1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Copyright (C) 2018 Davidlohr Bueso.
4 *
5 * Benchmark the various operations allowed for epoll_ctl(2).
6 * The idea is to concurrently stress a single epoll instance
7 */
8 #ifdef HAVE_EVENTFD_SUPPORT
9 /* For the CLR_() macros */
10 #include <string.h>
11 #include <pthread.h>
12
13 #include <errno.h>
14 #include <inttypes.h>
15 #include <signal.h>
16 #include <stdlib.h>
17 #include <unistd.h>
18 #include <linux/compiler.h>
19 #include <linux/kernel.h>
20 #include <sys/time.h>
21 #include <sys/resource.h>
22 #include <sys/epoll.h>
23 #include <sys/eventfd.h>
24 #include <perf/cpumap.h>
25
26 #include "../util/stat.h"
27 #include <subcmd/parse-options.h>
28 #include "bench.h"
29
30 #include <err.h>
31
32 #define printinfo(fmt, arg...) \
33 do { if (__verbose) printf(fmt, ## arg); } while (0)
34
35 static unsigned int nthreads = 0;
36 static unsigned int nsecs = 8;
37 static bool done, __verbose, randomize;
38
39 /*
40 * epoll related shared variables.
41 */
42
43 /* Maximum number of nesting allowed inside epoll sets */
44 #define EPOLL_MAXNESTS 4
45
46 enum {
47 OP_EPOLL_ADD,
48 OP_EPOLL_MOD,
49 OP_EPOLL_DEL,
50 EPOLL_NR_OPS,
51 };
52
53 static int epollfd;
54 static int *epollfdp;
55 static bool noaffinity;
56 static unsigned int nested = 0;
57
58 /* amount of fds to monitor, per thread */
59 static unsigned int nfds = 64;
60
61 static pthread_mutex_t thread_lock;
62 static unsigned int threads_starting;
63 static struct stats all_stats[EPOLL_NR_OPS];
64 static pthread_cond_t thread_parent, thread_worker;
65
66 struct worker {
67 int tid;
68 pthread_t thread;
69 unsigned long ops[EPOLL_NR_OPS];
70 int *fdmap;
71 };
72
73 static const struct option options[] = {
74 OPT_UINTEGER('t', "threads", &nthreads, "Specify amount of threads"),
75 OPT_UINTEGER('r', "runtime", &nsecs, "Specify runtime (in seconds)"),
76 OPT_UINTEGER('f', "nfds", &nfds, "Specify amount of file descriptors to monitor for each thread"),
77 OPT_BOOLEAN( 'n', "noaffinity", &noaffinity, "Disables CPU affinity"),
78 OPT_UINTEGER( 'N', "nested", &nested, "Nesting level epoll hierarchy (default is 0, no nesting)"),
79 OPT_BOOLEAN( 'R', "randomize", &randomize, "Perform random operations on random fds"),
80 OPT_BOOLEAN( 'v', "verbose", &__verbose, "Verbose mode"),
81 OPT_END()
82 };
83
84 static const char * const bench_epoll_ctl_usage[] = {
85 "perf bench epoll ctl <options>",
86 NULL
87 };
88
89 static void toggle_done(int sig __maybe_unused,
90 siginfo_t *info __maybe_unused,
91 void *uc __maybe_unused)
92 {
93 /* inform all threads that we're done for the day */
94 done = true;
95 gettimeofday(&bench__end, NULL);
96 timersub(&bench__end, &bench__start, &bench__runtime);
97 }
98
99 static void nest_epollfd(void)
100 {
101 unsigned int i;
102 struct epoll_event ev;
103
104 if (nested > EPOLL_MAXNESTS)
105 nested = EPOLL_MAXNESTS;
106 printinfo("Nesting level(s): %d\n", nested);
107
108 epollfdp = calloc(nested, sizeof(int));
109 if (!epollfdp)
110 err(EXIT_FAILURE, "calloc");
111
112 for (i = 0; i < nested; i++) {
113 epollfdp[i] = epoll_create(1);
114 if (epollfd < 0)
115 err(EXIT_FAILURE, "epoll_create");
116 }
117
118 ev.events = EPOLLHUP; /* anything */
119 ev.data.u64 = i; /* any number */
120
121 for (i = nested - 1; i; i--) {
122 if (epoll_ctl(epollfdp[i - 1], EPOLL_CTL_ADD,
123 epollfdp[i], &ev) < 0)
124 err(EXIT_FAILURE, "epoll_ctl");
125 }
126
127 if (epoll_ctl(epollfd, EPOLL_CTL_ADD, *epollfdp, &ev) < 0)
128 err(EXIT_FAILURE, "epoll_ctl");
129 }
130
131 static inline void do_epoll_op(struct worker *w, int op, int fd)
132 {
133 int error;
134 struct epoll_event ev;
135
136 ev.events = EPOLLIN;
137 ev.data.u64 = fd;
138
139 switch (op) {
140 case OP_EPOLL_ADD:
141 error = epoll_ctl(epollfd, EPOLL_CTL_ADD, fd, &ev);
142 break;
143 case OP_EPOLL_MOD:
144 ev.events = EPOLLOUT;
145 error = epoll_ctl(epollfd, EPOLL_CTL_MOD, fd, &ev);
146 break;
147 case OP_EPOLL_DEL:
148 error = epoll_ctl(epollfd, EPOLL_CTL_DEL, fd, NULL);
149 break;
150 default:
151 error = 1;
152 break;
153 }
154
155 if (!error)
156 w->ops[op]++;
157 }
158
159 static inline void do_random_epoll_op(struct worker *w)
160 {
161 unsigned long rnd1 = random(), rnd2 = random();
162 int op, fd;
163
164 fd = w->fdmap[rnd1 % nfds];
165 op = rnd2 % EPOLL_NR_OPS;
166
167 do_epoll_op(w, op, fd);
168 }
169
170 static void *workerfn(void *arg)
171 {
172 unsigned int i;
173 struct worker *w = (struct worker *) arg;
174 struct timespec ts = { .tv_sec = 0,
175 .tv_nsec = 250 };
176
177 pthread_mutex_lock(&thread_lock);
178 threads_starting--;
179 if (!threads_starting)
180 pthread_cond_signal(&thread_parent);
181 pthread_cond_wait(&thread_worker, &thread_lock);
182 pthread_mutex_unlock(&thread_lock);
183
184 /* Let 'em loose */
185 do {
186 /* random */
187 if (randomize) {
188 do_random_epoll_op(w);
189 } else {
190 for (i = 0; i < nfds; i++) {
191 do_epoll_op(w, OP_EPOLL_ADD, w->fdmap[i]);
192 do_epoll_op(w, OP_EPOLL_MOD, w->fdmap[i]);
193 do_epoll_op(w, OP_EPOLL_DEL, w->fdmap[i]);
194 }
195 }
196
197 nanosleep(&ts, NULL);
198 } while (!done);
199
200 return NULL;
201 }
202
203 static void init_fdmaps(struct worker *w, int pct)
204 {
205 unsigned int i;
206 int inc;
207 struct epoll_event ev;
208
209 if (!pct)
210 return;
211
212 inc = 100/pct;
213 for (i = 0; i < nfds; i+=inc) {
214 ev.data.fd = w->fdmap[i];
215 ev.events = EPOLLIN;
216
217 if (epoll_ctl(epollfd, EPOLL_CTL_ADD, w->fdmap[i], &ev) < 0)
218 err(EXIT_FAILURE, "epoll_ct");
219 }
220 }
221
222 static int do_threads(struct worker *worker, struct perf_cpu_map *cpu)
223 {
224 pthread_attr_t thread_attr, *attrp = NULL;
225 cpu_set_t cpuset;
226 unsigned int i, j;
227 int ret = 0;
228
229 if (!noaffinity)
230 pthread_attr_init(&thread_attr);
231
232 for (i = 0; i < nthreads; i++) {
233 struct worker *w = &worker[i];
234
235 w->tid = i;
236 w->fdmap = calloc(nfds, sizeof(int));
237 if (!w->fdmap)
238 return 1;
239
240 for (j = 0; j < nfds; j++) {
241 w->fdmap[j] = eventfd(0, EFD_NONBLOCK);
242 if (w->fdmap[j] < 0)
243 err(EXIT_FAILURE, "eventfd");
244 }
245
246 /*
247 * Lets add 50% of the fdmap to the epoll instance, and
248 * do it before any threads are started; otherwise there is
249 * an initial bias of the call failing (mod and del ops).
250 */
251 if (randomize)
252 init_fdmaps(w, 50);
253
254 if (!noaffinity) {
255 CPU_ZERO(&cpuset);
256 CPU_SET(perf_cpu_map__cpu(cpu, i % perf_cpu_map__nr(cpu)).cpu, &cpuset);
257
258 ret = pthread_attr_setaffinity_np(&thread_attr, sizeof(cpu_set_t), &cpuset);
259 if (ret)
260 err(EXIT_FAILURE, "pthread_attr_setaffinity_np");
261
262 attrp = &thread_attr;
263 }
264
265 ret = pthread_create(&w->thread, attrp, workerfn,
266 (void *)(struct worker *) w);
267 if (ret)
268 err(EXIT_FAILURE, "pthread_create");
269 }
270
271 if (!noaffinity)
272 pthread_attr_destroy(&thread_attr);
273
274 return ret;
275 }
276
277 static void print_summary(void)
278 {
279 int i;
280 unsigned long avg[EPOLL_NR_OPS];
281 double stddev[EPOLL_NR_OPS];
282
283 for (i = 0; i < EPOLL_NR_OPS; i++) {
284 avg[i] = avg_stats(&all_stats[i]);
285 stddev[i] = stddev_stats(&all_stats[i]);
286 }
287
288 printf("\nAveraged %ld ADD operations (+- %.2f%%)\n",
289 avg[OP_EPOLL_ADD], rel_stddev_stats(stddev[OP_EPOLL_ADD],
290 avg[OP_EPOLL_ADD]));
291 printf("Averaged %ld MOD operations (+- %.2f%%)\n",
292 avg[OP_EPOLL_MOD], rel_stddev_stats(stddev[OP_EPOLL_MOD],
293 avg[OP_EPOLL_MOD]));
294 printf("Averaged %ld DEL operations (+- %.2f%%)\n",
295 avg[OP_EPOLL_DEL], rel_stddev_stats(stddev[OP_EPOLL_DEL],
296 avg[OP_EPOLL_DEL]));
297 }
298
299 int bench_epoll_ctl(int argc, const char **argv)
300 {
301 int j, ret = 0;
302 struct sigaction act;
303 struct worker *worker = NULL;
304 struct perf_cpu_map *cpu;
305 struct rlimit rl, prevrl;
306 unsigned int i;
307
308 argc = parse_options(argc, argv, options, bench_epoll_ctl_usage, 0);
309 if (argc) {
310 usage_with_options(bench_epoll_ctl_usage, options);
311 exit(EXIT_FAILURE);
312 }
313
314 memset(&act, 0, sizeof(act));
315 sigfillset(&act.sa_mask);
316 act.sa_sigaction = toggle_done;
317 sigaction(SIGINT, &act, NULL);
318
319 cpu = perf_cpu_map__new(NULL);
320 if (!cpu)
321 goto errmem;
322
323 /* a single, main epoll instance */
324 epollfd = epoll_create(1);
325 if (epollfd < 0)
326 err(EXIT_FAILURE, "epoll_create");
327
328 /*
329 * Deal with nested epolls, if any.
330 */
331 if (nested)
332 nest_epollfd();
333
334 /* default to the number of CPUs */
335 if (!nthreads)
336 nthreads = perf_cpu_map__nr(cpu);
337
338 worker = calloc(nthreads, sizeof(*worker));
339 if (!worker)
340 goto errmem;
341
342 if (getrlimit(RLIMIT_NOFILE, &prevrl))
343 err(EXIT_FAILURE, "getrlimit");
344 rl.rlim_cur = rl.rlim_max = nfds * nthreads * 2 + 50;
345 printinfo("Setting RLIMIT_NOFILE rlimit from %" PRIu64 " to: %" PRIu64 "\n",
346 (uint64_t)prevrl.rlim_max, (uint64_t)rl.rlim_max);
347 if (setrlimit(RLIMIT_NOFILE, &rl) < 0)
348 err(EXIT_FAILURE, "setrlimit");
349
350 printf("Run summary [PID %d]: %d threads doing epoll_ctl ops "
351 "%d file-descriptors for %d secs.\n\n",
352 getpid(), nthreads, nfds, nsecs);
353
354 for (i = 0; i < EPOLL_NR_OPS; i++)
355 init_stats(&all_stats[i]);
356
357 pthread_mutex_init(&thread_lock, NULL);
358 pthread_cond_init(&thread_parent, NULL);
359 pthread_cond_init(&thread_worker, NULL);
360
361 threads_starting = nthreads;
362
363 gettimeofday(&bench__start, NULL);
364
365 do_threads(worker, cpu);
366
367 pthread_mutex_lock(&thread_lock);
368 while (threads_starting)
369 pthread_cond_wait(&thread_parent, &thread_lock);
370 pthread_cond_broadcast(&thread_worker);
371 pthread_mutex_unlock(&thread_lock);
372
373 sleep(nsecs);
374 toggle_done(0, NULL, NULL);
375 printinfo("main thread: toggling done\n");
376
377 for (i = 0; i < nthreads; i++) {
378 ret = pthread_join(worker[i].thread, NULL);
379 if (ret)
380 err(EXIT_FAILURE, "pthread_join");
381 }
382
383 /* cleanup & report results */
384 pthread_cond_destroy(&thread_parent);
385 pthread_cond_destroy(&thread_worker);
386 pthread_mutex_destroy(&thread_lock);
387
388 for (i = 0; i < nthreads; i++) {
389 unsigned long t[EPOLL_NR_OPS];
390
391 for (j = 0; j < EPOLL_NR_OPS; j++) {
392 t[j] = worker[i].ops[j];
393 update_stats(&all_stats[j], t[j]);
394 }
395
396 if (nfds == 1)
397 printf("[thread %2d] fdmap: %p [ add: %04ld; mod: %04ld; del: %04lds ops ]\n",
398 worker[i].tid, &worker[i].fdmap[0],
399 t[OP_EPOLL_ADD], t[OP_EPOLL_MOD], t[OP_EPOLL_DEL]);
400 else
401 printf("[thread %2d] fdmap: %p ... %p [ add: %04ld ops; mod: %04ld ops; del: %04ld ops ]\n",
402 worker[i].tid, &worker[i].fdmap[0],
403 &worker[i].fdmap[nfds-1],
404 t[OP_EPOLL_ADD], t[OP_EPOLL_MOD], t[OP_EPOLL_DEL]);
405 }
406
407 print_summary();
408
409 close(epollfd);
410 return ret;
411 errmem:
412 err(EXIT_FAILURE, "calloc");
413 }
414 #endif // HAVE_EVENTFD_SUPPORT
415
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