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/mutex.h"
12 #include "../util/stat.h"
13 #include <subcmd/parse-options.h>
14 #include <linux/compiler.h>
15 #include <linux/kernel.h>
16 #include <linux/zalloc.h>
17 #include <errno.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 #include <sys/mman.h>
26 
27 struct worker {
28 	int tid;
29 	u_int32_t *futex;
30 	pthread_t thread;
31 	unsigned long ops;
32 };
33 
34 static u_int32_t global_futex = 0;
35 static struct worker *worker;
36 static bool done = false;
37 static int futex_flag = 0;
38 static struct mutex thread_lock;
39 static unsigned int threads_starting;
40 static struct stats throughput_stats;
41 static struct cond thread_parent, thread_worker;
42 
43 static struct bench_futex_parameters params = {
44 	.runtime  = 10,
45 };
46 
47 static const struct option options[] = {
48 	OPT_UINTEGER('t', "threads", &params.nthreads, "Specify amount of threads"),
49 	OPT_UINTEGER('r', "runtime", &params.runtime, "Specify runtime (in seconds)"),
50 	OPT_BOOLEAN( 'M', "multi",   &params.multi, "Use multiple futexes"),
51 	OPT_BOOLEAN( 's', "silent",  &params.silent, "Silent mode: do not display data/details"),
52 	OPT_BOOLEAN( 'S', "shared",  &params.fshared, "Use shared futexes instead of private ones"),
53 	OPT_BOOLEAN( 'm', "mlockall", &params.mlockall, "Lock all current and future memory"),
54 	OPT_END()
55 };
56 
57 static const char * const bench_futex_lock_pi_usage[] = {
58 	"perf bench futex lock-pi <options>",
59 	NULL
60 };
61 
print_summary(void)62 static void print_summary(void)
63 {
64 	unsigned long avg = avg_stats(&throughput_stats);
65 	double stddev = stddev_stats(&throughput_stats);
66 
67 	printf("%sAveraged %ld operations/sec (+- %.2f%%), total secs = %d\n",
68 	       !params.silent ? "\n" : "", avg, rel_stddev_stats(stddev, avg),
69 	       (int)bench__runtime.tv_sec);
70 }
71 
toggle_done(int sig __maybe_unused,siginfo_t * info __maybe_unused,void * uc __maybe_unused)72 static void toggle_done(int sig __maybe_unused,
73 			siginfo_t *info __maybe_unused,
74 			void *uc __maybe_unused)
75 {
76 	/* inform all threads that we're done for the day */
77 	done = true;
78 	gettimeofday(&bench__end, NULL);
79 	timersub(&bench__end, &bench__start, &bench__runtime);
80 }
81 
workerfn(void * arg)82 static void *workerfn(void *arg)
83 {
84 	struct worker *w = (struct worker *) arg;
85 	unsigned long ops = w->ops;
86 
87 	mutex_lock(&thread_lock);
88 	threads_starting--;
89 	if (!threads_starting)
90 		cond_signal(&thread_parent);
91 	cond_wait(&thread_worker, &thread_lock);
92 	mutex_unlock(&thread_lock);
93 
94 	do {
95 		int ret;
96 	again:
97 		ret = futex_lock_pi(w->futex, NULL, futex_flag);
98 
99 		if (ret) { /* handle lock acquisition */
100 			if (!params.silent)
101 				warn("thread %d: Could not lock pi-lock for %p (%d)",
102 				     w->tid, w->futex, ret);
103 			if (done)
104 				break;
105 
106 			goto again;
107 		}
108 
109 		usleep(1);
110 		ret = futex_unlock_pi(w->futex, futex_flag);
111 		if (ret && !params.silent)
112 			warn("thread %d: Could not unlock pi-lock for %p (%d)",
113 			     w->tid, w->futex, ret);
114 		ops++; /* account for thread's share of work */
115 	}  while (!done);
116 
117 	w->ops = ops;
118 	return NULL;
119 }
120 
create_threads(struct worker * w,pthread_attr_t thread_attr,struct perf_cpu_map * cpu)121 static void create_threads(struct worker *w, pthread_attr_t thread_attr,
122 			   struct perf_cpu_map *cpu)
123 {
124 	cpu_set_t *cpuset;
125 	unsigned int i;
126 	int nrcpus =  perf_cpu_map__nr(cpu);
127 	size_t size;
128 
129 	threads_starting = params.nthreads;
130 
131 	cpuset = CPU_ALLOC(nrcpus);
132 	BUG_ON(!cpuset);
133 	size = CPU_ALLOC_SIZE(nrcpus);
134 
135 	for (i = 0; i < params.nthreads; i++) {
136 		worker[i].tid = i;
137 
138 		if (params.multi) {
139 			worker[i].futex = calloc(1, sizeof(u_int32_t));
140 			if (!worker[i].futex)
141 				err(EXIT_FAILURE, "calloc");
142 		} else
143 			worker[i].futex = &global_futex;
144 
145 		CPU_ZERO_S(size, cpuset);
146 		CPU_SET_S(perf_cpu_map__cpu(cpu, i % perf_cpu_map__nr(cpu)).cpu, size, cpuset);
147 
148 		if (pthread_attr_setaffinity_np(&thread_attr, size, cpuset)) {
149 			CPU_FREE(cpuset);
150 			err(EXIT_FAILURE, "pthread_attr_setaffinity_np");
151 		}
152 
153 		if (pthread_create(&w[i].thread, &thread_attr, workerfn, &worker[i])) {
154 			CPU_FREE(cpuset);
155 			err(EXIT_FAILURE, "pthread_create");
156 		}
157 	}
158 	CPU_FREE(cpuset);
159 }
160 
bench_futex_lock_pi(int argc,const char ** argv)161 int bench_futex_lock_pi(int argc, const char **argv)
162 {
163 	int ret = 0;
164 	unsigned int i;
165 	struct sigaction act;
166 	pthread_attr_t thread_attr;
167 	struct perf_cpu_map *cpu;
168 
169 	argc = parse_options(argc, argv, options, bench_futex_lock_pi_usage, 0);
170 	if (argc)
171 		goto err;
172 
173 	cpu = perf_cpu_map__new(NULL);
174 	if (!cpu)
175 		err(EXIT_FAILURE, "calloc");
176 
177 	memset(&act, 0, sizeof(act));
178 	sigfillset(&act.sa_mask);
179 	act.sa_sigaction = toggle_done;
180 	sigaction(SIGINT, &act, NULL);
181 
182 	if (params.mlockall) {
183 		if (mlockall(MCL_CURRENT | MCL_FUTURE))
184 			err(EXIT_FAILURE, "mlockall");
185 	}
186 
187 	if (!params.nthreads)
188 		params.nthreads = perf_cpu_map__nr(cpu);
189 
190 	worker = calloc(params.nthreads, sizeof(*worker));
191 	if (!worker)
192 		err(EXIT_FAILURE, "calloc");
193 
194 	if (!params.fshared)
195 		futex_flag = FUTEX_PRIVATE_FLAG;
196 
197 	printf("Run summary [PID %d]: %d threads doing pi lock/unlock pairing for %d secs.\n\n",
198 	       getpid(), params.nthreads, params.runtime);
199 
200 	init_stats(&throughput_stats);
201 	mutex_init(&thread_lock);
202 	cond_init(&thread_parent);
203 	cond_init(&thread_worker);
204 
205 	threads_starting = params.nthreads;
206 	pthread_attr_init(&thread_attr);
207 	gettimeofday(&bench__start, NULL);
208 
209 	create_threads(worker, thread_attr, cpu);
210 	pthread_attr_destroy(&thread_attr);
211 
212 	mutex_lock(&thread_lock);
213 	while (threads_starting)
214 		cond_wait(&thread_parent, &thread_lock);
215 	cond_broadcast(&thread_worker);
216 	mutex_unlock(&thread_lock);
217 
218 	sleep(params.runtime);
219 	toggle_done(0, NULL, NULL);
220 
221 	for (i = 0; i < params.nthreads; i++) {
222 		ret = pthread_join(worker[i].thread, NULL);
223 		if (ret)
224 			err(EXIT_FAILURE, "pthread_join");
225 	}
226 
227 	/* cleanup & report results */
228 	cond_destroy(&thread_parent);
229 	cond_destroy(&thread_worker);
230 	mutex_destroy(&thread_lock);
231 
232 	for (i = 0; i < params.nthreads; i++) {
233 		unsigned long t = bench__runtime.tv_sec > 0 ?
234 			worker[i].ops / bench__runtime.tv_sec : 0;
235 
236 		update_stats(&throughput_stats, t);
237 		if (!params.silent)
238 			printf("[thread %3d] futex: %p [ %ld ops/sec ]\n",
239 			       worker[i].tid, worker[i].futex, t);
240 
241 		if (params.multi)
242 			zfree(&worker[i].futex);
243 	}
244 
245 	print_summary();
246 
247 	free(worker);
248 	perf_cpu_map__put(cpu);
249 	return ret;
250 err:
251 	usage_with_options(bench_futex_lock_pi_usage, options);
252 	exit(EXIT_FAILURE);
253 }
254