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