hist.c 33.9 KB
Newer Older
1
#include "util.h"
2
#include "build-id.h"
3
#include "hist.h"
4 5
#include "session.h"
#include "sort.h"
6
#include "evlist.h"
7
#include "evsel.h"
8
#include "annotate.h"
9
#include "ui/progress.h"
10
#include <math.h>
11

12 13 14 15
static bool hists__filter_entry_by_dso(struct hists *hists,
				       struct hist_entry *he);
static bool hists__filter_entry_by_thread(struct hists *hists,
					  struct hist_entry *he);
16 17
static bool hists__filter_entry_by_symbol(struct hists *hists,
					  struct hist_entry *he);
18

19
u16 hists__col_len(struct hists *hists, enum hist_column col)
20
{
21
	return hists->col_len[col];
22 23
}

24
void hists__set_col_len(struct hists *hists, enum hist_column col, u16 len)
25
{
26
	hists->col_len[col] = len;
27 28
}

29
bool hists__new_col_len(struct hists *hists, enum hist_column col, u16 len)
30
{
31 32
	if (len > hists__col_len(hists, col)) {
		hists__set_col_len(hists, col, len);
33 34 35 36 37
		return true;
	}
	return false;
}

38
void hists__reset_col_len(struct hists *hists)
39 40 41 42
{
	enum hist_column col;

	for (col = 0; col < HISTC_NR_COLS; ++col)
43
		hists__set_col_len(hists, col, 0);
44 45
}

46 47 48 49 50 51 52 53 54 55
static void hists__set_unres_dso_col_len(struct hists *hists, int dso)
{
	const unsigned int unresolved_col_width = BITS_PER_LONG / 4;

	if (hists__col_len(hists, dso) < unresolved_col_width &&
	    !symbol_conf.col_width_list_str && !symbol_conf.field_sep &&
	    !symbol_conf.dso_list)
		hists__set_col_len(hists, dso, unresolved_col_width);
}

56
void hists__calc_col_len(struct hists *hists, struct hist_entry *h)
57
{
58
	const unsigned int unresolved_col_width = BITS_PER_LONG / 4;
59
	int symlen;
60 61
	u16 len;

62 63 64 65 66 67 68 69 70 71 72
	/*
	 * +4 accounts for '[x] ' priv level info
	 * +2 accounts for 0x prefix on raw addresses
	 * +3 accounts for ' y ' symtab origin info
	 */
	if (h->ms.sym) {
		symlen = h->ms.sym->namelen + 4;
		if (verbose)
			symlen += BITS_PER_LONG / 4 + 2 + 3;
		hists__new_col_len(hists, HISTC_SYMBOL, symlen);
	} else {
73 74
		symlen = unresolved_col_width + 4 + 2;
		hists__new_col_len(hists, HISTC_SYMBOL, symlen);
75
		hists__set_unres_dso_col_len(hists, HISTC_DSO);
76
	}
77 78

	len = thread__comm_len(h->thread);
79 80
	if (hists__new_col_len(hists, HISTC_COMM, len))
		hists__set_col_len(hists, HISTC_THREAD, len + 6);
81 82 83

	if (h->ms.map) {
		len = dso__name_len(h->ms.map->dso);
84
		hists__new_col_len(hists, HISTC_DSO, len);
85
	}
86

87 88 89
	if (h->parent)
		hists__new_col_len(hists, HISTC_PARENT, h->parent->namelen);

90 91 92
	if (h->branch_info) {
		if (h->branch_info->from.sym) {
			symlen = (int)h->branch_info->from.sym->namelen + 4;
93 94
			if (verbose)
				symlen += BITS_PER_LONG / 4 + 2 + 3;
95 96 97 98 99 100 101 102 103 104 105 106
			hists__new_col_len(hists, HISTC_SYMBOL_FROM, symlen);

			symlen = dso__name_len(h->branch_info->from.map->dso);
			hists__new_col_len(hists, HISTC_DSO_FROM, symlen);
		} else {
			symlen = unresolved_col_width + 4 + 2;
			hists__new_col_len(hists, HISTC_SYMBOL_FROM, symlen);
			hists__set_unres_dso_col_len(hists, HISTC_DSO_FROM);
		}

		if (h->branch_info->to.sym) {
			symlen = (int)h->branch_info->to.sym->namelen + 4;
107 108
			if (verbose)
				symlen += BITS_PER_LONG / 4 + 2 + 3;
109 110 111 112 113 114 115 116 117 118
			hists__new_col_len(hists, HISTC_SYMBOL_TO, symlen);

			symlen = dso__name_len(h->branch_info->to.map->dso);
			hists__new_col_len(hists, HISTC_DSO_TO, symlen);
		} else {
			symlen = unresolved_col_width + 4 + 2;
			hists__new_col_len(hists, HISTC_SYMBOL_TO, symlen);
			hists__set_unres_dso_col_len(hists, HISTC_DSO_TO);
		}
	}
119 120 121 122 123 124 125

	if (h->mem_info) {
		if (h->mem_info->daddr.sym) {
			symlen = (int)h->mem_info->daddr.sym->namelen + 4
			       + unresolved_col_width + 2;
			hists__new_col_len(hists, HISTC_MEM_DADDR_SYMBOL,
					   symlen);
D
Don Zickus 已提交
126 127
			hists__new_col_len(hists, HISTC_MEM_DCACHELINE,
					   symlen + 1);
128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152
		} else {
			symlen = unresolved_col_width + 4 + 2;
			hists__new_col_len(hists, HISTC_MEM_DADDR_SYMBOL,
					   symlen);
		}
		if (h->mem_info->daddr.map) {
			symlen = dso__name_len(h->mem_info->daddr.map->dso);
			hists__new_col_len(hists, HISTC_MEM_DADDR_DSO,
					   symlen);
		} else {
			symlen = unresolved_col_width + 4 + 2;
			hists__set_unres_dso_col_len(hists, HISTC_MEM_DADDR_DSO);
		}
	} else {
		symlen = unresolved_col_width + 4 + 2;
		hists__new_col_len(hists, HISTC_MEM_DADDR_SYMBOL, symlen);
		hists__set_unres_dso_col_len(hists, HISTC_MEM_DADDR_DSO);
	}

	hists__new_col_len(hists, HISTC_MEM_LOCKED, 6);
	hists__new_col_len(hists, HISTC_MEM_TLB, 22);
	hists__new_col_len(hists, HISTC_MEM_SNOOP, 12);
	hists__new_col_len(hists, HISTC_MEM_LVL, 21 + 3);
	hists__new_col_len(hists, HISTC_LOCAL_WEIGHT, 12);
	hists__new_col_len(hists, HISTC_GLOBAL_WEIGHT, 12);
153 154 155 156

	if (h->transaction)
		hists__new_col_len(hists, HISTC_TRANSACTION,
				   hist_entry__transaction_len());
157 158
}

159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174
void hists__output_recalc_col_len(struct hists *hists, int max_rows)
{
	struct rb_node *next = rb_first(&hists->entries);
	struct hist_entry *n;
	int row = 0;

	hists__reset_col_len(hists);

	while (next && row++ < max_rows) {
		n = rb_entry(next, struct hist_entry, rb_node);
		if (!n->filtered)
			hists__calc_col_len(hists, n);
		next = rb_next(&n->rb_node);
	}
}

175 176
static void he_stat__add_cpumode_period(struct he_stat *he_stat,
					unsigned int cpumode, u64 period)
177
{
178
	switch (cpumode) {
179
	case PERF_RECORD_MISC_KERNEL:
180
		he_stat->period_sys += period;
181 182
		break;
	case PERF_RECORD_MISC_USER:
183
		he_stat->period_us += period;
184 185
		break;
	case PERF_RECORD_MISC_GUEST_KERNEL:
186
		he_stat->period_guest_sys += period;
187 188
		break;
	case PERF_RECORD_MISC_GUEST_USER:
189
		he_stat->period_guest_us += period;
190 191 192 193 194 195
		break;
	default:
		break;
	}
}

196 197
static void he_stat__add_period(struct he_stat *he_stat, u64 period,
				u64 weight)
198
{
199

200
	he_stat->period		+= period;
201
	he_stat->weight		+= weight;
202 203 204 205 206 207 208 209 210 211 212
	he_stat->nr_events	+= 1;
}

static void he_stat__add_stat(struct he_stat *dest, struct he_stat *src)
{
	dest->period		+= src->period;
	dest->period_sys	+= src->period_sys;
	dest->period_us		+= src->period_us;
	dest->period_guest_sys	+= src->period_guest_sys;
	dest->period_guest_us	+= src->period_guest_us;
	dest->nr_events		+= src->nr_events;
213
	dest->weight		+= src->weight;
214 215
}

216
static void he_stat__decay(struct he_stat *he_stat)
217
{
218 219
	he_stat->period = (he_stat->period * 7) / 8;
	he_stat->nr_events = (he_stat->nr_events * 7) / 8;
220
	/* XXX need decay for weight too? */
221 222 223 224
}

static bool hists__decay_entry(struct hists *hists, struct hist_entry *he)
{
225
	u64 prev_period = he->stat.period;
226
	u64 diff;
227 228

	if (prev_period == 0)
229
		return true;
230

231
	he_stat__decay(&he->stat);
232 233
	if (symbol_conf.cumulate_callchain)
		he_stat__decay(he->stat_acc);
234

235 236 237
	diff = prev_period - he->stat.period;

	hists->stats.total_period -= diff;
238
	if (!he->filtered)
239
		hists->stats.total_non_filtered_period -= diff;
240

241
	return he->stat.period == 0;
242 243
}

244
void hists__decay_entries(struct hists *hists, bool zap_user, bool zap_kernel)
245 246 247 248 249 250 251
{
	struct rb_node *next = rb_first(&hists->entries);
	struct hist_entry *n;

	while (next) {
		n = rb_entry(next, struct hist_entry, rb_node);
		next = rb_next(&n->rb_node);
252 253 254 255 256
		/*
		 * We may be annotating this, for instance, so keep it here in
		 * case some it gets new samples, we'll eventually free it when
		 * the user stops browsing and it agains gets fully decayed.
		 */
257 258 259 260
		if (((zap_user && n->level == '.') ||
		     (zap_kernel && n->level != '.') ||
		     hists__decay_entry(hists, n)) &&
		    !n->used) {
261 262
			rb_erase(&n->rb_node, &hists->entries);

263
			if (sort__need_collapse)
264 265 266
				rb_erase(&n->rb_node_in, &hists->entries_collapsed);

			--hists->nr_entries;
267 268 269 270
			if (!n->filtered)
				--hists->nr_non_filtered_entries;

			hist_entry__free(n);
271 272 273 274
		}
	}
}

N
Namhyung Kim 已提交
275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296
void hists__delete_entries(struct hists *hists)
{
	struct rb_node *next = rb_first(&hists->entries);
	struct hist_entry *n;

	while (next) {
		n = rb_entry(next, struct hist_entry, rb_node);
		next = rb_next(&n->rb_node);

		rb_erase(&n->rb_node, &hists->entries);

		if (sort__need_collapse)
			rb_erase(&n->rb_node_in, &hists->entries_collapsed);

		--hists->nr_entries;
		if (!n->filtered)
			--hists->nr_non_filtered_entries;

		hist_entry__free(n);
	}
}

297
/*
298
 * histogram, sorted on item, collects periods
299 300
 */

301 302
static struct hist_entry *hist_entry__new(struct hist_entry *template,
					  bool sample_self)
303
{
304 305 306
	size_t callchain_size = 0;
	struct hist_entry *he;

307
	if (symbol_conf.use_callchain)
308 309 310
		callchain_size = sizeof(struct callchain_root);

	he = zalloc(sizeof(*he) + callchain_size);
311

312 313
	if (he != NULL) {
		*he = *template;
314

315 316 317 318 319 320 321
		if (symbol_conf.cumulate_callchain) {
			he->stat_acc = malloc(sizeof(he->stat));
			if (he->stat_acc == NULL) {
				free(he);
				return NULL;
			}
			memcpy(he->stat_acc, &he->stat, sizeof(he->stat));
322 323
			if (!sample_self)
				memset(&he->stat, 0, sizeof(he->stat));
324 325
		}

326 327
		if (he->ms.map)
			he->ms.map->referenced = true;
328 329

		if (he->branch_info) {
330 331
			/*
			 * This branch info is (a part of) allocated from
332
			 * sample__resolve_bstack() and will be freed after
333 334 335 336
			 * adding new entries.  So we need to save a copy.
			 */
			he->branch_info = malloc(sizeof(*he->branch_info));
			if (he->branch_info == NULL) {
337
				free(he->stat_acc);
338 339 340 341 342 343 344
				free(he);
				return NULL;
			}

			memcpy(he->branch_info, template->branch_info,
			       sizeof(*he->branch_info));

345 346 347 348 349 350
			if (he->branch_info->from.map)
				he->branch_info->from.map->referenced = true;
			if (he->branch_info->to.map)
				he->branch_info->to.map->referenced = true;
		}

351 352 353 354 355 356 357
		if (he->mem_info) {
			if (he->mem_info->iaddr.map)
				he->mem_info->iaddr.map->referenced = true;
			if (he->mem_info->daddr.map)
				he->mem_info->daddr.map->referenced = true;
		}

358
		if (symbol_conf.use_callchain)
359
			callchain_init(he->callchain);
360 361

		INIT_LIST_HEAD(&he->pairs.node);
362 363
	}

364
	return he;
365 366
}

367 368 369 370 371 372 373
static u8 symbol__parent_filter(const struct symbol *parent)
{
	if (symbol_conf.exclude_other && parent == NULL)
		return 1 << HIST_FILTER__PARENT;
	return 0;
}

374
static struct hist_entry *add_hist_entry(struct hists *hists,
375
					 struct hist_entry *entry,
376 377
					 struct addr_location *al,
					 bool sample_self)
378
{
379
	struct rb_node **p;
380 381
	struct rb_node *parent = NULL;
	struct hist_entry *he;
382
	int64_t cmp;
383 384
	u64 period = entry->stat.period;
	u64 weight = entry->stat.weight;
385

386 387
	p = &hists->entries_in->rb_node;

388 389
	while (*p != NULL) {
		parent = *p;
390
		he = rb_entry(parent, struct hist_entry, rb_node_in);
391

392 393 394 395 396 397 398
		/*
		 * Make sure that it receives arguments in a same order as
		 * hist_entry__collapse() so that we can use an appropriate
		 * function when searching an entry regardless which sort
		 * keys were used.
		 */
		cmp = hist_entry__cmp(he, entry);
399 400

		if (!cmp) {
401 402
			if (sample_self)
				he_stat__add_period(&he->stat, period, weight);
403 404
			if (symbol_conf.cumulate_callchain)
				he_stat__add_period(he->stat_acc, period, weight);
405

406
			/*
407
			 * This mem info was allocated from sample__resolve_mem
408 409
			 * and will not be used anymore.
			 */
410
			zfree(&entry->mem_info);
411

412 413 414 415 416 417 418 419 420 421 422
			/* If the map of an existing hist_entry has
			 * become out-of-date due to an exec() or
			 * similar, update it.  Otherwise we will
			 * mis-adjust symbol addresses when computing
			 * the history counter to increment.
			 */
			if (he->ms.map != entry->ms.map) {
				he->ms.map = entry->ms.map;
				if (he->ms.map)
					he->ms.map->referenced = true;
			}
423
			goto out;
424 425 426 427 428 429 430 431
		}

		if (cmp < 0)
			p = &(*p)->rb_left;
		else
			p = &(*p)->rb_right;
	}

432
	he = hist_entry__new(entry, sample_self);
433
	if (!he)
434
		return NULL;
435 436 437

	rb_link_node(&he->rb_node_in, parent, p);
	rb_insert_color(&he->rb_node_in, hists->entries_in);
438
out:
439 440
	if (sample_self)
		he_stat__add_cpumode_period(&he->stat, al->cpumode, period);
441 442
	if (symbol_conf.cumulate_callchain)
		he_stat__add_cpumode_period(he->stat_acc, al->cpumode, period);
443 444 445
	return he;
}

446
struct hist_entry *__hists__add_entry(struct hists *hists,
447
				      struct addr_location *al,
448 449 450
				      struct symbol *sym_parent,
				      struct branch_info *bi,
				      struct mem_info *mi,
451 452
				      u64 period, u64 weight, u64 transaction,
				      bool sample_self)
453 454 455
{
	struct hist_entry entry = {
		.thread	= al->thread,
456
		.comm = thread__comm(al->thread),
457 458 459 460
		.ms = {
			.map	= al->map,
			.sym	= al->sym,
		},
461 462 463 464
		.cpu	 = al->cpu,
		.cpumode = al->cpumode,
		.ip	 = al->addr,
		.level	 = al->level,
465
		.stat = {
466
			.nr_events = 1,
467
			.period	= period,
468
			.weight = weight,
469
		},
470
		.parent = sym_parent,
471
		.filtered = symbol__parent_filter(sym_parent) | al->filtered,
472
		.hists	= hists,
473 474
		.branch_info = bi,
		.mem_info = mi,
475
		.transaction = transaction,
476 477
	};

478
	return add_hist_entry(hists, &entry, al, sample_self);
479 480
}

481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513
static int
iter_next_nop_entry(struct hist_entry_iter *iter __maybe_unused,
		    struct addr_location *al __maybe_unused)
{
	return 0;
}

static int
iter_add_next_nop_entry(struct hist_entry_iter *iter __maybe_unused,
			struct addr_location *al __maybe_unused)
{
	return 0;
}

static int
iter_prepare_mem_entry(struct hist_entry_iter *iter, struct addr_location *al)
{
	struct perf_sample *sample = iter->sample;
	struct mem_info *mi;

	mi = sample__resolve_mem(sample, al);
	if (mi == NULL)
		return -ENOMEM;

	iter->priv = mi;
	return 0;
}

static int
iter_add_single_mem_entry(struct hist_entry_iter *iter, struct addr_location *al)
{
	u64 cost;
	struct mem_info *mi = iter->priv;
514
	struct hists *hists = evsel__hists(iter->evsel);
515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530
	struct hist_entry *he;

	if (mi == NULL)
		return -EINVAL;

	cost = iter->sample->weight;
	if (!cost)
		cost = 1;

	/*
	 * must pass period=weight in order to get the correct
	 * sorting from hists__collapse_resort() which is solely
	 * based on periods. We want sorting be done on nr_events * weight
	 * and this is indirectly achieved by passing period=weight here
	 * and the he_stat__add_period() function.
	 */
531
	he = __hists__add_entry(hists, al, iter->parent, NULL, mi,
532
				cost, cost, 0, true);
533 534 535 536 537 538 539 540
	if (!he)
		return -ENOMEM;

	iter->he = he;
	return 0;
}

static int
541 542
iter_finish_mem_entry(struct hist_entry_iter *iter,
		      struct addr_location *al __maybe_unused)
543 544
{
	struct perf_evsel *evsel = iter->evsel;
545
	struct hists *hists = evsel__hists(evsel);
546 547 548 549 550 551
	struct hist_entry *he = iter->he;
	int err = -EINVAL;

	if (he == NULL)
		goto out;

552
	hists__inc_nr_samples(hists, he->filtered);
553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588

	err = hist_entry__append_callchain(he, iter->sample);

out:
	/*
	 * We don't need to free iter->priv (mem_info) here since
	 * the mem info was either already freed in add_hist_entry() or
	 * passed to a new hist entry by hist_entry__new().
	 */
	iter->priv = NULL;

	iter->he = NULL;
	return err;
}

static int
iter_prepare_branch_entry(struct hist_entry_iter *iter, struct addr_location *al)
{
	struct branch_info *bi;
	struct perf_sample *sample = iter->sample;

	bi = sample__resolve_bstack(sample, al);
	if (!bi)
		return -ENOMEM;

	iter->curr = 0;
	iter->total = sample->branch_stack->nr;

	iter->priv = bi;
	return 0;
}

static int
iter_add_single_branch_entry(struct hist_entry_iter *iter __maybe_unused,
			     struct addr_location *al __maybe_unused)
{
589 590 591
	/* to avoid calling callback function */
	iter->he = NULL;

592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615
	return 0;
}

static int
iter_next_branch_entry(struct hist_entry_iter *iter, struct addr_location *al)
{
	struct branch_info *bi = iter->priv;
	int i = iter->curr;

	if (bi == NULL)
		return 0;

	if (iter->curr >= iter->total)
		return 0;

	al->map = bi[i].to.map;
	al->sym = bi[i].to.sym;
	al->addr = bi[i].to.addr;
	return 1;
}

static int
iter_add_next_branch_entry(struct hist_entry_iter *iter, struct addr_location *al)
{
616
	struct branch_info *bi;
617
	struct perf_evsel *evsel = iter->evsel;
618
	struct hists *hists = evsel__hists(evsel);
619 620 621 622 623 624 625 626 627 628 629 630 631
	struct hist_entry *he = NULL;
	int i = iter->curr;
	int err = 0;

	bi = iter->priv;

	if (iter->hide_unresolved && !(bi[i].from.sym && bi[i].to.sym))
		goto out;

	/*
	 * The report shows the percentage of total branches captured
	 * and not events sampled. Thus we use a pseudo period of 1.
	 */
632
	he = __hists__add_entry(hists, al, iter->parent, &bi[i], NULL,
633
				1, 1, 0, true);
634 635 636
	if (he == NULL)
		return -ENOMEM;

637
	hists__inc_nr_samples(hists, he->filtered);
638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668

out:
	iter->he = he;
	iter->curr++;
	return err;
}

static int
iter_finish_branch_entry(struct hist_entry_iter *iter,
			 struct addr_location *al __maybe_unused)
{
	zfree(&iter->priv);
	iter->he = NULL;

	return iter->curr >= iter->total ? 0 : -1;
}

static int
iter_prepare_normal_entry(struct hist_entry_iter *iter __maybe_unused,
			  struct addr_location *al __maybe_unused)
{
	return 0;
}

static int
iter_add_single_normal_entry(struct hist_entry_iter *iter, struct addr_location *al)
{
	struct perf_evsel *evsel = iter->evsel;
	struct perf_sample *sample = iter->sample;
	struct hist_entry *he;

669
	he = __hists__add_entry(evsel__hists(evsel), al, iter->parent, NULL, NULL,
670
				sample->period, sample->weight,
671
				sample->transaction, true);
672 673 674 675 676 677 678 679
	if (he == NULL)
		return -ENOMEM;

	iter->he = he;
	return 0;
}

static int
680 681
iter_finish_normal_entry(struct hist_entry_iter *iter,
			 struct addr_location *al __maybe_unused)
682 683 684 685 686 687 688 689 690 691
{
	struct hist_entry *he = iter->he;
	struct perf_evsel *evsel = iter->evsel;
	struct perf_sample *sample = iter->sample;

	if (he == NULL)
		return 0;

	iter->he = NULL;

692
	hists__inc_nr_samples(evsel__hists(evsel), he->filtered);
693 694 695 696

	return hist_entry__append_callchain(he, sample);
}

697 698 699 700
static int
iter_prepare_cumulative_entry(struct hist_entry_iter *iter __maybe_unused,
			      struct addr_location *al __maybe_unused)
{
701 702
	struct hist_entry **he_cache;

703
	callchain_cursor_commit(&callchain_cursor);
704 705 706 707 708 709 710 711 712 713 714 715 716

	/*
	 * This is for detecting cycles or recursions so that they're
	 * cumulated only one time to prevent entries more than 100%
	 * overhead.
	 */
	he_cache = malloc(sizeof(*he_cache) * (PERF_MAX_STACK_DEPTH + 1));
	if (he_cache == NULL)
		return -ENOMEM;

	iter->priv = he_cache;
	iter->curr = 0;

717 718 719 720 721 722 723 724
	return 0;
}

static int
iter_add_single_cumulative_entry(struct hist_entry_iter *iter,
				 struct addr_location *al)
{
	struct perf_evsel *evsel = iter->evsel;
725
	struct hists *hists = evsel__hists(evsel);
726
	struct perf_sample *sample = iter->sample;
727
	struct hist_entry **he_cache = iter->priv;
728 729 730
	struct hist_entry *he;
	int err = 0;

731
	he = __hists__add_entry(hists, al, iter->parent, NULL, NULL,
732 733 734 735 736 737
				sample->period, sample->weight,
				sample->transaction, true);
	if (he == NULL)
		return -ENOMEM;

	iter->he = he;
738
	he_cache[iter->curr++] = he;
739

740
	hist_entry__append_callchain(he, sample);
741 742 743 744 745 746 747

	/*
	 * We need to re-initialize the cursor since callchain_append()
	 * advanced the cursor to the end.
	 */
	callchain_cursor_commit(&callchain_cursor);

748
	hists__inc_nr_samples(hists, he->filtered);
749 750 751 752 753 754 755 756 757 758 759 760 761 762

	return err;
}

static int
iter_next_cumulative_entry(struct hist_entry_iter *iter,
			   struct addr_location *al)
{
	struct callchain_cursor_node *node;

	node = callchain_cursor_current(&callchain_cursor);
	if (node == NULL)
		return 0;

763
	return fill_callchain_info(al, node, iter->hide_unresolved);
764 765 766 767 768 769 770 771
}

static int
iter_add_next_cumulative_entry(struct hist_entry_iter *iter,
			       struct addr_location *al)
{
	struct perf_evsel *evsel = iter->evsel;
	struct perf_sample *sample = iter->sample;
772
	struct hist_entry **he_cache = iter->priv;
773
	struct hist_entry *he;
774 775 776 777 778 779 780 781 782 783 784 785
	struct hist_entry he_tmp = {
		.cpu = al->cpu,
		.thread = al->thread,
		.comm = thread__comm(al->thread),
		.ip = al->addr,
		.ms = {
			.map = al->map,
			.sym = al->sym,
		},
		.parent = iter->parent,
	};
	int i;
786 787 788 789 790
	struct callchain_cursor cursor;

	callchain_cursor_snapshot(&cursor, &callchain_cursor);

	callchain_cursor_advance(&callchain_cursor);
791 792 793 794 795 796

	/*
	 * Check if there's duplicate entries in the callchain.
	 * It's possible that it has cycles or recursive calls.
	 */
	for (i = 0; i < iter->curr; i++) {
797 798 799
		if (hist_entry__cmp(he_cache[i], &he_tmp) == 0) {
			/* to avoid calling callback function */
			iter->he = NULL;
800
			return 0;
801
		}
802
	}
803

804
	he = __hists__add_entry(evsel__hists(evsel), al, iter->parent, NULL, NULL,
805 806 807 808 809 810
				sample->period, sample->weight,
				sample->transaction, false);
	if (he == NULL)
		return -ENOMEM;

	iter->he = he;
811
	he_cache[iter->curr++] = he;
812

813 814
	if (symbol_conf.use_callchain)
		callchain_append(he->callchain, &cursor, sample->period);
815 816 817 818 819 820 821
	return 0;
}

static int
iter_finish_cumulative_entry(struct hist_entry_iter *iter,
			     struct addr_location *al __maybe_unused)
{
822
	zfree(&iter->priv);
823
	iter->he = NULL;
824

825 826 827
	return 0;
}

828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851
const struct hist_iter_ops hist_iter_mem = {
	.prepare_entry 		= iter_prepare_mem_entry,
	.add_single_entry 	= iter_add_single_mem_entry,
	.next_entry 		= iter_next_nop_entry,
	.add_next_entry 	= iter_add_next_nop_entry,
	.finish_entry 		= iter_finish_mem_entry,
};

const struct hist_iter_ops hist_iter_branch = {
	.prepare_entry 		= iter_prepare_branch_entry,
	.add_single_entry 	= iter_add_single_branch_entry,
	.next_entry 		= iter_next_branch_entry,
	.add_next_entry 	= iter_add_next_branch_entry,
	.finish_entry 		= iter_finish_branch_entry,
};

const struct hist_iter_ops hist_iter_normal = {
	.prepare_entry 		= iter_prepare_normal_entry,
	.add_single_entry 	= iter_add_single_normal_entry,
	.next_entry 		= iter_next_nop_entry,
	.add_next_entry 	= iter_add_next_nop_entry,
	.finish_entry 		= iter_finish_normal_entry,
};

852 853 854 855 856 857 858 859
const struct hist_iter_ops hist_iter_cumulative = {
	.prepare_entry 		= iter_prepare_cumulative_entry,
	.add_single_entry 	= iter_add_single_cumulative_entry,
	.next_entry 		= iter_next_cumulative_entry,
	.add_next_entry 	= iter_add_next_cumulative_entry,
	.finish_entry 		= iter_finish_cumulative_entry,
};

860 861
int hist_entry_iter__add(struct hist_entry_iter *iter, struct addr_location *al,
			 struct perf_evsel *evsel, struct perf_sample *sample,
862
			 int max_stack_depth, void *arg)
863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881
{
	int err, err2;

	err = sample__resolve_callchain(sample, &iter->parent, evsel, al,
					max_stack_depth);
	if (err)
		return err;

	iter->evsel = evsel;
	iter->sample = sample;

	err = iter->ops->prepare_entry(iter, al);
	if (err)
		goto out;

	err = iter->ops->add_single_entry(iter, al);
	if (err)
		goto out;

882 883 884 885 886 887
	if (iter->he && iter->add_entry_cb) {
		err = iter->add_entry_cb(iter, al, true, arg);
		if (err)
			goto out;
	}

888 889 890 891
	while (iter->ops->next_entry(iter, al)) {
		err = iter->ops->add_next_entry(iter, al);
		if (err)
			break;
892 893 894 895 896 897

		if (iter->he && iter->add_entry_cb) {
			err = iter->add_entry_cb(iter, al, false, arg);
			if (err)
				goto out;
		}
898 899 900 901 902 903 904 905 906 907
	}

out:
	err2 = iter->ops->finish_entry(iter, al);
	if (!err)
		err = err2;

	return err;
}

908 909 910
int64_t
hist_entry__cmp(struct hist_entry *left, struct hist_entry *right)
{
911
	struct perf_hpp_fmt *fmt;
912 913
	int64_t cmp = 0;

914
	perf_hpp__for_each_sort_list(fmt) {
915 916 917
		if (perf_hpp__should_skip(fmt))
			continue;

918
		cmp = fmt->cmp(left, right);
919 920 921 922 923 924 925 926 927 928
		if (cmp)
			break;
	}

	return cmp;
}

int64_t
hist_entry__collapse(struct hist_entry *left, struct hist_entry *right)
{
929
	struct perf_hpp_fmt *fmt;
930 931
	int64_t cmp = 0;

932
	perf_hpp__for_each_sort_list(fmt) {
933 934 935
		if (perf_hpp__should_skip(fmt))
			continue;

936
		cmp = fmt->collapse(left, right);
937 938 939 940 941 942 943 944 945
		if (cmp)
			break;
	}

	return cmp;
}

void hist_entry__free(struct hist_entry *he)
{
946 947
	zfree(&he->branch_info);
	zfree(&he->mem_info);
948
	zfree(&he->stat_acc);
949
	free_srcline(he->srcline);
950 951 952 953 954 955 956
	free(he);
}

/*
 * collapse the histogram
 */

957
static bool hists__collapse_insert_entry(struct hists *hists __maybe_unused,
958 959
					 struct rb_root *root,
					 struct hist_entry *he)
960
{
961
	struct rb_node **p = &root->rb_node;
962 963 964 965 966 967
	struct rb_node *parent = NULL;
	struct hist_entry *iter;
	int64_t cmp;

	while (*p != NULL) {
		parent = *p;
968
		iter = rb_entry(parent, struct hist_entry, rb_node_in);
969 970 971 972

		cmp = hist_entry__collapse(iter, he);

		if (!cmp) {
973
			he_stat__add_stat(&iter->stat, &he->stat);
974 975
			if (symbol_conf.cumulate_callchain)
				he_stat__add_stat(iter->stat_acc, he->stat_acc);
976

977
			if (symbol_conf.use_callchain) {
978 979 980
				callchain_cursor_reset(&callchain_cursor);
				callchain_merge(&callchain_cursor,
						iter->callchain,
981 982
						he->callchain);
			}
983
			hist_entry__free(he);
984
			return false;
985 986 987 988 989 990 991
		}

		if (cmp < 0)
			p = &(*p)->rb_left;
		else
			p = &(*p)->rb_right;
	}
992
	hists->nr_entries++;
993

994 995
	rb_link_node(&he->rb_node_in, parent, p);
	rb_insert_color(&he->rb_node_in, root);
996
	return true;
997 998
}

999
static struct rb_root *hists__get_rotate_entries_in(struct hists *hists)
1000
{
1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013
	struct rb_root *root;

	pthread_mutex_lock(&hists->lock);

	root = hists->entries_in;
	if (++hists->entries_in > &hists->entries_in_array[1])
		hists->entries_in = &hists->entries_in_array[0];

	pthread_mutex_unlock(&hists->lock);

	return root;
}

1014 1015 1016 1017
static void hists__apply_filters(struct hists *hists, struct hist_entry *he)
{
	hists__filter_entry_by_dso(hists, he);
	hists__filter_entry_by_thread(hists, he);
1018
	hists__filter_entry_by_symbol(hists, he);
1019 1020
}

1021
void hists__collapse_resort(struct hists *hists, struct ui_progress *prog)
1022 1023
{
	struct rb_root *root;
1024 1025 1026
	struct rb_node *next;
	struct hist_entry *n;

1027
	if (!sort__need_collapse)
1028 1029
		return;

1030 1031
	hists->nr_entries = 0;

1032
	root = hists__get_rotate_entries_in(hists);
1033

1034
	next = rb_first(root);
1035

1036
	while (next) {
1037 1038
		if (session_done())
			break;
1039 1040
		n = rb_entry(next, struct hist_entry, rb_node_in);
		next = rb_next(&n->rb_node_in);
1041

1042
		rb_erase(&n->rb_node_in, root);
1043 1044 1045 1046 1047 1048 1049 1050
		if (hists__collapse_insert_entry(hists, &hists->entries_collapsed, n)) {
			/*
			 * If it wasn't combined with one of the entries already
			 * collapsed, we need to apply the filters that may have
			 * been set by, say, the hist_browser.
			 */
			hists__apply_filters(hists, n);
		}
1051 1052
		if (prog)
			ui_progress__update(prog, 1);
1053
	}
1054
}
1055

1056
static int hist_entry__sort(struct hist_entry *a, struct hist_entry *b)
1057
{
1058 1059
	struct perf_hpp_fmt *fmt;
	int64_t cmp = 0;
1060

1061
	perf_hpp__for_each_sort_list(fmt) {
1062 1063 1064
		if (perf_hpp__should_skip(fmt))
			continue;

1065 1066
		cmp = fmt->sort(a, b);
		if (cmp)
1067 1068 1069
			break;
	}

1070
	return cmp;
1071 1072
}

1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101
static void hists__reset_filter_stats(struct hists *hists)
{
	hists->nr_non_filtered_entries = 0;
	hists->stats.total_non_filtered_period = 0;
}

void hists__reset_stats(struct hists *hists)
{
	hists->nr_entries = 0;
	hists->stats.total_period = 0;

	hists__reset_filter_stats(hists);
}

static void hists__inc_filter_stats(struct hists *hists, struct hist_entry *h)
{
	hists->nr_non_filtered_entries++;
	hists->stats.total_non_filtered_period += h->stat.period;
}

void hists__inc_stats(struct hists *hists, struct hist_entry *h)
{
	if (!h->filtered)
		hists__inc_filter_stats(hists, h);

	hists->nr_entries++;
	hists->stats.total_period += h->stat.period;
}

1102 1103 1104
static void __hists__insert_output_entry(struct rb_root *entries,
					 struct hist_entry *he,
					 u64 min_callchain_hits)
1105
{
1106
	struct rb_node **p = &entries->rb_node;
1107 1108 1109
	struct rb_node *parent = NULL;
	struct hist_entry *iter;

1110
	if (symbol_conf.use_callchain)
1111
		callchain_param.sort(&he->sorted_chain, he->callchain,
1112 1113 1114 1115 1116 1117
				      min_callchain_hits, &callchain_param);

	while (*p != NULL) {
		parent = *p;
		iter = rb_entry(parent, struct hist_entry, rb_node);

1118
		if (hist_entry__sort(he, iter) > 0)
1119 1120 1121 1122 1123 1124
			p = &(*p)->rb_left;
		else
			p = &(*p)->rb_right;
	}

	rb_link_node(&he->rb_node, parent, p);
1125
	rb_insert_color(&he->rb_node, entries);
1126 1127
}

1128
void hists__output_resort(struct hists *hists, struct ui_progress *prog)
1129
{
1130
	struct rb_root *root;
1131 1132 1133 1134
	struct rb_node *next;
	struct hist_entry *n;
	u64 min_callchain_hits;

1135
	min_callchain_hits = hists->stats.total_period * (callchain_param.min_percent / 100);
1136

1137
	if (sort__need_collapse)
1138 1139 1140 1141 1142 1143
		root = &hists->entries_collapsed;
	else
		root = hists->entries_in;

	next = rb_first(root);
	hists->entries = RB_ROOT;
1144

1145
	hists__reset_stats(hists);
1146
	hists__reset_col_len(hists);
1147

1148
	while (next) {
1149 1150
		n = rb_entry(next, struct hist_entry, rb_node_in);
		next = rb_next(&n->rb_node_in);
1151

1152
		__hists__insert_output_entry(&hists->entries, n, min_callchain_hits);
1153
		hists__inc_stats(hists, n);
1154 1155 1156

		if (!n->filtered)
			hists__calc_col_len(hists, n);
1157 1158 1159

		if (prog)
			ui_progress__update(prog, 1);
1160
	}
1161
}
1162

1163
static void hists__remove_entry_filter(struct hists *hists, struct hist_entry *h,
1164 1165 1166 1167 1168 1169
				       enum hist_filter filter)
{
	h->filtered &= ~(1 << filter);
	if (h->filtered)
		return;

1170 1171
	/* force fold unfiltered entry for simplicity */
	h->ms.unfolded = false;
1172
	h->row_offset = 0;
1173

1174
	hists->stats.nr_non_filtered_samples += h->stat.nr_events;
1175

1176
	hists__inc_filter_stats(hists, h);
1177
	hists__calc_col_len(hists, h);
1178 1179
}

1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192

static bool hists__filter_entry_by_dso(struct hists *hists,
				       struct hist_entry *he)
{
	if (hists->dso_filter != NULL &&
	    (he->ms.map == NULL || he->ms.map->dso != hists->dso_filter)) {
		he->filtered |= (1 << HIST_FILTER__DSO);
		return true;
	}

	return false;
}

1193
void hists__filter_by_dso(struct hists *hists)
1194 1195 1196
{
	struct rb_node *nd;

1197
	hists->stats.nr_non_filtered_samples = 0;
1198 1199

	hists__reset_filter_stats(hists);
1200
	hists__reset_col_len(hists);
1201

1202
	for (nd = rb_first(&hists->entries); nd; nd = rb_next(nd)) {
1203 1204 1205 1206 1207
		struct hist_entry *h = rb_entry(nd, struct hist_entry, rb_node);

		if (symbol_conf.exclude_other && !h->parent)
			continue;

1208
		if (hists__filter_entry_by_dso(hists, h))
1209 1210
			continue;

1211
		hists__remove_entry_filter(hists, h, HIST_FILTER__DSO);
1212 1213 1214
	}
}

1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226
static bool hists__filter_entry_by_thread(struct hists *hists,
					  struct hist_entry *he)
{
	if (hists->thread_filter != NULL &&
	    he->thread != hists->thread_filter) {
		he->filtered |= (1 << HIST_FILTER__THREAD);
		return true;
	}

	return false;
}

1227
void hists__filter_by_thread(struct hists *hists)
1228 1229 1230
{
	struct rb_node *nd;

1231
	hists->stats.nr_non_filtered_samples = 0;
1232 1233

	hists__reset_filter_stats(hists);
1234
	hists__reset_col_len(hists);
1235

1236
	for (nd = rb_first(&hists->entries); nd; nd = rb_next(nd)) {
1237 1238
		struct hist_entry *h = rb_entry(nd, struct hist_entry, rb_node);

1239
		if (hists__filter_entry_by_thread(hists, h))
1240
			continue;
1241

1242
		hists__remove_entry_filter(hists, h, HIST_FILTER__THREAD);
1243 1244
	}
}
1245

1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262
static bool hists__filter_entry_by_symbol(struct hists *hists,
					  struct hist_entry *he)
{
	if (hists->symbol_filter_str != NULL &&
	    (!he->ms.sym || strstr(he->ms.sym->name,
				   hists->symbol_filter_str) == NULL)) {
		he->filtered |= (1 << HIST_FILTER__SYMBOL);
		return true;
	}

	return false;
}

void hists__filter_by_symbol(struct hists *hists)
{
	struct rb_node *nd;

1263
	hists->stats.nr_non_filtered_samples = 0;
1264 1265

	hists__reset_filter_stats(hists);
1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277
	hists__reset_col_len(hists);

	for (nd = rb_first(&hists->entries); nd; nd = rb_next(nd)) {
		struct hist_entry *h = rb_entry(nd, struct hist_entry, rb_node);

		if (hists__filter_entry_by_symbol(hists, h))
			continue;

		hists__remove_entry_filter(hists, h, HIST_FILTER__SYMBOL);
	}
}

1278 1279 1280 1281 1282 1283
void events_stats__inc(struct events_stats *stats, u32 type)
{
	++stats->nr_events[0];
	++stats->nr_events[type];
}

1284
void hists__inc_nr_events(struct hists *hists, u32 type)
1285
{
1286
	events_stats__inc(&hists->stats, type);
1287
}
1288

1289 1290 1291 1292 1293 1294 1295
void hists__inc_nr_samples(struct hists *hists, bool filtered)
{
	events_stats__inc(&hists->stats, PERF_RECORD_SAMPLE);
	if (!filtered)
		hists->stats.nr_non_filtered_samples++;
}

1296 1297 1298
static struct hist_entry *hists__add_dummy_entry(struct hists *hists,
						 struct hist_entry *pair)
{
1299 1300
	struct rb_root *root;
	struct rb_node **p;
1301 1302
	struct rb_node *parent = NULL;
	struct hist_entry *he;
1303
	int64_t cmp;
1304

1305 1306 1307 1308 1309 1310 1311
	if (sort__need_collapse)
		root = &hists->entries_collapsed;
	else
		root = hists->entries_in;

	p = &root->rb_node;

1312 1313
	while (*p != NULL) {
		parent = *p;
1314
		he = rb_entry(parent, struct hist_entry, rb_node_in);
1315

1316
		cmp = hist_entry__collapse(he, pair);
1317 1318 1319 1320 1321 1322 1323 1324 1325 1326

		if (!cmp)
			goto out;

		if (cmp < 0)
			p = &(*p)->rb_left;
		else
			p = &(*p)->rb_right;
	}

1327
	he = hist_entry__new(pair, true);
1328
	if (he) {
1329 1330
		memset(&he->stat, 0, sizeof(he->stat));
		he->hists = hists;
1331 1332
		rb_link_node(&he->rb_node_in, parent, p);
		rb_insert_color(&he->rb_node_in, root);
1333
		hists__inc_stats(hists, he);
1334
		he->dummy = true;
1335 1336 1337 1338 1339
	}
out:
	return he;
}

1340 1341 1342
static struct hist_entry *hists__find_entry(struct hists *hists,
					    struct hist_entry *he)
{
1343 1344 1345 1346 1347 1348
	struct rb_node *n;

	if (sort__need_collapse)
		n = hists->entries_collapsed.rb_node;
	else
		n = hists->entries_in->rb_node;
1349 1350

	while (n) {
1351 1352
		struct hist_entry *iter = rb_entry(n, struct hist_entry, rb_node_in);
		int64_t cmp = hist_entry__collapse(iter, he);
1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 1367 1368 1369

		if (cmp < 0)
			n = n->rb_left;
		else if (cmp > 0)
			n = n->rb_right;
		else
			return iter;
	}

	return NULL;
}

/*
 * Look for pairs to link to the leader buckets (hist_entries):
 */
void hists__match(struct hists *leader, struct hists *other)
{
1370
	struct rb_root *root;
1371 1372 1373
	struct rb_node *nd;
	struct hist_entry *pos, *pair;

1374 1375 1376 1377 1378 1379 1380
	if (sort__need_collapse)
		root = &leader->entries_collapsed;
	else
		root = leader->entries_in;

	for (nd = rb_first(root); nd; nd = rb_next(nd)) {
		pos  = rb_entry(nd, struct hist_entry, rb_node_in);
1381 1382 1383
		pair = hists__find_entry(other, pos);

		if (pair)
1384
			hist_entry__add_pair(pair, pos);
1385 1386
	}
}
1387 1388 1389 1390 1391 1392 1393 1394

/*
 * Look for entries in the other hists that are not present in the leader, if
 * we find them, just add a dummy entry on the leader hists, with period=0,
 * nr_events=0, to serve as the list header.
 */
int hists__link(struct hists *leader, struct hists *other)
{
1395
	struct rb_root *root;
1396 1397 1398
	struct rb_node *nd;
	struct hist_entry *pos, *pair;

1399 1400 1401 1402 1403 1404 1405
	if (sort__need_collapse)
		root = &other->entries_collapsed;
	else
		root = other->entries_in;

	for (nd = rb_first(root); nd; nd = rb_next(nd)) {
		pos = rb_entry(nd, struct hist_entry, rb_node_in);
1406 1407 1408 1409 1410

		if (!hist_entry__has_pairs(pos)) {
			pair = hists__add_dummy_entry(leader, pos);
			if (pair == NULL)
				return -1;
1411
			hist_entry__add_pair(pos, pair);
1412 1413 1414 1415 1416
		}
	}

	return 0;
}
1417

1418 1419 1420 1421 1422 1423 1424 1425 1426 1427 1428 1429 1430 1431 1432

size_t perf_evlist__fprintf_nr_events(struct perf_evlist *evlist, FILE *fp)
{
	struct perf_evsel *pos;
	size_t ret = 0;

	evlist__for_each(evlist, pos) {
		ret += fprintf(fp, "%s stats:\n", perf_evsel__name(pos));
		ret += events_stats__fprintf(&evsel__hists(pos)->stats, fp);
	}

	return ret;
}


1433 1434 1435 1436 1437
u64 hists__total_period(struct hists *hists)
{
	return symbol_conf.filter_relative ? hists->stats.total_non_filtered_period :
		hists->stats.total_period;
}
N
Namhyung Kim 已提交
1438 1439 1440 1441 1442 1443 1444 1445 1446 1447 1448 1449 1450

int parse_filter_percentage(const struct option *opt __maybe_unused,
			    const char *arg, int unset __maybe_unused)
{
	if (!strcmp(arg, "relative"))
		symbol_conf.filter_relative = true;
	else if (!strcmp(arg, "absolute"))
		symbol_conf.filter_relative = false;
	else
		return -1;

	return 0;
}
1451 1452 1453 1454 1455 1456 1457 1458

int perf_hist_config(const char *var, const char *value)
{
	if (!strcmp(var, "hist.percentage"))
		return parse_filter_percentage(NULL, value, 0);

	return 0;
}
1459 1460 1461 1462 1463 1464 1465 1466 1467 1468 1469 1470 1471 1472 1473 1474 1475 1476 1477 1478 1479 1480 1481 1482 1483 1484 1485 1486

static int hists_evsel__init(struct perf_evsel *evsel)
{
	struct hists *hists = evsel__hists(evsel);

	memset(hists, 0, sizeof(*hists));
	hists->entries_in_array[0] = hists->entries_in_array[1] = RB_ROOT;
	hists->entries_in = &hists->entries_in_array[0];
	hists->entries_collapsed = RB_ROOT;
	hists->entries = RB_ROOT;
	pthread_mutex_init(&hists->lock, NULL);
	return 0;
}

/*
 * XXX We probably need a hists_evsel__exit() to free the hist_entries
 * stored in the rbtree...
 */

int hists__init(void)
{
	int err = perf_evsel__object_config(sizeof(struct hists_evsel),
					    hists_evsel__init, NULL);
	if (err)
		fputs("FATAL ERROR: Couldn't setup hists class\n", stderr);

	return err;
}