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

TOMOYO Linux Cross Reference
Linux/tools/perf/bench/futex-wake.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-wake: Block a bunch of threads on a futex and wake'em up, N at a time.
  5  *
  6  * This program is particularly useful to measure the latency of nthread wakeups
  7  * in non-error situations:  all waiters are queued and all wake calls wakeup
  8  * one or more tasks, and thus the waitqueue is never empty.
  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 /* all threads will block on the same futex */
 25 static u_int32_t futex1 = 0;
 26 
 27 /*
 28  * How many wakeups to do at a time.
 29  * Default to 1 in order to make the kernel work more.
 30  */
 31 static unsigned int nwakes = 1;
 32 
 33 pthread_t *worker;
 34 static bool done = false, silent = false, fshared = false;
 35 static pthread_mutex_t thread_lock;
 36 static pthread_cond_t thread_parent, thread_worker;
 37 static struct stats waketime_stats, wakeup_stats;
 38 static unsigned int ncpus, threads_starting, nthreads = 0;
 39 static int futex_flag = 0;
 40 
 41 static const struct option options[] = {
 42         OPT_UINTEGER('t', "threads", &nthreads, "Specify amount of threads"),
 43         OPT_UINTEGER('w', "nwakes",  &nwakes,   "Specify amount of threads to wake at once"),
 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_wake_usage[] = {
 50         "perf bench futex wake <options>",
 51         NULL
 52 };
 53 
 54 static void *workerfn(void *arg __maybe_unused)
 55 {
 56         pthread_mutex_lock(&thread_lock);
 57         threads_starting--;
 58         if (!threads_starting)
 59                 pthread_cond_signal(&thread_parent);
 60         pthread_cond_wait(&thread_worker, &thread_lock);
 61         pthread_mutex_unlock(&thread_lock);
 62 
 63         while (1) {
 64                 if (futex_wait(&futex1, 0, NULL, futex_flag) != EINTR)
 65                         break;
 66         }
 67 
 68         pthread_exit(NULL);
 69         return NULL;
 70 }
 71 
 72 static void print_summary(void)
 73 {
 74         double waketime_avg = avg_stats(&waketime_stats);
 75         double waketime_stddev = stddev_stats(&waketime_stats);
 76         unsigned int wakeup_avg = avg_stats(&wakeup_stats);
 77 
 78         printf("Wokeup %d of %d threads in %.4f ms (+-%.2f%%)\n",
 79                wakeup_avg,
 80                nthreads,
 81                waketime_avg/1e3,
 82                rel_stddev_stats(waketime_stddev, waketime_avg));
 83 }
 84 
 85 static void block_threads(pthread_t *w,
 86                           pthread_attr_t thread_attr)
 87 {
 88         cpu_set_t cpu;
 89         unsigned int i;
 90 
 91         threads_starting = nthreads;
 92 
 93         /* create and block all threads */
 94         for (i = 0; i < nthreads; i++) {
 95                 CPU_ZERO(&cpu);
 96                 CPU_SET(i % ncpus, &cpu);
 97 
 98                 if (pthread_attr_setaffinity_np(&thread_attr, sizeof(cpu_set_t), &cpu))
 99                         err(EXIT_FAILURE, "pthread_attr_setaffinity_np");
100 
101                 if (pthread_create(&w[i], &thread_attr, workerfn, NULL))
102                         err(EXIT_FAILURE, "pthread_create");
103         }
104 }
105 
106 static void toggle_done(int sig __maybe_unused,
107                         siginfo_t *info __maybe_unused,
108                         void *uc __maybe_unused)
109 {
110         done = true;
111 }
112 
113 int bench_futex_wake(int argc, const char **argv,
114                      const char *prefix __maybe_unused)
115 {
116         int ret = 0;
117         unsigned int i, j;
118         struct sigaction act;
119         pthread_attr_t thread_attr;
120 
121         argc = parse_options(argc, argv, options, bench_futex_wake_usage, 0);
122         if (argc) {
123                 usage_with_options(bench_futex_wake_usage, options);
124                 exit(EXIT_FAILURE);
125         }
126 
127         ncpus = sysconf(_SC_NPROCESSORS_ONLN);
128 
129         sigfillset(&act.sa_mask);
130         act.sa_sigaction = toggle_done;
131         sigaction(SIGINT, &act, NULL);
132 
133         if (!nthreads)
134                 nthreads = ncpus;
135 
136         worker = calloc(nthreads, sizeof(*worker));
137         if (!worker)
138                 err(EXIT_FAILURE, "calloc");
139 
140         if (!fshared)
141                 futex_flag = FUTEX_PRIVATE_FLAG;
142 
143         printf("Run summary [PID %d]: blocking on %d threads (at [%s] futex %p), "
144                "waking up %d at a time.\n\n",
145                getpid(), nthreads, fshared ? "shared":"private",  &futex1, nwakes);
146 
147         init_stats(&wakeup_stats);
148         init_stats(&waketime_stats);
149         pthread_attr_init(&thread_attr);
150         pthread_mutex_init(&thread_lock, NULL);
151         pthread_cond_init(&thread_parent, NULL);
152         pthread_cond_init(&thread_worker, NULL);
153 
154         for (j = 0; j < bench_repeat && !done; j++) {
155                 unsigned int nwoken = 0;
156                 struct timeval start, end, runtime;
157 
158                 /* create, launch & block all threads */
159                 block_threads(worker, thread_attr);
160 
161                 /* make sure all threads are already blocked */
162                 pthread_mutex_lock(&thread_lock);
163                 while (threads_starting)
164                         pthread_cond_wait(&thread_parent, &thread_lock);
165                 pthread_cond_broadcast(&thread_worker);
166                 pthread_mutex_unlock(&thread_lock);
167 
168                 usleep(100000);
169 
170                 /* Ok, all threads are patiently blocked, start waking folks up */
171                 gettimeofday(&start, NULL);
172                 while (nwoken != nthreads)
173                         nwoken += futex_wake(&futex1, nwakes, futex_flag);
174                 gettimeofday(&end, NULL);
175                 timersub(&end, &start, &runtime);
176 
177                 update_stats(&wakeup_stats, nwoken);
178                 update_stats(&waketime_stats, runtime.tv_usec);
179 
180                 if (!silent) {
181                         printf("[Run %d]: Wokeup %d of %d threads in %.4f ms\n",
182                                j + 1, nwoken, nthreads, runtime.tv_usec/1e3);
183                 }
184 
185                 for (i = 0; i < nthreads; i++) {
186                         ret = pthread_join(worker[i], NULL);
187                         if (ret)
188                                 err(EXIT_FAILURE, "pthread_join");
189                 }
190 
191         }
192 
193         /* cleanup & report results */
194         pthread_cond_destroy(&thread_parent);
195         pthread_cond_destroy(&thread_worker);
196         pthread_mutex_destroy(&thread_lock);
197         pthread_attr_destroy(&thread_attr);
198 
199         print_summary();
200 
201         free(worker);
202         return ret;
203 }
204 

~ [ 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