1 /******************************************************************************
2  *
3  *   Copyright © International Business Machines  Corp., 2006-2008
4  *
5  *   This program is free software;  you can redistribute it and/or modify
6  *   it under the terms of the GNU General Public License as published by
7  *   the Free Software Foundation; either version 2 of the License, or
8  *   (at your option) any later version.
9  *
10  * DESCRIPTION
11  *      This test excercises the futex syscall op codes needed for requeuing
12  *      priority inheritance aware POSIX condition variables and mutexes.
13  *
14  * AUTHORS
15  *      Sripathi Kodi <sripathik@in.ibm.com>
16  *      Darren Hart <dvhart@linux.intel.com>
17  *
18  * HISTORY
19  *      2008-Jan-13: Initial version by Sripathi Kodi <sripathik@in.ibm.com>
20  *      2009-Nov-6: futex test adaptation by Darren Hart <dvhart@linux.intel.com>
21  *
22  *****************************************************************************/
23 
24 #include <errno.h>
25 #include <limits.h>
26 #include <pthread.h>
27 #include <stdio.h>
28 #include <stdlib.h>
29 #include <signal.h>
30 #include <string.h>
31 #include "atomic.h"
32 #include "futextest.h"
33 #include "logging.h"
34 
35 #define MAX_WAKE_ITERS 1000
36 #define THREAD_MAX 10
37 #define SIGNAL_PERIOD_US 100
38 
39 atomic_t waiters_blocked = ATOMIC_INITIALIZER;
40 atomic_t waiters_woken = ATOMIC_INITIALIZER;
41 
42 futex_t f1 = FUTEX_INITIALIZER;
43 futex_t f2 = FUTEX_INITIALIZER;
44 futex_t wake_complete = FUTEX_INITIALIZER;
45 
46 /* Test option defaults */
47 static long timeout_ns;
48 static int broadcast;
49 static int owner;
50 static int locked;
51 
52 struct thread_arg {
53 	long id;
54 	struct timespec *timeout;
55 	int lock;
56 	int ret;
57 };
58 #define THREAD_ARG_INITIALIZER { 0, NULL, 0, 0 }
59 
60 void usage(char *prog)
61 {
62 	printf("Usage: %s\n", prog);
63 	printf("  -b	Broadcast wakeup (all waiters)\n");
64 	printf("  -c	Use color\n");
65 	printf("  -h	Display this help message\n");
66 	printf("  -l	Lock the pi futex across requeue\n");
67 	printf("  -o	Use a third party pi futex owner during requeue (cancels -l)\n");
68 	printf("  -t N	Timeout in nanoseconds (default: 0)\n");
69 	printf("  -v L	Verbosity level: %d=QUIET %d=CRITICAL %d=INFO\n",
70 	       VQUIET, VCRITICAL, VINFO);
71 }
72 
73 int create_rt_thread(pthread_t *pth, void*(*func)(void *), void *arg,
74 		     int policy, int prio)
75 {
76 	int ret;
77 	struct sched_param schedp;
78 	pthread_attr_t attr;
79 
80 	pthread_attr_init(&attr);
81 	memset(&schedp, 0, sizeof(schedp));
82 
83 	ret = pthread_attr_setinheritsched(&attr, PTHREAD_EXPLICIT_SCHED);
84 	if (ret) {
85 		error("pthread_attr_setinheritsched\n", ret);
86 		return -1;
87 	}
88 
89 	ret = pthread_attr_setschedpolicy(&attr, policy);
90 	if (ret) {
91 		error("pthread_attr_setschedpolicy\n", ret);
92 		return -1;
93 	}
94 
95 	schedp.sched_priority = prio;
96 	ret = pthread_attr_setschedparam(&attr, &schedp);
97 	if (ret) {
98 		error("pthread_attr_setschedparam\n", ret);
99 		return -1;
100 	}
101 
102 	ret = pthread_create(pth, &attr, func, arg);
103 	if (ret) {
104 		error("pthread_create\n", ret);
105 		return -1;
106 	}
107 	return 0;
108 }
109 
110 
111 void *waiterfn(void *arg)
112 {
113 	struct thread_arg *args = (struct thread_arg *)arg;
114 	futex_t old_val;
115 
116 	info("Waiter %ld: running\n", args->id);
117 	/* Each thread sleeps for a different amount of time
118 	 * This is to avoid races, because we don't lock the
119 	 * external mutex here */
120 	usleep(1000 * (long)args->id);
121 
122 	old_val = f1;
123 	atomic_inc(&waiters_blocked);
124 	info("Calling futex_wait_requeue_pi: %p (%u) -> %p\n",
125 	     &f1, f1, &f2);
126 	args->ret = futex_wait_requeue_pi(&f1, old_val, &f2, args->timeout,
127 					  FUTEX_PRIVATE_FLAG);
128 
129 	info("waiter %ld woke with %d %s\n", args->id, args->ret,
130 	     args->ret < 0 ? strerror(errno) : "");
131 	atomic_inc(&waiters_woken);
132 	if (args->ret < 0) {
133 		if (args->timeout && errno == ETIMEDOUT)
134 			args->ret = 0;
135 		else {
136 			args->ret = RET_ERROR;
137 			error("futex_wait_requeue_pi\n", errno);
138 		}
139 		futex_lock_pi(&f2, NULL, 0, FUTEX_PRIVATE_FLAG);
140 	}
141 	futex_unlock_pi(&f2, FUTEX_PRIVATE_FLAG);
142 
143 	info("Waiter %ld: exiting with %d\n", args->id, args->ret);
144 	pthread_exit((void *)&args->ret);
145 }
146 
147 void *broadcast_wakerfn(void *arg)
148 {
149 	struct thread_arg *args = (struct thread_arg *)arg;
150 	int nr_requeue = INT_MAX;
151 	int task_count = 0;
152 	futex_t old_val;
153 	int nr_wake = 1;
154 	int i = 0;
155 
156 	info("Waker: waiting for waiters to block\n");
157 	while (waiters_blocked.val < THREAD_MAX)
158 		usleep(1000);
159 	usleep(1000);
160 
161 	info("Waker: Calling broadcast\n");
162 	if (args->lock) {
163 		info("Calling FUTEX_LOCK_PI on mutex=%x @ %p\n", f2, &f2);
164 		futex_lock_pi(&f2, NULL, 0, FUTEX_PRIVATE_FLAG);
165 	}
166  continue_requeue:
167 	old_val = f1;
168 	args->ret = futex_cmp_requeue_pi(&f1, old_val, &f2, nr_wake, nr_requeue,
169 				   FUTEX_PRIVATE_FLAG);
170 	if (args->ret < 0) {
171 		args->ret = RET_ERROR;
172 		error("FUTEX_CMP_REQUEUE_PI failed\n", errno);
173 	} else if (++i < MAX_WAKE_ITERS) {
174 		task_count += args->ret;
175 		if (task_count < THREAD_MAX - waiters_woken.val)
176 			goto continue_requeue;
177 	} else {
178 		error("max broadcast iterations (%d) reached with %d/%d tasks woken or requeued\n",
179 		       0, MAX_WAKE_ITERS, task_count, THREAD_MAX);
180 		args->ret = RET_ERROR;
181 	}
182 
183 	futex_wake(&wake_complete, 1, FUTEX_PRIVATE_FLAG);
184 
185 	if (args->lock)
186 		futex_unlock_pi(&f2, FUTEX_PRIVATE_FLAG);
187 
188 	if (args->ret > 0)
189 		args->ret = task_count;
190 
191 	info("Waker: exiting with %d\n", args->ret);
192 	pthread_exit((void *)&args->ret);
193 }
194 
195 void *signal_wakerfn(void *arg)
196 {
197 	struct thread_arg *args = (struct thread_arg *)arg;
198 	unsigned int old_val;
199 	int nr_requeue = 0;
200 	int task_count = 0;
201 	int nr_wake = 1;
202 	int i = 0;
203 
204 	info("Waker: waiting for waiters to block\n");
205 	while (waiters_blocked.val < THREAD_MAX)
206 		usleep(1000);
207 	usleep(1000);
208 
209 	while (task_count < THREAD_MAX && waiters_woken.val < THREAD_MAX) {
210 		info("task_count: %d, waiters_woken: %d\n",
211 		     task_count, waiters_woken.val);
212 		if (args->lock) {
213 			info("Calling FUTEX_LOCK_PI on mutex=%x @ %p\n",
214 			     f2, &f2);
215 			futex_lock_pi(&f2, NULL, 0, FUTEX_PRIVATE_FLAG);
216 		}
217 		info("Waker: Calling signal\n");
218 		/* cond_signal */
219 		old_val = f1;
220 		args->ret = futex_cmp_requeue_pi(&f1, old_val, &f2,
221 						 nr_wake, nr_requeue,
222 						 FUTEX_PRIVATE_FLAG);
223 		if (args->ret < 0)
224 			args->ret = -errno;
225 		info("futex: %x\n", f2);
226 		if (args->lock) {
227 			info("Calling FUTEX_UNLOCK_PI on mutex=%x @ %p\n",
228 			     f2, &f2);
229 			futex_unlock_pi(&f2, FUTEX_PRIVATE_FLAG);
230 		}
231 		info("futex: %x\n", f2);
232 		if (args->ret < 0) {
233 			error("FUTEX_CMP_REQUEUE_PI failed\n", errno);
234 			args->ret = RET_ERROR;
235 			break;
236 		}
237 
238 		task_count += args->ret;
239 		usleep(SIGNAL_PERIOD_US);
240 		i++;
241 		/* we have to loop at least THREAD_MAX times */
242 		if (i > MAX_WAKE_ITERS + THREAD_MAX) {
243 			error("max signaling iterations (%d) reached, giving up on pending waiters.\n",
244 			      0, MAX_WAKE_ITERS + THREAD_MAX);
245 			args->ret = RET_ERROR;
246 			break;
247 		}
248 	}
249 
250 	futex_wake(&wake_complete, 1, FUTEX_PRIVATE_FLAG);
251 
252 	if (args->ret >= 0)
253 		args->ret = task_count;
254 
255 	info("Waker: exiting with %d\n", args->ret);
256 	info("Waker: waiters_woken: %d\n", waiters_woken.val);
257 	pthread_exit((void *)&args->ret);
258 }
259 
260 void *third_party_blocker(void *arg)
261 {
262 	struct thread_arg *args = (struct thread_arg *)arg;
263 	int ret2 = 0;
264 
265 	args->ret = futex_lock_pi(&f2, NULL, 0, FUTEX_PRIVATE_FLAG);
266 	if (args->ret)
267 		goto out;
268 	args->ret = futex_wait(&wake_complete, wake_complete, NULL,
269 			       FUTEX_PRIVATE_FLAG);
270 	ret2 = futex_unlock_pi(&f2, FUTEX_PRIVATE_FLAG);
271 
272  out:
273 	if (args->ret || ret2) {
274 		error("third_party_blocker() futex error", 0);
275 		args->ret = RET_ERROR;
276 	}
277 
278 	pthread_exit((void *)&args->ret);
279 }
280 
281 int unit_test(int broadcast, long lock, int third_party_owner, long timeout_ns)
282 {
283 	void *(*wakerfn)(void *) = signal_wakerfn;
284 	struct thread_arg blocker_arg = THREAD_ARG_INITIALIZER;
285 	struct thread_arg waker_arg = THREAD_ARG_INITIALIZER;
286 	pthread_t waiter[THREAD_MAX], waker, blocker;
287 	struct timespec ts, *tsp = NULL;
288 	struct thread_arg args[THREAD_MAX];
289 	int *waiter_ret;
290 	int i, ret = RET_PASS;
291 
292 	if (timeout_ns) {
293 		time_t secs;
294 
295 		info("timeout_ns = %ld\n", timeout_ns);
296 		ret = clock_gettime(CLOCK_MONOTONIC, &ts);
297 		secs = (ts.tv_nsec + timeout_ns) / 1000000000;
298 		ts.tv_nsec = ((int64_t)ts.tv_nsec + timeout_ns) % 1000000000;
299 		ts.tv_sec += secs;
300 		info("ts.tv_sec  = %ld\n", ts.tv_sec);
301 		info("ts.tv_nsec = %ld\n", ts.tv_nsec);
302 		tsp = &ts;
303 	}
304 
305 	if (broadcast)
306 		wakerfn = broadcast_wakerfn;
307 
308 	if (third_party_owner) {
309 		if (create_rt_thread(&blocker, third_party_blocker,
310 				     (void *)&blocker_arg, SCHED_FIFO, 1)) {
311 			error("Creating third party blocker thread failed\n",
312 			      errno);
313 			ret = RET_ERROR;
314 			goto out;
315 		}
316 	}
317 
318 	atomic_set(&waiters_woken, 0);
319 	for (i = 0; i < THREAD_MAX; i++) {
320 		args[i].id = i;
321 		args[i].timeout = tsp;
322 		info("Starting thread %d\n", i);
323 		if (create_rt_thread(&waiter[i], waiterfn, (void *)&args[i],
324 				     SCHED_FIFO, 1)) {
325 			error("Creating waiting thread failed\n", errno);
326 			ret = RET_ERROR;
327 			goto out;
328 		}
329 	}
330 	waker_arg.lock = lock;
331 	if (create_rt_thread(&waker, wakerfn, (void *)&waker_arg,
332 			     SCHED_FIFO, 1)) {
333 		error("Creating waker thread failed\n", errno);
334 		ret = RET_ERROR;
335 		goto out;
336 	}
337 
338 	/* Wait for threads to finish */
339 	/* Store the first error or failure encountered in waiter_ret */
340 	waiter_ret = &args[0].ret;
341 	for (i = 0; i < THREAD_MAX; i++)
342 		pthread_join(waiter[i],
343 			     *waiter_ret ? NULL : (void **)&waiter_ret);
344 
345 	if (third_party_owner)
346 		pthread_join(blocker, NULL);
347 	pthread_join(waker, NULL);
348 
349 out:
350 	if (!ret) {
351 		if (*waiter_ret)
352 			ret = *waiter_ret;
353 		else if (waker_arg.ret < 0)
354 			ret = waker_arg.ret;
355 		else if (blocker_arg.ret)
356 			ret = blocker_arg.ret;
357 	}
358 
359 	return ret;
360 }
361 
362 int main(int argc, char *argv[])
363 {
364 	int c, ret;
365 
366 	while ((c = getopt(argc, argv, "bchlot:v:")) != -1) {
367 		switch (c) {
368 		case 'b':
369 			broadcast = 1;
370 			break;
371 		case 'c':
372 			log_color(1);
373 			break;
374 		case 'h':
375 			usage(basename(argv[0]));
376 			exit(0);
377 		case 'l':
378 			locked = 1;
379 			break;
380 		case 'o':
381 			owner = 1;
382 			locked = 0;
383 			break;
384 		case 't':
385 			timeout_ns = atoi(optarg);
386 			break;
387 		case 'v':
388 			log_verbosity(atoi(optarg));
389 			break;
390 		default:
391 			usage(basename(argv[0]));
392 			exit(1);
393 		}
394 	}
395 
396 	printf("%s: Test requeue functionality\n", basename(argv[0]));
397 	printf("\tArguments: broadcast=%d locked=%d owner=%d timeout=%ldns\n",
398 	       broadcast, locked, owner, timeout_ns);
399 
400 	/*
401 	 * FIXME: unit_test is obsolete now that we parse options and the
402 	 * various style of runs are done by run.sh - simplify the code and move
403 	 * unit_test into main()
404 	 */
405 	ret = unit_test(broadcast, locked, owner, timeout_ns);
406 
407 	print_result(ret);
408 	return ret;
409 }
410