xref: /openbmc/linux/tools/perf/bench/futex-lock-pi.c (revision 82003e04)
1 /*
2  * Copyright (C) 2015 Davidlohr Bueso.
3  */
4 
5 /* For the CLR_() macros */
6 #include <pthread.h>
7 
8 #include <signal.h>
9 #include "../util/stat.h"
10 #include <subcmd/parse-options.h>
11 #include <linux/compiler.h>
12 #include <linux/kernel.h>
13 #include <errno.h>
14 #include "bench.h"
15 #include "futex.h"
16 
17 #include <err.h>
18 #include <stdlib.h>
19 #include <sys/time.h>
20 
21 struct worker {
22 	int tid;
23 	u_int32_t *futex;
24 	pthread_t thread;
25 	unsigned long ops;
26 };
27 
28 static u_int32_t global_futex = 0;
29 static struct worker *worker;
30 static unsigned int nsecs = 10;
31 static bool silent = false, multi = false;
32 static bool done = false, fshared = false;
33 static unsigned int ncpus, nthreads = 0;
34 static int futex_flag = 0;
35 struct timeval start, end, runtime;
36 static pthread_mutex_t thread_lock;
37 static unsigned int threads_starting;
38 static struct stats throughput_stats;
39 static pthread_cond_t thread_parent, thread_worker;
40 
41 static const struct option options[] = {
42 	OPT_UINTEGER('t', "threads",  &nthreads, "Specify amount of threads"),
43 	OPT_UINTEGER('r', "runtime", &nsecs,     "Specify runtime (in seconds)"),
44 	OPT_BOOLEAN( 'M', "multi",   &multi,     "Use multiple futexes"),
45 	OPT_BOOLEAN( 's', "silent",  &silent,    "Silent mode: do not display data/details"),
46 	OPT_BOOLEAN( 'S', "shared",  &fshared,   "Use shared futexes instead of private ones"),
47 	OPT_END()
48 };
49 
50 static const char * const bench_futex_lock_pi_usage[] = {
51 	"perf bench futex requeue <options>",
52 	NULL
53 };
54 
55 static void print_summary(void)
56 {
57 	unsigned long avg = avg_stats(&throughput_stats);
58 	double stddev = stddev_stats(&throughput_stats);
59 
60 	printf("%sAveraged %ld operations/sec (+- %.2f%%), total secs = %d\n",
61 	       !silent ? "\n" : "", avg, rel_stddev_stats(stddev, avg),
62 	       (int) runtime.tv_sec);
63 }
64 
65 static void toggle_done(int sig __maybe_unused,
66 			siginfo_t *info __maybe_unused,
67 			void *uc __maybe_unused)
68 {
69 	/* inform all threads that we're done for the day */
70 	done = true;
71 	gettimeofday(&end, NULL);
72 	timersub(&end, &start, &runtime);
73 }
74 
75 static void *workerfn(void *arg)
76 {
77 	struct worker *w = (struct worker *) arg;
78 
79 	pthread_mutex_lock(&thread_lock);
80 	threads_starting--;
81 	if (!threads_starting)
82 		pthread_cond_signal(&thread_parent);
83 	pthread_cond_wait(&thread_worker, &thread_lock);
84 	pthread_mutex_unlock(&thread_lock);
85 
86 	do {
87 		int ret;
88 	again:
89 		ret = futex_lock_pi(w->futex, NULL, futex_flag);
90 
91 		if (ret) { /* handle lock acquisition */
92 			if (!silent)
93 				warn("thread %d: Could not lock pi-lock for %p (%d)",
94 				     w->tid, w->futex, ret);
95 			if (done)
96 				break;
97 
98 			goto again;
99 		}
100 
101 		usleep(1);
102 		ret = futex_unlock_pi(w->futex, futex_flag);
103 		if (ret && !silent)
104 			warn("thread %d: Could not unlock pi-lock for %p (%d)",
105 			     w->tid, w->futex, ret);
106 		w->ops++; /* account for thread's share of work */
107 	}  while (!done);
108 
109 	return NULL;
110 }
111 
112 static void create_threads(struct worker *w, pthread_attr_t thread_attr)
113 {
114 	cpu_set_t cpu;
115 	unsigned int i;
116 
117 	threads_starting = nthreads;
118 
119 	for (i = 0; i < nthreads; i++) {
120 		worker[i].tid = i;
121 
122 		if (multi) {
123 			worker[i].futex = calloc(1, sizeof(u_int32_t));
124 			if (!worker[i].futex)
125 				err(EXIT_FAILURE, "calloc");
126 		} else
127 			worker[i].futex = &global_futex;
128 
129 		CPU_ZERO(&cpu);
130 		CPU_SET(i % ncpus, &cpu);
131 
132 		if (pthread_attr_setaffinity_np(&thread_attr, sizeof(cpu_set_t), &cpu))
133 			err(EXIT_FAILURE, "pthread_attr_setaffinity_np");
134 
135 		if (pthread_create(&w[i].thread, &thread_attr, workerfn, &worker[i]))
136 			err(EXIT_FAILURE, "pthread_create");
137 	}
138 }
139 
140 int bench_futex_lock_pi(int argc, const char **argv,
141 			const char *prefix __maybe_unused)
142 {
143 	int ret = 0;
144 	unsigned int i;
145 	struct sigaction act;
146 	pthread_attr_t thread_attr;
147 
148 	argc = parse_options(argc, argv, options, bench_futex_lock_pi_usage, 0);
149 	if (argc)
150 		goto err;
151 
152 	ncpus = sysconf(_SC_NPROCESSORS_ONLN);
153 
154 	sigfillset(&act.sa_mask);
155 	act.sa_sigaction = toggle_done;
156 	sigaction(SIGINT, &act, NULL);
157 
158 	if (!nthreads)
159 		nthreads = ncpus;
160 
161 	worker = calloc(nthreads, sizeof(*worker));
162 	if (!worker)
163 		err(EXIT_FAILURE, "calloc");
164 
165 	if (!fshared)
166 		futex_flag = FUTEX_PRIVATE_FLAG;
167 
168 	printf("Run summary [PID %d]: %d threads doing pi lock/unlock pairing for %d secs.\n\n",
169 	       getpid(), nthreads, nsecs);
170 
171 	init_stats(&throughput_stats);
172 	pthread_mutex_init(&thread_lock, NULL);
173 	pthread_cond_init(&thread_parent, NULL);
174 	pthread_cond_init(&thread_worker, NULL);
175 
176 	threads_starting = nthreads;
177 	pthread_attr_init(&thread_attr);
178 	gettimeofday(&start, NULL);
179 
180 	create_threads(worker, thread_attr);
181 	pthread_attr_destroy(&thread_attr);
182 
183 	pthread_mutex_lock(&thread_lock);
184 	while (threads_starting)
185 		pthread_cond_wait(&thread_parent, &thread_lock);
186 	pthread_cond_broadcast(&thread_worker);
187 	pthread_mutex_unlock(&thread_lock);
188 
189 	sleep(nsecs);
190 	toggle_done(0, NULL, NULL);
191 
192 	for (i = 0; i < nthreads; i++) {
193 		ret = pthread_join(worker[i].thread, NULL);
194 		if (ret)
195 			err(EXIT_FAILURE, "pthread_join");
196 	}
197 
198 	/* cleanup & report results */
199 	pthread_cond_destroy(&thread_parent);
200 	pthread_cond_destroy(&thread_worker);
201 	pthread_mutex_destroy(&thread_lock);
202 
203 	for (i = 0; i < nthreads; i++) {
204 		unsigned long t = worker[i].ops/runtime.tv_sec;
205 
206 		update_stats(&throughput_stats, t);
207 		if (!silent)
208 			printf("[thread %3d] futex: %p [ %ld ops/sec ]\n",
209 			       worker[i].tid, worker[i].futex, t);
210 
211 		if (multi)
212 			free(worker[i].futex);
213 	}
214 
215 	print_summary();
216 
217 	free(worker);
218 	return ret;
219 err:
220 	usage_with_options(bench_futex_lock_pi_usage, options);
221 	exit(EXIT_FAILURE);
222 }
223