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 <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	/* inform all threads that we're done for the day */
 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) { /* handle lock acquisition */
 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++; /* account for thread's share of work */
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	/* 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 = 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}