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10#include "bench.h"
11#include <linux/compiler.h>
12#include "../util/debug.h"
13
14#ifndef HAVE_PTHREAD_BARRIER
15int bench_futex_wake_parallel(int argc __maybe_unused, const char **argv __maybe_unused)
16{
17 pr_err("%s: pthread_barrier_t unavailable, disabling this test...\n", __func__);
18 return 0;
19}
20#else
21
22#include <string.h>
23#include <pthread.h>
24
25#include <signal.h>
26#include "../util/stat.h"
27#include <subcmd/parse-options.h>
28#include <linux/kernel.h>
29#include <linux/time64.h>
30#include <errno.h>
31#include "futex.h"
32#include <perf/cpumap.h>
33
34#include <err.h>
35#include <stdlib.h>
36#include <sys/time.h>
37#include <sys/mman.h>
38
39struct thread_data {
40 pthread_t worker;
41 unsigned int nwoken;
42 struct timeval runtime;
43};
44
45static unsigned int nwakes = 1;
46
47
48static u_int32_t futex = 0;
49
50static pthread_t *blocked_worker;
51static bool done = false;
52static pthread_mutex_t thread_lock;
53static pthread_cond_t thread_parent, thread_worker;
54static pthread_barrier_t barrier;
55static struct stats waketime_stats, wakeup_stats;
56static unsigned int threads_starting;
57static int futex_flag = 0;
58
59static struct bench_futex_parameters params;
60
61static const struct option options[] = {
62 OPT_UINTEGER('t', "threads", ¶ms.nthreads, "Specify amount of threads"),
63 OPT_UINTEGER('w', "nwakers", ¶ms.nwakes, "Specify amount of waking threads"),
64 OPT_BOOLEAN( 's', "silent", ¶ms.silent, "Silent mode: do not display data/details"),
65 OPT_BOOLEAN( 'S', "shared", ¶ms.fshared, "Use shared futexes instead of private ones"),
66 OPT_BOOLEAN( 'm', "mlockall", ¶ms.mlockall, "Lock all current and future memory"),
67
68 OPT_END()
69};
70
71static const char * const bench_futex_wake_parallel_usage[] = {
72 "perf bench futex wake-parallel <options>",
73 NULL
74};
75
76static void *waking_workerfn(void *arg)
77{
78 struct thread_data *waker = (struct thread_data *) arg;
79 struct timeval start, end;
80
81 pthread_barrier_wait(&barrier);
82
83 gettimeofday(&start, NULL);
84
85 waker->nwoken = futex_wake(&futex, nwakes, futex_flag);
86 if (waker->nwoken != nwakes)
87 warnx("couldn't wakeup all tasks (%d/%d)",
88 waker->nwoken, nwakes);
89
90 gettimeofday(&end, NULL);
91 timersub(&end, &start, &waker->runtime);
92
93 pthread_exit(NULL);
94 return NULL;
95}
96
97static void wakeup_threads(struct thread_data *td, pthread_attr_t thread_attr)
98{
99 unsigned int i;
100
101 pthread_attr_setdetachstate(&thread_attr, PTHREAD_CREATE_JOINABLE);
102
103 pthread_barrier_init(&barrier, NULL, params.nwakes + 1);
104
105
106 for (i = 0; i < params.nwakes; i++) {
107
108
109
110
111
112 if (pthread_create(&td[i].worker, &thread_attr,
113 waking_workerfn, (void *)&td[i]))
114 err(EXIT_FAILURE, "pthread_create");
115 }
116
117 pthread_barrier_wait(&barrier);
118
119 for (i = 0; i < params.nwakes; i++)
120 if (pthread_join(td[i].worker, NULL))
121 err(EXIT_FAILURE, "pthread_join");
122
123 pthread_barrier_destroy(&barrier);
124}
125
126static void *blocked_workerfn(void *arg __maybe_unused)
127{
128 pthread_mutex_lock(&thread_lock);
129 threads_starting--;
130 if (!threads_starting)
131 pthread_cond_signal(&thread_parent);
132 pthread_cond_wait(&thread_worker, &thread_lock);
133 pthread_mutex_unlock(&thread_lock);
134
135 while (1) {
136 if (futex_wait(&futex, 0, NULL, futex_flag) != EINTR)
137 break;
138 }
139
140 pthread_exit(NULL);
141 return NULL;
142}
143
144static void block_threads(pthread_t *w, pthread_attr_t thread_attr,
145 struct perf_cpu_map *cpu)
146{
147 cpu_set_t cpuset;
148 unsigned int i;
149
150 threads_starting = params.nthreads;
151
152
153 for (i = 0; i < params.nthreads; i++) {
154 CPU_ZERO(&cpuset);
155 CPU_SET(perf_cpu_map__cpu(cpu, i % perf_cpu_map__nr(cpu)).cpu, &cpuset);
156
157 if (pthread_attr_setaffinity_np(&thread_attr, sizeof(cpu_set_t), &cpuset))
158 err(EXIT_FAILURE, "pthread_attr_setaffinity_np");
159
160 if (pthread_create(&w[i], &thread_attr, blocked_workerfn, NULL))
161 err(EXIT_FAILURE, "pthread_create");
162 }
163}
164
165static void print_run(struct thread_data *waking_worker, unsigned int run_num)
166{
167 unsigned int i, wakeup_avg;
168 double waketime_avg, waketime_stddev;
169 struct stats __waketime_stats, __wakeup_stats;
170
171 init_stats(&__wakeup_stats);
172 init_stats(&__waketime_stats);
173
174 for (i = 0; i < params.nwakes; i++) {
175 update_stats(&__waketime_stats, waking_worker[i].runtime.tv_usec);
176 update_stats(&__wakeup_stats, waking_worker[i].nwoken);
177 }
178
179 waketime_avg = avg_stats(&__waketime_stats);
180 waketime_stddev = stddev_stats(&__waketime_stats);
181 wakeup_avg = avg_stats(&__wakeup_stats);
182
183 printf("[Run %d]: Avg per-thread latency (waking %d/%d threads) "
184 "in %.4f ms (+-%.2f%%)\n", run_num + 1, wakeup_avg,
185 params.nthreads, waketime_avg / USEC_PER_MSEC,
186 rel_stddev_stats(waketime_stddev, waketime_avg));
187}
188
189static void print_summary(void)
190{
191 unsigned int wakeup_avg;
192 double waketime_avg, waketime_stddev;
193
194 waketime_avg = avg_stats(&waketime_stats);
195 waketime_stddev = stddev_stats(&waketime_stats);
196 wakeup_avg = avg_stats(&wakeup_stats);
197
198 printf("Avg per-thread latency (waking %d/%d threads) in %.4f ms (+-%.2f%%)\n",
199 wakeup_avg,
200 params.nthreads,
201 waketime_avg / USEC_PER_MSEC,
202 rel_stddev_stats(waketime_stddev, waketime_avg));
203}
204
205
206static void do_run_stats(struct thread_data *waking_worker)
207{
208 unsigned int i;
209
210 for (i = 0; i < params.nwakes; i++) {
211 update_stats(&waketime_stats, waking_worker[i].runtime.tv_usec);
212 update_stats(&wakeup_stats, waking_worker[i].nwoken);
213 }
214
215}
216
217static void toggle_done(int sig __maybe_unused,
218 siginfo_t *info __maybe_unused,
219 void *uc __maybe_unused)
220{
221 done = true;
222}
223
224int bench_futex_wake_parallel(int argc, const char **argv)
225{
226 int ret = 0;
227 unsigned int i, j;
228 struct sigaction act;
229 pthread_attr_t thread_attr;
230 struct thread_data *waking_worker;
231 struct perf_cpu_map *cpu;
232
233 argc = parse_options(argc, argv, options,
234 bench_futex_wake_parallel_usage, 0);
235 if (argc) {
236 usage_with_options(bench_futex_wake_parallel_usage, options);
237 exit(EXIT_FAILURE);
238 }
239
240 memset(&act, 0, sizeof(act));
241 sigfillset(&act.sa_mask);
242 act.sa_sigaction = toggle_done;
243 sigaction(SIGINT, &act, NULL);
244
245 if (params.mlockall) {
246 if (mlockall(MCL_CURRENT | MCL_FUTURE))
247 err(EXIT_FAILURE, "mlockall");
248 }
249
250 cpu = perf_cpu_map__new(NULL);
251 if (!cpu)
252 err(EXIT_FAILURE, "calloc");
253
254 if (!params.nthreads)
255 params.nthreads = perf_cpu_map__nr(cpu);
256
257
258 if (params.nwakes > params.nthreads ||
259 !params.nwakes)
260 params.nwakes = params.nthreads;
261
262 if (params.nthreads % params.nwakes)
263 errx(EXIT_FAILURE, "Must be perfectly divisible");
264
265
266
267
268 nwakes = params.nthreads/params.nwakes;
269
270 blocked_worker = calloc(params.nthreads, sizeof(*blocked_worker));
271 if (!blocked_worker)
272 err(EXIT_FAILURE, "calloc");
273
274 if (!params.fshared)
275 futex_flag = FUTEX_PRIVATE_FLAG;
276
277 printf("Run summary [PID %d]: blocking on %d threads (at [%s] "
278 "futex %p), %d threads waking up %d at a time.\n\n",
279 getpid(), params.nthreads, params.fshared ? "shared":"private",
280 &futex, params.nwakes, nwakes);
281
282 init_stats(&wakeup_stats);
283 init_stats(&waketime_stats);
284
285 pthread_attr_init(&thread_attr);
286 pthread_mutex_init(&thread_lock, NULL);
287 pthread_cond_init(&thread_parent, NULL);
288 pthread_cond_init(&thread_worker, NULL);
289
290 for (j = 0; j < bench_repeat && !done; j++) {
291 waking_worker = calloc(params.nwakes, sizeof(*waking_worker));
292 if (!waking_worker)
293 err(EXIT_FAILURE, "calloc");
294
295
296 block_threads(blocked_worker, thread_attr, cpu);
297
298
299 pthread_mutex_lock(&thread_lock);
300 while (threads_starting)
301 pthread_cond_wait(&thread_parent, &thread_lock);
302 pthread_cond_broadcast(&thread_worker);
303 pthread_mutex_unlock(&thread_lock);
304
305 usleep(100000);
306
307
308 wakeup_threads(waking_worker, thread_attr);
309
310 for (i = 0; i < params.nthreads; i++) {
311 ret = pthread_join(blocked_worker[i], NULL);
312 if (ret)
313 err(EXIT_FAILURE, "pthread_join");
314 }
315
316 do_run_stats(waking_worker);
317 if (!params.silent)
318 print_run(waking_worker, j);
319
320 free(waking_worker);
321 }
322
323
324 pthread_cond_destroy(&thread_parent);
325 pthread_cond_destroy(&thread_worker);
326 pthread_mutex_destroy(&thread_lock);
327 pthread_attr_destroy(&thread_attr);
328
329 print_summary();
330
331 free(blocked_worker);
332 perf_cpu_map__put(cpu);
333 return ret;
334}
335#endif
336