mask);
122         act.sa_sigaction = toggle_done;
123         sigaction(SIGINT, &act, NULL);
124 
125         if (!nthreads)
126                 nthreads = ncpus;
127 
128         worker = calloc(nthreads, sizeof(*worker));
129         if (!worker)
130                 err(EXIT_FAILURE, "calloc");
131 
132         if (!fshared)
133                 futex_flag = FUTEX_PRIVATE_FLAG;
134 
135         if (nrequeue > nthreads)
136                 nrequeue = nthreads;
137 
138         printf("Run summary [PID %d]: Requeuing %d threads (from [%s] %p to %p), "
139                "%d at a time.\n\n",  getpid(), nthreads,
140                fshared ? "shared":"private", &futex1, &futex2, nrequeue);
141 
142         init_stats(&requeued_stats);
143         init_stats(&requeuetime_stats);
144         pthread_attr_init(&thread_attr);
145         pthread_mutex_init(&thread_lock, NULL);
146         pthread_cond_init(&thread_parent, NULL);
147         pthread_cond_init(&thread_worker, NULL);
148 
149         for (j = 0; j < bench_repeat && !done; j++) {
150                 unsigned int nrequeued = 0;
151                 struct timeval start, end, runtime;
152 
153                 /* create, launch & block all threads */
154                 block_threads(worker, thread_attr);
155 
156                 /* make sure all threads are already blocked */
157                 pthread_mutex_lock(&thread_lock);
158                 while (threads_starting)
159                         pthread_cond_wait(&thread_parent, &thread_lock);
160                 pthread_cond_broadcast(&thread_worker);
161                 pthread_mutex_unlock(&thread_lock);
162 
163                 usleep(100000);
164 
165                 /* Ok, all threads are patiently blocked, start requeueing */
166                 gettimeofday(&start, NULL);
167                 while (nrequeued < nthreads) {
168                         /*
169                          * Do not wakeup any tasks blocked on futex1, allowing
170                          * us to really measure futex_wait functionality.
171                          */
172                         nrequeued += futex_cmp_requeue(&futex1, 0, &futex2, 0,
173                                                        nrequeue, futex_flag);
174                 }
175 
176                 gettimeofday(&end, NULL);
177                 timersub(&end, &start, &runtime);
178 
179                 update_stats(&requeued_stats, nrequeued);
180                 update_stats(&requeuetime_stats, runtime.tv_usec);
181 
182                 if (!silent) {
183                         printf("[Run %d]: Requeued %d of %d threads in %.4f ms\n",
184                                j + 1, nrequeued, nthreads, runtime.tv_usec/1e3);
185                 }
186 
187                 /* everybody should be blocked on futex2, wake'em up */
188                 nrequeued = futex_wake(&futex2, nrequeued, futex_flag);
189                 if (nthreads != nrequeued)
190                         warnx("couldn't wakeup all tasks (%d/%d)", nrequeued, nthreads);
191 
192                 for (i = 0; i < nthreads; i++) {
193                         ret = pthread_join(worker[i], NULL);
194                         if (ret)
195                                 err(EXIT_FAILURE, "pthread_join");
196                 }
197         }
198 
199         /* cleanup & report results */
200         pthread_cond_destroy(&thread_parent);
201         pthread_cond_destroy(&thread_worker);
202         pthread_mutex_destroy(&thread_lock);
203         pthread_attr_destroy(&thread_attr);
204 
205         print_summary();
206 
207         free(worker);
208         return ret;
209 err:
210         usage_with_options(bench_futex_requeue_usage, options);
211         exit(EXIT_FAILURE);
212 }
213 

~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

kernel.org | git.kernel.org | LWN.net | Project Home | Wiki (Japanese) | Wiki (English) | SVN repository | Mail admin

Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.

osdn.jp