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8cb76d99 FW |
1 | /* |
2 | * Copyright (C) 2009, Frederic Weisbecker <fweisbec@gmail.com> | |
3 | * | |
4 | * Handle the callchains from the stream in an ad-hoc radix tree and then | |
5 | * sort them in an rbtree. | |
6 | * | |
deac911c FW |
7 | * Using a radix for code path provides a fast retrieval and factorizes |
8 | * memory use. Also that lets us use the paths in a hierarchical graph view. | |
9 | * | |
8cb76d99 FW |
10 | */ |
11 | ||
12 | #include <stdlib.h> | |
13 | #include <stdio.h> | |
14 | #include <stdbool.h> | |
15 | #include <errno.h> | |
16 | ||
17 | #include "callchain.h" | |
18 | ||
19 | ||
deac911c FW |
20 | static void |
21 | rb_insert_callchain(struct rb_root *root, struct callchain_node *chain) | |
8cb76d99 FW |
22 | { |
23 | struct rb_node **p = &root->rb_node; | |
24 | struct rb_node *parent = NULL; | |
25 | struct callchain_node *rnode; | |
26 | ||
27 | while (*p) { | |
28 | parent = *p; | |
29 | rnode = rb_entry(parent, struct callchain_node, rb_node); | |
30 | ||
31 | if (rnode->hit < chain->hit) | |
32 | p = &(*p)->rb_left; | |
33 | else | |
34 | p = &(*p)->rb_right; | |
35 | } | |
36 | ||
37 | rb_link_node(&chain->rb_node, parent, p); | |
38 | rb_insert_color(&chain->rb_node, root); | |
39 | } | |
40 | ||
41 | /* | |
42 | * Once we get every callchains from the stream, we can now | |
43 | * sort them by hit | |
44 | */ | |
45 | void sort_chain_to_rbtree(struct rb_root *rb_root, struct callchain_node *node) | |
46 | { | |
47 | struct callchain_node *child; | |
48 | ||
49 | list_for_each_entry(child, &node->children, brothers) | |
50 | sort_chain_to_rbtree(rb_root, child); | |
51 | ||
52 | if (node->hit) | |
53 | rb_insert_callchain(rb_root, node); | |
54 | } | |
55 | ||
deac911c FW |
56 | /* |
57 | * Create a child for a parent. If inherit_children, then the new child | |
58 | * will become the new parent of it's parent children | |
59 | */ | |
60 | static struct callchain_node * | |
61 | create_child(struct callchain_node *parent, bool inherit_children) | |
8cb76d99 FW |
62 | { |
63 | struct callchain_node *new; | |
64 | ||
65 | new = malloc(sizeof(*new)); | |
66 | if (!new) { | |
67 | perror("not enough memory to create child for code path tree"); | |
68 | return NULL; | |
69 | } | |
70 | new->parent = parent; | |
71 | INIT_LIST_HEAD(&new->children); | |
72 | INIT_LIST_HEAD(&new->val); | |
deac911c FW |
73 | |
74 | if (inherit_children) { | |
75 | struct callchain_node *next; | |
76 | ||
77 | list_splice(&parent->children, &new->children); | |
78 | INIT_LIST_HEAD(&parent->children); | |
79 | ||
80 | list_for_each_entry(next, &new->children, brothers) | |
81 | next->parent = new; | |
82 | } | |
8cb76d99 FW |
83 | list_add_tail(&new->brothers, &parent->children); |
84 | ||
85 | return new; | |
86 | } | |
87 | ||
deac911c FW |
88 | /* |
89 | * Fill the node with callchain values | |
90 | */ | |
8cb76d99 | 91 | static void |
deac911c FW |
92 | fill_node(struct callchain_node *node, struct ip_callchain *chain, |
93 | int start, struct symbol **syms) | |
8cb76d99 | 94 | { |
f37a291c | 95 | unsigned int i; |
8cb76d99 FW |
96 | |
97 | for (i = start; i < chain->nr; i++) { | |
98 | struct callchain_list *call; | |
99 | ||
9198aa77 | 100 | call = malloc(sizeof(*call)); |
8cb76d99 FW |
101 | if (!call) { |
102 | perror("not enough memory for the code path tree"); | |
103 | return; | |
104 | } | |
105 | call->ip = chain->ips[i]; | |
4424961a | 106 | call->sym = syms[i]; |
8cb76d99 FW |
107 | list_add_tail(&call->list, &node->val); |
108 | } | |
deac911c FW |
109 | node->val_nr = chain->nr - start; |
110 | if (!node->val_nr) | |
111 | printf("Warning: empty node in callchain tree\n"); | |
8cb76d99 FW |
112 | } |
113 | ||
deac911c FW |
114 | static void |
115 | add_child(struct callchain_node *parent, struct ip_callchain *chain, | |
116 | int start, struct symbol **syms) | |
8cb76d99 FW |
117 | { |
118 | struct callchain_node *new; | |
119 | ||
deac911c FW |
120 | new = create_child(parent, false); |
121 | fill_node(new, chain, start, syms); | |
8cb76d99 FW |
122 | |
123 | new->hit = 1; | |
124 | } | |
125 | ||
deac911c FW |
126 | /* |
127 | * Split the parent in two parts (a new child is created) and | |
128 | * give a part of its callchain to the created child. | |
129 | * Then create another child to host the given callchain of new branch | |
130 | */ | |
8cb76d99 FW |
131 | static void |
132 | split_add_child(struct callchain_node *parent, struct ip_callchain *chain, | |
deac911c FW |
133 | struct callchain_list *to_split, int idx_parents, int idx_local, |
134 | struct symbol **syms) | |
8cb76d99 FW |
135 | { |
136 | struct callchain_node *new; | |
deac911c | 137 | struct list_head *old_tail; |
f37a291c | 138 | unsigned int idx_total = idx_parents + idx_local; |
8cb76d99 FW |
139 | |
140 | /* split */ | |
deac911c FW |
141 | new = create_child(parent, true); |
142 | ||
143 | /* split the callchain and move a part to the new child */ | |
144 | old_tail = parent->val.prev; | |
145 | list_del_range(&to_split->list, old_tail); | |
146 | new->val.next = &to_split->list; | |
147 | new->val.prev = old_tail; | |
148 | to_split->list.prev = &new->val; | |
149 | old_tail->next = &new->val; | |
8cb76d99 | 150 | |
deac911c FW |
151 | /* split the hits */ |
152 | new->hit = parent->hit; | |
153 | new->val_nr = parent->val_nr - idx_local; | |
154 | parent->val_nr = idx_local; | |
155 | ||
156 | /* create a new child for the new branch if any */ | |
157 | if (idx_total < chain->nr) { | |
158 | parent->hit = 0; | |
159 | add_child(parent, chain, idx_total, syms); | |
160 | } else { | |
161 | parent->hit = 1; | |
162 | } | |
8cb76d99 FW |
163 | } |
164 | ||
165 | static int | |
166 | __append_chain(struct callchain_node *root, struct ip_callchain *chain, | |
f37a291c | 167 | unsigned int start, struct symbol **syms); |
8cb76d99 | 168 | |
deac911c | 169 | static void |
4424961a | 170 | __append_chain_children(struct callchain_node *root, struct ip_callchain *chain, |
f37a291c | 171 | struct symbol **syms, unsigned int start) |
8cb76d99 FW |
172 | { |
173 | struct callchain_node *rnode; | |
174 | ||
175 | /* lookup in childrens */ | |
176 | list_for_each_entry(rnode, &root->children, brothers) { | |
f37a291c IM |
177 | unsigned int ret = __append_chain(rnode, chain, start, syms); |
178 | ||
8cb76d99 | 179 | if (!ret) |
deac911c | 180 | return; |
8cb76d99 | 181 | } |
deac911c FW |
182 | /* nothing in children, add to the current node */ |
183 | add_child(root, chain, start, syms); | |
8cb76d99 FW |
184 | } |
185 | ||
186 | static int | |
187 | __append_chain(struct callchain_node *root, struct ip_callchain *chain, | |
f37a291c | 188 | unsigned int start, struct symbol **syms) |
8cb76d99 FW |
189 | { |
190 | struct callchain_list *cnode; | |
f37a291c | 191 | unsigned int i = start; |
8cb76d99 FW |
192 | bool found = false; |
193 | ||
deac911c FW |
194 | /* |
195 | * Lookup in the current node | |
196 | * If we have a symbol, then compare the start to match | |
197 | * anywhere inside a function. | |
198 | */ | |
8cb76d99 | 199 | list_for_each_entry(cnode, &root->val, list) { |
deac911c FW |
200 | if (i == chain->nr) |
201 | break; | |
202 | if (cnode->sym && syms[i]) { | |
203 | if (cnode->sym->start != syms[i]->start) | |
204 | break; | |
205 | } else if (cnode->ip != chain->ips[i]) | |
8cb76d99 FW |
206 | break; |
207 | if (!found) | |
208 | found = true; | |
deac911c | 209 | i++; |
8cb76d99 FW |
210 | } |
211 | ||
212 | /* matches not, relay on the parent */ | |
213 | if (!found) | |
214 | return -1; | |
215 | ||
216 | /* we match only a part of the node. Split it and add the new chain */ | |
deac911c FW |
217 | if (i - start < root->val_nr) { |
218 | split_add_child(root, chain, cnode, start, i - start, syms); | |
8cb76d99 FW |
219 | return 0; |
220 | } | |
221 | ||
222 | /* we match 100% of the path, increment the hit */ | |
deac911c | 223 | if (i - start == root->val_nr && i == chain->nr) { |
8cb76d99 FW |
224 | root->hit++; |
225 | return 0; | |
226 | } | |
227 | ||
deac911c FW |
228 | /* We match the node and still have a part remaining */ |
229 | __append_chain_children(root, chain, syms, i); | |
230 | ||
231 | return 0; | |
8cb76d99 FW |
232 | } |
233 | ||
4424961a FW |
234 | void append_chain(struct callchain_node *root, struct ip_callchain *chain, |
235 | struct symbol **syms) | |
8cb76d99 | 236 | { |
deac911c | 237 | __append_chain_children(root, chain, syms, 0); |
8cb76d99 | 238 | } |