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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 | ||
14f4654c FW |
19 | #define chain_for_each_child(child, parent) \ |
20 | list_for_each_entry(child, &parent->children, brothers) | |
21 | ||
8cb76d99 | 22 | |
deac911c FW |
23 | static void |
24 | rb_insert_callchain(struct rb_root *root, struct callchain_node *chain) | |
8cb76d99 FW |
25 | { |
26 | struct rb_node **p = &root->rb_node; | |
27 | struct rb_node *parent = NULL; | |
28 | struct callchain_node *rnode; | |
29 | ||
30 | while (*p) { | |
31 | parent = *p; | |
32 | rnode = rb_entry(parent, struct callchain_node, rb_node); | |
33 | ||
34 | if (rnode->hit < chain->hit) | |
35 | p = &(*p)->rb_left; | |
36 | else | |
37 | p = &(*p)->rb_right; | |
38 | } | |
39 | ||
40 | rb_link_node(&chain->rb_node, parent, p); | |
41 | rb_insert_color(&chain->rb_node, root); | |
42 | } | |
43 | ||
44 | /* | |
45 | * Once we get every callchains from the stream, we can now | |
46 | * sort them by hit | |
47 | */ | |
48 | void sort_chain_to_rbtree(struct rb_root *rb_root, struct callchain_node *node) | |
49 | { | |
50 | struct callchain_node *child; | |
51 | ||
14f4654c | 52 | chain_for_each_child(child, node) |
8cb76d99 FW |
53 | sort_chain_to_rbtree(rb_root, child); |
54 | ||
55 | if (node->hit) | |
56 | rb_insert_callchain(rb_root, node); | |
57 | } | |
58 | ||
deac911c FW |
59 | /* |
60 | * Create a child for a parent. If inherit_children, then the new child | |
61 | * will become the new parent of it's parent children | |
62 | */ | |
63 | static struct callchain_node * | |
64 | create_child(struct callchain_node *parent, bool inherit_children) | |
8cb76d99 FW |
65 | { |
66 | struct callchain_node *new; | |
67 | ||
68 | new = malloc(sizeof(*new)); | |
69 | if (!new) { | |
70 | perror("not enough memory to create child for code path tree"); | |
71 | return NULL; | |
72 | } | |
73 | new->parent = parent; | |
74 | INIT_LIST_HEAD(&new->children); | |
75 | INIT_LIST_HEAD(&new->val); | |
deac911c FW |
76 | |
77 | if (inherit_children) { | |
78 | struct callchain_node *next; | |
79 | ||
80 | list_splice(&parent->children, &new->children); | |
81 | INIT_LIST_HEAD(&parent->children); | |
82 | ||
14f4654c | 83 | chain_for_each_child(next, new) |
deac911c FW |
84 | next->parent = new; |
85 | } | |
8cb76d99 FW |
86 | list_add_tail(&new->brothers, &parent->children); |
87 | ||
88 | return new; | |
89 | } | |
90 | ||
deac911c FW |
91 | /* |
92 | * Fill the node with callchain values | |
93 | */ | |
8cb76d99 | 94 | static void |
deac911c FW |
95 | fill_node(struct callchain_node *node, struct ip_callchain *chain, |
96 | int start, struct symbol **syms) | |
8cb76d99 | 97 | { |
f37a291c | 98 | unsigned int i; |
8cb76d99 FW |
99 | |
100 | for (i = start; i < chain->nr; i++) { | |
101 | struct callchain_list *call; | |
102 | ||
9198aa77 | 103 | call = malloc(sizeof(*call)); |
8cb76d99 FW |
104 | if (!call) { |
105 | perror("not enough memory for the code path tree"); | |
106 | return; | |
107 | } | |
108 | call->ip = chain->ips[i]; | |
4424961a | 109 | call->sym = syms[i]; |
8cb76d99 FW |
110 | list_add_tail(&call->list, &node->val); |
111 | } | |
deac911c FW |
112 | node->val_nr = chain->nr - start; |
113 | if (!node->val_nr) | |
114 | printf("Warning: empty node in callchain tree\n"); | |
8cb76d99 FW |
115 | } |
116 | ||
deac911c FW |
117 | static void |
118 | add_child(struct callchain_node *parent, struct ip_callchain *chain, | |
119 | int start, struct symbol **syms) | |
8cb76d99 FW |
120 | { |
121 | struct callchain_node *new; | |
122 | ||
deac911c FW |
123 | new = create_child(parent, false); |
124 | fill_node(new, chain, start, syms); | |
8cb76d99 FW |
125 | |
126 | new->hit = 1; | |
127 | } | |
128 | ||
deac911c FW |
129 | /* |
130 | * Split the parent in two parts (a new child is created) and | |
131 | * give a part of its callchain to the created child. | |
132 | * Then create another child to host the given callchain of new branch | |
133 | */ | |
8cb76d99 FW |
134 | static void |
135 | split_add_child(struct callchain_node *parent, struct ip_callchain *chain, | |
deac911c FW |
136 | struct callchain_list *to_split, int idx_parents, int idx_local, |
137 | struct symbol **syms) | |
8cb76d99 FW |
138 | { |
139 | struct callchain_node *new; | |
deac911c | 140 | struct list_head *old_tail; |
f37a291c | 141 | unsigned int idx_total = idx_parents + idx_local; |
8cb76d99 FW |
142 | |
143 | /* split */ | |
deac911c FW |
144 | new = create_child(parent, true); |
145 | ||
146 | /* split the callchain and move a part to the new child */ | |
147 | old_tail = parent->val.prev; | |
148 | list_del_range(&to_split->list, old_tail); | |
149 | new->val.next = &to_split->list; | |
150 | new->val.prev = old_tail; | |
151 | to_split->list.prev = &new->val; | |
152 | old_tail->next = &new->val; | |
8cb76d99 | 153 | |
deac911c FW |
154 | /* split the hits */ |
155 | new->hit = parent->hit; | |
156 | new->val_nr = parent->val_nr - idx_local; | |
157 | parent->val_nr = idx_local; | |
158 | ||
159 | /* create a new child for the new branch if any */ | |
160 | if (idx_total < chain->nr) { | |
161 | parent->hit = 0; | |
162 | add_child(parent, chain, idx_total, syms); | |
163 | } else { | |
164 | parent->hit = 1; | |
165 | } | |
8cb76d99 FW |
166 | } |
167 | ||
168 | static int | |
169 | __append_chain(struct callchain_node *root, struct ip_callchain *chain, | |
f37a291c | 170 | unsigned int start, struct symbol **syms); |
8cb76d99 | 171 | |
deac911c | 172 | static void |
4424961a | 173 | __append_chain_children(struct callchain_node *root, struct ip_callchain *chain, |
f37a291c | 174 | struct symbol **syms, unsigned int start) |
8cb76d99 FW |
175 | { |
176 | struct callchain_node *rnode; | |
177 | ||
178 | /* lookup in childrens */ | |
14f4654c | 179 | chain_for_each_child(rnode, root) { |
f37a291c IM |
180 | unsigned int ret = __append_chain(rnode, chain, start, syms); |
181 | ||
8cb76d99 | 182 | if (!ret) |
deac911c | 183 | return; |
8cb76d99 | 184 | } |
deac911c FW |
185 | /* nothing in children, add to the current node */ |
186 | add_child(root, chain, start, syms); | |
8cb76d99 FW |
187 | } |
188 | ||
189 | static int | |
190 | __append_chain(struct callchain_node *root, struct ip_callchain *chain, | |
f37a291c | 191 | unsigned int start, struct symbol **syms) |
8cb76d99 FW |
192 | { |
193 | struct callchain_list *cnode; | |
f37a291c | 194 | unsigned int i = start; |
8cb76d99 FW |
195 | bool found = false; |
196 | ||
deac911c FW |
197 | /* |
198 | * Lookup in the current node | |
199 | * If we have a symbol, then compare the start to match | |
200 | * anywhere inside a function. | |
201 | */ | |
8cb76d99 | 202 | list_for_each_entry(cnode, &root->val, list) { |
deac911c FW |
203 | if (i == chain->nr) |
204 | break; | |
205 | if (cnode->sym && syms[i]) { | |
206 | if (cnode->sym->start != syms[i]->start) | |
207 | break; | |
208 | } else if (cnode->ip != chain->ips[i]) | |
8cb76d99 FW |
209 | break; |
210 | if (!found) | |
211 | found = true; | |
deac911c | 212 | i++; |
8cb76d99 FW |
213 | } |
214 | ||
215 | /* matches not, relay on the parent */ | |
216 | if (!found) | |
217 | return -1; | |
218 | ||
219 | /* we match only a part of the node. Split it and add the new chain */ | |
deac911c FW |
220 | if (i - start < root->val_nr) { |
221 | split_add_child(root, chain, cnode, start, i - start, syms); | |
8cb76d99 FW |
222 | return 0; |
223 | } | |
224 | ||
225 | /* we match 100% of the path, increment the hit */ | |
deac911c | 226 | if (i - start == root->val_nr && i == chain->nr) { |
8cb76d99 FW |
227 | root->hit++; |
228 | return 0; | |
229 | } | |
230 | ||
deac911c FW |
231 | /* We match the node and still have a part remaining */ |
232 | __append_chain_children(root, chain, syms, i); | |
233 | ||
234 | return 0; | |
8cb76d99 FW |
235 | } |
236 | ||
4424961a FW |
237 | void append_chain(struct callchain_node *root, struct ip_callchain *chain, |
238 | struct symbol **syms) | |
8cb76d99 | 239 | { |
deac911c | 240 | __append_chain_children(root, chain, syms, 0); |
8cb76d99 | 241 | } |