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b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
a0439711 DB |
2 | /* |
3 | * Copyright (C) 2013 Davidlohr Bueso <davidlohr@hp.com> | |
4 | * | |
5 | * futex-hash: Stress the hell out of the Linux kernel futex uaddr hashing. | |
6 | * | |
7 | * This program is particularly useful for measuring the kernel's futex hash | |
8 | * table/function implementation. In order for it to make sense, use with as | |
9 | * many threads and futexes as possible. | |
10 | */ | |
11 | ||
8a158589 | 12 | /* For the CLR_() macros */ |
a0f213e1 | 13 | #include <string.h> |
8a158589 ACM |
14 | #include <pthread.h> |
15 | ||
9c304f6c ACM |
16 | #include <errno.h> |
17 | #include <signal.h> | |
18 | #include <stdlib.h> | |
86695f59 | 19 | #include <linux/compiler.h> |
9c304f6c | 20 | #include <linux/kernel.h> |
d8f9da24 | 21 | #include <linux/zalloc.h> |
9c304f6c | 22 | #include <sys/time.h> |
87ffb6c6 | 23 | #include <internal/cpumap.h> |
9c3516d1 | 24 | #include <perf/cpumap.h> |
9c304f6c | 25 | |
a0439711 | 26 | #include "../util/stat.h" |
4b6ab94e | 27 | #include <subcmd/parse-options.h> |
a0439711 DB |
28 | #include "bench.h" |
29 | #include "futex.h" | |
30 | ||
31 | #include <err.h> | |
a0439711 DB |
32 | |
33 | static unsigned int nthreads = 0; | |
34 | static unsigned int nsecs = 10; | |
35 | /* amount of futexes per thread */ | |
36 | static unsigned int nfutexes = 1024; | |
37 | static bool fshared = false, done = false, silent = false; | |
86c87e13 | 38 | static int futex_flag = 0; |
a0439711 | 39 | |
e4d9b04b | 40 | struct timeval bench__start, bench__end, bench__runtime; |
a0439711 DB |
41 | static pthread_mutex_t thread_lock; |
42 | static unsigned int threads_starting; | |
43 | static struct stats throughput_stats; | |
44 | static pthread_cond_t thread_parent, thread_worker; | |
45 | ||
46 | struct worker { | |
47 | int tid; | |
48 | u_int32_t *futex; | |
49 | pthread_t thread; | |
50 | unsigned long ops; | |
e2e1680f | 51 | }; |
a0439711 DB |
52 | |
53 | static const struct option options[] = { | |
54 | OPT_UINTEGER('t', "threads", &nthreads, "Specify amount of threads"), | |
55 | OPT_UINTEGER('r', "runtime", &nsecs, "Specify runtime (in seconds)"), | |
56 | OPT_UINTEGER('f', "futexes", &nfutexes, "Specify amount of futexes per threads"), | |
57 | OPT_BOOLEAN( 's', "silent", &silent, "Silent mode: do not display data/details"), | |
58 | OPT_BOOLEAN( 'S', "shared", &fshared, "Use shared futexes instead of private ones"), | |
59 | OPT_END() | |
60 | }; | |
61 | ||
62 | static const char * const bench_futex_hash_usage[] = { | |
63 | "perf bench futex hash <options>", | |
64 | NULL | |
65 | }; | |
66 | ||
67 | static void *workerfn(void *arg) | |
68 | { | |
69 | int ret; | |
a0439711 | 70 | struct worker *w = (struct worker *) arg; |
e2e1680f DB |
71 | unsigned int i; |
72 | unsigned long ops = w->ops; /* avoid cacheline bouncing */ | |
a0439711 DB |
73 | |
74 | pthread_mutex_lock(&thread_lock); | |
75 | threads_starting--; | |
76 | if (!threads_starting) | |
77 | pthread_cond_signal(&thread_parent); | |
78 | pthread_cond_wait(&thread_worker, &thread_lock); | |
79 | pthread_mutex_unlock(&thread_lock); | |
80 | ||
81 | do { | |
e2e1680f | 82 | for (i = 0; i < nfutexes; i++, ops++) { |
a0439711 DB |
83 | /* |
84 | * We want the futex calls to fail in order to stress | |
85 | * the hashing of uaddr and not measure other steps, | |
86 | * such as internal waitqueue handling, thus enlarging | |
87 | * the critical region protected by hb->lock. | |
88 | */ | |
86c87e13 | 89 | ret = futex_wait(&w->futex[i], 1234, NULL, futex_flag); |
a0439711 DB |
90 | if (!silent && |
91 | (!ret || errno != EAGAIN || errno != EWOULDBLOCK)) | |
92 | warn("Non-expected futex return call"); | |
93 | } | |
94 | } while (!done); | |
95 | ||
e2e1680f | 96 | w->ops = ops; |
a0439711 DB |
97 | return NULL; |
98 | } | |
99 | ||
100 | static void toggle_done(int sig __maybe_unused, | |
101 | siginfo_t *info __maybe_unused, | |
102 | void *uc __maybe_unused) | |
103 | { | |
104 | /* inform all threads that we're done for the day */ | |
105 | done = true; | |
e4d9b04b ACM |
106 | gettimeofday(&bench__end, NULL); |
107 | timersub(&bench__end, &bench__start, &bench__runtime); | |
a0439711 DB |
108 | } |
109 | ||
110 | static void print_summary(void) | |
111 | { | |
112 | unsigned long avg = avg_stats(&throughput_stats); | |
113 | double stddev = stddev_stats(&throughput_stats); | |
114 | ||
115 | printf("%sAveraged %ld operations/sec (+- %.2f%%), total secs = %d\n", | |
116 | !silent ? "\n" : "", avg, rel_stddev_stats(stddev, avg), | |
e4d9b04b | 117 | (int)bench__runtime.tv_sec); |
a0439711 DB |
118 | } |
119 | ||
b0ad8ea6 | 120 | int bench_futex_hash(int argc, const char **argv) |
a0439711 DB |
121 | { |
122 | int ret = 0; | |
3b2323c2 | 123 | cpu_set_t cpuset; |
a0439711 | 124 | struct sigaction act; |
3b2323c2 | 125 | unsigned int i; |
a0439711 DB |
126 | pthread_attr_t thread_attr; |
127 | struct worker *worker = NULL; | |
f854839b | 128 | struct perf_cpu_map *cpu; |
a0439711 DB |
129 | |
130 | argc = parse_options(argc, argv, options, bench_futex_hash_usage, 0); | |
131 | if (argc) { | |
132 | usage_with_options(bench_futex_hash_usage, options); | |
133 | exit(EXIT_FAILURE); | |
134 | } | |
135 | ||
9c3516d1 | 136 | cpu = perf_cpu_map__new(NULL); |
3b2323c2 DB |
137 | if (!cpu) |
138 | goto errmem; | |
a0439711 | 139 | |
7b919a53 | 140 | memset(&act, 0, sizeof(act)); |
a0439711 DB |
141 | sigfillset(&act.sa_mask); |
142 | act.sa_sigaction = toggle_done; | |
143 | sigaction(SIGINT, &act, NULL); | |
144 | ||
145 | if (!nthreads) /* default to the number of CPUs */ | |
3b2323c2 | 146 | nthreads = cpu->nr; |
a0439711 DB |
147 | |
148 | worker = calloc(nthreads, sizeof(*worker)); | |
149 | if (!worker) | |
150 | goto errmem; | |
151 | ||
86c87e13 DB |
152 | if (!fshared) |
153 | futex_flag = FUTEX_PRIVATE_FLAG; | |
154 | ||
a0439711 DB |
155 | printf("Run summary [PID %d]: %d threads, each operating on %d [%s] futexes for %d secs.\n\n", |
156 | getpid(), nthreads, nfutexes, fshared ? "shared":"private", nsecs); | |
157 | ||
158 | init_stats(&throughput_stats); | |
159 | pthread_mutex_init(&thread_lock, NULL); | |
160 | pthread_cond_init(&thread_parent, NULL); | |
161 | pthread_cond_init(&thread_worker, NULL); | |
162 | ||
163 | threads_starting = nthreads; | |
164 | pthread_attr_init(&thread_attr); | |
e4d9b04b | 165 | gettimeofday(&bench__start, NULL); |
a0439711 DB |
166 | for (i = 0; i < nthreads; i++) { |
167 | worker[i].tid = i; | |
168 | worker[i].futex = calloc(nfutexes, sizeof(*worker[i].futex)); | |
169 | if (!worker[i].futex) | |
170 | goto errmem; | |
171 | ||
3b2323c2 DB |
172 | CPU_ZERO(&cpuset); |
173 | CPU_SET(cpu->map[i % cpu->nr], &cpuset); | |
a0439711 | 174 | |
3b2323c2 | 175 | ret = pthread_attr_setaffinity_np(&thread_attr, sizeof(cpu_set_t), &cpuset); |
a0439711 DB |
176 | if (ret) |
177 | err(EXIT_FAILURE, "pthread_attr_setaffinity_np"); | |
178 | ||
179 | ret = pthread_create(&worker[i].thread, &thread_attr, workerfn, | |
180 | (void *)(struct worker *) &worker[i]); | |
181 | if (ret) | |
182 | err(EXIT_FAILURE, "pthread_create"); | |
183 | ||
184 | } | |
185 | pthread_attr_destroy(&thread_attr); | |
186 | ||
187 | pthread_mutex_lock(&thread_lock); | |
188 | while (threads_starting) | |
189 | pthread_cond_wait(&thread_parent, &thread_lock); | |
190 | pthread_cond_broadcast(&thread_worker); | |
191 | pthread_mutex_unlock(&thread_lock); | |
192 | ||
193 | sleep(nsecs); | |
194 | toggle_done(0, NULL, NULL); | |
195 | ||
196 | for (i = 0; i < nthreads; i++) { | |
197 | ret = pthread_join(worker[i].thread, NULL); | |
198 | if (ret) | |
199 | err(EXIT_FAILURE, "pthread_join"); | |
200 | } | |
201 | ||
202 | /* cleanup & report results */ | |
203 | pthread_cond_destroy(&thread_parent); | |
204 | pthread_cond_destroy(&thread_worker); | |
205 | pthread_mutex_destroy(&thread_lock); | |
206 | ||
207 | for (i = 0; i < nthreads; i++) { | |
e4d9b04b | 208 | unsigned long t = worker[i].ops / bench__runtime.tv_sec; |
a0439711 DB |
209 | update_stats(&throughput_stats, t); |
210 | if (!silent) { | |
211 | if (nfutexes == 1) | |
212 | printf("[thread %2d] futex: %p [ %ld ops/sec ]\n", | |
213 | worker[i].tid, &worker[i].futex[0], t); | |
214 | else | |
215 | printf("[thread %2d] futexes: %p ... %p [ %ld ops/sec ]\n", | |
216 | worker[i].tid, &worker[i].futex[0], | |
217 | &worker[i].futex[nfutexes-1], t); | |
218 | } | |
219 | ||
d8f9da24 | 220 | zfree(&worker[i].futex); |
a0439711 DB |
221 | } |
222 | ||
223 | print_summary(); | |
224 | ||
225 | free(worker); | |
3b2323c2 | 226 | free(cpu); |
a0439711 DB |
227 | return ret; |
228 | errmem: | |
229 | err(EXIT_FAILURE, "calloc"); | |
230 | } |