1 // SPDX-FileCopyrightText: 2010 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
2 // SPDX-FileCopyrightText: 2010 Paolo Bonzini <pbonzini@redhat.com>
4 // SPDX-License-Identifier: GPL-2.0-or-later
7 * Userspace RCU library - example RCU-based lock-free concurrent queue
16 #include <sys/types.h>
22 #include <urcu/arch.h>
23 #include <urcu/assert.h>
24 #include <urcu/tls-compat.h>
25 #include <urcu/uatomic.h>
26 #include "thread-id.h"
28 /* hardcoded number of CPUs */
31 #ifndef DYNAMIC_LINK_TEST
34 #include <urcu/wfcqueue.h>
41 static enum test_sync test_sync
;
43 static int test_force_sync
;
45 static volatile int test_stop_enqueue
, test_stop_dequeue
;
47 static unsigned long rduration
;
49 static unsigned long duration
;
51 /* read-side C.S. duration, in loops */
52 static unsigned long wdelay
;
54 static inline void loop_sleep(unsigned long loops
)
60 static int verbose_mode
;
62 static int test_dequeue
, test_splice
, test_wait_empty
;
63 static unsigned int test_enqueue_stopped
;
65 #define printf_verbose(fmt, args...) \
68 printf(fmt, ## args); \
71 static unsigned int cpu_affinities
[NR_CPUS
];
72 static unsigned int next_aff
= 0;
73 static int use_affinity
= 0;
75 pthread_mutex_t affinity_mutex
= PTHREAD_MUTEX_INITIALIZER
;
77 static void set_affinity(void)
79 #ifdef HAVE_SCHED_SETAFFINITY
82 #endif /* HAVE_SCHED_SETAFFINITY */
87 #ifdef HAVE_SCHED_SETAFFINITY
88 ret
= pthread_mutex_lock(&affinity_mutex
);
90 perror("Error in pthread mutex lock");
93 cpu
= cpu_affinities
[next_aff
++];
94 ret
= pthread_mutex_unlock(&affinity_mutex
);
96 perror("Error in pthread mutex unlock");
102 sched_setaffinity(0, sizeof(mask
), &mask
);
103 #endif /* HAVE_SCHED_SETAFFINITY */
107 * returns 0 if test should end.
109 static int test_duration_dequeue(void)
111 return !uatomic_load(&test_stop_dequeue
, CMM_RELAXED
);
114 static int test_duration_enqueue(void)
116 return !uatomic_load(&test_stop_enqueue
, CMM_RELAXED
);
119 static DEFINE_URCU_TLS(unsigned long long, nr_dequeues
);
120 static DEFINE_URCU_TLS(unsigned long long, nr_enqueues
);
122 static DEFINE_URCU_TLS(unsigned long long, nr_successful_dequeues
);
123 static DEFINE_URCU_TLS(unsigned long long, nr_successful_enqueues
);
124 static DEFINE_URCU_TLS(unsigned long long, nr_empty_dest_enqueues
);
125 static DEFINE_URCU_TLS(unsigned long long, nr_splice
);
126 static DEFINE_URCU_TLS(unsigned long long, nr_dequeue_last
);
128 static unsigned int nr_enqueuers
;
129 static unsigned int nr_dequeuers
;
131 static struct cds_wfcq_head
__attribute__((aligned(CAA_CACHE_LINE_SIZE
))) head
;
132 static struct cds_wfcq_tail
__attribute__((aligned(CAA_CACHE_LINE_SIZE
))) tail
;
134 static void *thr_enqueuer(void *_count
)
136 unsigned long long *count
= _count
;
139 printf_verbose("thread_begin %s, tid %lu\n",
140 "enqueuer", urcu_get_thread_id());
147 struct cds_wfcq_node
*node
= malloc(sizeof(*node
));
150 cds_wfcq_node_init(node
);
151 was_nonempty
= cds_wfcq_enqueue(&head
, &tail
, node
);
152 URCU_TLS(nr_successful_enqueues
)++;
154 URCU_TLS(nr_empty_dest_enqueues
)++;
156 if (caa_unlikely(wdelay
))
159 URCU_TLS(nr_enqueues
)++;
160 if (caa_unlikely(!test_duration_enqueue()))
164 uatomic_inc(&test_enqueue_stopped
);
165 count
[0] = URCU_TLS(nr_enqueues
);
166 count
[1] = URCU_TLS(nr_successful_enqueues
);
167 count
[2] = URCU_TLS(nr_empty_dest_enqueues
);
168 printf_verbose("enqueuer thread_end, tid %lu, "
169 "enqueues %llu successful_enqueues %llu, "
170 "empty_dest_enqueues %llu\n",
171 urcu_get_thread_id(),
172 URCU_TLS(nr_enqueues
),
173 URCU_TLS(nr_successful_enqueues
),
174 URCU_TLS(nr_empty_dest_enqueues
));
179 static void do_test_dequeue(enum test_sync sync
)
181 struct cds_wfcq_node
*node
;
184 if (sync
== TEST_SYNC_MUTEX
)
185 node
= cds_wfcq_dequeue_with_state_blocking(&head
, &tail
,
188 node
= __cds_wfcq_dequeue_with_state_blocking(&head
, &tail
,
191 if (state
& CDS_WFCQ_STATE_LAST
)
192 URCU_TLS(nr_dequeue_last
)++;
196 URCU_TLS(nr_successful_dequeues
)++;
198 URCU_TLS(nr_dequeues
)++;
201 static void do_test_splice(enum test_sync sync
)
203 struct cds_wfcq_head tmp_head
;
204 struct cds_wfcq_tail tmp_tail
;
205 struct cds_wfcq_node
*node
, *n
;
206 enum cds_wfcq_ret ret
;
208 cds_wfcq_init(&tmp_head
, &tmp_tail
);
210 if (sync
== TEST_SYNC_MUTEX
)
211 ret
= cds_wfcq_splice_blocking(&tmp_head
, &tmp_tail
,
214 ret
= __cds_wfcq_splice_blocking(&tmp_head
, &tmp_tail
,
218 case CDS_WFCQ_RET_WOULDBLOCK
:
219 urcu_posix_assert(0); /* blocking call */
221 case CDS_WFCQ_RET_DEST_EMPTY
:
222 URCU_TLS(nr_splice
)++;
223 URCU_TLS(nr_dequeue_last
)++;
226 case CDS_WFCQ_RET_DEST_NON_EMPTY
:
227 urcu_posix_assert(0); /* entirely unexpected */
229 case CDS_WFCQ_RET_SRC_EMPTY
:
230 /* ok, we could even skip iteration on dest if we wanted */
234 __cds_wfcq_for_each_blocking_safe(&tmp_head
, &tmp_tail
, node
, n
) {
236 URCU_TLS(nr_successful_dequeues
)++;
237 URCU_TLS(nr_dequeues
)++;
239 cds_wfcq_destroy(&tmp_head
, &tmp_tail
);
242 static void *thr_dequeuer(void *_count
)
244 unsigned long long *count
= _count
;
245 unsigned int counter
= 0;
247 printf_verbose("thread_begin %s, tid %lu\n",
248 "dequeuer", urcu_get_thread_id());
255 if (test_dequeue
&& test_splice
) {
257 do_test_dequeue(test_sync
);
259 do_test_splice(test_sync
);
263 do_test_dequeue(test_sync
);
265 do_test_splice(test_sync
);
267 if (caa_unlikely(!test_duration_dequeue()))
269 if (caa_unlikely(rduration
))
270 loop_sleep(rduration
);
273 printf_verbose("dequeuer thread_end, tid %lu, "
274 "dequeues %llu, successful_dequeues %llu, "
276 urcu_get_thread_id(),
277 URCU_TLS(nr_dequeues
), URCU_TLS(nr_successful_dequeues
),
278 URCU_TLS(nr_splice
));
279 count
[0] = URCU_TLS(nr_dequeues
);
280 count
[1] = URCU_TLS(nr_successful_dequeues
);
281 count
[2] = URCU_TLS(nr_splice
);
282 count
[3] = URCU_TLS(nr_dequeue_last
);
286 static void test_end(unsigned long long *nr_dequeues_l
,
287 unsigned long long *nr_dequeue_last_l
)
289 struct cds_wfcq_node
*node
;
293 node
= cds_wfcq_dequeue_with_state_blocking(&head
, &tail
,
296 if (state
& CDS_WFCQ_STATE_LAST
)
297 (*nr_dequeue_last_l
)++;
304 static void show_usage(char **argv
)
306 printf("Usage : %s nr_dequeuers nr_enqueuers duration (s) <OPTIONS>\n",
308 printf("OPTIONS:\n");
309 printf(" [-d delay] (enqueuer period (in loops))\n");
310 printf(" [-c duration] (dequeuer period (in loops))\n");
311 printf(" [-v] (verbose output)\n");
312 printf(" [-a cpu#] [-a cpu#]... (affinity)\n");
313 printf(" [-q] (test dequeue)\n");
314 printf(" [-s] (test splice, enabled by default)\n");
315 printf(" [-M] (use mutex external synchronization)\n");
316 printf(" Note: default: no external synchronization used.\n");
317 printf(" [-f] (force user-provided synchronization)\n");
318 printf(" [-w] Wait for dequeuer to empty queue\n");
322 int main(int argc
, char **argv
)
325 pthread_t
*tid_enqueuer
, *tid_dequeuer
;
327 unsigned long long *count_enqueuer
, *count_dequeuer
;
328 unsigned long long tot_enqueues
= 0, tot_dequeues
= 0;
329 unsigned long long tot_successful_enqueues
= 0,
330 tot_successful_dequeues
= 0,
331 tot_empty_dest_enqueues
= 0,
332 tot_splice
= 0, tot_dequeue_last
= 0;
333 unsigned long long end_dequeues
= 0;
334 int i
, a
, retval
= 0;
342 err
= sscanf(argv
[1], "%u", &nr_dequeuers
);
348 err
= sscanf(argv
[2], "%u", &nr_enqueuers
);
354 err
= sscanf(argv
[3], "%lu", &duration
);
360 for (i
= 4; i
< argc
; i
++) {
361 if (argv
[i
][0] != '-')
363 switch (argv
[i
][1]) {
370 cpu_affinities
[next_aff
++] = a
;
372 printf_verbose("Adding CPU %d affinity\n", a
);
379 rduration
= atol(argv
[++i
]);
386 wdelay
= atol(argv
[++i
]);
398 test_sync
= TEST_SYNC_MUTEX
;
409 /* activate splice test by default */
410 if (!test_dequeue
&& !test_splice
)
413 if (test_sync
== TEST_SYNC_NONE
&& nr_dequeuers
> 1 && test_dequeue
) {
414 if (test_force_sync
) {
415 fprintf(stderr
, "[WARNING] Using dequeue concurrently "
416 "with other dequeue or splice without external "
417 "synchronization. Expect run-time failure.\n");
419 printf("Enforcing mutex synchronization\n");
420 test_sync
= TEST_SYNC_MUTEX
;
424 printf_verbose("running test for %lu seconds, %u enqueuers, "
426 duration
, nr_enqueuers
, nr_dequeuers
);
428 printf_verbose("dequeue test activated.\n");
430 printf_verbose("splice test activated.\n");
431 if (test_sync
== TEST_SYNC_MUTEX
)
432 printf_verbose("External sync: mutex.\n");
434 printf_verbose("External sync: none.\n");
436 printf_verbose("Wait for dequeuers to empty queue.\n");
437 printf_verbose("Writer delay : %lu loops.\n", rduration
);
438 printf_verbose("Reader duration : %lu loops.\n", wdelay
);
439 printf_verbose("thread %-6s, tid %lu\n",
440 "main", urcu_get_thread_id());
442 tid_enqueuer
= calloc(nr_enqueuers
, sizeof(*tid_enqueuer
));
443 tid_dequeuer
= calloc(nr_dequeuers
, sizeof(*tid_dequeuer
));
444 count_enqueuer
= calloc(nr_enqueuers
, 3 * sizeof(*count_enqueuer
));
445 count_dequeuer
= calloc(nr_dequeuers
, 4 * sizeof(*count_dequeuer
));
446 cds_wfcq_init(&head
, &tail
);
450 for (i_thr
= 0; i_thr
< nr_enqueuers
; i_thr
++) {
451 err
= pthread_create(&tid_enqueuer
[i_thr
], NULL
, thr_enqueuer
,
452 &count_enqueuer
[3 * i_thr
]);
456 for (i_thr
= 0; i_thr
< nr_dequeuers
; i_thr
++) {
457 err
= pthread_create(&tid_dequeuer
[i_thr
], NULL
, thr_dequeuer
,
458 &count_dequeuer
[4 * i_thr
]);
467 for (i_thr
= 0; i_thr
< duration
; i_thr
++) {
470 fwrite(".", sizeof(char), 1, stdout
);
475 uatomic_store(&test_stop_enqueue
, 1, CMM_RELEASE
);
477 if (test_wait_empty
) {
478 while (nr_enqueuers
!= uatomic_read(&test_enqueue_stopped
)) {
481 while (!cds_wfcq_empty(&head
, &tail
)) {
486 uatomic_store(&test_stop_dequeue
, 1, CMM_RELAXED
);
488 for (i_thr
= 0; i_thr
< nr_enqueuers
; i_thr
++) {
489 err
= pthread_join(tid_enqueuer
[i_thr
], &tret
);
492 tot_enqueues
+= count_enqueuer
[3 * i_thr
];
493 tot_successful_enqueues
+= count_enqueuer
[3 * i_thr
+ 1];
494 tot_empty_dest_enqueues
+= count_enqueuer
[3 * i_thr
+ 2];
496 for (i_thr
= 0; i_thr
< nr_dequeuers
; i_thr
++) {
497 err
= pthread_join(tid_dequeuer
[i_thr
], &tret
);
500 tot_dequeues
+= count_dequeuer
[4 * i_thr
];
501 tot_successful_dequeues
+= count_dequeuer
[4 * i_thr
+ 1];
502 tot_splice
+= count_dequeuer
[4 * i_thr
+ 2];
503 tot_dequeue_last
+= count_dequeuer
[4 * i_thr
+ 3];
506 test_end(&end_dequeues
, &tot_dequeue_last
);
508 printf_verbose("total number of enqueues : %llu, dequeues %llu\n",
509 tot_enqueues
, tot_dequeues
);
510 printf_verbose("total number of successful enqueues : %llu, "
511 "enqueues to empty dest : %llu, "
512 "successful dequeues %llu, "
513 "splice : %llu, dequeue_last : %llu\n",
514 tot_successful_enqueues
,
515 tot_empty_dest_enqueues
,
516 tot_successful_dequeues
,
517 tot_splice
, tot_dequeue_last
);
518 printf("SUMMARY %-25s testdur %4lu nr_enqueuers %3u wdelay %6lu "
520 "rdur %6lu nr_enqueues %12llu nr_dequeues %12llu "
521 "successful enqueues %12llu enqueues to empty dest %12llu "
522 "successful dequeues %12llu splice %12llu "
524 "end_dequeues %llu nr_ops %12llu\n",
525 argv
[0], duration
, nr_enqueuers
, wdelay
,
526 nr_dequeuers
, rduration
, tot_enqueues
, tot_dequeues
,
527 tot_successful_enqueues
,
528 tot_empty_dest_enqueues
,
529 tot_successful_dequeues
, tot_splice
, tot_dequeue_last
,
531 tot_enqueues
+ tot_dequeues
);
533 if (tot_successful_enqueues
!= tot_successful_dequeues
+ end_dequeues
) {
534 printf("WARNING! Discrepancy between nr succ. enqueues %llu vs "
535 "succ. dequeues + end dequeues %llu.\n",
536 tot_successful_enqueues
,
537 tot_successful_dequeues
+ end_dequeues
);
542 * If only using splice to dequeue, the enqueuer should see
543 * exactly as many empty queues than the number of non-empty
546 if (tot_empty_dest_enqueues
!= tot_dequeue_last
) {
547 printf("WARNING! Discrepancy between empty enqueue (%llu) and "
548 "number of dequeue of last element (%llu)\n",
549 tot_empty_dest_enqueues
,
553 cds_wfcq_destroy(&head
, &tail
);
554 free(count_enqueuer
);
555 free(count_dequeuer
);