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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2015 Davidlohr Bueso.
4 *
5 * Block a bunch of threads and let parallel waker threads wakeup an
6 * equal amount of them. The program output reflects the avg latency
7 * for each individual thread to service its share of work. Ultimately
8 * it can be used to measure futex_wake() changes.
9 */
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 /* HAVE_PTHREAD_BARRIER */
21/* For the CLR_() macros */
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 "cpumap.h"
33
34#include <err.h>
35#include <stdlib.h>
36#include <sys/time.h>
37
38struct thread_data {
39 pthread_t worker;
40 unsigned int nwoken;
41 struct timeval runtime;
42};
43
44static unsigned int nwakes = 1;
45
46/* all threads will block on the same futex -- hash bucket chaos ;) */
47static u_int32_t futex = 0;
48
49static pthread_t *blocked_worker;
50static bool done = false, silent = false, fshared = false;
51static unsigned int nblocked_threads = 0, nwaking_threads = 0;
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 const struct option options[] = {
60 OPT_UINTEGER('t', "threads", &nblocked_threads, "Specify amount of threads"),
61 OPT_UINTEGER('w', "nwakers", &nwaking_threads, "Specify amount of waking threads"),
62 OPT_BOOLEAN( 's', "silent", &silent, "Silent mode: do not display data/details"),
63 OPT_BOOLEAN( 'S', "shared", &fshared, "Use shared futexes instead of private ones"),
64 OPT_END()
65};
66
67static const char * const bench_futex_wake_parallel_usage[] = {
68 "perf bench futex wake-parallel <options>",
69 NULL
70};
71
72static void *waking_workerfn(void *arg)
73{
74 struct thread_data *waker = (struct thread_data *) arg;
75 struct timeval start, end;
76
77 pthread_barrier_wait(&barrier);
78
79 gettimeofday(&start, NULL);
80
81 waker->nwoken = futex_wake(&futex, nwakes, futex_flag);
82 if (waker->nwoken != nwakes)
83 warnx("couldn't wakeup all tasks (%d/%d)",
84 waker->nwoken, nwakes);
85
86 gettimeofday(&end, NULL);
87 timersub(&end, &start, &waker->runtime);
88
89 pthread_exit(NULL);
90 return NULL;
91}
92
93static void wakeup_threads(struct thread_data *td, pthread_attr_t thread_attr)
94{
95 unsigned int i;
96
97 pthread_attr_setdetachstate(&thread_attr, PTHREAD_CREATE_JOINABLE);
98
99 pthread_barrier_init(&barrier, NULL, nwaking_threads + 1);
100
101 /* create and block all threads */
102 for (i = 0; i < nwaking_threads; i++) {
103 /*
104 * Thread creation order will impact per-thread latency
105 * as it will affect the order to acquire the hb spinlock.
106 * For now let the scheduler decide.
107 */
108 if (pthread_create(&td[i].worker, &thread_attr,
109 waking_workerfn, (void *)&td[i]))
110 err(EXIT_FAILURE, "pthread_create");
111 }
112
113 pthread_barrier_wait(&barrier);
114
115 for (i = 0; i < nwaking_threads; i++)
116 if (pthread_join(td[i].worker, NULL))
117 err(EXIT_FAILURE, "pthread_join");
118
119 pthread_barrier_destroy(&barrier);
120}
121
122static void *blocked_workerfn(void *arg __maybe_unused)
123{
124 pthread_mutex_lock(&thread_lock);
125 threads_starting--;
126 if (!threads_starting)
127 pthread_cond_signal(&thread_parent);
128 pthread_cond_wait(&thread_worker, &thread_lock);
129 pthread_mutex_unlock(&thread_lock);
130
131 while (1) { /* handle spurious wakeups */
132 if (futex_wait(&futex, 0, NULL, futex_flag) != EINTR)
133 break;
134 }
135
136 pthread_exit(NULL);
137 return NULL;
138}
139
140static void block_threads(pthread_t *w, pthread_attr_t thread_attr,
141 struct cpu_map *cpu)
142{
143 cpu_set_t cpuset;
144 unsigned int i;
145
146 threads_starting = nblocked_threads;
147
148 /* create and block all threads */
149 for (i = 0; i < nblocked_threads; i++) {
150 CPU_ZERO(&cpuset);
151 CPU_SET(cpu->map[i % cpu->nr], &cpuset);
152
153 if (pthread_attr_setaffinity_np(&thread_attr, sizeof(cpu_set_t), &cpuset))
154 err(EXIT_FAILURE, "pthread_attr_setaffinity_np");
155
156 if (pthread_create(&w[i], &thread_attr, blocked_workerfn, NULL))
157 err(EXIT_FAILURE, "pthread_create");
158 }
159}
160
161static void print_run(struct thread_data *waking_worker, unsigned int run_num)
162{
163 unsigned int i, wakeup_avg;
164 double waketime_avg, waketime_stddev;
165 struct stats __waketime_stats, __wakeup_stats;
166
167 init_stats(&__wakeup_stats);
168 init_stats(&__waketime_stats);
169
170 for (i = 0; i < nwaking_threads; i++) {
171 update_stats(&__waketime_stats, waking_worker[i].runtime.tv_usec);
172 update_stats(&__wakeup_stats, waking_worker[i].nwoken);
173 }
174
175 waketime_avg = avg_stats(&__waketime_stats);
176 waketime_stddev = stddev_stats(&__waketime_stats);
177 wakeup_avg = avg_stats(&__wakeup_stats);
178
179 printf("[Run %d]: Avg per-thread latency (waking %d/%d threads) "
180 "in %.4f ms (+-%.2f%%)\n", run_num + 1, wakeup_avg,
181 nblocked_threads, waketime_avg / USEC_PER_MSEC,
182 rel_stddev_stats(waketime_stddev, waketime_avg));
183}
184
185static void print_summary(void)
186{
187 unsigned int wakeup_avg;
188 double waketime_avg, waketime_stddev;
189
190 waketime_avg = avg_stats(&waketime_stats);
191 waketime_stddev = stddev_stats(&waketime_stats);
192 wakeup_avg = avg_stats(&wakeup_stats);
193
194 printf("Avg per-thread latency (waking %d/%d threads) in %.4f ms (+-%.2f%%)\n",
195 wakeup_avg,
196 nblocked_threads,
197 waketime_avg / USEC_PER_MSEC,
198 rel_stddev_stats(waketime_stddev, waketime_avg));
199}
200
201
202static void do_run_stats(struct thread_data *waking_worker)
203{
204 unsigned int i;
205
206 for (i = 0; i < nwaking_threads; i++) {
207 update_stats(&waketime_stats, waking_worker[i].runtime.tv_usec);
208 update_stats(&wakeup_stats, waking_worker[i].nwoken);
209 }
210
211}
212
213static void toggle_done(int sig __maybe_unused,
214 siginfo_t *info __maybe_unused,
215 void *uc __maybe_unused)
216{
217 done = true;
218}
219
220int bench_futex_wake_parallel(int argc, const char **argv)
221{
222 int ret = 0;
223 unsigned int i, j;
224 struct sigaction act;
225 pthread_attr_t thread_attr;
226 struct thread_data *waking_worker;
227 struct cpu_map *cpu;
228
229 argc = parse_options(argc, argv, options,
230 bench_futex_wake_parallel_usage, 0);
231 if (argc) {
232 usage_with_options(bench_futex_wake_parallel_usage, options);
233 exit(EXIT_FAILURE);
234 }
235
236 sigfillset(&act.sa_mask);
237 act.sa_sigaction = toggle_done;
238 sigaction(SIGINT, &act, NULL);
239
240 cpu = cpu_map__new(NULL);
241 if (!cpu)
242 err(EXIT_FAILURE, "calloc");
243
244 if (!nblocked_threads)
245 nblocked_threads = cpu->nr;
246
247 /* some sanity checks */
248 if (nwaking_threads > nblocked_threads || !nwaking_threads)
249 nwaking_threads = nblocked_threads;
250
251 if (nblocked_threads % nwaking_threads)
252 errx(EXIT_FAILURE, "Must be perfectly divisible");
253 /*
254 * Each thread will wakeup nwakes tasks in
255 * a single futex_wait call.
256 */
257 nwakes = nblocked_threads/nwaking_threads;
258
259 blocked_worker = calloc(nblocked_threads, sizeof(*blocked_worker));
260 if (!blocked_worker)
261 err(EXIT_FAILURE, "calloc");
262
263 if (!fshared)
264 futex_flag = FUTEX_PRIVATE_FLAG;
265
266 printf("Run summary [PID %d]: blocking on %d threads (at [%s] "
267 "futex %p), %d threads waking up %d at a time.\n\n",
268 getpid(), nblocked_threads, fshared ? "shared":"private",
269 &futex, nwaking_threads, nwakes);
270
271 init_stats(&wakeup_stats);
272 init_stats(&waketime_stats);
273
274 pthread_attr_init(&thread_attr);
275 pthread_mutex_init(&thread_lock, NULL);
276 pthread_cond_init(&thread_parent, NULL);
277 pthread_cond_init(&thread_worker, NULL);
278
279 for (j = 0; j < bench_repeat && !done; j++) {
280 waking_worker = calloc(nwaking_threads, sizeof(*waking_worker));
281 if (!waking_worker)
282 err(EXIT_FAILURE, "calloc");
283
284 /* create, launch & block all threads */
285 block_threads(blocked_worker, thread_attr, cpu);
286
287 /* make sure all threads are already blocked */
288 pthread_mutex_lock(&thread_lock);
289 while (threads_starting)
290 pthread_cond_wait(&thread_parent, &thread_lock);
291 pthread_cond_broadcast(&thread_worker);
292 pthread_mutex_unlock(&thread_lock);
293
294 usleep(100000);
295
296 /* Ok, all threads are patiently blocked, start waking folks up */
297 wakeup_threads(waking_worker, thread_attr);
298
299 for (i = 0; i < nblocked_threads; i++) {
300 ret = pthread_join(blocked_worker[i], NULL);
301 if (ret)
302 err(EXIT_FAILURE, "pthread_join");
303 }
304
305 do_run_stats(waking_worker);
306 if (!silent)
307 print_run(waking_worker, j);
308
309 free(waking_worker);
310 }
311
312 /* cleanup & report results */
313 pthread_cond_destroy(&thread_parent);
314 pthread_cond_destroy(&thread_worker);
315 pthread_mutex_destroy(&thread_lock);
316 pthread_attr_destroy(&thread_attr);
317
318 print_summary();
319
320 free(blocked_worker);
321 return ret;
322}
323#endif /* HAVE_PTHREAD_BARRIER */
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2015 Davidlohr Bueso.
4 *
5 * Block a bunch of threads and let parallel waker threads wakeup an
6 * equal amount of them. The program output reflects the avg latency
7 * for each individual thread to service its share of work. Ultimately
8 * it can be used to measure futex_wake() changes.
9 */
10#include "bench.h"
11#include <linux/compiler.h>
12#include "../util/debug.h"
13#include "../util/mutex.h"
14
15#ifndef HAVE_PTHREAD_BARRIER
16int bench_futex_wake_parallel(int argc __maybe_unused, const char **argv __maybe_unused)
17{
18 pr_err("%s: pthread_barrier_t unavailable, disabling this test...\n", __func__);
19 return 0;
20}
21#else /* HAVE_PTHREAD_BARRIER */
22/* For the CLR_() macros */
23#include <string.h>
24#include <pthread.h>
25
26#include <signal.h>
27#include "../util/stat.h"
28#include <subcmd/parse-options.h>
29#include <linux/kernel.h>
30#include <linux/time64.h>
31#include <errno.h>
32#include "futex.h"
33#include <perf/cpumap.h>
34
35#include <err.h>
36#include <stdlib.h>
37#include <sys/time.h>
38#include <sys/mman.h>
39
40struct thread_data {
41 pthread_t worker;
42 unsigned int nwoken;
43 struct timeval runtime;
44};
45
46static unsigned int nwakes = 1;
47
48/* all threads will block on the same futex -- hash bucket chaos ;) */
49static u_int32_t futex = 0;
50
51static pthread_t *blocked_worker;
52static bool done = false;
53static struct mutex thread_lock;
54static struct cond thread_parent, thread_worker;
55static pthread_barrier_t barrier;
56static struct stats waketime_stats, wakeup_stats;
57static unsigned int threads_starting;
58static int futex_flag = 0;
59
60static struct bench_futex_parameters params;
61
62static const struct option options[] = {
63 OPT_UINTEGER('t', "threads", ¶ms.nthreads, "Specify amount of threads"),
64 OPT_UINTEGER('w', "nwakers", ¶ms.nwakes, "Specify amount of waking threads"),
65 OPT_BOOLEAN( 's', "silent", ¶ms.silent, "Silent mode: do not display data/details"),
66 OPT_BOOLEAN( 'S', "shared", ¶ms.fshared, "Use shared futexes instead of private ones"),
67 OPT_BOOLEAN( 'm', "mlockall", ¶ms.mlockall, "Lock all current and future memory"),
68
69 OPT_END()
70};
71
72static const char * const bench_futex_wake_parallel_usage[] = {
73 "perf bench futex wake-parallel <options>",
74 NULL
75};
76
77static void *waking_workerfn(void *arg)
78{
79 struct thread_data *waker = (struct thread_data *) arg;
80 struct timeval start, end;
81
82 pthread_barrier_wait(&barrier);
83
84 gettimeofday(&start, NULL);
85
86 waker->nwoken = futex_wake(&futex, nwakes, futex_flag);
87 if (waker->nwoken != nwakes)
88 warnx("couldn't wakeup all tasks (%d/%d)",
89 waker->nwoken, nwakes);
90
91 gettimeofday(&end, NULL);
92 timersub(&end, &start, &waker->runtime);
93
94 pthread_exit(NULL);
95 return NULL;
96}
97
98static void wakeup_threads(struct thread_data *td)
99{
100 unsigned int i;
101 pthread_attr_t thread_attr;
102
103 pthread_attr_init(&thread_attr);
104 pthread_attr_setdetachstate(&thread_attr, PTHREAD_CREATE_JOINABLE);
105
106 pthread_barrier_init(&barrier, NULL, params.nwakes + 1);
107
108 /* create and block all threads */
109 for (i = 0; i < params.nwakes; i++) {
110 /*
111 * Thread creation order will impact per-thread latency
112 * as it will affect the order to acquire the hb spinlock.
113 * For now let the scheduler decide.
114 */
115 if (pthread_create(&td[i].worker, &thread_attr,
116 waking_workerfn, (void *)&td[i]))
117 err(EXIT_FAILURE, "pthread_create");
118 }
119
120 pthread_barrier_wait(&barrier);
121
122 for (i = 0; i < params.nwakes; i++)
123 if (pthread_join(td[i].worker, NULL))
124 err(EXIT_FAILURE, "pthread_join");
125
126 pthread_barrier_destroy(&barrier);
127 pthread_attr_destroy(&thread_attr);
128}
129
130static void *blocked_workerfn(void *arg __maybe_unused)
131{
132 mutex_lock(&thread_lock);
133 threads_starting--;
134 if (!threads_starting)
135 cond_signal(&thread_parent);
136 cond_wait(&thread_worker, &thread_lock);
137 mutex_unlock(&thread_lock);
138
139 while (1) { /* handle spurious wakeups */
140 if (futex_wait(&futex, 0, NULL, futex_flag) != EINTR)
141 break;
142 }
143
144 pthread_exit(NULL);
145 return NULL;
146}
147
148static void block_threads(pthread_t *w, struct perf_cpu_map *cpu)
149{
150 cpu_set_t *cpuset;
151 unsigned int i;
152 int nrcpus = perf_cpu_map__nr(cpu);
153 size_t size;
154
155 threads_starting = params.nthreads;
156
157 cpuset = CPU_ALLOC(nrcpus);
158 BUG_ON(!cpuset);
159 size = CPU_ALLOC_SIZE(nrcpus);
160
161 /* create and block all threads */
162 for (i = 0; i < params.nthreads; i++) {
163 pthread_attr_t thread_attr;
164
165 pthread_attr_init(&thread_attr);
166 CPU_ZERO_S(size, cpuset);
167 CPU_SET_S(perf_cpu_map__cpu(cpu, i % perf_cpu_map__nr(cpu)).cpu, size, cpuset);
168
169 if (pthread_attr_setaffinity_np(&thread_attr, size, cpuset)) {
170 CPU_FREE(cpuset);
171 err(EXIT_FAILURE, "pthread_attr_setaffinity_np");
172 }
173
174 if (pthread_create(&w[i], &thread_attr, blocked_workerfn, NULL)) {
175 CPU_FREE(cpuset);
176 err(EXIT_FAILURE, "pthread_create");
177 }
178 pthread_attr_destroy(&thread_attr);
179 }
180 CPU_FREE(cpuset);
181}
182
183static void print_run(struct thread_data *waking_worker, unsigned int run_num)
184{
185 unsigned int i, wakeup_avg;
186 double waketime_avg, waketime_stddev;
187 struct stats __waketime_stats, __wakeup_stats;
188
189 init_stats(&__wakeup_stats);
190 init_stats(&__waketime_stats);
191
192 for (i = 0; i < params.nwakes; i++) {
193 update_stats(&__waketime_stats, waking_worker[i].runtime.tv_usec);
194 update_stats(&__wakeup_stats, waking_worker[i].nwoken);
195 }
196
197 waketime_avg = avg_stats(&__waketime_stats);
198 waketime_stddev = stddev_stats(&__waketime_stats);
199 wakeup_avg = avg_stats(&__wakeup_stats);
200
201 printf("[Run %d]: Avg per-thread latency (waking %d/%d threads) "
202 "in %.4f ms (+-%.2f%%)\n", run_num + 1, wakeup_avg,
203 params.nthreads, waketime_avg / USEC_PER_MSEC,
204 rel_stddev_stats(waketime_stddev, waketime_avg));
205}
206
207static void print_summary(void)
208{
209 unsigned int wakeup_avg;
210 double waketime_avg, waketime_stddev;
211
212 waketime_avg = avg_stats(&waketime_stats);
213 waketime_stddev = stddev_stats(&waketime_stats);
214 wakeup_avg = avg_stats(&wakeup_stats);
215
216 printf("Avg per-thread latency (waking %d/%d threads) in %.4f ms (+-%.2f%%)\n",
217 wakeup_avg,
218 params.nthreads,
219 waketime_avg / USEC_PER_MSEC,
220 rel_stddev_stats(waketime_stddev, waketime_avg));
221}
222
223
224static void do_run_stats(struct thread_data *waking_worker)
225{
226 unsigned int i;
227
228 for (i = 0; i < params.nwakes; i++) {
229 update_stats(&waketime_stats, waking_worker[i].runtime.tv_usec);
230 update_stats(&wakeup_stats, waking_worker[i].nwoken);
231 }
232
233}
234
235static void toggle_done(int sig __maybe_unused,
236 siginfo_t *info __maybe_unused,
237 void *uc __maybe_unused)
238{
239 done = true;
240}
241
242int bench_futex_wake_parallel(int argc, const char **argv)
243{
244 int ret = 0;
245 unsigned int i, j;
246 struct sigaction act;
247 struct thread_data *waking_worker;
248 struct perf_cpu_map *cpu;
249
250 argc = parse_options(argc, argv, options,
251 bench_futex_wake_parallel_usage, 0);
252 if (argc) {
253 usage_with_options(bench_futex_wake_parallel_usage, options);
254 exit(EXIT_FAILURE);
255 }
256
257 memset(&act, 0, sizeof(act));
258 sigfillset(&act.sa_mask);
259 act.sa_sigaction = toggle_done;
260 sigaction(SIGINT, &act, NULL);
261
262 if (params.mlockall) {
263 if (mlockall(MCL_CURRENT | MCL_FUTURE))
264 err(EXIT_FAILURE, "mlockall");
265 }
266
267 cpu = perf_cpu_map__new_online_cpus();
268 if (!cpu)
269 err(EXIT_FAILURE, "calloc");
270
271 if (!params.nthreads)
272 params.nthreads = perf_cpu_map__nr(cpu);
273
274 /* some sanity checks */
275 if (params.nwakes > params.nthreads ||
276 !params.nwakes)
277 params.nwakes = params.nthreads;
278
279 if (params.nthreads % params.nwakes)
280 errx(EXIT_FAILURE, "Must be perfectly divisible");
281 /*
282 * Each thread will wakeup nwakes tasks in
283 * a single futex_wait call.
284 */
285 nwakes = params.nthreads/params.nwakes;
286
287 blocked_worker = calloc(params.nthreads, sizeof(*blocked_worker));
288 if (!blocked_worker)
289 err(EXIT_FAILURE, "calloc");
290
291 if (!params.fshared)
292 futex_flag = FUTEX_PRIVATE_FLAG;
293
294 printf("Run summary [PID %d]: blocking on %d threads (at [%s] "
295 "futex %p), %d threads waking up %d at a time.\n\n",
296 getpid(), params.nthreads, params.fshared ? "shared":"private",
297 &futex, params.nwakes, nwakes);
298
299 init_stats(&wakeup_stats);
300 init_stats(&waketime_stats);
301
302 mutex_init(&thread_lock);
303 cond_init(&thread_parent);
304 cond_init(&thread_worker);
305
306 for (j = 0; j < bench_repeat && !done; j++) {
307 waking_worker = calloc(params.nwakes, sizeof(*waking_worker));
308 if (!waking_worker)
309 err(EXIT_FAILURE, "calloc");
310
311 /* create, launch & block all threads */
312 block_threads(blocked_worker, cpu);
313
314 /* make sure all threads are already blocked */
315 mutex_lock(&thread_lock);
316 while (threads_starting)
317 cond_wait(&thread_parent, &thread_lock);
318 cond_broadcast(&thread_worker);
319 mutex_unlock(&thread_lock);
320
321 usleep(100000);
322
323 /* Ok, all threads are patiently blocked, start waking folks up */
324 wakeup_threads(waking_worker);
325
326 for (i = 0; i < params.nthreads; i++) {
327 ret = pthread_join(blocked_worker[i], NULL);
328 if (ret)
329 err(EXIT_FAILURE, "pthread_join");
330 }
331
332 do_run_stats(waking_worker);
333 if (!params.silent)
334 print_run(waking_worker, j);
335
336 free(waking_worker);
337 }
338
339 /* cleanup & report results */
340 cond_destroy(&thread_parent);
341 cond_destroy(&thread_worker);
342 mutex_destroy(&thread_lock);
343
344 print_summary();
345
346 free(blocked_worker);
347 perf_cpu_map__put(cpu);
348 return ret;
349}
350#endif /* HAVE_PTHREAD_BARRIER */