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