xref: /openbmc/qemu/tests/unit/test-coroutine.c (revision 2df1eb27) 
1 /*
2  * Coroutine tests
3  *
4  * Copyright IBM, Corp. 2011
5  *
6  * Authors:
7  *  Stefan Hajnoczi    <stefanha@linux.vnet.ibm.com>
8  *
9  * This work is licensed under the terms of the GNU LGPL, version 2 or later.
10  * See the COPYING.LIB file in the top-level directory.
11  *
12  */
13 
14 #include "qemu/osdep.h"
15 #include "qemu/coroutine_int.h"
16 
17 /*
18  * Check that qemu_in_coroutine() works
19  */
20 
21 static void coroutine_fn verify_in_coroutine(void *opaque)
22 {
23     g_assert(qemu_in_coroutine());
24 }
25 
26 static void test_in_coroutine(void)
27 {
28     Coroutine *coroutine;
29 
30     g_assert(!qemu_in_coroutine());
31 
32     coroutine = qemu_coroutine_create(verify_in_coroutine, NULL);
33     qemu_coroutine_enter(coroutine);
34 }
35 
36 /*
37  * Check that qemu_coroutine_self() works
38  */
39 
40 static void coroutine_fn verify_self(void *opaque)
41 {
42     Coroutine **p_co = opaque;
43     g_assert(qemu_coroutine_self() == *p_co);
44 }
45 
46 static void test_self(void)
47 {
48     Coroutine *coroutine;
49 
50     coroutine = qemu_coroutine_create(verify_self, &coroutine);
51     qemu_coroutine_enter(coroutine);
52 }
53 
54 /*
55  * Check that qemu_coroutine_entered() works
56  */
57 
58 static void coroutine_fn verify_entered_step_2(void *opaque)
59 {
60     Coroutine *caller = (Coroutine *)opaque;
61 
62     g_assert(qemu_coroutine_entered(caller));
63     g_assert(qemu_coroutine_entered(qemu_coroutine_self()));
64     qemu_coroutine_yield();
65 
66     /* Once more to check it still works after yielding */
67     g_assert(qemu_coroutine_entered(caller));
68     g_assert(qemu_coroutine_entered(qemu_coroutine_self()));
69 }
70 
71 static void coroutine_fn verify_entered_step_1(void *opaque)
72 {
73     Coroutine *self = qemu_coroutine_self();
74     Coroutine *coroutine;
75 
76     g_assert(qemu_coroutine_entered(self));
77 
78     coroutine = qemu_coroutine_create(verify_entered_step_2, self);
79     g_assert(!qemu_coroutine_entered(coroutine));
80     qemu_coroutine_enter(coroutine);
81     g_assert(!qemu_coroutine_entered(coroutine));
82     qemu_coroutine_enter(coroutine);
83 }
84 
85 static void test_entered(void)
86 {
87     Coroutine *coroutine;
88 
89     coroutine = qemu_coroutine_create(verify_entered_step_1, NULL);
90     g_assert(!qemu_coroutine_entered(coroutine));
91     qemu_coroutine_enter(coroutine);
92 }
93 
94 /*
95  * Check that coroutines may nest multiple levels
96  */
97 
98 typedef struct {
99     unsigned int n_enter;   /* num coroutines entered */
100     unsigned int n_return;  /* num coroutines returned */
101     unsigned int max;       /* maximum level of nesting */
102 } NestData;
103 
104 static void coroutine_fn nest(void *opaque)
105 {
106     NestData *nd = opaque;
107 
108     nd->n_enter++;
109 
110     if (nd->n_enter < nd->max) {
111         Coroutine *child;
112 
113         child = qemu_coroutine_create(nest, nd);
114         qemu_coroutine_enter(child);
115     }
116 
117     nd->n_return++;
118 }
119 
120 static void test_nesting(void)
121 {
122     Coroutine *root;
123     NestData nd = {
124         .n_enter  = 0,
125         .n_return = 0,
126         .max      = 128,
127     };
128 
129     root = qemu_coroutine_create(nest, &nd);
130     qemu_coroutine_enter(root);
131 
132     /* Must enter and return from max nesting level */
133     g_assert_cmpint(nd.n_enter, ==, nd.max);
134     g_assert_cmpint(nd.n_return, ==, nd.max);
135 }
136 
137 /*
138  * Check that yield/enter transfer control correctly
139  */
140 
141 static void coroutine_fn yield_5_times(void *opaque)
142 {
143     bool *done = opaque;
144     int i;
145 
146     for (i = 0; i < 5; i++) {
147         qemu_coroutine_yield();
148     }
149     *done = true;
150 }
151 
152 static void test_yield(void)
153 {
154     Coroutine *coroutine;
155     bool done = false;
156     int i = -1; /* one extra time to return from coroutine */
157 
158     coroutine = qemu_coroutine_create(yield_5_times, &done);
159     while (!done) {
160         qemu_coroutine_enter(coroutine);
161         i++;
162     }
163     g_assert_cmpint(i, ==, 5); /* coroutine must yield 5 times */
164 }
165 
166 static void coroutine_fn c2_fn(void *opaque)
167 {
168     qemu_coroutine_yield();
169 }
170 
171 static void coroutine_fn c1_fn(void *opaque)
172 {
173     Coroutine *c2 = opaque;
174     qemu_coroutine_enter(c2);
175 }
176 
177 static void test_no_dangling_access(void)
178 {
179     Coroutine *c1;
180     Coroutine *c2;
181     Coroutine tmp;
182 
183     c2 = qemu_coroutine_create(c2_fn, NULL);
184     c1 = qemu_coroutine_create(c1_fn, c2);
185 
186     qemu_coroutine_enter(c1);
187 
188     /* c1 shouldn't be used any more now; make sure we segfault if it is */
189     tmp = *c1;
190     memset(c1, 0xff, sizeof(Coroutine));
191     qemu_coroutine_enter(c2);
192 
193     /* Must restore the coroutine now to avoid corrupted pool */
194     *c1 = tmp;
195 }
196 
197 static bool locked;
198 static int done_count;
199 
200 static void coroutine_fn mutex_fn(void *opaque)
201 {
202     CoMutex *m = opaque;
203     qemu_co_mutex_lock(m);
204     assert(!locked);
205     locked = true;
206     qemu_coroutine_yield();
207     locked = false;
208     qemu_co_mutex_unlock(m);
209     done_count++;
210 }
211 
212 static void coroutine_fn lockable_fn(void *opaque)
213 {
214     QemuLockable *x = opaque;
215     qemu_lockable_lock(x);
216     assert(!locked);
217     locked = true;
218     qemu_coroutine_yield();
219     locked = false;
220     qemu_lockable_unlock(x);
221     done_count++;
222 }
223 
224 static void do_test_co_mutex(CoroutineEntry *entry, void *opaque)
225 {
226     Coroutine *c1 = qemu_coroutine_create(entry, opaque);
227     Coroutine *c2 = qemu_coroutine_create(entry, opaque);
228 
229     done_count = 0;
230     qemu_coroutine_enter(c1);
231     g_assert(locked);
232     qemu_coroutine_enter(c2);
233 
234     /* Unlock queues c2.  It is then started automatically when c1 yields or
235      * terminates.
236      */
237     qemu_coroutine_enter(c1);
238     g_assert_cmpint(done_count, ==, 1);
239     g_assert(locked);
240 
241     qemu_coroutine_enter(c2);
242     g_assert_cmpint(done_count, ==, 2);
243     g_assert(!locked);
244 }
245 
246 static void test_co_mutex(void)
247 {
248     CoMutex m;
249 
250     qemu_co_mutex_init(&m);
251     do_test_co_mutex(mutex_fn, &m);
252 }
253 
254 static void test_co_mutex_lockable(void)
255 {
256     CoMutex m;
257     CoMutex *null_pointer = NULL;
258 
259     qemu_co_mutex_init(&m);
260     do_test_co_mutex(lockable_fn, QEMU_MAKE_LOCKABLE(&m));
261 
262     g_assert(QEMU_MAKE_LOCKABLE(null_pointer) == NULL);
263 }
264 
265 static CoRwlock rwlock;
266 
267 /* Test that readers are properly sent back to the queue when upgrading,
268  * even if they are the sole readers.  The test scenario is as follows:
269  *
270  *
271  * | c1           | c2         |
272  * |--------------+------------+
273  * | rdlock       |            |
274  * | yield        |            |
275  * |              | wrlock     |
276  * |              | <queued>   |
277  * | upgrade      |            |
278  * | <queued>     | <dequeued> |
279  * |              | unlock     |
280  * | <dequeued>   |            |
281  * | unlock       |            |
282  */
283 
284 static void coroutine_fn rwlock_yield_upgrade(void *opaque)
285 {
286     qemu_co_rwlock_rdlock(&rwlock);
287     qemu_coroutine_yield();
288 
289     qemu_co_rwlock_upgrade(&rwlock);
290     qemu_co_rwlock_unlock(&rwlock);
291 
292     *(bool *)opaque = true;
293 }
294 
295 static void coroutine_fn rwlock_wrlock_yield(void *opaque)
296 {
297     qemu_co_rwlock_wrlock(&rwlock);
298     qemu_coroutine_yield();
299 
300     qemu_co_rwlock_unlock(&rwlock);
301     *(bool *)opaque = true;
302 }
303 
304 static void test_co_rwlock_upgrade(void)
305 {
306     bool c1_done = false;
307     bool c2_done = false;
308     Coroutine *c1, *c2;
309 
310     qemu_co_rwlock_init(&rwlock);
311     c1 = qemu_coroutine_create(rwlock_yield_upgrade, &c1_done);
312     c2 = qemu_coroutine_create(rwlock_wrlock_yield, &c2_done);
313 
314     qemu_coroutine_enter(c1);
315     qemu_coroutine_enter(c2);
316 
317     /* c1 now should go to sleep.  */
318     qemu_coroutine_enter(c1);
319     g_assert(!c1_done);
320 
321     qemu_coroutine_enter(c2);
322     g_assert(c1_done);
323     g_assert(c2_done);
324 }
325 
326 static void coroutine_fn rwlock_rdlock_yield(void *opaque)
327 {
328     qemu_co_rwlock_rdlock(&rwlock);
329     qemu_coroutine_yield();
330 
331     qemu_co_rwlock_unlock(&rwlock);
332     qemu_coroutine_yield();
333 
334     *(bool *)opaque = true;
335 }
336 
337 static void coroutine_fn rwlock_wrlock_downgrade(void *opaque)
338 {
339     qemu_co_rwlock_wrlock(&rwlock);
340 
341     qemu_co_rwlock_downgrade(&rwlock);
342     qemu_co_rwlock_unlock(&rwlock);
343     *(bool *)opaque = true;
344 }
345 
346 static void coroutine_fn rwlock_rdlock(void *opaque)
347 {
348     qemu_co_rwlock_rdlock(&rwlock);
349 
350     qemu_co_rwlock_unlock(&rwlock);
351     *(bool *)opaque = true;
352 }
353 
354 static void coroutine_fn rwlock_wrlock(void *opaque)
355 {
356     qemu_co_rwlock_wrlock(&rwlock);
357 
358     qemu_co_rwlock_unlock(&rwlock);
359     *(bool *)opaque = true;
360 }
361 
362 /*
363  * Check that downgrading a reader-writer lock does not cause a hang.
364  *
365  * Four coroutines are used to produce a situation where there are
366  * both reader and writer hopefuls waiting to acquire an rwlock that
367  * is held by a reader.
368  *
369  * The correct sequence of operations we aim to provoke can be
370  * represented as:
371  *
372  * | c1     | c2         | c3         | c4         |
373  * |--------+------------+------------+------------|
374  * | rdlock |            |            |            |
375  * | yield  |            |            |            |
376  * |        | wrlock     |            |            |
377  * |        | <queued>   |            |            |
378  * |        |            | rdlock     |            |
379  * |        |            | <queued>   |            |
380  * |        |            |            | wrlock     |
381  * |        |            |            | <queued>   |
382  * | unlock |            |            |            |
383  * | yield  |            |            |            |
384  * |        | <dequeued> |            |            |
385  * |        | downgrade  |            |            |
386  * |        |            | <dequeued> |            |
387  * |        |            | unlock     |            |
388  * |        | ...        |            |            |
389  * |        | unlock     |            |            |
390  * |        |            |            | <dequeued> |
391  * |        |            |            | unlock     |
392  */
393 static void test_co_rwlock_downgrade(void)
394 {
395     bool c1_done = false;
396     bool c2_done = false;
397     bool c3_done = false;
398     bool c4_done = false;
399     Coroutine *c1, *c2, *c3, *c4;
400 
401     qemu_co_rwlock_init(&rwlock);
402 
403     c1 = qemu_coroutine_create(rwlock_rdlock_yield, &c1_done);
404     c2 = qemu_coroutine_create(rwlock_wrlock_downgrade, &c2_done);
405     c3 = qemu_coroutine_create(rwlock_rdlock, &c3_done);
406     c4 = qemu_coroutine_create(rwlock_wrlock, &c4_done);
407 
408     qemu_coroutine_enter(c1);
409     qemu_coroutine_enter(c2);
410     qemu_coroutine_enter(c3);
411     qemu_coroutine_enter(c4);
412 
413     qemu_coroutine_enter(c1);
414 
415     g_assert(c2_done);
416     g_assert(c3_done);
417     g_assert(c4_done);
418 
419     qemu_coroutine_enter(c1);
420 
421     g_assert(c1_done);
422 }
423 
424 /*
425  * Check that creation, enter, and return work
426  */
427 
428 static void coroutine_fn set_and_exit(void *opaque)
429 {
430     bool *done = opaque;
431 
432     *done = true;
433 }
434 
435 static void test_lifecycle(void)
436 {
437     Coroutine *coroutine;
438     bool done = false;
439 
440     /* Create, enter, and return from coroutine */
441     coroutine = qemu_coroutine_create(set_and_exit, &done);
442     qemu_coroutine_enter(coroutine);
443     g_assert(done); /* expect done to be true (first time) */
444 
445     /* Repeat to check that no state affects this test */
446     done = false;
447     coroutine = qemu_coroutine_create(set_and_exit, &done);
448     qemu_coroutine_enter(coroutine);
449     g_assert(done); /* expect done to be true (second time) */
450 }
451 
452 
453 #define RECORD_SIZE 10 /* Leave some room for expansion */
454 struct coroutine_position {
455     int func;
456     int state;
457 };
458 static struct coroutine_position records[RECORD_SIZE];
459 static unsigned record_pos;
460 
461 static void record_push(int func, int state)
462 {
463     struct coroutine_position *cp = &records[record_pos++];
464     g_assert_cmpint(record_pos, <, RECORD_SIZE);
465     cp->func = func;
466     cp->state = state;
467 }
468 
469 static void coroutine_fn co_order_test(void *opaque)
470 {
471     record_push(2, 1);
472     g_assert(qemu_in_coroutine());
473     qemu_coroutine_yield();
474     record_push(2, 2);
475     g_assert(qemu_in_coroutine());
476 }
477 
478 static void do_order_test(void)
479 {
480     Coroutine *co;
481 
482     co = qemu_coroutine_create(co_order_test, NULL);
483     record_push(1, 1);
484     qemu_coroutine_enter(co);
485     record_push(1, 2);
486     g_assert(!qemu_in_coroutine());
487     qemu_coroutine_enter(co);
488     record_push(1, 3);
489     g_assert(!qemu_in_coroutine());
490 }
491 
492 static void test_order(void)
493 {
494     int i;
495     const struct coroutine_position expected_pos[] = {
496         {1, 1,}, {2, 1}, {1, 2}, {2, 2}, {1, 3}
497     };
498     do_order_test();
499     g_assert_cmpint(record_pos, ==, 5);
500     for (i = 0; i < record_pos; i++) {
501         g_assert_cmpint(records[i].func , ==, expected_pos[i].func );
502         g_assert_cmpint(records[i].state, ==, expected_pos[i].state);
503     }
504 }
505 /*
506  * Lifecycle benchmark
507  */
508 
509 static void coroutine_fn empty_coroutine(void *opaque)
510 {
511     /* Do nothing */
512 }
513 
514 static void perf_lifecycle(void)
515 {
516     Coroutine *coroutine;
517     unsigned int i, max;
518     double duration;
519 
520     max = 1000000;
521 
522     g_test_timer_start();
523     for (i = 0; i < max; i++) {
524         coroutine = qemu_coroutine_create(empty_coroutine, NULL);
525         qemu_coroutine_enter(coroutine);
526     }
527     duration = g_test_timer_elapsed();
528 
529     g_test_message("Lifecycle %u iterations: %f s", max, duration);
530 }
531 
532 static void perf_nesting(void)
533 {
534     unsigned int i, maxcycles, maxnesting;
535     double duration;
536 
537     maxcycles = 10000;
538     maxnesting = 1000;
539     Coroutine *root;
540 
541     g_test_timer_start();
542     for (i = 0; i < maxcycles; i++) {
543         NestData nd = {
544             .n_enter  = 0,
545             .n_return = 0,
546             .max      = maxnesting,
547         };
548         root = qemu_coroutine_create(nest, &nd);
549         qemu_coroutine_enter(root);
550     }
551     duration = g_test_timer_elapsed();
552 
553     g_test_message("Nesting %u iterations of %u depth each: %f s",
554         maxcycles, maxnesting, duration);
555 }
556 
557 /*
558  * Yield benchmark
559  */
560 
561 static void coroutine_fn yield_loop(void *opaque)
562 {
563     unsigned int *counter = opaque;
564 
565     while ((*counter) > 0) {
566         (*counter)--;
567         qemu_coroutine_yield();
568     }
569 }
570 
571 static void perf_yield(void)
572 {
573     unsigned int i, maxcycles;
574     double duration;
575 
576     maxcycles = 100000000;
577     i = maxcycles;
578     Coroutine *coroutine = qemu_coroutine_create(yield_loop, &i);
579 
580     g_test_timer_start();
581     while (i > 0) {
582         qemu_coroutine_enter(coroutine);
583     }
584     duration = g_test_timer_elapsed();
585 
586     g_test_message("Yield %u iterations: %f s", maxcycles, duration);
587 }
588 
589 static __attribute__((noinline)) void dummy(unsigned *i)
590 {
591     (*i)--;
592 }
593 
594 static void perf_baseline(void)
595 {
596     unsigned int i, maxcycles;
597     double duration;
598 
599     maxcycles = 100000000;
600     i = maxcycles;
601 
602     g_test_timer_start();
603     while (i > 0) {
604         dummy(&i);
605     }
606     duration = g_test_timer_elapsed();
607 
608     g_test_message("Function call %u iterations: %f s", maxcycles, duration);
609 }
610 
611 static __attribute__((noinline)) void coroutine_fn perf_cost_func(void *opaque)
612 {
613     qemu_coroutine_yield();
614 }
615 
616 static void perf_cost(void)
617 {
618     const unsigned long maxcycles = 40000000;
619     unsigned long i = 0;
620     double duration;
621     unsigned long ops;
622     Coroutine *co;
623 
624     g_test_timer_start();
625     while (i++ < maxcycles) {
626         co = qemu_coroutine_create(perf_cost_func, &i);
627         qemu_coroutine_enter(co);
628         qemu_coroutine_enter(co);
629     }
630     duration = g_test_timer_elapsed();
631     ops = (long)(maxcycles / (duration * 1000));
632 
633     g_test_message("Run operation %lu iterations %f s, %luK operations/s, "
634                    "%luns per coroutine",
635                    maxcycles,
636                    duration, ops,
637                    (unsigned long)(1000000000.0 * duration / maxcycles));
638 }
639 
640 int main(int argc, char **argv)
641 {
642     g_test_init(&argc, &argv, NULL);
643 
644     /* This test assumes there is a freelist and marks freed coroutine memory
645      * with a sentinel value.  If there is no freelist this would legitimately
646      * crash, so skip it.
647      */
648     if (IS_ENABLED(CONFIG_COROUTINE_POOL)) {
649         g_test_add_func("/basic/no-dangling-access", test_no_dangling_access);
650     }
651 
652     g_test_add_func("/basic/lifecycle", test_lifecycle);
653     g_test_add_func("/basic/yield", test_yield);
654     g_test_add_func("/basic/nesting", test_nesting);
655     g_test_add_func("/basic/self", test_self);
656     g_test_add_func("/basic/entered", test_entered);
657     g_test_add_func("/basic/in_coroutine", test_in_coroutine);
658     g_test_add_func("/basic/order", test_order);
659     g_test_add_func("/locking/co-mutex", test_co_mutex);
660     g_test_add_func("/locking/co-mutex/lockable", test_co_mutex_lockable);
661     g_test_add_func("/locking/co-rwlock/upgrade", test_co_rwlock_upgrade);
662     g_test_add_func("/locking/co-rwlock/downgrade", test_co_rwlock_downgrade);
663     if (g_test_perf()) {
664         g_test_add_func("/perf/lifecycle", perf_lifecycle);
665         g_test_add_func("/perf/nesting", perf_nesting);
666         g_test_add_func("/perf/yield", perf_yield);
667         g_test_add_func("/perf/function-call", perf_baseline);
668         g_test_add_func("/perf/cost", perf_cost);
669     }
670     return g_test_run();
671 }
672