1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Copyright (C) 2015 Davidlohr Bueso.
4 */
5
6 /* For the CLR_() macros */
7 #include <string.h>
8 #include <pthread.h>
9
10 #include <signal.h>
11 #include "../util/stat.h"
12 #include <subcmd/parse-options.h>
13 #include <linux/compiler.h>
14 #include <linux/kernel.h>
15 #include <linux/zalloc.h>
16 #include <errno.h>
17 #include <internal/cpumap.h>
18 #include <perf/cpumap.h>
19 #include "bench.h"
20 #include "futex.h"
21
22 #include <err.h>
23 #include <stdlib.h>
24 #include <sys/time.h>
25
26 struct worker {
27 int tid;
28 u_int32_t *futex;
29 pthread_t thread;
30 unsigned long ops;
31 };
32
33 static u_int32_t global_futex = 0;
34 static struct worker *worker;
35 static unsigned int nsecs = 10;
36 static bool silent = false, multi = false;
37 static bool done = false, fshared = false;
38 static unsigned int nthreads = 0;
39 static int futex_flag = 0;
40 static pthread_mutex_t thread_lock;
41 static unsigned int threads_starting;
42 static struct stats throughput_stats;
43 static pthread_cond_t thread_parent, thread_worker;
44
45 static const struct option options[] = {
46 OPT_UINTEGER('t', "threads", &nthreads, "Specify amount of threads"),
47 OPT_UINTEGER('r', "runtime", &nsecs, "Specify runtime (in seconds)"),
48 OPT_BOOLEAN( 'M', "multi", &multi, "Use multiple futexes"),
49 OPT_BOOLEAN( 's', "silent", &silent, "Silent mode: do not display data/details"),
50 OPT_BOOLEAN( 'S', "shared", &fshared, "Use shared futexes instead of private ones"),
51 OPT_END()
52 };
53
54 static const char * const bench_futex_lock_pi_usage[] = {
55 "perf bench futex lock-pi <options>",
56 NULL
57 };
58
print_summary(void)59 static void print_summary(void)
60 {
61 unsigned long avg = avg_stats(&throughput_stats);
62 double stddev = stddev_stats(&throughput_stats);
63
64 printf("%sAveraged %ld operations/sec (+- %.2f%%), total secs = %d\n",
65 !silent ? "\n" : "", avg, rel_stddev_stats(stddev, avg),
66 (int)bench__runtime.tv_sec);
67 }
68
toggle_done(int sig __maybe_unused,siginfo_t * info __maybe_unused,void * uc __maybe_unused)69 static void toggle_done(int sig __maybe_unused,
70 siginfo_t *info __maybe_unused,
71 void *uc __maybe_unused)
72 {
73 /* inform all threads that we're done for the day */
74 done = true;
75 gettimeofday(&bench__end, NULL);
76 timersub(&bench__end, &bench__start, &bench__runtime);
77 }
78
workerfn(void * arg)79 static void *workerfn(void *arg)
80 {
81 struct worker *w = (struct worker *) arg;
82 unsigned long ops = w->ops;
83
84 pthread_mutex_lock(&thread_lock);
85 threads_starting--;
86 if (!threads_starting)
87 pthread_cond_signal(&thread_parent);
88 pthread_cond_wait(&thread_worker, &thread_lock);
89 pthread_mutex_unlock(&thread_lock);
90
91 do {
92 int ret;
93 again:
94 ret = futex_lock_pi(w->futex, NULL, futex_flag);
95
96 if (ret) { /* handle lock acquisition */
97 if (!silent)
98 warn("thread %d: Could not lock pi-lock for %p (%d)",
99 w->tid, w->futex, ret);
100 if (done)
101 break;
102
103 goto again;
104 }
105
106 usleep(1);
107 ret = futex_unlock_pi(w->futex, futex_flag);
108 if (ret && !silent)
109 warn("thread %d: Could not unlock pi-lock for %p (%d)",
110 w->tid, w->futex, ret);
111 ops++; /* account for thread's share of work */
112 } while (!done);
113
114 w->ops = ops;
115 return NULL;
116 }
117
create_threads(struct worker * w,pthread_attr_t thread_attr,struct perf_cpu_map * cpu)118 static void create_threads(struct worker *w, pthread_attr_t thread_attr,
119 struct perf_cpu_map *cpu)
120 {
121 cpu_set_t cpuset;
122 unsigned int i;
123
124 threads_starting = nthreads;
125
126 for (i = 0; i < nthreads; i++) {
127 worker[i].tid = i;
128
129 if (multi) {
130 worker[i].futex = calloc(1, sizeof(u_int32_t));
131 if (!worker[i].futex)
132 err(EXIT_FAILURE, "calloc");
133 } else
134 worker[i].futex = &global_futex;
135
136 CPU_ZERO(&cpuset);
137 CPU_SET(cpu->map[i % cpu->nr], &cpuset);
138
139 if (pthread_attr_setaffinity_np(&thread_attr, sizeof(cpu_set_t), &cpuset))
140 err(EXIT_FAILURE, "pthread_attr_setaffinity_np");
141
142 if (pthread_create(&w[i].thread, &thread_attr, workerfn, &worker[i]))
143 err(EXIT_FAILURE, "pthread_create");
144 }
145 }
146
bench_futex_lock_pi(int argc,const char ** argv)147 int bench_futex_lock_pi(int argc, const char **argv)
148 {
149 int ret = 0;
150 unsigned int i;
151 struct sigaction act;
152 pthread_attr_t thread_attr;
153 struct perf_cpu_map *cpu;
154
155 argc = parse_options(argc, argv, options, bench_futex_lock_pi_usage, 0);
156 if (argc)
157 goto err;
158
159 cpu = perf_cpu_map__new(NULL);
160 if (!cpu)
161 err(EXIT_FAILURE, "calloc");
162
163 sigfillset(&act.sa_mask);
164 act.sa_sigaction = toggle_done;
165 sigaction(SIGINT, &act, NULL);
166
167 if (!nthreads)
168 nthreads = cpu->nr;
169
170 worker = calloc(nthreads, sizeof(*worker));
171 if (!worker)
172 err(EXIT_FAILURE, "calloc");
173
174 if (!fshared)
175 futex_flag = FUTEX_PRIVATE_FLAG;
176
177 printf("Run summary [PID %d]: %d threads doing pi lock/unlock pairing for %d secs.\n\n",
178 getpid(), nthreads, nsecs);
179
180 init_stats(&throughput_stats);
181 pthread_mutex_init(&thread_lock, NULL);
182 pthread_cond_init(&thread_parent, NULL);
183 pthread_cond_init(&thread_worker, NULL);
184
185 threads_starting = nthreads;
186 pthread_attr_init(&thread_attr);
187 gettimeofday(&bench__start, NULL);
188
189 create_threads(worker, thread_attr, cpu);
190 pthread_attr_destroy(&thread_attr);
191
192 pthread_mutex_lock(&thread_lock);
193 while (threads_starting)
194 pthread_cond_wait(&thread_parent, &thread_lock);
195 pthread_cond_broadcast(&thread_worker);
196 pthread_mutex_unlock(&thread_lock);
197
198 sleep(nsecs);
199 toggle_done(0, NULL, NULL);
200
201 for (i = 0; i < nthreads; i++) {
202 ret = pthread_join(worker[i].thread, NULL);
203 if (ret)
204 err(EXIT_FAILURE, "pthread_join");
205 }
206
207 /* cleanup & report results */
208 pthread_cond_destroy(&thread_parent);
209 pthread_cond_destroy(&thread_worker);
210 pthread_mutex_destroy(&thread_lock);
211
212 for (i = 0; i < nthreads; i++) {
213 unsigned long t = worker[i].ops / bench__runtime.tv_sec;
214
215 update_stats(&throughput_stats, t);
216 if (!silent)
217 printf("[thread %3d] futex: %p [ %ld ops/sec ]\n",
218 worker[i].tid, worker[i].futex, t);
219
220 if (multi)
221 zfree(&worker[i].futex);
222 }
223
224 print_summary();
225
226 free(worker);
227 perf_cpu_map__put(cpu);
228 return ret;
229 err:
230 usage_with_options(bench_futex_lock_pi_usage, options);
231 exit(EXIT_FAILURE);
232 }
233