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;
 40static pthread_mutex_t thread_lock;
 41static unsigned int threads_starting;
 42static struct stats throughput_stats;
 43static pthread_cond_t thread_parent, thread_worker;
 44
 45static const struct option options[] = {
 46	OPT_UINTEGER('t', "threads",  &nthreads, "Specify amount of threads"),
 47	OPT_UINTEGER('r', "runtime", &nsecs,     "Specify runtime (in seconds)"),
 48	OPT_BOOLEAN( 'M', "multi",   &multi,     "Use multiple futexes"),
 49	OPT_BOOLEAN( 's', "silent",  &silent,    "Silent mode: do not display data/details"),
 50	OPT_BOOLEAN( 'S', "shared",  &fshared,   "Use shared futexes instead of private ones"),
 51	OPT_END()
 52};
 53
 54static const char * const bench_futex_lock_pi_usage[] = {
 55	"perf bench futex lock-pi <options>",
 56	NULL
 57};
 58
 59static void print_summary(void)
 60{
 61	unsigned long avg = avg_stats(&throughput_stats);
 62	double stddev = stddev_stats(&throughput_stats);
 63
 64	printf("%sAveraged %ld operations/sec (+- %.2f%%), total secs = %d\n",
 65	       !silent ? "\n" : "", avg, rel_stddev_stats(stddev, avg),
 66	       (int)bench__runtime.tv_sec);
 67}
 68
 69static void toggle_done(int sig __maybe_unused,
 70			siginfo_t *info __maybe_unused,
 71			void *uc __maybe_unused)
 72{
 73	/* inform all threads that we're done for the day */
 74	done = true;
 75	gettimeofday(&bench__end, NULL);
 76	timersub(&bench__end, &bench__start, &bench__runtime);
 77}
 78
 79static void *workerfn(void *arg)
 80{
 81	struct worker *w = (struct worker *) arg;
 82	unsigned long ops = w->ops;
 83
 84	pthread_mutex_lock(&thread_lock);
 85	threads_starting--;
 86	if (!threads_starting)
 87		pthread_cond_signal(&thread_parent);
 88	pthread_cond_wait(&thread_worker, &thread_lock);
 89	pthread_mutex_unlock(&thread_lock);
 90
 91	do {
 92		int ret;
 93	again:
 94		ret = futex_lock_pi(w->futex, NULL, futex_flag);
 95
 96		if (ret) { /* handle lock acquisition */
 97			if (!silent)
 98				warn("thread %d: Could not lock pi-lock for %p (%d)",
 99				     w->tid, w->futex, ret);
100			if (done)
101				break;
102
103			goto again;
104		}
105
106		usleep(1);
107		ret = futex_unlock_pi(w->futex, futex_flag);
108		if (ret && !silent)
109			warn("thread %d: Could not unlock pi-lock for %p (%d)",
110			     w->tid, w->futex, ret);
111		ops++; /* account for thread's share of work */
112	}  while (!done);
113
114	w->ops = ops;
115	return NULL;
116}
117
118static void create_threads(struct worker *w, pthread_attr_t thread_attr,
119			   struct perf_cpu_map *cpu)
120{
121	cpu_set_t cpuset;
122	unsigned int i;
123
124	threads_starting = nthreads;
125
126	for (i = 0; i < nthreads; i++) {
127		worker[i].tid = i;
128
129		if (multi) {
130			worker[i].futex = calloc(1, sizeof(u_int32_t));
131			if (!worker[i].futex)
132				err(EXIT_FAILURE, "calloc");
133		} else
134			worker[i].futex = &global_futex;
135
136		CPU_ZERO(&cpuset);
137		CPU_SET(cpu->map[i % cpu->nr], &cpuset);
138
139		if (pthread_attr_setaffinity_np(&thread_attr, sizeof(cpu_set_t), &cpuset))
140			err(EXIT_FAILURE, "pthread_attr_setaffinity_np");
141
142		if (pthread_create(&w[i].thread, &thread_attr, workerfn, &worker[i]))
143			err(EXIT_FAILURE, "pthread_create");
144	}
145}
146
147int bench_futex_lock_pi(int argc, const char **argv)
148{
149	int ret = 0;
150	unsigned int i;
151	struct sigaction act;
152	pthread_attr_t thread_attr;
153	struct perf_cpu_map *cpu;
154
155	argc = parse_options(argc, argv, options, bench_futex_lock_pi_usage, 0);
156	if (argc)
157		goto err;
158
159	cpu = perf_cpu_map__new(NULL);
160	if (!cpu)
161		err(EXIT_FAILURE, "calloc");
162
163	memset(&act, 0, sizeof(act));
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(&bench__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 = bench__runtime.tv_sec > 0 ?
215			worker[i].ops / bench__runtime.tv_sec : 0;
216
217		update_stats(&throughput_stats, t);
218		if (!silent)
219			printf("[thread %3d] futex: %p [ %ld ops/sec ]\n",
220			       worker[i].tid, worker[i].futex, t);
221
222		if (multi)
223			zfree(&worker[i].futex);
224	}
225
226	print_summary();
227
228	free(worker);
229	return ret;
230err:
231	usage_with_options(bench_futex_lock_pi_usage, options);
232	exit(EXIT_FAILURE);
233}