4 * Userspace RCU library - example RCU-based lock-free stack
6 * Copyright February 2010 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
7 * Copyright February 2010 - Paolo Bonzini <pbonzini@redhat.com>
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License as published by
11 * the Free Software Foundation; either version 2 of the License, or
12 * (at your option) any later version.
14 * This program is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 * GNU General Public License for more details.
19 * You should have received a copy of the GNU General Public License along
20 * with this program; if not, write to the Free Software Foundation, Inc.,
21 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
25 #include "../config.h"
32 #include <sys/types.h>
39 #include <urcu/arch.h>
40 #include <urcu/tls-compat.h>
41 #include <urcu/uatomic.h>
48 /* hardcoded number of CPUs */
51 #if defined(_syscall0)
52 _syscall0(pid_t
, gettid
)
53 #elif defined(__NR_gettid)
54 static inline pid_t
gettid(void)
56 return syscall(__NR_gettid
);
59 #warning "use pid as tid"
60 static inline pid_t
gettid(void)
66 #ifndef DYNAMIC_LINK_TEST
69 #include <urcu/wfstack.h>
72 * External synchronization used.
79 static enum test_sync test_sync
;
81 static int test_force_sync
;
83 static volatile int test_go
, test_stop_enqueue
, test_stop_dequeue
;
85 static unsigned long rduration
;
87 static unsigned long duration
;
89 /* read-side C.S. duration, in loops */
90 static unsigned long wdelay
;
92 static inline void loop_sleep(unsigned long loops
)
98 static int verbose_mode
;
100 static int test_pop
, test_pop_all
, test_wait_empty
;
101 static int test_enqueue_stopped
;
103 #define printf_verbose(fmt, args...) \
106 printf(fmt, ## args); \
109 static unsigned int cpu_affinities
[NR_CPUS
];
110 static unsigned int next_aff
= 0;
111 static int use_affinity
= 0;
113 pthread_mutex_t affinity_mutex
= PTHREAD_MUTEX_INITIALIZER
;
115 static void set_affinity(void)
117 #if HAVE_SCHED_SETAFFINITY
120 #endif /* HAVE_SCHED_SETAFFINITY */
125 #if HAVE_SCHED_SETAFFINITY
126 ret
= pthread_mutex_lock(&affinity_mutex
);
128 perror("Error in pthread mutex lock");
131 cpu
= cpu_affinities
[next_aff
++];
132 ret
= pthread_mutex_unlock(&affinity_mutex
);
134 perror("Error in pthread mutex unlock");
140 #if SCHED_SETAFFINITY_ARGS == 2
141 sched_setaffinity(0, &mask
);
143 sched_setaffinity(0, sizeof(mask
), &mask
);
145 #endif /* HAVE_SCHED_SETAFFINITY */
149 * returns 0 if test should end.
151 static int test_duration_dequeue(void)
153 return !test_stop_dequeue
;
156 static int test_duration_enqueue(void)
158 return !test_stop_enqueue
;
161 static DEFINE_URCU_TLS(unsigned long long, nr_dequeues
);
162 static DEFINE_URCU_TLS(unsigned long long, nr_enqueues
);
164 static DEFINE_URCU_TLS(unsigned long long, nr_successful_dequeues
);
165 static DEFINE_URCU_TLS(unsigned long long, nr_successful_enqueues
);
166 static DEFINE_URCU_TLS(unsigned long long, nr_empty_dest_enqueues
);
167 static DEFINE_URCU_TLS(unsigned long long, nr_pop_all
);
169 static unsigned int nr_enqueuers
;
170 static unsigned int nr_dequeuers
;
172 static struct cds_wfs_stack s
;
174 static void *thr_enqueuer(void *_count
)
176 unsigned long long *count
= _count
;
179 printf_verbose("thread_begin %s, thread id : %lx, tid %lu\n",
180 "enqueuer", (unsigned long) pthread_self(),
181 (unsigned long) gettid());
191 struct cds_wfs_node
*node
= malloc(sizeof(*node
));
194 cds_wfs_node_init(node
);
195 was_nonempty
= cds_wfs_push(&s
, node
);
196 URCU_TLS(nr_successful_enqueues
)++;
198 URCU_TLS(nr_empty_dest_enqueues
)++;
200 if (caa_unlikely(wdelay
))
203 URCU_TLS(nr_enqueues
)++;
204 if (caa_unlikely(!test_duration_enqueue()))
208 uatomic_inc(&test_enqueue_stopped
);
209 count
[0] = URCU_TLS(nr_enqueues
);
210 count
[1] = URCU_TLS(nr_successful_enqueues
);
211 count
[2] = URCU_TLS(nr_empty_dest_enqueues
);
212 printf_verbose("enqueuer thread_end, thread id : %lx, tid %lu, "
213 "enqueues %llu successful_enqueues %llu, "
214 "empty_dest_enqueues %llu\n",
216 (unsigned long) gettid(),
217 URCU_TLS(nr_enqueues
),
218 URCU_TLS(nr_successful_enqueues
),
219 URCU_TLS(nr_empty_dest_enqueues
));
224 static void do_test_pop(enum test_sync sync
)
226 struct cds_wfs_node
*node
;
228 if (sync
== TEST_SYNC_MUTEX
)
229 cds_wfs_pop_lock(&s
);
230 node
= __cds_wfs_pop_blocking(&s
);
231 if (sync
== TEST_SYNC_MUTEX
)
232 cds_wfs_pop_unlock(&s
);
236 URCU_TLS(nr_successful_dequeues
)++;
238 URCU_TLS(nr_dequeues
)++;
241 static void do_test_pop_all(enum test_sync sync
)
243 struct cds_wfs_head
*head
;
244 struct cds_wfs_node
*node
, *n
;
246 if (sync
== TEST_SYNC_MUTEX
)
247 cds_wfs_pop_lock(&s
);
248 head
= __cds_wfs_pop_all(&s
);
249 if (sync
== TEST_SYNC_MUTEX
)
250 cds_wfs_pop_unlock(&s
);
253 if (cds_wfs_first(head
) == NULL
)
256 URCU_TLS(nr_pop_all
)++;
258 cds_wfs_for_each_blocking_safe(head
, node
, n
) {
260 URCU_TLS(nr_successful_dequeues
)++;
261 URCU_TLS(nr_dequeues
)++;
265 static void *thr_dequeuer(void *_count
)
267 unsigned long long *count
= _count
;
268 unsigned int counter
;
270 printf_verbose("thread_begin %s, thread id : %lx, tid %lu\n",
271 "dequeuer", (unsigned long) pthread_self(),
272 (unsigned long) gettid());
281 assert(test_pop
|| test_pop_all
);
284 if (test_pop
&& test_pop_all
) {
286 do_test_pop(test_sync
);
288 do_test_pop_all(test_sync
);
292 do_test_pop(test_sync
);
294 do_test_pop_all(test_sync
);
297 if (caa_unlikely(!test_duration_dequeue()))
299 if (caa_unlikely(rduration
))
300 loop_sleep(rduration
);
303 printf_verbose("dequeuer thread_end, thread id : %lx, tid %lu, "
304 "dequeues %llu, successful_dequeues %llu "
307 (unsigned long) gettid(),
308 URCU_TLS(nr_dequeues
), URCU_TLS(nr_successful_dequeues
),
309 URCU_TLS(nr_pop_all
));
310 count
[0] = URCU_TLS(nr_dequeues
);
311 count
[1] = URCU_TLS(nr_successful_dequeues
);
312 count
[2] = URCU_TLS(nr_pop_all
);
316 static void test_end(struct cds_wfs_stack
*s
, unsigned long long *nr_dequeues
)
318 struct cds_wfs_node
*node
;
321 node
= cds_wfs_pop_blocking(s
);
329 static void show_usage(int argc
, char **argv
)
331 printf("Usage : %s nr_dequeuers nr_enqueuers duration (s)", argv
[0]);
332 printf(" [-d delay] (enqueuer period (in loops))");
333 printf(" [-c duration] (dequeuer period (in loops))");
334 printf(" [-v] (verbose output)");
335 printf(" [-a cpu#] [-a cpu#]... (affinity)");
336 printf(" [-p] (test pop)");
337 printf(" [-P] (test pop_all, enabled by default)");
338 printf(" [-M] (use mutex external synchronization)");
339 printf(" Note: default: no external synchronization used.");
340 printf(" [-f] (force user-provided synchronization)");
341 printf(" [-w] Wait for dequeuer to empty stack");
345 int main(int argc
, char **argv
)
348 pthread_t
*tid_enqueuer
, *tid_dequeuer
;
350 unsigned long long *count_enqueuer
, *count_dequeuer
;
351 unsigned long long tot_enqueues
= 0, tot_dequeues
= 0;
352 unsigned long long tot_successful_enqueues
= 0,
353 tot_successful_dequeues
= 0,
354 tot_empty_dest_enqueues
= 0,
356 unsigned long long end_dequeues
= 0;
357 int i
, a
, retval
= 0;
360 show_usage(argc
, argv
);
364 err
= sscanf(argv
[1], "%u", &nr_dequeuers
);
366 show_usage(argc
, argv
);
370 err
= sscanf(argv
[2], "%u", &nr_enqueuers
);
372 show_usage(argc
, argv
);
376 err
= sscanf(argv
[3], "%lu", &duration
);
378 show_usage(argc
, argv
);
382 for (i
= 4; i
< argc
; i
++) {
383 if (argv
[i
][0] != '-')
385 switch (argv
[i
][1]) {
388 show_usage(argc
, argv
);
392 cpu_affinities
[next_aff
++] = a
;
394 printf_verbose("Adding CPU %d affinity\n", a
);
398 show_usage(argc
, argv
);
401 rduration
= atol(argv
[++i
]);
405 show_usage(argc
, argv
);
408 wdelay
= atol(argv
[++i
]);
420 test_sync
= TEST_SYNC_MUTEX
;
431 /* activate pop_all test by default */
432 if (!test_pop
&& !test_pop_all
)
435 if (test_sync
== TEST_SYNC_NONE
&& nr_dequeuers
> 1 && test_pop
) {
436 if (test_force_sync
) {
437 fprintf(stderr
, "[WARNING] Using pop concurrently "
438 "with other pop or pop_all without external "
439 "synchronization. Expect run-time failure.\n");
441 printf("Enforcing mutex synchronization\n");
442 test_sync
= TEST_SYNC_MUTEX
;
446 printf_verbose("running test for %lu seconds, %u enqueuers, "
448 duration
, nr_enqueuers
, nr_dequeuers
);
450 printf_verbose("pop test activated.\n");
452 printf_verbose("pop_all test activated.\n");
453 if (test_sync
== TEST_SYNC_MUTEX
)
454 printf_verbose("External sync: mutex.\n");
456 printf_verbose("External sync: none.\n");
458 printf_verbose("Wait for dequeuers to empty stack.\n");
459 printf_verbose("Writer delay : %lu loops.\n", rduration
);
460 printf_verbose("Reader duration : %lu loops.\n", wdelay
);
461 printf_verbose("thread %-6s, thread id : %lx, tid %lu\n",
462 "main", (unsigned long) pthread_self(),
463 (unsigned long) gettid());
465 tid_enqueuer
= malloc(sizeof(*tid_enqueuer
) * nr_enqueuers
);
466 tid_dequeuer
= malloc(sizeof(*tid_dequeuer
) * nr_dequeuers
);
467 count_enqueuer
= malloc(3 * sizeof(*count_enqueuer
) * nr_enqueuers
);
468 count_dequeuer
= malloc(3 * sizeof(*count_dequeuer
) * nr_dequeuers
);
473 for (i
= 0; i
< nr_enqueuers
; i
++) {
474 err
= pthread_create(&tid_enqueuer
[i
], NULL
, thr_enqueuer
,
475 &count_enqueuer
[3 * i
]);
479 for (i
= 0; i
< nr_dequeuers
; i
++) {
480 err
= pthread_create(&tid_dequeuer
[i
], NULL
, thr_dequeuer
,
481 &count_dequeuer
[3 * i
]);
490 for (i
= 0; i
< duration
; i
++) {
496 test_stop_enqueue
= 1;
498 if (test_wait_empty
) {
499 while (nr_enqueuers
!= uatomic_read(&test_enqueue_stopped
)) {
502 while (!cds_wfs_empty(&s
)) {
507 test_stop_dequeue
= 1;
509 for (i
= 0; i
< nr_enqueuers
; i
++) {
510 err
= pthread_join(tid_enqueuer
[i
], &tret
);
513 tot_enqueues
+= count_enqueuer
[3 * i
];
514 tot_successful_enqueues
+= count_enqueuer
[3 * i
+ 1];
515 tot_empty_dest_enqueues
+= count_enqueuer
[3 * i
+ 2];
517 for (i
= 0; i
< nr_dequeuers
; i
++) {
518 err
= pthread_join(tid_dequeuer
[i
], &tret
);
521 tot_dequeues
+= count_dequeuer
[3 * i
];
522 tot_successful_dequeues
+= count_dequeuer
[3 * i
+ 1];
523 tot_pop_all
+= count_dequeuer
[3 * i
+ 2];
526 test_end(&s
, &end_dequeues
);
528 printf_verbose("total number of enqueues : %llu, dequeues %llu\n",
529 tot_enqueues
, tot_dequeues
);
530 printf_verbose("total number of successful enqueues : %llu, "
531 "enqueues to empty dest : %llu, "
532 "successful dequeues %llu, "
534 tot_successful_enqueues
,
535 tot_empty_dest_enqueues
,
536 tot_successful_dequeues
,
538 printf("SUMMARY %-25s testdur %4lu nr_enqueuers %3u wdelay %6lu "
540 "rdur %6lu nr_enqueues %12llu nr_dequeues %12llu "
541 "successful enqueues %12llu enqueues to empty dest %12llu "
542 "successful dequeues %12llu pop_all %12llu "
543 "end_dequeues %llu nr_ops %12llu\n",
544 argv
[0], duration
, nr_enqueuers
, wdelay
,
545 nr_dequeuers
, rduration
, tot_enqueues
, tot_dequeues
,
546 tot_successful_enqueues
,
547 tot_empty_dest_enqueues
,
548 tot_successful_dequeues
, tot_pop_all
, end_dequeues
,
549 tot_enqueues
+ tot_dequeues
);
550 if (tot_successful_enqueues
!= tot_successful_dequeues
+ end_dequeues
) {
551 printf("WARNING! Discrepancy between nr succ. enqueues %llu vs "
552 "succ. dequeues + end dequeues %llu.\n",
553 tot_successful_enqueues
,
554 tot_successful_dequeues
+ end_dequeues
);
558 * If only using pop_all to dequeue, the enqueuer should see
559 * exactly as many empty queues than the number of non-empty
562 if (test_wait_empty
&& test_pop_all
&& !test_pop
563 && tot_empty_dest_enqueues
!= tot_pop_all
) {
564 printf("WARNING! Discrepancy between empty enqueue (%llu) and "
565 "number of non-empty pop_all (%llu)\n",
566 tot_empty_dest_enqueues
,
570 free(count_enqueuer
);
571 free(count_dequeuer
);