This source file includes following definitions.
- workerfn
- print_summary
- block_threads
- toggle_done
- bench_futex_wake
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13 #include <string.h>
14 #include <pthread.h>
15
16 #include <signal.h>
17 #include "../util/stat.h"
18 #include <subcmd/parse-options.h>
19 #include <linux/compiler.h>
20 #include <linux/kernel.h>
21 #include <linux/time64.h>
22 #include <errno.h>
23 #include <internal/cpumap.h>
24 #include <perf/cpumap.h>
25 #include "bench.h"
26 #include "futex.h"
27
28 #include <err.h>
29 #include <stdlib.h>
30 #include <sys/time.h>
31
32
33 static u_int32_t futex1 = 0;
34
35
36
37
38
39 static unsigned int nwakes = 1;
40
41 pthread_t *worker;
42 static bool done = false, silent = false, fshared = false;
43 static pthread_mutex_t thread_lock;
44 static pthread_cond_t thread_parent, thread_worker;
45 static struct stats waketime_stats, wakeup_stats;
46 static unsigned int threads_starting, nthreads = 0;
47 static int futex_flag = 0;
48
49 static const struct option options[] = {
50 OPT_UINTEGER('t', "threads", &nthreads, "Specify amount of threads"),
51 OPT_UINTEGER('w', "nwakes", &nwakes, "Specify amount of threads to wake at once"),
52 OPT_BOOLEAN( 's', "silent", &silent, "Silent mode: do not display data/details"),
53 OPT_BOOLEAN( 'S', "shared", &fshared, "Use shared futexes instead of private ones"),
54 OPT_END()
55 };
56
57 static const char * const bench_futex_wake_usage[] = {
58 "perf bench futex wake <options>",
59 NULL
60 };
61
62 static void *workerfn(void *arg __maybe_unused)
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 while (1) {
72 if (futex_wait(&futex1, 0, NULL, futex_flag) != EINTR)
73 break;
74 }
75
76 pthread_exit(NULL);
77 return NULL;
78 }
79
80 static void print_summary(void)
81 {
82 double waketime_avg = avg_stats(&waketime_stats);
83 double waketime_stddev = stddev_stats(&waketime_stats);
84 unsigned int wakeup_avg = avg_stats(&wakeup_stats);
85
86 printf("Wokeup %d of %d threads in %.4f ms (+-%.2f%%)\n",
87 wakeup_avg,
88 nthreads,
89 waketime_avg / USEC_PER_MSEC,
90 rel_stddev_stats(waketime_stddev, waketime_avg));
91 }
92
93 static void block_threads(pthread_t *w,
94 pthread_attr_t thread_attr, struct perf_cpu_map *cpu)
95 {
96 cpu_set_t cpuset;
97 unsigned int i;
98
99 threads_starting = nthreads;
100
101
102 for (i = 0; i < nthreads; i++) {
103 CPU_ZERO(&cpuset);
104 CPU_SET(cpu->map[i % cpu->nr], &cpuset);
105
106 if (pthread_attr_setaffinity_np(&thread_attr, sizeof(cpu_set_t), &cpuset))
107 err(EXIT_FAILURE, "pthread_attr_setaffinity_np");
108
109 if (pthread_create(&w[i], &thread_attr, workerfn, NULL))
110 err(EXIT_FAILURE, "pthread_create");
111 }
112 }
113
114 static void toggle_done(int sig __maybe_unused,
115 siginfo_t *info __maybe_unused,
116 void *uc __maybe_unused)
117 {
118 done = true;
119 }
120
121 int bench_futex_wake(int argc, const char **argv)
122 {
123 int ret = 0;
124 unsigned int i, j;
125 struct sigaction act;
126 pthread_attr_t thread_attr;
127 struct perf_cpu_map *cpu;
128
129 argc = parse_options(argc, argv, options, bench_futex_wake_usage, 0);
130 if (argc) {
131 usage_with_options(bench_futex_wake_usage, options);
132 exit(EXIT_FAILURE);
133 }
134
135 cpu = perf_cpu_map__new(NULL);
136 if (!cpu)
137 err(EXIT_FAILURE, "calloc");
138
139 sigfillset(&act.sa_mask);
140 act.sa_sigaction = toggle_done;
141 sigaction(SIGINT, &act, NULL);
142
143 if (!nthreads)
144 nthreads = cpu->nr;
145
146 worker = calloc(nthreads, sizeof(*worker));
147 if (!worker)
148 err(EXIT_FAILURE, "calloc");
149
150 if (!fshared)
151 futex_flag = FUTEX_PRIVATE_FLAG;
152
153 printf("Run summary [PID %d]: blocking on %d threads (at [%s] futex %p), "
154 "waking up %d at a time.\n\n",
155 getpid(), nthreads, fshared ? "shared":"private", &futex1, nwakes);
156
157 init_stats(&wakeup_stats);
158 init_stats(&waketime_stats);
159 pthread_attr_init(&thread_attr);
160 pthread_mutex_init(&thread_lock, NULL);
161 pthread_cond_init(&thread_parent, NULL);
162 pthread_cond_init(&thread_worker, NULL);
163
164 for (j = 0; j < bench_repeat && !done; j++) {
165 unsigned int nwoken = 0;
166 struct timeval start, end, runtime;
167
168
169 block_threads(worker, thread_attr, cpu);
170
171
172 pthread_mutex_lock(&thread_lock);
173 while (threads_starting)
174 pthread_cond_wait(&thread_parent, &thread_lock);
175 pthread_cond_broadcast(&thread_worker);
176 pthread_mutex_unlock(&thread_lock);
177
178 usleep(100000);
179
180
181 gettimeofday(&start, NULL);
182 while (nwoken != nthreads)
183 nwoken += futex_wake(&futex1, nwakes, futex_flag);
184 gettimeofday(&end, NULL);
185 timersub(&end, &start, &runtime);
186
187 update_stats(&wakeup_stats, nwoken);
188 update_stats(&waketime_stats, runtime.tv_usec);
189
190 if (!silent) {
191 printf("[Run %d]: Wokeup %d of %d threads in %.4f ms\n",
192 j + 1, nwoken, nthreads, runtime.tv_usec / (double)USEC_PER_MSEC);
193 }
194
195 for (i = 0; i < nthreads; i++) {
196 ret = pthread_join(worker[i], NULL);
197 if (ret)
198 err(EXIT_FAILURE, "pthread_join");
199 }
200
201 }
202
203
204 pthread_cond_destroy(&thread_parent);
205 pthread_cond_destroy(&thread_worker);
206 pthread_mutex_destroy(&thread_lock);
207 pthread_attr_destroy(&thread_attr);
208
209 print_summary();
210
211 free(worker);
212 return ret;
213 }