Merge tag 'clk-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/clk/linux
[linux-2.6-microblaze.git] / tools / perf / bench / futex-wake.c
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (C) 2013  Davidlohr Bueso <davidlohr@hp.com>
4  *
5  * futex-wake: Block a bunch of threads on a futex and wake'em up, N at a time.
6  *
7  * This program is particularly useful to measure the latency of nthread wakeups
8  * in non-error situations:  all waiters are queued and all wake calls wakeup
9  * one or more tasks, and thus the waitqueue is never empty.
10  */
11
12 /* For the CLR_() macros */
13 #include <string.h>
14 #include <pthread.h>
15
16 #include <signal.h>
17 #include "../util/stat.h"
18 #include <subcmd/parse-options.h>
19 #include <linux/compiler.h>
20 #include <linux/kernel.h>
21 #include <linux/time64.h>
22 #include <errno.h>
23 #include <internal/cpumap.h>
24 #include <perf/cpumap.h>
25 #include "bench.h"
26 #include "futex.h"
27
28 #include <err.h>
29 #include <stdlib.h>
30 #include <sys/time.h>
31
32 /* all threads will block on the same futex */
33 static u_int32_t futex1 = 0;
34
35 /*
36  * How many wakeups to do at a time.
37  * Default to 1 in order to make the kernel work more.
38  */
39 static unsigned int nwakes = 1;
40
41 pthread_t *worker;
42 static bool done = false, silent = false, fshared = false;
43 static pthread_mutex_t thread_lock;
44 static pthread_cond_t thread_parent, thread_worker;
45 static struct stats waketime_stats, wakeup_stats;
46 static unsigned int threads_starting, nthreads = 0;
47 static int futex_flag = 0;
48
49 static const struct option options[] = {
50         OPT_UINTEGER('t', "threads", &nthreads, "Specify amount of threads"),
51         OPT_UINTEGER('w', "nwakes",  &nwakes,   "Specify amount of threads to wake at once"),
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
57 static const char * const bench_futex_wake_usage[] = {
58         "perf bench futex wake <options>",
59         NULL
60 };
61
62 static void *workerfn(void *arg __maybe_unused)
63 {
64         pthread_mutex_lock(&thread_lock);
65         threads_starting--;
66         if (!threads_starting)
67                 pthread_cond_signal(&thread_parent);
68         pthread_cond_wait(&thread_worker, &thread_lock);
69         pthread_mutex_unlock(&thread_lock);
70
71         while (1) {
72                 if (futex_wait(&futex1, 0, NULL, futex_flag) != EINTR)
73                         break;
74         }
75
76         pthread_exit(NULL);
77         return NULL;
78 }
79
80 static void print_summary(void)
81 {
82         double waketime_avg = avg_stats(&waketime_stats);
83         double waketime_stddev = stddev_stats(&waketime_stats);
84         unsigned int wakeup_avg = avg_stats(&wakeup_stats);
85
86         printf("Wokeup %d of %d threads in %.4f ms (+-%.2f%%)\n",
87                wakeup_avg,
88                nthreads,
89                waketime_avg / USEC_PER_MSEC,
90                rel_stddev_stats(waketime_stddev, waketime_avg));
91 }
92
93 static void block_threads(pthread_t *w,
94                           pthread_attr_t thread_attr, struct perf_cpu_map *cpu)
95 {
96         cpu_set_t cpuset;
97         unsigned int i;
98
99         threads_starting = nthreads;
100
101         /* create and block all threads */
102         for (i = 0; i < nthreads; i++) {
103                 CPU_ZERO(&cpuset);
104                 CPU_SET(cpu->map[i % cpu->nr], &cpuset);
105
106                 if (pthread_attr_setaffinity_np(&thread_attr, sizeof(cpu_set_t), &cpuset))
107                         err(EXIT_FAILURE, "pthread_attr_setaffinity_np");
108
109                 if (pthread_create(&w[i], &thread_attr, workerfn, NULL))
110                         err(EXIT_FAILURE, "pthread_create");
111         }
112 }
113
114 static void toggle_done(int sig __maybe_unused,
115                         siginfo_t *info __maybe_unused,
116                         void *uc __maybe_unused)
117 {
118         done = true;
119 }
120
121 int bench_futex_wake(int argc, const char **argv)
122 {
123         int ret = 0;
124         unsigned int i, j;
125         struct sigaction act;
126         pthread_attr_t thread_attr;
127         struct perf_cpu_map *cpu;
128
129         argc = parse_options(argc, argv, options, bench_futex_wake_usage, 0);
130         if (argc) {
131                 usage_with_options(bench_futex_wake_usage, options);
132                 exit(EXIT_FAILURE);
133         }
134
135         cpu = perf_cpu_map__new(NULL);
136         if (!cpu)
137                 err(EXIT_FAILURE, "calloc");
138
139         memset(&act, 0, sizeof(act));
140         sigfillset(&act.sa_mask);
141         act.sa_sigaction = toggle_done;
142         sigaction(SIGINT, &act, NULL);
143
144         if (!nthreads)
145                 nthreads = cpu->nr;
146
147         worker = calloc(nthreads, sizeof(*worker));
148         if (!worker)
149                 err(EXIT_FAILURE, "calloc");
150
151         if (!fshared)
152                 futex_flag = FUTEX_PRIVATE_FLAG;
153
154         printf("Run summary [PID %d]: blocking on %d threads (at [%s] futex %p), "
155                "waking up %d at a time.\n\n",
156                getpid(), nthreads, fshared ? "shared":"private",  &futex1, nwakes);
157
158         init_stats(&wakeup_stats);
159         init_stats(&waketime_stats);
160         pthread_attr_init(&thread_attr);
161         pthread_mutex_init(&thread_lock, NULL);
162         pthread_cond_init(&thread_parent, NULL);
163         pthread_cond_init(&thread_worker, NULL);
164
165         for (j = 0; j < bench_repeat && !done; j++) {
166                 unsigned int nwoken = 0;
167                 struct timeval start, end, runtime;
168
169                 /* create, launch & block all threads */
170                 block_threads(worker, thread_attr, cpu);
171
172                 /* make sure all threads are already blocked */
173                 pthread_mutex_lock(&thread_lock);
174                 while (threads_starting)
175                         pthread_cond_wait(&thread_parent, &thread_lock);
176                 pthread_cond_broadcast(&thread_worker);
177                 pthread_mutex_unlock(&thread_lock);
178
179                 usleep(100000);
180
181                 /* Ok, all threads are patiently blocked, start waking folks up */
182                 gettimeofday(&start, NULL);
183                 while (nwoken != nthreads)
184                         nwoken += futex_wake(&futex1, nwakes, futex_flag);
185                 gettimeofday(&end, NULL);
186                 timersub(&end, &start, &runtime);
187
188                 update_stats(&wakeup_stats, nwoken);
189                 update_stats(&waketime_stats, runtime.tv_usec);
190
191                 if (!silent) {
192                         printf("[Run %d]: Wokeup %d of %d threads in %.4f ms\n",
193                                j + 1, nwoken, nthreads, runtime.tv_usec / (double)USEC_PER_MSEC);
194                 }
195
196                 for (i = 0; i < nthreads; i++) {
197                         ret = pthread_join(worker[i], NULL);
198                         if (ret)
199                                 err(EXIT_FAILURE, "pthread_join");
200                 }
201
202         }
203
204         /* cleanup & report results */
205         pthread_cond_destroy(&thread_parent);
206         pthread_cond_destroy(&thread_worker);
207         pthread_mutex_destroy(&thread_lock);
208         pthread_attr_destroy(&thread_attr);
209
210         print_summary();
211
212         free(worker);
213         return ret;
214 }