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