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
 21struct worker {
 22	int tid;
 23	u_int32_t *futex;
 24	pthread_t thread;
 25	unsigned long ops;
 26};
 27
 28static u_int32_t global_futex = 0;
 29static struct worker *worker;
 30static unsigned int nsecs = 10;
 31static bool silent = false, multi = false;
 32static bool done = false, fshared = false;
 33static unsigned int ncpus, nthreads = 0;
 34static int futex_flag = 0;
 35struct timeval start, end, runtime;
 36static pthread_mutex_t thread_lock;
 37static unsigned int threads_starting;
 38static struct stats throughput_stats;
 39static pthread_cond_t thread_parent, thread_worker;
 40
 41static 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
 50static const char * const bench_futex_lock_pi_usage[] = {
 51	"perf bench futex lock-pi <options>",
 52	NULL
 53};
 54
 55static 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
 65static 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
 75static void *workerfn(void *arg)
 76{
 77	struct worker *w = (struct worker *) arg;
 78	unsigned long ops = w->ops;
 79
 80	pthread_mutex_lock(&thread_lock);
 81	threads_starting--;
 82	if (!threads_starting)
 83		pthread_cond_signal(&thread_parent);
 84	pthread_cond_wait(&thread_worker, &thread_lock);
 85	pthread_mutex_unlock(&thread_lock);
 86
 87	do {
 88		int ret;
 89	again:
 90		ret = futex_lock_pi(w->futex, NULL, futex_flag);
 91
 92		if (ret) { /* handle lock acquisition */
 93			if (!silent)
 94				warn("thread %d: Could not lock pi-lock for %p (%d)",
 95				     w->tid, w->futex, ret);
 96			if (done)
 97				break;
 98
 99			goto again;
100		}
101
102		usleep(1);
103		ret = futex_unlock_pi(w->futex, futex_flag);
104		if (ret && !silent)
105			warn("thread %d: Could not unlock pi-lock for %p (%d)",
106			     w->tid, w->futex, ret);
107		ops++; /* account for thread's share of work */
108	}  while (!done);
109
110	w->ops = ops;
111	return NULL;
112}
113
114static void create_threads(struct worker *w, pthread_attr_t thread_attr)
115{
116	cpu_set_t cpu;
117	unsigned int i;
118
119	threads_starting = nthreads;
120
121	for (i = 0; i < nthreads; i++) {
122		worker[i].tid = i;
123
124		if (multi) {
125			worker[i].futex = calloc(1, sizeof(u_int32_t));
126			if (!worker[i].futex)
127				err(EXIT_FAILURE, "calloc");
128		} else
129			worker[i].futex = &global_futex;
130
131		CPU_ZERO(&cpu);
132		CPU_SET(i % ncpus, &cpu);
133
134		if (pthread_attr_setaffinity_np(&thread_attr, sizeof(cpu_set_t), &cpu))
135			err(EXIT_FAILURE, "pthread_attr_setaffinity_np");
136
137		if (pthread_create(&w[i].thread, &thread_attr, workerfn, &worker[i]))
138			err(EXIT_FAILURE, "pthread_create");
139	}
140}
141
142int bench_futex_lock_pi(int argc, const char **argv,
143			const char *prefix __maybe_unused)
144{
145	int ret = 0;
146	unsigned int i;
147	struct sigaction act;
148	pthread_attr_t thread_attr;
149
150	argc = parse_options(argc, argv, options, bench_futex_lock_pi_usage, 0);
151	if (argc)
152		goto err;
153
154	ncpus = sysconf(_SC_NPROCESSORS_ONLN);
155	nsecs = futexbench_sanitize_numeric(nsecs);
156
157	sigfillset(&act.sa_mask);
158	act.sa_sigaction = toggle_done;
159	sigaction(SIGINT, &act, NULL);
160
161	if (!nthreads)
162		nthreads = ncpus;
163	else
164		nthreads = futexbench_sanitize_numeric(nthreads);
165
166	worker = calloc(nthreads, sizeof(*worker));
167	if (!worker)
168		err(EXIT_FAILURE, "calloc");
169
170	if (!fshared)
171		futex_flag = FUTEX_PRIVATE_FLAG;
172
173	printf("Run summary [PID %d]: %d threads doing pi lock/unlock pairing for %d secs.\n\n",
174	       getpid(), nthreads, nsecs);
175
176	init_stats(&throughput_stats);
177	pthread_mutex_init(&thread_lock, NULL);
178	pthread_cond_init(&thread_parent, NULL);
179	pthread_cond_init(&thread_worker, NULL);
180
181	threads_starting = nthreads;
182	pthread_attr_init(&thread_attr);
183	gettimeofday(&start, NULL);
184
185	create_threads(worker, thread_attr);
186	pthread_attr_destroy(&thread_attr);
187
188	pthread_mutex_lock(&thread_lock);
189	while (threads_starting)
190		pthread_cond_wait(&thread_parent, &thread_lock);
191	pthread_cond_broadcast(&thread_worker);
192	pthread_mutex_unlock(&thread_lock);
193
194	sleep(nsecs);
195	toggle_done(0, NULL, NULL);
196
197	for (i = 0; i < nthreads; i++) {
198		ret = pthread_join(worker[i].thread, NULL);
199		if (ret)
200			err(EXIT_FAILURE, "pthread_join");
201	}
202
203	/* cleanup & report results */
204	pthread_cond_destroy(&thread_parent);
205	pthread_cond_destroy(&thread_worker);
206	pthread_mutex_destroy(&thread_lock);
207
208	for (i = 0; i < nthreads; i++) {
209		unsigned long t = worker[i].ops/runtime.tv_sec;
210
211		update_stats(&throughput_stats, t);
212		if (!silent)
213			printf("[thread %3d] futex: %p [ %ld ops/sec ]\n",
214			       worker[i].tid, worker[i].futex, t);
215
216		if (multi)
217			free(worker[i].futex);
218	}
219
220	print_summary();
221
222	free(worker);
223	return ret;
224err:
225	usage_with_options(bench_futex_lock_pi_usage, options);
226	exit(EXIT_FAILURE);
227}