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