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00b7ec5c ME |
1 | /* |
2 | * Context switch microbenchmark. | |
3 | * | |
4 | * Copyright (C) 2015 Anton Blanchard <anton@au.ibm.com>, IBM | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or | |
7 | * modify it under the terms of the GNU General Public License | |
8 | * as published by the Free Software Foundation; either version | |
9 | * 2 of the License, or (at your option) any later version. | |
10 | */ | |
11 | ||
12 | #define _GNU_SOURCE | |
13 | #include <sched.h> | |
14 | #include <string.h> | |
15 | #include <stdio.h> | |
16 | #include <unistd.h> | |
17 | #include <stdlib.h> | |
18 | #include <getopt.h> | |
19 | #include <signal.h> | |
20 | #include <assert.h> | |
21 | #include <pthread.h> | |
22 | #include <limits.h> | |
23 | #include <sys/time.h> | |
24 | #include <sys/syscall.h> | |
25 | #include <sys/types.h> | |
26 | #include <sys/shm.h> | |
27 | #include <linux/futex.h> | |
28 | ||
29 | static unsigned int timeout = INT_MAX; | |
30 | ||
31 | static int touch_vdso; | |
32 | struct timeval tv; | |
33 | ||
34 | static int touch_fp; | |
35 | double fp; | |
36 | ||
37 | static int touch_vector; | |
38 | typedef int v4si __attribute__ ((vector_size (16))); | |
39 | v4si a, b, c; | |
40 | ||
41 | #ifdef __powerpc__ | |
42 | static int touch_altivec; | |
43 | ||
44 | static void __attribute__((__target__("no-vsx"))) altivec_touch_fn(void) | |
45 | { | |
46 | c = a + b; | |
47 | } | |
48 | #endif | |
49 | ||
50 | static void touch(void) | |
51 | { | |
52 | if (touch_vdso) | |
53 | gettimeofday(&tv, NULL); | |
54 | ||
55 | if (touch_fp) | |
56 | fp += 0.1; | |
57 | ||
58 | #ifdef __powerpc__ | |
59 | if (touch_altivec) | |
60 | altivec_touch_fn(); | |
61 | #endif | |
62 | ||
63 | if (touch_vector) | |
64 | c = a + b; | |
65 | ||
66 | asm volatile("# %0 %1 %2": : "r"(&tv), "r"(&fp), "r"(&c)); | |
67 | } | |
68 | ||
69 | static void start_thread_on(void *(*fn)(void *), void *arg, unsigned long cpu) | |
70 | { | |
71 | pthread_t tid; | |
72 | cpu_set_t cpuset; | |
73 | pthread_attr_t attr; | |
74 | ||
75 | CPU_ZERO(&cpuset); | |
76 | CPU_SET(cpu, &cpuset); | |
77 | ||
78 | pthread_attr_init(&attr); | |
79 | ||
80 | if (pthread_attr_setaffinity_np(&attr, sizeof(cpu_set_t), &cpuset)) { | |
81 | perror("pthread_attr_setaffinity_np"); | |
82 | exit(1); | |
83 | } | |
84 | ||
85 | if (pthread_create(&tid, &attr, fn, arg)) { | |
86 | perror("pthread_create"); | |
87 | exit(1); | |
88 | } | |
89 | } | |
90 | ||
91 | static void start_process_on(void *(*fn)(void *), void *arg, unsigned long cpu) | |
92 | { | |
93 | int pid; | |
94 | cpu_set_t cpuset; | |
95 | ||
96 | pid = fork(); | |
97 | if (pid == -1) { | |
98 | perror("fork"); | |
99 | exit(1); | |
100 | } | |
101 | ||
102 | if (pid) | |
103 | return; | |
104 | ||
105 | CPU_ZERO(&cpuset); | |
106 | CPU_SET(cpu, &cpuset); | |
107 | ||
108 | if (sched_setaffinity(0, sizeof(cpuset), &cpuset)) { | |
109 | perror("sched_setaffinity"); | |
110 | exit(1); | |
111 | } | |
112 | ||
113 | fn(arg); | |
114 | ||
115 | exit(0); | |
116 | } | |
117 | ||
118 | static unsigned long iterations; | |
119 | static unsigned long iterations_prev; | |
120 | ||
121 | static void sigalrm_handler(int junk) | |
122 | { | |
123 | unsigned long i = iterations; | |
124 | ||
125 | printf("%ld\n", i - iterations_prev); | |
126 | iterations_prev = i; | |
127 | ||
128 | if (--timeout == 0) | |
129 | kill(0, SIGUSR1); | |
130 | ||
131 | alarm(1); | |
132 | } | |
133 | ||
134 | static void sigusr1_handler(int junk) | |
135 | { | |
136 | exit(0); | |
137 | } | |
138 | ||
139 | struct actions { | |
140 | void (*setup)(int, int); | |
141 | void *(*thread1)(void *); | |
142 | void *(*thread2)(void *); | |
143 | }; | |
144 | ||
145 | #define READ 0 | |
146 | #define WRITE 1 | |
147 | ||
148 | static int pipe_fd1[2]; | |
149 | static int pipe_fd2[2]; | |
150 | ||
151 | static void pipe_setup(int cpu1, int cpu2) | |
152 | { | |
153 | if (pipe(pipe_fd1) || pipe(pipe_fd2)) | |
154 | exit(1); | |
155 | } | |
156 | ||
157 | static void *pipe_thread1(void *arg) | |
158 | { | |
159 | signal(SIGALRM, sigalrm_handler); | |
160 | alarm(1); | |
161 | ||
162 | while (1) { | |
163 | assert(read(pipe_fd1[READ], &c, 1) == 1); | |
164 | touch(); | |
165 | ||
166 | assert(write(pipe_fd2[WRITE], &c, 1) == 1); | |
167 | touch(); | |
168 | ||
169 | iterations += 2; | |
170 | } | |
171 | ||
172 | return NULL; | |
173 | } | |
174 | ||
175 | static void *pipe_thread2(void *arg) | |
176 | { | |
177 | while (1) { | |
178 | assert(write(pipe_fd1[WRITE], &c, 1) == 1); | |
179 | touch(); | |
180 | ||
181 | assert(read(pipe_fd2[READ], &c, 1) == 1); | |
182 | touch(); | |
183 | } | |
184 | ||
185 | return NULL; | |
186 | } | |
187 | ||
188 | static struct actions pipe_actions = { | |
189 | .setup = pipe_setup, | |
190 | .thread1 = pipe_thread1, | |
191 | .thread2 = pipe_thread2, | |
192 | }; | |
193 | ||
194 | static void yield_setup(int cpu1, int cpu2) | |
195 | { | |
196 | if (cpu1 != cpu2) { | |
197 | fprintf(stderr, "Both threads must be on the same CPU for yield test\n"); | |
198 | exit(1); | |
199 | } | |
200 | } | |
201 | ||
202 | static void *yield_thread1(void *arg) | |
203 | { | |
204 | signal(SIGALRM, sigalrm_handler); | |
205 | alarm(1); | |
206 | ||
207 | while (1) { | |
208 | sched_yield(); | |
209 | touch(); | |
210 | ||
211 | iterations += 2; | |
212 | } | |
213 | ||
214 | return NULL; | |
215 | } | |
216 | ||
217 | static void *yield_thread2(void *arg) | |
218 | { | |
219 | while (1) { | |
220 | sched_yield(); | |
221 | touch(); | |
222 | } | |
223 | ||
224 | return NULL; | |
225 | } | |
226 | ||
227 | static struct actions yield_actions = { | |
228 | .setup = yield_setup, | |
229 | .thread1 = yield_thread1, | |
230 | .thread2 = yield_thread2, | |
231 | }; | |
232 | ||
233 | static long sys_futex(void *addr1, int op, int val1, struct timespec *timeout, | |
234 | void *addr2, int val3) | |
235 | { | |
236 | return syscall(SYS_futex, addr1, op, val1, timeout, addr2, val3); | |
237 | } | |
238 | ||
239 | static unsigned long cmpxchg(unsigned long *p, unsigned long expected, | |
240 | unsigned long desired) | |
241 | { | |
242 | unsigned long exp = expected; | |
243 | ||
244 | __atomic_compare_exchange_n(p, &exp, desired, 0, | |
245 | __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST); | |
246 | return exp; | |
247 | } | |
248 | ||
249 | static unsigned long xchg(unsigned long *p, unsigned long val) | |
250 | { | |
251 | return __atomic_exchange_n(p, val, __ATOMIC_SEQ_CST); | |
252 | } | |
253 | ||
254 | static int mutex_lock(unsigned long *m) | |
255 | { | |
256 | int c; | |
257 | ||
258 | c = cmpxchg(m, 0, 1); | |
259 | if (!c) | |
260 | return 0; | |
261 | ||
262 | if (c == 1) | |
263 | c = xchg(m, 2); | |
264 | ||
265 | while (c) { | |
266 | sys_futex(m, FUTEX_WAIT, 2, NULL, NULL, 0); | |
267 | c = xchg(m, 2); | |
268 | } | |
269 | ||
270 | return 0; | |
271 | } | |
272 | ||
273 | static int mutex_unlock(unsigned long *m) | |
274 | { | |
275 | if (*m == 2) | |
276 | *m = 0; | |
277 | else if (xchg(m, 0) == 1) | |
278 | return 0; | |
279 | ||
280 | sys_futex(m, FUTEX_WAKE, 1, NULL, NULL, 0); | |
281 | ||
282 | return 0; | |
283 | } | |
284 | ||
285 | static unsigned long *m1, *m2; | |
286 | ||
287 | static void futex_setup(int cpu1, int cpu2) | |
288 | { | |
289 | int shmid; | |
290 | void *shmaddr; | |
291 | ||
292 | shmid = shmget(IPC_PRIVATE, getpagesize(), SHM_R | SHM_W); | |
293 | if (shmid < 0) { | |
294 | perror("shmget"); | |
295 | exit(1); | |
296 | } | |
297 | ||
298 | shmaddr = shmat(shmid, NULL, 0); | |
299 | if (shmaddr == (char *)-1) { | |
300 | perror("shmat"); | |
301 | shmctl(shmid, IPC_RMID, NULL); | |
302 | exit(1); | |
303 | } | |
304 | ||
305 | shmctl(shmid, IPC_RMID, NULL); | |
306 | ||
307 | m1 = shmaddr; | |
308 | m2 = shmaddr + sizeof(*m1); | |
309 | ||
310 | *m1 = 0; | |
311 | *m2 = 0; | |
312 | ||
313 | mutex_lock(m1); | |
314 | mutex_lock(m2); | |
315 | } | |
316 | ||
317 | static void *futex_thread1(void *arg) | |
318 | { | |
319 | signal(SIGALRM, sigalrm_handler); | |
320 | alarm(1); | |
321 | ||
322 | while (1) { | |
323 | mutex_lock(m2); | |
324 | mutex_unlock(m1); | |
325 | ||
326 | iterations += 2; | |
327 | } | |
328 | ||
329 | return NULL; | |
330 | } | |
331 | ||
332 | static void *futex_thread2(void *arg) | |
333 | { | |
334 | while (1) { | |
335 | mutex_unlock(m2); | |
336 | mutex_lock(m1); | |
337 | } | |
338 | ||
339 | return NULL; | |
340 | } | |
341 | ||
342 | static struct actions futex_actions = { | |
343 | .setup = futex_setup, | |
344 | .thread1 = futex_thread1, | |
345 | .thread2 = futex_thread2, | |
346 | }; | |
347 | ||
348 | static int processes; | |
349 | ||
350 | static struct option options[] = { | |
351 | { "test", required_argument, 0, 't' }, | |
352 | { "process", no_argument, &processes, 1 }, | |
353 | { "timeout", required_argument, 0, 's' }, | |
354 | { "vdso", no_argument, &touch_vdso, 1 }, | |
355 | { "fp", no_argument, &touch_fp, 1 }, | |
356 | #ifdef __powerpc__ | |
357 | { "altivec", no_argument, &touch_altivec, 1 }, | |
358 | #endif | |
359 | { "vector", no_argument, &touch_vector, 1 }, | |
360 | { 0, }, | |
361 | }; | |
362 | ||
363 | static void usage(void) | |
364 | { | |
365 | fprintf(stderr, "Usage: context_switch2 <options> CPU1 CPU2\n\n"); | |
366 | fprintf(stderr, "\t\t--test=X\tpipe, futex or yield\n"); | |
367 | fprintf(stderr, "\t\t--process\tUse processes (default threads)\n"); | |
368 | fprintf(stderr, "\t\t--timeout=X\tDuration in seconds to run\n"); | |
369 | fprintf(stderr, "\t\t--vdso\t\ttouch VDSO\n"); | |
370 | fprintf(stderr, "\t\t--fp\t\ttouch FP\n"); | |
371 | #ifdef __powerpc__ | |
372 | fprintf(stderr, "\t\t--altivec\ttouch altivec\n"); | |
373 | #endif | |
374 | fprintf(stderr, "\t\t--vector\ttouch vector\n"); | |
375 | } | |
376 | ||
377 | int main(int argc, char *argv[]) | |
378 | { | |
379 | signed char c; | |
380 | struct actions *actions = &pipe_actions; | |
381 | int cpu1; | |
382 | int cpu2; | |
383 | static void (*start_fn)(void *(*fn)(void *), void *arg, unsigned long cpu); | |
384 | ||
385 | while (1) { | |
386 | int option_index = 0; | |
387 | ||
388 | c = getopt_long(argc, argv, "", options, &option_index); | |
389 | ||
390 | if (c == -1) | |
391 | break; | |
392 | ||
393 | switch (c) { | |
394 | case 0: | |
395 | if (options[option_index].flag != 0) | |
396 | break; | |
397 | ||
398 | usage(); | |
399 | exit(1); | |
400 | break; | |
401 | ||
402 | case 't': | |
403 | if (!strcmp(optarg, "pipe")) { | |
404 | actions = &pipe_actions; | |
405 | } else if (!strcmp(optarg, "yield")) { | |
406 | actions = &yield_actions; | |
407 | } else if (!strcmp(optarg, "futex")) { | |
408 | actions = &futex_actions; | |
409 | } else { | |
410 | usage(); | |
411 | exit(1); | |
412 | } | |
413 | break; | |
414 | ||
415 | case 's': | |
416 | timeout = atoi(optarg); | |
417 | break; | |
418 | ||
419 | default: | |
420 | usage(); | |
421 | exit(1); | |
422 | } | |
423 | } | |
424 | ||
425 | if (processes) | |
426 | start_fn = start_process_on; | |
427 | else | |
428 | start_fn = start_thread_on; | |
429 | ||
430 | if (((argc - optind) != 2)) { | |
431 | usage(); | |
432 | exit(1); | |
433 | } | |
434 | ||
435 | /* Create a new process group so we can signal everyone for exit */ | |
436 | setpgid(getpid(), getpid()); | |
437 | ||
438 | signal(SIGUSR1, sigusr1_handler); | |
439 | ||
440 | cpu1 = atoi(argv[optind++]); | |
441 | cpu2 = atoi(argv[optind++]); | |
442 | ||
443 | actions->setup(cpu1, cpu2); | |
444 | ||
445 | start_fn(actions->thread1, NULL, cpu1); | |
446 | start_fn(actions->thread2, NULL, cpu2); | |
447 | ||
448 | while (1) | |
449 | sleep(3600); | |
450 | ||
451 | return 0; | |
452 | } |