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00447ccd AH |
1 | /* |
2 | * thread-stack.c: Synthesize a thread's stack using call / return events | |
3 | * Copyright (c) 2014, Intel Corporation. | |
4 | * | |
5 | * This program is free software; you can redistribute it and/or modify it | |
6 | * under the terms and conditions of the GNU General Public License, | |
7 | * version 2, as published by the Free Software Foundation. | |
8 | * | |
9 | * This program is distributed in the hope it will be useful, but WITHOUT | |
10 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
11 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for | |
12 | * more details. | |
13 | * | |
14 | */ | |
15 | ||
92a9e4f7 AH |
16 | #include <linux/rbtree.h> |
17 | #include <linux/list.h> | |
00447ccd AH |
18 | #include "thread.h" |
19 | #include "event.h" | |
92a9e4f7 | 20 | #include "machine.h" |
00447ccd AH |
21 | #include "util.h" |
22 | #include "debug.h" | |
92a9e4f7 AH |
23 | #include "symbol.h" |
24 | #include "comm.h" | |
451db126 | 25 | #include "call-path.h" |
00447ccd AH |
26 | #include "thread-stack.h" |
27 | ||
92a9e4f7 AH |
28 | #define STACK_GROWTH 2048 |
29 | ||
30 | /** | |
31 | * struct thread_stack_entry - thread stack entry. | |
32 | * @ret_addr: return address | |
33 | * @timestamp: timestamp (if known) | |
34 | * @ref: external reference (e.g. db_id of sample) | |
35 | * @branch_count: the branch count when the entry was created | |
36 | * @cp: call path | |
37 | * @no_call: a 'call' was not seen | |
38 | */ | |
00447ccd AH |
39 | struct thread_stack_entry { |
40 | u64 ret_addr; | |
92a9e4f7 AH |
41 | u64 timestamp; |
42 | u64 ref; | |
43 | u64 branch_count; | |
44 | struct call_path *cp; | |
45 | bool no_call; | |
00447ccd AH |
46 | }; |
47 | ||
92a9e4f7 AH |
48 | /** |
49 | * struct thread_stack - thread stack constructed from 'call' and 'return' | |
50 | * branch samples. | |
51 | * @stack: array that holds the stack | |
52 | * @cnt: number of entries in the stack | |
53 | * @sz: current maximum stack size | |
54 | * @trace_nr: current trace number | |
55 | * @branch_count: running branch count | |
56 | * @kernel_start: kernel start address | |
57 | * @last_time: last timestamp | |
58 | * @crp: call/return processor | |
59 | * @comm: current comm | |
60 | */ | |
00447ccd AH |
61 | struct thread_stack { |
62 | struct thread_stack_entry *stack; | |
63 | size_t cnt; | |
64 | size_t sz; | |
65 | u64 trace_nr; | |
92a9e4f7 AH |
66 | u64 branch_count; |
67 | u64 kernel_start; | |
68 | u64 last_time; | |
69 | struct call_return_processor *crp; | |
70 | struct comm *comm; | |
00447ccd AH |
71 | }; |
72 | ||
73 | static int thread_stack__grow(struct thread_stack *ts) | |
74 | { | |
75 | struct thread_stack_entry *new_stack; | |
76 | size_t sz, new_sz; | |
77 | ||
78 | new_sz = ts->sz + STACK_GROWTH; | |
79 | sz = new_sz * sizeof(struct thread_stack_entry); | |
80 | ||
81 | new_stack = realloc(ts->stack, sz); | |
82 | if (!new_stack) | |
83 | return -ENOMEM; | |
84 | ||
85 | ts->stack = new_stack; | |
86 | ts->sz = new_sz; | |
87 | ||
88 | return 0; | |
89 | } | |
90 | ||
92a9e4f7 AH |
91 | static struct thread_stack *thread_stack__new(struct thread *thread, |
92 | struct call_return_processor *crp) | |
00447ccd AH |
93 | { |
94 | struct thread_stack *ts; | |
95 | ||
96 | ts = zalloc(sizeof(struct thread_stack)); | |
97 | if (!ts) | |
98 | return NULL; | |
99 | ||
100 | if (thread_stack__grow(ts)) { | |
101 | free(ts); | |
102 | return NULL; | |
103 | } | |
104 | ||
92a9e4f7 AH |
105 | if (thread->mg && thread->mg->machine) |
106 | ts->kernel_start = machine__kernel_start(thread->mg->machine); | |
107 | else | |
108 | ts->kernel_start = 1ULL << 63; | |
109 | ts->crp = crp; | |
110 | ||
00447ccd AH |
111 | return ts; |
112 | } | |
113 | ||
114 | static int thread_stack__push(struct thread_stack *ts, u64 ret_addr) | |
115 | { | |
116 | int err = 0; | |
117 | ||
118 | if (ts->cnt == ts->sz) { | |
119 | err = thread_stack__grow(ts); | |
120 | if (err) { | |
121 | pr_warning("Out of memory: discarding thread stack\n"); | |
122 | ts->cnt = 0; | |
123 | } | |
124 | } | |
125 | ||
126 | ts->stack[ts->cnt++].ret_addr = ret_addr; | |
127 | ||
128 | return err; | |
129 | } | |
130 | ||
131 | static void thread_stack__pop(struct thread_stack *ts, u64 ret_addr) | |
132 | { | |
133 | size_t i; | |
134 | ||
135 | /* | |
136 | * In some cases there may be functions which are not seen to return. | |
137 | * For example when setjmp / longjmp has been used. Or the perf context | |
138 | * switch in the kernel which doesn't stop and start tracing in exactly | |
139 | * the same code path. When that happens the return address will be | |
140 | * further down the stack. If the return address is not found at all, | |
141 | * we assume the opposite (i.e. this is a return for a call that wasn't | |
142 | * seen for some reason) and leave the stack alone. | |
143 | */ | |
144 | for (i = ts->cnt; i; ) { | |
145 | if (ts->stack[--i].ret_addr == ret_addr) { | |
146 | ts->cnt = i; | |
147 | return; | |
148 | } | |
149 | } | |
150 | } | |
151 | ||
92a9e4f7 AH |
152 | static bool thread_stack__in_kernel(struct thread_stack *ts) |
153 | { | |
154 | if (!ts->cnt) | |
155 | return false; | |
156 | ||
157 | return ts->stack[ts->cnt - 1].cp->in_kernel; | |
158 | } | |
159 | ||
160 | static int thread_stack__call_return(struct thread *thread, | |
161 | struct thread_stack *ts, size_t idx, | |
162 | u64 timestamp, u64 ref, bool no_return) | |
163 | { | |
164 | struct call_return_processor *crp = ts->crp; | |
165 | struct thread_stack_entry *tse; | |
166 | struct call_return cr = { | |
167 | .thread = thread, | |
168 | .comm = ts->comm, | |
169 | .db_id = 0, | |
170 | }; | |
171 | ||
172 | tse = &ts->stack[idx]; | |
173 | cr.cp = tse->cp; | |
174 | cr.call_time = tse->timestamp; | |
175 | cr.return_time = timestamp; | |
176 | cr.branch_count = ts->branch_count - tse->branch_count; | |
177 | cr.call_ref = tse->ref; | |
178 | cr.return_ref = ref; | |
179 | if (tse->no_call) | |
180 | cr.flags |= CALL_RETURN_NO_CALL; | |
181 | if (no_return) | |
182 | cr.flags |= CALL_RETURN_NO_RETURN; | |
183 | ||
184 | return crp->process(&cr, crp->data); | |
185 | } | |
186 | ||
a5499b37 | 187 | static int __thread_stack__flush(struct thread *thread, struct thread_stack *ts) |
92a9e4f7 AH |
188 | { |
189 | struct call_return_processor *crp = ts->crp; | |
190 | int err; | |
191 | ||
192 | if (!crp) { | |
193 | ts->cnt = 0; | |
194 | return 0; | |
195 | } | |
196 | ||
197 | while (ts->cnt) { | |
198 | err = thread_stack__call_return(thread, ts, --ts->cnt, | |
199 | ts->last_time, 0, true); | |
200 | if (err) { | |
201 | pr_err("Error flushing thread stack!\n"); | |
202 | ts->cnt = 0; | |
203 | return err; | |
204 | } | |
205 | } | |
206 | ||
207 | return 0; | |
208 | } | |
209 | ||
a5499b37 AH |
210 | int thread_stack__flush(struct thread *thread) |
211 | { | |
212 | if (thread->ts) | |
213 | return __thread_stack__flush(thread, thread->ts); | |
214 | ||
215 | return 0; | |
216 | } | |
217 | ||
00447ccd AH |
218 | int thread_stack__event(struct thread *thread, u32 flags, u64 from_ip, |
219 | u64 to_ip, u16 insn_len, u64 trace_nr) | |
220 | { | |
221 | if (!thread) | |
222 | return -EINVAL; | |
223 | ||
224 | if (!thread->ts) { | |
92a9e4f7 | 225 | thread->ts = thread_stack__new(thread, NULL); |
00447ccd AH |
226 | if (!thread->ts) { |
227 | pr_warning("Out of memory: no thread stack\n"); | |
228 | return -ENOMEM; | |
229 | } | |
230 | thread->ts->trace_nr = trace_nr; | |
231 | } | |
232 | ||
233 | /* | |
234 | * When the trace is discontinuous, the trace_nr changes. In that case | |
235 | * the stack might be completely invalid. Better to report nothing than | |
92a9e4f7 | 236 | * to report something misleading, so flush the stack. |
00447ccd AH |
237 | */ |
238 | if (trace_nr != thread->ts->trace_nr) { | |
92a9e4f7 | 239 | if (thread->ts->trace_nr) |
a5499b37 | 240 | __thread_stack__flush(thread, thread->ts); |
00447ccd | 241 | thread->ts->trace_nr = trace_nr; |
00447ccd AH |
242 | } |
243 | ||
92a9e4f7 AH |
244 | /* Stop here if thread_stack__process() is in use */ |
245 | if (thread->ts->crp) | |
246 | return 0; | |
247 | ||
00447ccd AH |
248 | if (flags & PERF_IP_FLAG_CALL) { |
249 | u64 ret_addr; | |
250 | ||
251 | if (!to_ip) | |
252 | return 0; | |
253 | ret_addr = from_ip + insn_len; | |
254 | if (ret_addr == to_ip) | |
255 | return 0; /* Zero-length calls are excluded */ | |
256 | return thread_stack__push(thread->ts, ret_addr); | |
257 | } else if (flags & PERF_IP_FLAG_RETURN) { | |
258 | if (!from_ip) | |
259 | return 0; | |
260 | thread_stack__pop(thread->ts, to_ip); | |
261 | } | |
262 | ||
263 | return 0; | |
264 | } | |
265 | ||
92a9e4f7 AH |
266 | void thread_stack__set_trace_nr(struct thread *thread, u64 trace_nr) |
267 | { | |
268 | if (!thread || !thread->ts) | |
269 | return; | |
270 | ||
271 | if (trace_nr != thread->ts->trace_nr) { | |
272 | if (thread->ts->trace_nr) | |
a5499b37 | 273 | __thread_stack__flush(thread, thread->ts); |
92a9e4f7 AH |
274 | thread->ts->trace_nr = trace_nr; |
275 | } | |
276 | } | |
277 | ||
00447ccd AH |
278 | void thread_stack__free(struct thread *thread) |
279 | { | |
280 | if (thread->ts) { | |
a5499b37 | 281 | __thread_stack__flush(thread, thread->ts); |
00447ccd AH |
282 | zfree(&thread->ts->stack); |
283 | zfree(&thread->ts); | |
284 | } | |
285 | } | |
286 | ||
287 | void thread_stack__sample(struct thread *thread, struct ip_callchain *chain, | |
288 | size_t sz, u64 ip) | |
289 | { | |
290 | size_t i; | |
291 | ||
292 | if (!thread || !thread->ts) | |
293 | chain->nr = 1; | |
294 | else | |
295 | chain->nr = min(sz, thread->ts->cnt + 1); | |
296 | ||
297 | chain->ips[0] = ip; | |
298 | ||
299 | for (i = 1; i < chain->nr; i++) | |
300 | chain->ips[i] = thread->ts->stack[thread->ts->cnt - i].ret_addr; | |
301 | } | |
92a9e4f7 | 302 | |
92a9e4f7 AH |
303 | struct call_return_processor * |
304 | call_return_processor__new(int (*process)(struct call_return *cr, void *data), | |
305 | void *data) | |
306 | { | |
307 | struct call_return_processor *crp; | |
308 | ||
309 | crp = zalloc(sizeof(struct call_return_processor)); | |
310 | if (!crp) | |
311 | return NULL; | |
312 | crp->cpr = call_path_root__new(); | |
313 | if (!crp->cpr) | |
314 | goto out_free; | |
315 | crp->process = process; | |
316 | crp->data = data; | |
317 | return crp; | |
318 | ||
319 | out_free: | |
320 | free(crp); | |
321 | return NULL; | |
322 | } | |
323 | ||
324 | void call_return_processor__free(struct call_return_processor *crp) | |
325 | { | |
326 | if (crp) { | |
327 | call_path_root__free(crp->cpr); | |
328 | free(crp); | |
329 | } | |
330 | } | |
331 | ||
332 | static int thread_stack__push_cp(struct thread_stack *ts, u64 ret_addr, | |
333 | u64 timestamp, u64 ref, struct call_path *cp, | |
334 | bool no_call) | |
335 | { | |
336 | struct thread_stack_entry *tse; | |
337 | int err; | |
338 | ||
339 | if (ts->cnt == ts->sz) { | |
340 | err = thread_stack__grow(ts); | |
341 | if (err) | |
342 | return err; | |
343 | } | |
344 | ||
345 | tse = &ts->stack[ts->cnt++]; | |
346 | tse->ret_addr = ret_addr; | |
347 | tse->timestamp = timestamp; | |
348 | tse->ref = ref; | |
349 | tse->branch_count = ts->branch_count; | |
350 | tse->cp = cp; | |
351 | tse->no_call = no_call; | |
352 | ||
353 | return 0; | |
354 | } | |
355 | ||
356 | static int thread_stack__pop_cp(struct thread *thread, struct thread_stack *ts, | |
357 | u64 ret_addr, u64 timestamp, u64 ref, | |
358 | struct symbol *sym) | |
359 | { | |
360 | int err; | |
361 | ||
362 | if (!ts->cnt) | |
363 | return 1; | |
364 | ||
365 | if (ts->cnt == 1) { | |
366 | struct thread_stack_entry *tse = &ts->stack[0]; | |
367 | ||
368 | if (tse->cp->sym == sym) | |
369 | return thread_stack__call_return(thread, ts, --ts->cnt, | |
370 | timestamp, ref, false); | |
371 | } | |
372 | ||
373 | if (ts->stack[ts->cnt - 1].ret_addr == ret_addr) { | |
374 | return thread_stack__call_return(thread, ts, --ts->cnt, | |
375 | timestamp, ref, false); | |
376 | } else { | |
377 | size_t i = ts->cnt - 1; | |
378 | ||
379 | while (i--) { | |
380 | if (ts->stack[i].ret_addr != ret_addr) | |
381 | continue; | |
382 | i += 1; | |
383 | while (ts->cnt > i) { | |
384 | err = thread_stack__call_return(thread, ts, | |
385 | --ts->cnt, | |
386 | timestamp, ref, | |
387 | true); | |
388 | if (err) | |
389 | return err; | |
390 | } | |
391 | return thread_stack__call_return(thread, ts, --ts->cnt, | |
392 | timestamp, ref, false); | |
393 | } | |
394 | } | |
395 | ||
396 | return 1; | |
397 | } | |
398 | ||
399 | static int thread_stack__bottom(struct thread *thread, struct thread_stack *ts, | |
400 | struct perf_sample *sample, | |
401 | struct addr_location *from_al, | |
402 | struct addr_location *to_al, u64 ref) | |
403 | { | |
404 | struct call_path_root *cpr = ts->crp->cpr; | |
405 | struct call_path *cp; | |
406 | struct symbol *sym; | |
407 | u64 ip; | |
408 | ||
409 | if (sample->ip) { | |
410 | ip = sample->ip; | |
411 | sym = from_al->sym; | |
412 | } else if (sample->addr) { | |
413 | ip = sample->addr; | |
414 | sym = to_al->sym; | |
415 | } else { | |
416 | return 0; | |
417 | } | |
418 | ||
419 | cp = call_path__findnew(cpr, &cpr->call_path, sym, ip, | |
420 | ts->kernel_start); | |
421 | if (!cp) | |
422 | return -ENOMEM; | |
423 | ||
424 | return thread_stack__push_cp(thread->ts, ip, sample->time, ref, cp, | |
425 | true); | |
426 | } | |
427 | ||
428 | static int thread_stack__no_call_return(struct thread *thread, | |
429 | struct thread_stack *ts, | |
430 | struct perf_sample *sample, | |
431 | struct addr_location *from_al, | |
432 | struct addr_location *to_al, u64 ref) | |
433 | { | |
434 | struct call_path_root *cpr = ts->crp->cpr; | |
435 | struct call_path *cp, *parent; | |
436 | u64 ks = ts->kernel_start; | |
437 | int err; | |
438 | ||
439 | if (sample->ip >= ks && sample->addr < ks) { | |
440 | /* Return to userspace, so pop all kernel addresses */ | |
441 | while (thread_stack__in_kernel(ts)) { | |
442 | err = thread_stack__call_return(thread, ts, --ts->cnt, | |
443 | sample->time, ref, | |
444 | true); | |
445 | if (err) | |
446 | return err; | |
447 | } | |
448 | ||
449 | /* If the stack is empty, push the userspace address */ | |
450 | if (!ts->cnt) { | |
451 | cp = call_path__findnew(cpr, &cpr->call_path, | |
452 | to_al->sym, sample->addr, | |
453 | ts->kernel_start); | |
454 | if (!cp) | |
455 | return -ENOMEM; | |
456 | return thread_stack__push_cp(ts, 0, sample->time, ref, | |
457 | cp, true); | |
458 | } | |
459 | } else if (thread_stack__in_kernel(ts) && sample->ip < ks) { | |
460 | /* Return to userspace, so pop all kernel addresses */ | |
461 | while (thread_stack__in_kernel(ts)) { | |
462 | err = thread_stack__call_return(thread, ts, --ts->cnt, | |
463 | sample->time, ref, | |
464 | true); | |
465 | if (err) | |
466 | return err; | |
467 | } | |
468 | } | |
469 | ||
470 | if (ts->cnt) | |
471 | parent = ts->stack[ts->cnt - 1].cp; | |
472 | else | |
473 | parent = &cpr->call_path; | |
474 | ||
475 | /* This 'return' had no 'call', so push and pop top of stack */ | |
476 | cp = call_path__findnew(cpr, parent, from_al->sym, sample->ip, | |
477 | ts->kernel_start); | |
478 | if (!cp) | |
479 | return -ENOMEM; | |
480 | ||
481 | err = thread_stack__push_cp(ts, sample->addr, sample->time, ref, cp, | |
482 | true); | |
483 | if (err) | |
484 | return err; | |
485 | ||
486 | return thread_stack__pop_cp(thread, ts, sample->addr, sample->time, ref, | |
487 | to_al->sym); | |
488 | } | |
489 | ||
490 | static int thread_stack__trace_begin(struct thread *thread, | |
491 | struct thread_stack *ts, u64 timestamp, | |
492 | u64 ref) | |
493 | { | |
494 | struct thread_stack_entry *tse; | |
495 | int err; | |
496 | ||
497 | if (!ts->cnt) | |
498 | return 0; | |
499 | ||
500 | /* Pop trace end */ | |
501 | tse = &ts->stack[ts->cnt - 1]; | |
502 | if (tse->cp->sym == NULL && tse->cp->ip == 0) { | |
503 | err = thread_stack__call_return(thread, ts, --ts->cnt, | |
504 | timestamp, ref, false); | |
505 | if (err) | |
506 | return err; | |
507 | } | |
508 | ||
509 | return 0; | |
510 | } | |
511 | ||
512 | static int thread_stack__trace_end(struct thread_stack *ts, | |
513 | struct perf_sample *sample, u64 ref) | |
514 | { | |
515 | struct call_path_root *cpr = ts->crp->cpr; | |
516 | struct call_path *cp; | |
517 | u64 ret_addr; | |
518 | ||
519 | /* No point having 'trace end' on the bottom of the stack */ | |
520 | if (!ts->cnt || (ts->cnt == 1 && ts->stack[0].ref == ref)) | |
521 | return 0; | |
522 | ||
523 | cp = call_path__findnew(cpr, ts->stack[ts->cnt - 1].cp, NULL, 0, | |
524 | ts->kernel_start); | |
525 | if (!cp) | |
526 | return -ENOMEM; | |
527 | ||
528 | ret_addr = sample->ip + sample->insn_len; | |
529 | ||
530 | return thread_stack__push_cp(ts, ret_addr, sample->time, ref, cp, | |
531 | false); | |
532 | } | |
533 | ||
534 | int thread_stack__process(struct thread *thread, struct comm *comm, | |
535 | struct perf_sample *sample, | |
536 | struct addr_location *from_al, | |
537 | struct addr_location *to_al, u64 ref, | |
538 | struct call_return_processor *crp) | |
539 | { | |
540 | struct thread_stack *ts = thread->ts; | |
541 | int err = 0; | |
542 | ||
543 | if (ts) { | |
544 | if (!ts->crp) { | |
545 | /* Supersede thread_stack__event() */ | |
546 | thread_stack__free(thread); | |
547 | thread->ts = thread_stack__new(thread, crp); | |
548 | if (!thread->ts) | |
549 | return -ENOMEM; | |
550 | ts = thread->ts; | |
551 | ts->comm = comm; | |
552 | } | |
553 | } else { | |
554 | thread->ts = thread_stack__new(thread, crp); | |
555 | if (!thread->ts) | |
556 | return -ENOMEM; | |
557 | ts = thread->ts; | |
558 | ts->comm = comm; | |
559 | } | |
560 | ||
561 | /* Flush stack on exec */ | |
562 | if (ts->comm != comm && thread->pid_ == thread->tid) { | |
a5499b37 | 563 | err = __thread_stack__flush(thread, ts); |
92a9e4f7 AH |
564 | if (err) |
565 | return err; | |
566 | ts->comm = comm; | |
567 | } | |
568 | ||
569 | /* If the stack is empty, put the current symbol on the stack */ | |
570 | if (!ts->cnt) { | |
571 | err = thread_stack__bottom(thread, ts, sample, from_al, to_al, | |
572 | ref); | |
573 | if (err) | |
574 | return err; | |
575 | } | |
576 | ||
577 | ts->branch_count += 1; | |
578 | ts->last_time = sample->time; | |
579 | ||
580 | if (sample->flags & PERF_IP_FLAG_CALL) { | |
581 | struct call_path_root *cpr = ts->crp->cpr; | |
582 | struct call_path *cp; | |
583 | u64 ret_addr; | |
584 | ||
585 | if (!sample->ip || !sample->addr) | |
586 | return 0; | |
587 | ||
588 | ret_addr = sample->ip + sample->insn_len; | |
589 | if (ret_addr == sample->addr) | |
590 | return 0; /* Zero-length calls are excluded */ | |
591 | ||
592 | cp = call_path__findnew(cpr, ts->stack[ts->cnt - 1].cp, | |
593 | to_al->sym, sample->addr, | |
594 | ts->kernel_start); | |
595 | if (!cp) | |
596 | return -ENOMEM; | |
597 | err = thread_stack__push_cp(ts, ret_addr, sample->time, ref, | |
598 | cp, false); | |
599 | } else if (sample->flags & PERF_IP_FLAG_RETURN) { | |
600 | if (!sample->ip || !sample->addr) | |
601 | return 0; | |
602 | ||
603 | err = thread_stack__pop_cp(thread, ts, sample->addr, | |
604 | sample->time, ref, from_al->sym); | |
605 | if (err) { | |
606 | if (err < 0) | |
607 | return err; | |
608 | err = thread_stack__no_call_return(thread, ts, sample, | |
609 | from_al, to_al, ref); | |
610 | } | |
611 | } else if (sample->flags & PERF_IP_FLAG_TRACE_BEGIN) { | |
612 | err = thread_stack__trace_begin(thread, ts, sample->time, ref); | |
613 | } else if (sample->flags & PERF_IP_FLAG_TRACE_END) { | |
614 | err = thread_stack__trace_end(ts, sample, ref); | |
615 | } | |
616 | ||
617 | return err; | |
618 | } | |
e216708d AH |
619 | |
620 | size_t thread_stack__depth(struct thread *thread) | |
621 | { | |
622 | if (!thread->ts) | |
623 | return 0; | |
624 | return thread->ts->cnt; | |
625 | } |