summaryrefslogtreecommitdiffstats
path: root/tools/perf/util/callchain.c
blob: e3970e3eaacf45bc7a10db4a86314c2fdd79fbb5 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
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
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
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
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
/*
 * Copyright (C) 2009-2011, Frederic Weisbecker <fweisbec@gmail.com>
 *
 * Handle the callchains from the stream in an ad-hoc radix tree and then
 * sort them in an rbtree.
 *
 * Using a radix for code path provides a fast retrieval and factorizes
 * memory use. Also that lets us use the paths in a hierarchical graph view.
 *
 */

#include <stdlib.h>
#include <stdio.h>
#include <stdbool.h>
#include <errno.h>
#include <math.h>

#include "hist.h"
#include "util.h"
#include "callchain.h"

__thread struct callchain_cursor callchain_cursor;

static void
rb_insert_callchain(struct rb_root *root, struct callchain_node *chain,
		    enum chain_mode mode)
{
	struct rb_node **p = &root->rb_node;
	struct rb_node *parent = NULL;
	struct callchain_node *rnode;
	u64 chain_cumul = callchain_cumul_hits(chain);

	while (*p) {
		u64 rnode_cumul;

		parent = *p;
		rnode = rb_entry(parent, struct callchain_node, rb_node);
		rnode_cumul = callchain_cumul_hits(rnode);

		switch (mode) {
		case CHAIN_FLAT:
			if (rnode->hit < chain->hit)
				p = &(*p)->rb_left;
			else
				p = &(*p)->rb_right;
			break;
		case CHAIN_GRAPH_ABS: /* Falldown */
		case CHAIN_GRAPH_REL:
			if (rnode_cumul < chain_cumul)
				p = &(*p)->rb_left;
			else
				p = &(*p)->rb_right;
			break;
		case CHAIN_NONE:
		default:
			break;
		}
	}

	rb_link_node(&chain->rb_node, parent, p);
	rb_insert_color(&chain->rb_node, root);
}

static void
__sort_chain_flat(struct rb_root *rb_root, struct callchain_node *node,
		  u64 min_hit)
{
	struct rb_node *n;
	struct callchain_node *child;

	n = rb_first(&node->rb_root_in);
	while (n) {
		child = rb_entry(n, struct callchain_node, rb_node_in);
		n = rb_next(n);

		__sort_chain_flat(rb_root, child, min_hit);
	}

	if (node->hit && node->hit >= min_hit)
		rb_insert_callchain(rb_root, node, CHAIN_FLAT);
}

/*
 * Once we get every callchains from the stream, we can now
 * sort them by hit
 */
static void
sort_chain_flat(struct rb_root *rb_root, struct callchain_root *root,
		u64 min_hit, struct callchain_param *param __maybe_unused)
{
	__sort_chain_flat(rb_root, &root->node, min_hit);
}

static void __sort_chain_graph_abs(struct callchain_node *node,
				   u64 min_hit)
{
	struct rb_node *n;
	struct callchain_node *child;

	node->rb_root = RB_ROOT;
	n = rb_first(&node->rb_root_in);

	while (n) {
		child = rb_entry(n, struct callchain_node, rb_node_in);
		n = rb_next(n);

		__sort_chain_graph_abs(child, min_hit);
		if (callchain_cumul_hits(child) >= min_hit)
			rb_insert_callchain(&node->rb_root, child,
					    CHAIN_GRAPH_ABS);
	}
}

static void
sort_chain_graph_abs(struct rb_root *rb_root, struct callchain_root *chain_root,
		     u64 min_hit, struct callchain_param *param __maybe_unused)
{
	__sort_chain_graph_abs(&chain_root->node, min_hit);
	rb_root->rb_node = chain_root->node.rb_root.rb_node;
}

static void __sort_chain_graph_rel(struct callchain_node *node,
				   double min_percent)
{
	struct rb_node *n;
	struct callchain_node *child;
	u64 min_hit;

	node->rb_root = RB_ROOT;
	min_hit = ceil(node->children_hit * min_percent);

	n = rb_first(&node->rb_root_in);
	while (n) {
		child = rb_entry(n, struct callchain_node, rb_node_in);
		n = rb_next(n);

		__sort_chain_graph_rel(child, min_percent);
		if (callchain_cumul_hits(child) >= min_hit)
			rb_insert_callchain(&node->rb_root, child,
					    CHAIN_GRAPH_REL);
	}
}

static void
sort_chain_graph_rel(struct rb_root *rb_root, struct callchain_root *chain_root,
		     u64 min_hit __maybe_unused, struct callchain_param *param)
{
	__sort_chain_graph_rel(&chain_root->node, param->min_percent / 100.0);
	rb_root->rb_node = chain_root->node.rb_root.rb_node;
}

int callchain_register_param(struct callchain_param *param)
{
	switch (param->mode) {
	case CHAIN_GRAPH_ABS:
		param->sort = sort_chain_graph_abs;
		break;
	case CHAIN_GRAPH_REL:
		param->sort = sort_chain_graph_rel;
		break;
	case CHAIN_FLAT:
		param->sort = sort_chain_flat;
		break;
	case CHAIN_NONE:
	default:
		return -1;
	}
	return 0;
}

/*
 * Create a child for a parent. If inherit_children, then the new child
 * will become the new parent of it's parent children
 */
static struct callchain_node *
create_child(struct callchain_node *parent, bool inherit_children)
{
	struct callchain_node *new;

	new = zalloc(sizeof(*new));
	if (!new) {
		perror("not enough memory to create child for code path tree");
		return NULL;
	}
	new->parent = parent;
	INIT_LIST_HEAD(&new->val);

	if (inherit_children) {
		struct rb_node *n;
		struct callchain_node *child;

		new->rb_root_in = parent->rb_root_in;
		parent->rb_root_in = RB_ROOT;

		n = rb_first(&new->rb_root_in);
		while (n) {
			child = rb_entry(n, struct callchain_node, rb_node_in);
			child->parent = new;
			n = rb_next(n);
		}

		/* make it the first child */
		rb_link_node(&new->rb_node_in, NULL, &parent->rb_root_in.rb_node);
		rb_insert_color(&new->rb_node_in, &parent->rb_root_in);
	}

	return new;
}


/*
 * Fill the node with callchain values
 */
static void
fill_node(struct callchain_node *node, struct callchain_cursor *cursor)
{
	struct callchain_cursor_node *cursor_node;

	node->val_nr = cursor->nr - cursor->pos;
	if (!node->val_nr)
		pr_warning("Warning: empty node in callchain tree\n");

	cursor_node = callchain_cursor_current(cursor);

	while (cursor_node) {
		struct callchain_list *call;

		call = zalloc(sizeof(*call));
		if (!call) {
			perror("not enough memory for the code path tree");
			return;
		}
		call->ip = cursor_node->ip;
		call->ms.sym = cursor_node->sym;
		call->ms.map = cursor_node->map;
		list_add_tail(&call->list, &node->val);

		callchain_cursor_advance(cursor);
		cursor_node = callchain_cursor_current(cursor);
	}
}

static struct callchain_node *
add_child(struct callchain_node *parent,
	  struct callchain_cursor *cursor,
	  u64 period)
{
	struct callchain_node *new;

	new = create_child(parent, false);
	fill_node(new, cursor);

	new->children_hit = 0;
	new->hit = period;
	return new;
}

static s64 match_chain(struct callchain_cursor_node *node,
		      struct callchain_list *cnode)
{
	struct symbol *sym = node->sym;

	if (cnode->ms.sym && sym &&
	    callchain_param.key == CCKEY_FUNCTION)
		return cnode->ms.sym->start - sym->start;
	else
		return cnode->ip - node->ip;
}

/*
 * Split the parent in two parts (a new child is created) and
 * give a part of its callchain to the created child.
 * Then create another child to host the given callchain of new branch
 */
static void
split_add_child(struct callchain_node *parent,
		struct callchain_cursor *cursor,
		struct callchain_list *to_split,
		u64 idx_parents, u64 idx_local, u64 period)
{
	struct callchain_node *new;
	struct list_head *old_tail;
	unsigned int idx_total = idx_parents + idx_local;

	/* split */
	new = create_child(parent, true);

	/* split the callchain and move a part to the new child */
	old_tail = parent->val.prev;
	list_del_range(&to_split->list, old_tail);
	new->val.next = &to_split->list;
	new->val.prev = old_tail;
	to_split->list.prev = &new->val;
	old_tail->next = &new->val;

	/* split the hits */
	new->hit = parent->hit;
	new->children_hit = parent->children_hit;
	parent->children_hit = callchain_cumul_hits(new);
	new->val_nr = parent->val_nr - idx_local;
	parent->val_nr = idx_local;

	/* create a new child for the new branch if any */
	if (idx_total < cursor->nr) {
		struct callchain_node *first;
		struct callchain_list *cnode;
		struct callchain_cursor_node *node;
		struct rb_node *p, **pp;

		parent->hit = 0;
		parent->children_hit += period;

		node = callchain_cursor_current(cursor);
		new = add_child(parent, cursor, period);

		/*
		 * This is second child since we moved parent's children
		 * to new (first) child above.
		 */
		p = parent->rb_root_in.rb_node;
		first = rb_entry(p, struct callchain_node, rb_node_in);
		cnode = list_first_entry(&first->val, struct callchain_list,
					 list);

		if (match_chain(node, cnode) < 0)
			pp = &p->rb_left;
		else
			pp = &p->rb_right;

		rb_link_node(&new->rb_node_in, p, pp);
		rb_insert_color(&new->rb_node_in, &parent->rb_root_in);
	} else {
		parent->hit = period;
	}
}

static int
append_chain(struct callchain_node *root,
	     struct callchain_cursor *cursor,
	     u64 period);

static void
append_chain_children(struct callchain_node *root,
		      struct callchain_cursor *cursor,
		      u64 period)
{
	struct callchain_node *rnode;
	struct callchain_cursor_node *node;
	struct rb_node **p = &root->rb_root_in.rb_node;
	struct rb_node *parent = NULL;

	node = callchain_cursor_current(cursor);
	if (!node)
		return;

	/* lookup in childrens */
	while (*p) {
		s64 ret;
		struct callchain_list *cnode;

		parent = *p;
		rnode = rb_entry(parent, struct callchain_node, rb_node_in);
		cnode = list_first_entry(&rnode->val, struct callchain_list,
					 list);

		/* just check first entry */
		ret = match_chain(node, cnode);
		if (ret == 0) {
			append_chain(rnode, cursor, period);
			goto inc_children_hit;
		}

		if (ret < 0)
			p = &parent->rb_left;
		else
			p = &parent->rb_right;
	}
	/* nothing in children, add to the current node */
	rnode = add_child(root, cursor, period);
	rb_link_node(&rnode->rb_node_in, parent, p);
	rb_insert_color(&rnode->rb_node_in, &root->rb_root_in);

inc_children_hit:
	root->children_hit += period;
}

static int
append_chain(struct callchain_node *root,
	     struct callchain_cursor *cursor,
	     u64 period)
{
	struct callchain_cursor_node *curr_snap = cursor->curr;
	struct callchain_list *cnode;
	u64 start = cursor->pos;
	bool found = false;
	u64 matches;

	/*
	 * Lookup in the current node
	 * If we have a symbol, then compare the start to match
	 * anywhere inside a function, unless function
	 * mode is disabled.
	 */
	list_for_each_entry(cnode, &root->val, list) {
		struct callchain_cursor_node *node;

		node = callchain_cursor_current(cursor);
		if (!node)
			break;

		if (match_chain(node, cnode) != 0)
			break;

		found = true;

		callchain_cursor_advance(cursor);
	}

	/* matches not, relay no the parent */
	if (!found) {
		cursor->curr = curr_snap;
		cursor->pos = start;
		return -1;
	}

	matches = cursor->pos - start;

	/* we match only a part of the node. Split it and add the new chain */
	if (matches < root->val_nr) {
		split_add_child(root, cursor, cnode, start, matches, period);
		return 0;
	}

	/* we match 100% of the path, increment the hit */
	if (matches == root->val_nr && cursor->pos == cursor->nr) {
		root->hit += period;
		return 0;
	}

	/* We match the node and still have a part remaining */
	append_chain_children(root, cursor, period);

	return 0;
}

int callchain_append(struct callchain_root *root,
		     struct callchain_cursor *cursor,
		     u64 period)
{
	if (!cursor->nr)
		return 0;

	callchain_cursor_commit(cursor);

	append_chain_children(&root->node, cursor, period);

	if (cursor->nr > root->max_depth)
		root->max_depth = cursor->nr;

	return 0;
}

static int
merge_chain_branch(struct callchain_cursor *cursor,
		   struct callchain_node *dst, struct callchain_node *src)
{
	struct callchain_cursor_node **old_last = cursor->last;
	struct callchain_node *child;
	struct callchain_list *list, *next_list;
	struct rb_node *n;
	int old_pos = cursor->nr;
	int err = 0;

	list_for_each_entry_safe(list, next_list, &src->val, list) {
		callchain_cursor_append(cursor, list->ip,
					list->ms.map, list->ms.sym);
		list_del(&list->list);
		free(list);
	}

	if (src->hit) {
		callchain_cursor_commit(cursor);
		append_chain_children(dst, cursor, src->hit);
	}

	n = rb_first(&src->rb_root_in);
	while (n) {
		child = container_of(n, struct callchain_node, rb_node_in);
		n = rb_next(n);
		rb_erase(&child->rb_node_in, &src->rb_root_in);

		err = merge_chain_branch(cursor, dst, child);
		if (err)
			break;

		free(child);
	}

	cursor->nr = old_pos;
	cursor->last = old_last;

	return err;
}

int callchain_merge(struct callchain_cursor *cursor,
		    struct callchain_root *dst, struct callchain_root *src)
{
	return merge_chain_branch(cursor, &dst->node, &src->node);
}

int callchain_cursor_append(struct callchain_cursor *cursor,
			    u64 ip, struct map *map, struct symbol *sym)
{
	struct callchain_cursor_node *node = *cursor->last;

	if (!node) {
		node = calloc(1, sizeof(*node));
		if (!node)
			return -ENOMEM;

		*cursor->last = node;
	}

	node->ip = ip;
	node->map = map;
	node->sym = sym;

	cursor->nr++;

	cursor->last = &node->next;

	return 0;
}
OpenPOWER on IntegriCloud