xref: /linux/tools/perf/util/hist.c (revision d0b73b488c55df905ea8faaad079f8535629ed26)
1 #include "annotate.h"
2 #include "util.h"
3 #include "build-id.h"
4 #include "hist.h"
5 #include "session.h"
6 #include "sort.h"
7 #include <math.h>
8 
9 static bool hists__filter_entry_by_dso(struct hists *hists,
10 				       struct hist_entry *he);
11 static bool hists__filter_entry_by_thread(struct hists *hists,
12 					  struct hist_entry *he);
13 static bool hists__filter_entry_by_symbol(struct hists *hists,
14 					  struct hist_entry *he);
15 
16 enum hist_filter {
17 	HIST_FILTER__DSO,
18 	HIST_FILTER__THREAD,
19 	HIST_FILTER__PARENT,
20 	HIST_FILTER__SYMBOL,
21 };
22 
23 struct callchain_param	callchain_param = {
24 	.mode	= CHAIN_GRAPH_REL,
25 	.min_percent = 0.5,
26 	.order  = ORDER_CALLEE
27 };
28 
29 u16 hists__col_len(struct hists *hists, enum hist_column col)
30 {
31 	return hists->col_len[col];
32 }
33 
34 void hists__set_col_len(struct hists *hists, enum hist_column col, u16 len)
35 {
36 	hists->col_len[col] = len;
37 }
38 
39 bool hists__new_col_len(struct hists *hists, enum hist_column col, u16 len)
40 {
41 	if (len > hists__col_len(hists, col)) {
42 		hists__set_col_len(hists, col, len);
43 		return true;
44 	}
45 	return false;
46 }
47 
48 void hists__reset_col_len(struct hists *hists)
49 {
50 	enum hist_column col;
51 
52 	for (col = 0; col < HISTC_NR_COLS; ++col)
53 		hists__set_col_len(hists, col, 0);
54 }
55 
56 static void hists__set_unres_dso_col_len(struct hists *hists, int dso)
57 {
58 	const unsigned int unresolved_col_width = BITS_PER_LONG / 4;
59 
60 	if (hists__col_len(hists, dso) < unresolved_col_width &&
61 	    !symbol_conf.col_width_list_str && !symbol_conf.field_sep &&
62 	    !symbol_conf.dso_list)
63 		hists__set_col_len(hists, dso, unresolved_col_width);
64 }
65 
66 void hists__calc_col_len(struct hists *hists, struct hist_entry *h)
67 {
68 	const unsigned int unresolved_col_width = BITS_PER_LONG / 4;
69 	u16 len;
70 
71 	if (h->ms.sym)
72 		hists__new_col_len(hists, HISTC_SYMBOL, h->ms.sym->namelen + 4);
73 	else
74 		hists__set_unres_dso_col_len(hists, HISTC_DSO);
75 
76 	len = thread__comm_len(h->thread);
77 	if (hists__new_col_len(hists, HISTC_COMM, len))
78 		hists__set_col_len(hists, HISTC_THREAD, len + 6);
79 
80 	if (h->ms.map) {
81 		len = dso__name_len(h->ms.map->dso);
82 		hists__new_col_len(hists, HISTC_DSO, len);
83 	}
84 
85 	if (h->branch_info) {
86 		int symlen;
87 		/*
88 		 * +4 accounts for '[x] ' priv level info
89 		 * +2 account of 0x prefix on raw addresses
90 		 */
91 		if (h->branch_info->from.sym) {
92 			symlen = (int)h->branch_info->from.sym->namelen + 4;
93 			hists__new_col_len(hists, HISTC_SYMBOL_FROM, symlen);
94 
95 			symlen = dso__name_len(h->branch_info->from.map->dso);
96 			hists__new_col_len(hists, HISTC_DSO_FROM, symlen);
97 		} else {
98 			symlen = unresolved_col_width + 4 + 2;
99 			hists__new_col_len(hists, HISTC_SYMBOL_FROM, symlen);
100 			hists__set_unres_dso_col_len(hists, HISTC_DSO_FROM);
101 		}
102 
103 		if (h->branch_info->to.sym) {
104 			symlen = (int)h->branch_info->to.sym->namelen + 4;
105 			hists__new_col_len(hists, HISTC_SYMBOL_TO, symlen);
106 
107 			symlen = dso__name_len(h->branch_info->to.map->dso);
108 			hists__new_col_len(hists, HISTC_DSO_TO, symlen);
109 		} else {
110 			symlen = unresolved_col_width + 4 + 2;
111 			hists__new_col_len(hists, HISTC_SYMBOL_TO, symlen);
112 			hists__set_unres_dso_col_len(hists, HISTC_DSO_TO);
113 		}
114 	}
115 }
116 
117 void hists__output_recalc_col_len(struct hists *hists, int max_rows)
118 {
119 	struct rb_node *next = rb_first(&hists->entries);
120 	struct hist_entry *n;
121 	int row = 0;
122 
123 	hists__reset_col_len(hists);
124 
125 	while (next && row++ < max_rows) {
126 		n = rb_entry(next, struct hist_entry, rb_node);
127 		if (!n->filtered)
128 			hists__calc_col_len(hists, n);
129 		next = rb_next(&n->rb_node);
130 	}
131 }
132 
133 static void hist_entry__add_cpumode_period(struct hist_entry *he,
134 					   unsigned int cpumode, u64 period)
135 {
136 	switch (cpumode) {
137 	case PERF_RECORD_MISC_KERNEL:
138 		he->stat.period_sys += period;
139 		break;
140 	case PERF_RECORD_MISC_USER:
141 		he->stat.period_us += period;
142 		break;
143 	case PERF_RECORD_MISC_GUEST_KERNEL:
144 		he->stat.period_guest_sys += period;
145 		break;
146 	case PERF_RECORD_MISC_GUEST_USER:
147 		he->stat.period_guest_us += period;
148 		break;
149 	default:
150 		break;
151 	}
152 }
153 
154 static void he_stat__add_period(struct he_stat *he_stat, u64 period)
155 {
156 	he_stat->period		+= period;
157 	he_stat->nr_events	+= 1;
158 }
159 
160 static void he_stat__add_stat(struct he_stat *dest, struct he_stat *src)
161 {
162 	dest->period		+= src->period;
163 	dest->period_sys	+= src->period_sys;
164 	dest->period_us		+= src->period_us;
165 	dest->period_guest_sys	+= src->period_guest_sys;
166 	dest->period_guest_us	+= src->period_guest_us;
167 	dest->nr_events		+= src->nr_events;
168 }
169 
170 static void hist_entry__decay(struct hist_entry *he)
171 {
172 	he->stat.period = (he->stat.period * 7) / 8;
173 	he->stat.nr_events = (he->stat.nr_events * 7) / 8;
174 }
175 
176 static bool hists__decay_entry(struct hists *hists, struct hist_entry *he)
177 {
178 	u64 prev_period = he->stat.period;
179 
180 	if (prev_period == 0)
181 		return true;
182 
183 	hist_entry__decay(he);
184 
185 	if (!he->filtered)
186 		hists->stats.total_period -= prev_period - he->stat.period;
187 
188 	return he->stat.period == 0;
189 }
190 
191 static void __hists__decay_entries(struct hists *hists, bool zap_user,
192 				   bool zap_kernel, bool threaded)
193 {
194 	struct rb_node *next = rb_first(&hists->entries);
195 	struct hist_entry *n;
196 
197 	while (next) {
198 		n = rb_entry(next, struct hist_entry, rb_node);
199 		next = rb_next(&n->rb_node);
200 		/*
201 		 * We may be annotating this, for instance, so keep it here in
202 		 * case some it gets new samples, we'll eventually free it when
203 		 * the user stops browsing and it agains gets fully decayed.
204 		 */
205 		if (((zap_user && n->level == '.') ||
206 		     (zap_kernel && n->level != '.') ||
207 		     hists__decay_entry(hists, n)) &&
208 		    !n->used) {
209 			rb_erase(&n->rb_node, &hists->entries);
210 
211 			if (sort__need_collapse || threaded)
212 				rb_erase(&n->rb_node_in, &hists->entries_collapsed);
213 
214 			hist_entry__free(n);
215 			--hists->nr_entries;
216 		}
217 	}
218 }
219 
220 void hists__decay_entries(struct hists *hists, bool zap_user, bool zap_kernel)
221 {
222 	return __hists__decay_entries(hists, zap_user, zap_kernel, false);
223 }
224 
225 void hists__decay_entries_threaded(struct hists *hists,
226 				   bool zap_user, bool zap_kernel)
227 {
228 	return __hists__decay_entries(hists, zap_user, zap_kernel, true);
229 }
230 
231 /*
232  * histogram, sorted on item, collects periods
233  */
234 
235 static struct hist_entry *hist_entry__new(struct hist_entry *template)
236 {
237 	size_t callchain_size = symbol_conf.use_callchain ? sizeof(struct callchain_root) : 0;
238 	struct hist_entry *he = malloc(sizeof(*he) + callchain_size);
239 
240 	if (he != NULL) {
241 		*he = *template;
242 
243 		if (he->ms.map)
244 			he->ms.map->referenced = true;
245 		if (symbol_conf.use_callchain)
246 			callchain_init(he->callchain);
247 
248 		INIT_LIST_HEAD(&he->pairs.node);
249 	}
250 
251 	return he;
252 }
253 
254 static void hists__inc_nr_entries(struct hists *hists, struct hist_entry *h)
255 {
256 	if (!h->filtered) {
257 		hists__calc_col_len(hists, h);
258 		++hists->nr_entries;
259 		hists->stats.total_period += h->stat.period;
260 	}
261 }
262 
263 static u8 symbol__parent_filter(const struct symbol *parent)
264 {
265 	if (symbol_conf.exclude_other && parent == NULL)
266 		return 1 << HIST_FILTER__PARENT;
267 	return 0;
268 }
269 
270 static struct hist_entry *add_hist_entry(struct hists *hists,
271 				      struct hist_entry *entry,
272 				      struct addr_location *al,
273 				      u64 period)
274 {
275 	struct rb_node **p;
276 	struct rb_node *parent = NULL;
277 	struct hist_entry *he;
278 	int cmp;
279 
280 	pthread_mutex_lock(&hists->lock);
281 
282 	p = &hists->entries_in->rb_node;
283 
284 	while (*p != NULL) {
285 		parent = *p;
286 		he = rb_entry(parent, struct hist_entry, rb_node_in);
287 
288 		cmp = hist_entry__cmp(entry, he);
289 
290 		if (!cmp) {
291 			he_stat__add_period(&he->stat, period);
292 
293 			/* If the map of an existing hist_entry has
294 			 * become out-of-date due to an exec() or
295 			 * similar, update it.  Otherwise we will
296 			 * mis-adjust symbol addresses when computing
297 			 * the history counter to increment.
298 			 */
299 			if (he->ms.map != entry->ms.map) {
300 				he->ms.map = entry->ms.map;
301 				if (he->ms.map)
302 					he->ms.map->referenced = true;
303 			}
304 			goto out;
305 		}
306 
307 		if (cmp < 0)
308 			p = &(*p)->rb_left;
309 		else
310 			p = &(*p)->rb_right;
311 	}
312 
313 	he = hist_entry__new(entry);
314 	if (!he)
315 		goto out_unlock;
316 
317 	rb_link_node(&he->rb_node_in, parent, p);
318 	rb_insert_color(&he->rb_node_in, hists->entries_in);
319 out:
320 	hist_entry__add_cpumode_period(he, al->cpumode, period);
321 out_unlock:
322 	pthread_mutex_unlock(&hists->lock);
323 	return he;
324 }
325 
326 struct hist_entry *__hists__add_branch_entry(struct hists *self,
327 					     struct addr_location *al,
328 					     struct symbol *sym_parent,
329 					     struct branch_info *bi,
330 					     u64 period)
331 {
332 	struct hist_entry entry = {
333 		.thread	= al->thread,
334 		.ms = {
335 			.map	= bi->to.map,
336 			.sym	= bi->to.sym,
337 		},
338 		.cpu	= al->cpu,
339 		.ip	= bi->to.addr,
340 		.level	= al->level,
341 		.stat = {
342 			.period	= period,
343 			.nr_events = 1,
344 		},
345 		.parent = sym_parent,
346 		.filtered = symbol__parent_filter(sym_parent),
347 		.branch_info = bi,
348 		.hists	= self,
349 	};
350 
351 	return add_hist_entry(self, &entry, al, period);
352 }
353 
354 struct hist_entry *__hists__add_entry(struct hists *self,
355 				      struct addr_location *al,
356 				      struct symbol *sym_parent, u64 period)
357 {
358 	struct hist_entry entry = {
359 		.thread	= al->thread,
360 		.ms = {
361 			.map	= al->map,
362 			.sym	= al->sym,
363 		},
364 		.cpu	= al->cpu,
365 		.ip	= al->addr,
366 		.level	= al->level,
367 		.stat = {
368 			.period	= period,
369 			.nr_events = 1,
370 		},
371 		.parent = sym_parent,
372 		.filtered = symbol__parent_filter(sym_parent),
373 		.hists	= self,
374 	};
375 
376 	return add_hist_entry(self, &entry, al, period);
377 }
378 
379 int64_t
380 hist_entry__cmp(struct hist_entry *left, struct hist_entry *right)
381 {
382 	struct sort_entry *se;
383 	int64_t cmp = 0;
384 
385 	list_for_each_entry(se, &hist_entry__sort_list, list) {
386 		cmp = se->se_cmp(left, right);
387 		if (cmp)
388 			break;
389 	}
390 
391 	return cmp;
392 }
393 
394 int64_t
395 hist_entry__collapse(struct hist_entry *left, struct hist_entry *right)
396 {
397 	struct sort_entry *se;
398 	int64_t cmp = 0;
399 
400 	list_for_each_entry(se, &hist_entry__sort_list, list) {
401 		int64_t (*f)(struct hist_entry *, struct hist_entry *);
402 
403 		f = se->se_collapse ?: se->se_cmp;
404 
405 		cmp = f(left, right);
406 		if (cmp)
407 			break;
408 	}
409 
410 	return cmp;
411 }
412 
413 void hist_entry__free(struct hist_entry *he)
414 {
415 	free(he->branch_info);
416 	free(he);
417 }
418 
419 /*
420  * collapse the histogram
421  */
422 
423 static bool hists__collapse_insert_entry(struct hists *hists __maybe_unused,
424 					 struct rb_root *root,
425 					 struct hist_entry *he)
426 {
427 	struct rb_node **p = &root->rb_node;
428 	struct rb_node *parent = NULL;
429 	struct hist_entry *iter;
430 	int64_t cmp;
431 
432 	while (*p != NULL) {
433 		parent = *p;
434 		iter = rb_entry(parent, struct hist_entry, rb_node_in);
435 
436 		cmp = hist_entry__collapse(iter, he);
437 
438 		if (!cmp) {
439 			he_stat__add_stat(&iter->stat, &he->stat);
440 
441 			if (symbol_conf.use_callchain) {
442 				callchain_cursor_reset(&callchain_cursor);
443 				callchain_merge(&callchain_cursor,
444 						iter->callchain,
445 						he->callchain);
446 			}
447 			hist_entry__free(he);
448 			return false;
449 		}
450 
451 		if (cmp < 0)
452 			p = &(*p)->rb_left;
453 		else
454 			p = &(*p)->rb_right;
455 	}
456 
457 	rb_link_node(&he->rb_node_in, parent, p);
458 	rb_insert_color(&he->rb_node_in, root);
459 	return true;
460 }
461 
462 static struct rb_root *hists__get_rotate_entries_in(struct hists *hists)
463 {
464 	struct rb_root *root;
465 
466 	pthread_mutex_lock(&hists->lock);
467 
468 	root = hists->entries_in;
469 	if (++hists->entries_in > &hists->entries_in_array[1])
470 		hists->entries_in = &hists->entries_in_array[0];
471 
472 	pthread_mutex_unlock(&hists->lock);
473 
474 	return root;
475 }
476 
477 static void hists__apply_filters(struct hists *hists, struct hist_entry *he)
478 {
479 	hists__filter_entry_by_dso(hists, he);
480 	hists__filter_entry_by_thread(hists, he);
481 	hists__filter_entry_by_symbol(hists, he);
482 }
483 
484 static void __hists__collapse_resort(struct hists *hists, bool threaded)
485 {
486 	struct rb_root *root;
487 	struct rb_node *next;
488 	struct hist_entry *n;
489 
490 	if (!sort__need_collapse && !threaded)
491 		return;
492 
493 	root = hists__get_rotate_entries_in(hists);
494 	next = rb_first(root);
495 
496 	while (next) {
497 		n = rb_entry(next, struct hist_entry, rb_node_in);
498 		next = rb_next(&n->rb_node_in);
499 
500 		rb_erase(&n->rb_node_in, root);
501 		if (hists__collapse_insert_entry(hists, &hists->entries_collapsed, n)) {
502 			/*
503 			 * If it wasn't combined with one of the entries already
504 			 * collapsed, we need to apply the filters that may have
505 			 * been set by, say, the hist_browser.
506 			 */
507 			hists__apply_filters(hists, n);
508 		}
509 	}
510 }
511 
512 void hists__collapse_resort(struct hists *hists)
513 {
514 	return __hists__collapse_resort(hists, false);
515 }
516 
517 void hists__collapse_resort_threaded(struct hists *hists)
518 {
519 	return __hists__collapse_resort(hists, true);
520 }
521 
522 /*
523  * reverse the map, sort on period.
524  */
525 
526 static void __hists__insert_output_entry(struct rb_root *entries,
527 					 struct hist_entry *he,
528 					 u64 min_callchain_hits)
529 {
530 	struct rb_node **p = &entries->rb_node;
531 	struct rb_node *parent = NULL;
532 	struct hist_entry *iter;
533 
534 	if (symbol_conf.use_callchain)
535 		callchain_param.sort(&he->sorted_chain, he->callchain,
536 				      min_callchain_hits, &callchain_param);
537 
538 	while (*p != NULL) {
539 		parent = *p;
540 		iter = rb_entry(parent, struct hist_entry, rb_node);
541 
542 		if (he->stat.period > iter->stat.period)
543 			p = &(*p)->rb_left;
544 		else
545 			p = &(*p)->rb_right;
546 	}
547 
548 	rb_link_node(&he->rb_node, parent, p);
549 	rb_insert_color(&he->rb_node, entries);
550 }
551 
552 static void __hists__output_resort(struct hists *hists, bool threaded)
553 {
554 	struct rb_root *root;
555 	struct rb_node *next;
556 	struct hist_entry *n;
557 	u64 min_callchain_hits;
558 
559 	min_callchain_hits = hists->stats.total_period * (callchain_param.min_percent / 100);
560 
561 	if (sort__need_collapse || threaded)
562 		root = &hists->entries_collapsed;
563 	else
564 		root = hists->entries_in;
565 
566 	next = rb_first(root);
567 	hists->entries = RB_ROOT;
568 
569 	hists->nr_entries = 0;
570 	hists->stats.total_period = 0;
571 	hists__reset_col_len(hists);
572 
573 	while (next) {
574 		n = rb_entry(next, struct hist_entry, rb_node_in);
575 		next = rb_next(&n->rb_node_in);
576 
577 		__hists__insert_output_entry(&hists->entries, n, min_callchain_hits);
578 		hists__inc_nr_entries(hists, n);
579 	}
580 }
581 
582 void hists__output_resort(struct hists *hists)
583 {
584 	return __hists__output_resort(hists, false);
585 }
586 
587 void hists__output_resort_threaded(struct hists *hists)
588 {
589 	return __hists__output_resort(hists, true);
590 }
591 
592 static void hists__remove_entry_filter(struct hists *hists, struct hist_entry *h,
593 				       enum hist_filter filter)
594 {
595 	h->filtered &= ~(1 << filter);
596 	if (h->filtered)
597 		return;
598 
599 	++hists->nr_entries;
600 	if (h->ms.unfolded)
601 		hists->nr_entries += h->nr_rows;
602 	h->row_offset = 0;
603 	hists->stats.total_period += h->stat.period;
604 	hists->stats.nr_events[PERF_RECORD_SAMPLE] += h->stat.nr_events;
605 
606 	hists__calc_col_len(hists, h);
607 }
608 
609 
610 static bool hists__filter_entry_by_dso(struct hists *hists,
611 				       struct hist_entry *he)
612 {
613 	if (hists->dso_filter != NULL &&
614 	    (he->ms.map == NULL || he->ms.map->dso != hists->dso_filter)) {
615 		he->filtered |= (1 << HIST_FILTER__DSO);
616 		return true;
617 	}
618 
619 	return false;
620 }
621 
622 void hists__filter_by_dso(struct hists *hists)
623 {
624 	struct rb_node *nd;
625 
626 	hists->nr_entries = hists->stats.total_period = 0;
627 	hists->stats.nr_events[PERF_RECORD_SAMPLE] = 0;
628 	hists__reset_col_len(hists);
629 
630 	for (nd = rb_first(&hists->entries); nd; nd = rb_next(nd)) {
631 		struct hist_entry *h = rb_entry(nd, struct hist_entry, rb_node);
632 
633 		if (symbol_conf.exclude_other && !h->parent)
634 			continue;
635 
636 		if (hists__filter_entry_by_dso(hists, h))
637 			continue;
638 
639 		hists__remove_entry_filter(hists, h, HIST_FILTER__DSO);
640 	}
641 }
642 
643 static bool hists__filter_entry_by_thread(struct hists *hists,
644 					  struct hist_entry *he)
645 {
646 	if (hists->thread_filter != NULL &&
647 	    he->thread != hists->thread_filter) {
648 		he->filtered |= (1 << HIST_FILTER__THREAD);
649 		return true;
650 	}
651 
652 	return false;
653 }
654 
655 void hists__filter_by_thread(struct hists *hists)
656 {
657 	struct rb_node *nd;
658 
659 	hists->nr_entries = hists->stats.total_period = 0;
660 	hists->stats.nr_events[PERF_RECORD_SAMPLE] = 0;
661 	hists__reset_col_len(hists);
662 
663 	for (nd = rb_first(&hists->entries); nd; nd = rb_next(nd)) {
664 		struct hist_entry *h = rb_entry(nd, struct hist_entry, rb_node);
665 
666 		if (hists__filter_entry_by_thread(hists, h))
667 			continue;
668 
669 		hists__remove_entry_filter(hists, h, HIST_FILTER__THREAD);
670 	}
671 }
672 
673 static bool hists__filter_entry_by_symbol(struct hists *hists,
674 					  struct hist_entry *he)
675 {
676 	if (hists->symbol_filter_str != NULL &&
677 	    (!he->ms.sym || strstr(he->ms.sym->name,
678 				   hists->symbol_filter_str) == NULL)) {
679 		he->filtered |= (1 << HIST_FILTER__SYMBOL);
680 		return true;
681 	}
682 
683 	return false;
684 }
685 
686 void hists__filter_by_symbol(struct hists *hists)
687 {
688 	struct rb_node *nd;
689 
690 	hists->nr_entries = hists->stats.total_period = 0;
691 	hists->stats.nr_events[PERF_RECORD_SAMPLE] = 0;
692 	hists__reset_col_len(hists);
693 
694 	for (nd = rb_first(&hists->entries); nd; nd = rb_next(nd)) {
695 		struct hist_entry *h = rb_entry(nd, struct hist_entry, rb_node);
696 
697 		if (hists__filter_entry_by_symbol(hists, h))
698 			continue;
699 
700 		hists__remove_entry_filter(hists, h, HIST_FILTER__SYMBOL);
701 	}
702 }
703 
704 int hist_entry__inc_addr_samples(struct hist_entry *he, int evidx, u64 ip)
705 {
706 	return symbol__inc_addr_samples(he->ms.sym, he->ms.map, evidx, ip);
707 }
708 
709 int hist_entry__annotate(struct hist_entry *he, size_t privsize)
710 {
711 	return symbol__annotate(he->ms.sym, he->ms.map, privsize);
712 }
713 
714 void hists__inc_nr_events(struct hists *hists, u32 type)
715 {
716 	++hists->stats.nr_events[0];
717 	++hists->stats.nr_events[type];
718 }
719 
720 static struct hist_entry *hists__add_dummy_entry(struct hists *hists,
721 						 struct hist_entry *pair)
722 {
723 	struct rb_node **p = &hists->entries.rb_node;
724 	struct rb_node *parent = NULL;
725 	struct hist_entry *he;
726 	int cmp;
727 
728 	while (*p != NULL) {
729 		parent = *p;
730 		he = rb_entry(parent, struct hist_entry, rb_node);
731 
732 		cmp = hist_entry__cmp(pair, he);
733 
734 		if (!cmp)
735 			goto out;
736 
737 		if (cmp < 0)
738 			p = &(*p)->rb_left;
739 		else
740 			p = &(*p)->rb_right;
741 	}
742 
743 	he = hist_entry__new(pair);
744 	if (he) {
745 		memset(&he->stat, 0, sizeof(he->stat));
746 		he->hists = hists;
747 		rb_link_node(&he->rb_node, parent, p);
748 		rb_insert_color(&he->rb_node, &hists->entries);
749 		hists__inc_nr_entries(hists, he);
750 	}
751 out:
752 	return he;
753 }
754 
755 static struct hist_entry *hists__find_entry(struct hists *hists,
756 					    struct hist_entry *he)
757 {
758 	struct rb_node *n = hists->entries.rb_node;
759 
760 	while (n) {
761 		struct hist_entry *iter = rb_entry(n, struct hist_entry, rb_node);
762 		int64_t cmp = hist_entry__cmp(he, iter);
763 
764 		if (cmp < 0)
765 			n = n->rb_left;
766 		else if (cmp > 0)
767 			n = n->rb_right;
768 		else
769 			return iter;
770 	}
771 
772 	return NULL;
773 }
774 
775 /*
776  * Look for pairs to link to the leader buckets (hist_entries):
777  */
778 void hists__match(struct hists *leader, struct hists *other)
779 {
780 	struct rb_node *nd;
781 	struct hist_entry *pos, *pair;
782 
783 	for (nd = rb_first(&leader->entries); nd; nd = rb_next(nd)) {
784 		pos  = rb_entry(nd, struct hist_entry, rb_node);
785 		pair = hists__find_entry(other, pos);
786 
787 		if (pair)
788 			hist__entry_add_pair(pos, pair);
789 	}
790 }
791 
792 /*
793  * Look for entries in the other hists that are not present in the leader, if
794  * we find them, just add a dummy entry on the leader hists, with period=0,
795  * nr_events=0, to serve as the list header.
796  */
797 int hists__link(struct hists *leader, struct hists *other)
798 {
799 	struct rb_node *nd;
800 	struct hist_entry *pos, *pair;
801 
802 	for (nd = rb_first(&other->entries); nd; nd = rb_next(nd)) {
803 		pos = rb_entry(nd, struct hist_entry, rb_node);
804 
805 		if (!hist_entry__has_pairs(pos)) {
806 			pair = hists__add_dummy_entry(leader, pos);
807 			if (pair == NULL)
808 				return -1;
809 			hist__entry_add_pair(pair, pos);
810 		}
811 	}
812 
813 	return 0;
814 }
815