1
2
3
4
5
6
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 <perf/cpumap.h>
18#include "bench.h"
19#include "futex.h"
20
21#include <err.h>
22#include <stdlib.h>
23#include <sys/time.h>
24
25struct worker {
26 int tid;
27 u_int32_t *futex;
28 pthread_t thread;
29 unsigned long ops;
30};
31
32static u_int32_t global_futex = 0;
33static struct worker *worker;
34static unsigned int nsecs = 10;
35static bool silent = false, multi = false;
36static bool done = false, fshared = false;
37static unsigned int nthreads = 0;
38static int futex_flag = 0;
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
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_BOOLEAN( 'M', "multi", &multi, "Use multiple futexes"),
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_lock_pi_usage[] = {
54 "perf bench futex lock-pi <options>",
55 NULL
56};
57
58static void print_summary(void)
59{
60 unsigned long avg = avg_stats(&throughput_stats);
61 double stddev = stddev_stats(&throughput_stats);
62
63 printf("%sAveraged %ld operations/sec (+- %.2f%%), total secs = %d\n",
64 !silent ? "\n" : "", avg, rel_stddev_stats(stddev, avg),
65 (int)bench__runtime.tv_sec);
66}
67
68static void toggle_done(int sig __maybe_unused,
69 siginfo_t *info __maybe_unused,
70 void *uc __maybe_unused)
71{
72
73 done = true;
74 gettimeofday(&bench__end, NULL);
75 timersub(&bench__end, &bench__start, &bench__runtime);
76}
77
78static void *workerfn(void *arg)
79{
80 struct worker *w = (struct worker *) arg;
81 unsigned long ops = w->ops;
82
83 pthread_mutex_lock(&thread_lock);
84 threads_starting--;
85 if (!threads_starting)
86 pthread_cond_signal(&thread_parent);
87 pthread_cond_wait(&thread_worker, &thread_lock);
88 pthread_mutex_unlock(&thread_lock);
89
90 do {
91 int ret;
92 again:
93 ret = futex_lock_pi(w->futex, NULL, futex_flag);
94
95 if (ret) {
96 if (!silent)
97 warn("thread %d: Could not lock pi-lock for %p (%d)",
98 w->tid, w->futex, ret);
99 if (done)
100 break;
101
102 goto again;
103 }
104
105 usleep(1);
106 ret = futex_unlock_pi(w->futex, futex_flag);
107 if (ret && !silent)
108 warn("thread %d: Could not unlock pi-lock for %p (%d)",
109 w->tid, w->futex, ret);
110 ops++;
111 } while (!done);
112
113 w->ops = ops;
114 return NULL;
115}
116
117static void create_threads(struct worker *w, pthread_attr_t thread_attr,
118 struct perf_cpu_map *cpu)
119{
120 cpu_set_t cpuset;
121 unsigned int i;
122
123 threads_starting = nthreads;
124
125 for (i = 0; i < nthreads; i++) {
126 worker[i].tid = i;
127
128 if (multi) {
129 worker[i].futex = calloc(1, sizeof(u_int32_t));
130 if (!worker[i].futex)
131 err(EXIT_FAILURE, "calloc");
132 } else
133 worker[i].futex = &global_futex;
134
135 CPU_ZERO(&cpuset);
136 CPU_SET(cpu->map[i % cpu->nr], &cpuset);
137
138 if (pthread_attr_setaffinity_np(&thread_attr, sizeof(cpu_set_t), &cpuset))
139 err(EXIT_FAILURE, "pthread_attr_setaffinity_np");
140
141 if (pthread_create(&w[i].thread, &thread_attr, workerfn, &worker[i]))
142 err(EXIT_FAILURE, "pthread_create");
143 }
144}
145
146int bench_futex_lock_pi(int argc, const char **argv)
147{
148 int ret = 0;
149 unsigned int i;
150 struct sigaction act;
151 pthread_attr_t thread_attr;
152 struct perf_cpu_map *cpu;
153
154 argc = parse_options(argc, argv, options, bench_futex_lock_pi_usage, 0);
155 if (argc)
156 goto err;
157
158 cpu = perf_cpu_map__new(NULL);
159 if (!cpu)
160 err(EXIT_FAILURE, "calloc");
161
162 memset(&act, 0, sizeof(act));
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
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 = bench__runtime.tv_sec > 0 ?
214 worker[i].ops / bench__runtime.tv_sec : 0;
215
216 update_stats(&throughput_stats, t);
217 if (!silent)
218 printf("[thread %3d] futex: %p [ %ld ops/sec ]\n",
219 worker[i].tid, worker[i].futex, t);
220
221 if (multi)
222 zfree(&worker[i].futex);
223 }
224
225 print_summary();
226
227 free(worker);
228 return ret;
229err:
230 usage_with_options(bench_futex_lock_pi_usage, options);
231 exit(EXIT_FAILURE);
232}
233
