summaryrefslogtreecommitdiff
path: root/tools/perf/util/callchain.c
blob: a9873aafcd928a432b47c5fb691b999877661c7a (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
/*
 * Copyright (C) 2009, 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 "callchain.h"

#define chain_for_each_child(child, parent)	\
	list_for_each_entry(child, &parent->children, brothers)

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;

	while (*p) {
		parent = *p;
		rnode = rb_entry(parent, struct callchain_node, rb_node);

		switch (mode) {
		case FLAT:
			if (rnode->hit < chain->hit)
				p = &(*p)->rb_left;
			else
				p = &(*p)->rb_right;
			break;
		case GRAPH:
			if (rnode->cumul_hit < chain->cumul_hit)
				p = &(*p)->rb_left;
			else
				p = &(*p)->rb_right;
			break;
		default:
			break;
		}
	}

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

/*
 * Once we get every callchains from the stream, we can now
 * sort them by hit
 */
void sort_chain_flat(struct rb_root *rb_root, struct callchain_node *node)
{
	struct callchain_node *child;

	chain_for_each_child(child, node)
		sort_chain_flat(rb_root, child);

	if (node->hit)
		rb_insert_callchain(rb_root, node, FLAT);
}

static void __sort_chain_graph(struct callchain_node *node)
{
	struct callchain_node *child;

	node->rb_root = RB_ROOT;
	node->cumul_hit = node->hit;

	chain_for_each_child(child, node) {
		__sort_chain_graph(child);
		rb_insert_callchain(&node->rb_root, child, GRAPH);
		node->cumul_hit += child->cumul_hit;
	}
}

void
sort_chain_graph(struct rb_root *rb_root, struct callchain_node *chain_root)
{
	__sort_chain_graph(chain_root);
	rb_root->rb_node = chain_root->rb_root.rb_node;
}

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

	if (inherit_children) {
		struct callchain_node *next;

		list_splice(&parent->children, &new->children);
		INIT_LIST_HEAD(&parent->children);

		chain_for_each_child(next, new)
			next->parent = new;
	}
	list_add_tail(&new->brothers, &parent->children);

	return new;
}

/*
 * Fill the node with callchain values
 */
static void
fill_node(struct callchain_node *node, struct ip_callchain *chain,
	  int start, struct symbol **syms)
{
	unsigned int i;

	for (i = start; i < chain->nr; i++) {
		struct callchain_list *call;

		call = malloc(sizeof(*call));
		if (!call) {
			perror("not enough memory for the code path tree");
			return;
		}
		call->ip = chain->ips[i];
		call->sym = syms[i];
		list_add_tail(&call->list, &node->val);
	}
	node->val_nr = chain->nr - start;
	if (!node->val_nr)
		printf("Warning: empty node in callchain tree\n");
}

static void
add_child(struct callchain_node *parent, struct ip_callchain *chain,
	  int start, struct symbol **syms)
{
	struct callchain_node *new;

	new = create_child(parent, false);
	fill_node(new, chain, start, syms);

	new->hit = 1;
}

/*
 * 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 ip_callchain *chain,
		struct callchain_list *to_split, int idx_parents, int idx_local,
		struct symbol **syms)
{
	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->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 < chain->nr) {
		parent->hit = 0;
		add_child(parent, chain, idx_total, syms);
	} else {
		parent->hit = 1;
	}
}

static int
__append_chain(struct callchain_node *root, struct ip_callchain *chain,
	       unsigned int start, struct symbol **syms);

static void
__append_chain_children(struct callchain_node *root, struct ip_callchain *chain,
			struct symbol **syms, unsigned int start)
{
	struct callchain_node *rnode;

	/* lookup in childrens */
	chain_for_each_child(rnode, root) {
		unsigned int ret = __append_chain(rnode, chain, start, syms);

		if (!ret)
			return;
	}
	/* nothing in children, add to the current node */
	add_child(root, chain, start, syms);
}

static int
__append_chain(struct callchain_node *root, struct ip_callchain *chain,
	       unsigned int start, struct symbol **syms)
{
	struct callchain_list *cnode;
	unsigned int i = start;
	bool found = false;

	/*
	 * Lookup in the current node
	 * If we have a symbol, then compare the start to match
	 * anywhere inside a function.
	 */
	list_for_each_entry(cnode, &root->val, list) {
		if (i == chain->nr)
			break;
		if (cnode->sym && syms[i]) {
			if (cnode->sym->start != syms[i]->start)
				break;
		} else if (cnode->ip != chain->ips[i])
			break;
		if (!found)
			found = true;
		i++;
	}

	/* matches not, relay on the parent */
	if (!found)
		return -1;

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

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

	/* We match the node and still have a part remaining */
	__append_chain_children(root, chain, syms, i);

	return 0;
}

void append_chain(struct callchain_node *root, struct ip_callchain *chain,
		  struct symbol **syms)
{
	__append_chain_children(root, chain, syms, 0);
}