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1 | /* |
2 | * Copyright (C) 2009-2011, 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 | * |
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 | * |
10 | */ |
11 | |
12 | #include <stdlib.h> |
13 | #include <stdio.h> |
14 | #include <stdbool.h> |
15 | #include <errno.h> |
16 | #include <math.h> |
17 | |
18 | #include "util.h" |
19 | #include "callchain.h" |
20 | |
21 | __thread struct callchain_cursor callchain_cursor; |
22 | |
23 | bool ip_callchain__valid(struct ip_callchain *chain, |
24 | const union perf_event *event) |
25 | { |
26 | unsigned int chain_size = event->header.size; |
27 | chain_size -= (unsigned long)&event->ip.__more_data - (unsigned long)event; |
28 | return chain->nr * sizeof(u64) <= chain_size; |
29 | } |
30 | |
31 | #define chain_for_each_child(child, parent) \ |
32 | list_for_each_entry(child, &parent->children, siblings) |
33 | |
34 | #define chain_for_each_child_safe(child, next, parent) \ |
35 | list_for_each_entry_safe(child, next, &parent->children, siblings) |
36 | |
37 | static void |
38 | rb_insert_callchain(struct rb_root *root, struct callchain_node *chain, |
39 | enum chain_mode mode) |
40 | { |
41 | struct rb_node **p = &root->rb_node; |
42 | struct rb_node *parent = NULL; |
43 | struct callchain_node *rnode; |
44 | u64 chain_cumul = callchain_cumul_hits(chain); |
45 | |
46 | while (*p) { |
47 | u64 rnode_cumul; |
48 | |
49 | parent = *p; |
50 | rnode = rb_entry(parent, struct callchain_node, rb_node); |
51 | rnode_cumul = callchain_cumul_hits(rnode); |
52 | |
53 | switch (mode) { |
54 | case CHAIN_FLAT: |
55 | if (rnode->hit < chain->hit) |
56 | p = &(*p)->rb_left; |
57 | else |
58 | p = &(*p)->rb_right; |
59 | break; |
60 | case CHAIN_GRAPH_ABS: /* Falldown */ |
61 | case CHAIN_GRAPH_REL: |
62 | if (rnode_cumul < chain_cumul) |
63 | p = &(*p)->rb_left; |
64 | else |
65 | p = &(*p)->rb_right; |
66 | break; |
67 | case CHAIN_NONE: |
68 | default: |
69 | break; |
70 | } |
71 | } |
72 | |
73 | rb_link_node(&chain->rb_node, parent, p); |
74 | rb_insert_color(&chain->rb_node, root); |
75 | } |
76 | |
77 | static void |
78 | __sort_chain_flat(struct rb_root *rb_root, struct callchain_node *node, |
79 | u64 min_hit) |
80 | { |
81 | struct callchain_node *child; |
82 | |
83 | chain_for_each_child(child, node) |
84 | __sort_chain_flat(rb_root, child, min_hit); |
85 | |
86 | if (node->hit && node->hit >= min_hit) |
87 | rb_insert_callchain(rb_root, node, CHAIN_FLAT); |
88 | } |
89 | |
90 | /* |
91 | * Once we get every callchains from the stream, we can now |
92 | * sort them by hit |
93 | */ |
94 | static void |
95 | sort_chain_flat(struct rb_root *rb_root, struct callchain_root *root, |
96 | u64 min_hit, struct callchain_param *param __used) |
97 | { |
98 | __sort_chain_flat(rb_root, &root->node, min_hit); |
99 | } |
100 | |
101 | static void __sort_chain_graph_abs(struct callchain_node *node, |
102 | u64 min_hit) |
103 | { |
104 | struct callchain_node *child; |
105 | |
106 | node->rb_root = RB_ROOT; |
107 | |
108 | chain_for_each_child(child, node) { |
109 | __sort_chain_graph_abs(child, min_hit); |
110 | if (callchain_cumul_hits(child) >= min_hit) |
111 | rb_insert_callchain(&node->rb_root, child, |
112 | CHAIN_GRAPH_ABS); |
113 | } |
114 | } |
115 | |
116 | static void |
117 | sort_chain_graph_abs(struct rb_root *rb_root, struct callchain_root *chain_root, |
118 | u64 min_hit, struct callchain_param *param __used) |
119 | { |
120 | __sort_chain_graph_abs(&chain_root->node, min_hit); |
121 | rb_root->rb_node = chain_root->node.rb_root.rb_node; |
122 | } |
123 | |
124 | static void __sort_chain_graph_rel(struct callchain_node *node, |
125 | double min_percent) |
126 | { |
127 | struct callchain_node *child; |
128 | u64 min_hit; |
129 | |
130 | node->rb_root = RB_ROOT; |
131 | min_hit = ceil(node->children_hit * min_percent); |
132 | |
133 | chain_for_each_child(child, node) { |
134 | __sort_chain_graph_rel(child, min_percent); |
135 | if (callchain_cumul_hits(child) >= min_hit) |
136 | rb_insert_callchain(&node->rb_root, child, |
137 | CHAIN_GRAPH_REL); |
138 | } |
139 | } |
140 | |
141 | static void |
142 | sort_chain_graph_rel(struct rb_root *rb_root, struct callchain_root *chain_root, |
143 | u64 min_hit __used, struct callchain_param *param) |
144 | { |
145 | __sort_chain_graph_rel(&chain_root->node, param->min_percent / 100.0); |
146 | rb_root->rb_node = chain_root->node.rb_root.rb_node; |
147 | } |
148 | |
149 | int callchain_register_param(struct callchain_param *param) |
150 | { |
151 | switch (param->mode) { |
152 | case CHAIN_GRAPH_ABS: |
153 | param->sort = sort_chain_graph_abs; |
154 | break; |
155 | case CHAIN_GRAPH_REL: |
156 | param->sort = sort_chain_graph_rel; |
157 | break; |
158 | case CHAIN_FLAT: |
159 | param->sort = sort_chain_flat; |
160 | break; |
161 | case CHAIN_NONE: |
162 | default: |
163 | return -1; |
164 | } |
165 | return 0; |
166 | } |
167 | |
168 | /* |
169 | * Create a child for a parent. If inherit_children, then the new child |
170 | * will become the new parent of it's parent children |
171 | */ |
172 | static struct callchain_node * |
173 | create_child(struct callchain_node *parent, bool inherit_children) |
174 | { |
175 | struct callchain_node *new; |
176 | |
177 | new = zalloc(sizeof(*new)); |
178 | if (!new) { |
179 | perror("not enough memory to create child for code path tree"); |
180 | return NULL; |
181 | } |
182 | new->parent = parent; |
183 | INIT_LIST_HEAD(&new->children); |
184 | INIT_LIST_HEAD(&new->val); |
185 | |
186 | if (inherit_children) { |
187 | struct callchain_node *next; |
188 | |
189 | list_splice(&parent->children, &new->children); |
190 | INIT_LIST_HEAD(&parent->children); |
191 | |
192 | chain_for_each_child(next, new) |
193 | next->parent = new; |
194 | } |
195 | list_add_tail(&new->siblings, &parent->children); |
196 | |
197 | return new; |
198 | } |
199 | |
200 | |
201 | /* |
202 | * Fill the node with callchain values |
203 | */ |
204 | static void |
205 | fill_node(struct callchain_node *node, struct callchain_cursor *cursor) |
206 | { |
207 | struct callchain_cursor_node *cursor_node; |
208 | |
209 | node->val_nr = cursor->nr - cursor->pos; |
210 | if (!node->val_nr) |
211 | pr_warning("Warning: empty node in callchain tree\n"); |
212 | |
213 | cursor_node = callchain_cursor_current(cursor); |
214 | |
215 | while (cursor_node) { |
216 | struct callchain_list *call; |
217 | |
218 | call = zalloc(sizeof(*call)); |
219 | if (!call) { |
220 | perror("not enough memory for the code path tree"); |
221 | return; |
222 | } |
223 | call->ip = cursor_node->ip; |
224 | call->ms.sym = cursor_node->sym; |
225 | call->ms.map = cursor_node->map; |
226 | list_add_tail(&call->list, &node->val); |
227 | |
228 | callchain_cursor_advance(cursor); |
229 | cursor_node = callchain_cursor_current(cursor); |
230 | } |
231 | } |
232 | |
233 | static void |
234 | add_child(struct callchain_node *parent, |
235 | struct callchain_cursor *cursor, |
236 | u64 period) |
237 | { |
238 | struct callchain_node *new; |
239 | |
240 | new = create_child(parent, false); |
241 | fill_node(new, cursor); |
242 | |
243 | new->children_hit = 0; |
244 | new->hit = period; |
245 | } |
246 | |
247 | /* |
248 | * Split the parent in two parts (a new child is created) and |
249 | * give a part of its callchain to the created child. |
250 | * Then create another child to host the given callchain of new branch |
251 | */ |
252 | static void |
253 | split_add_child(struct callchain_node *parent, |
254 | struct callchain_cursor *cursor, |
255 | struct callchain_list *to_split, |
256 | u64 idx_parents, u64 idx_local, u64 period) |
257 | { |
258 | struct callchain_node *new; |
259 | struct list_head *old_tail; |
260 | unsigned int idx_total = idx_parents + idx_local; |
261 | |
262 | /* split */ |
263 | new = create_child(parent, true); |
264 | |
265 | /* split the callchain and move a part to the new child */ |
266 | old_tail = parent->val.prev; |
267 | list_del_range(&to_split->list, old_tail); |
268 | new->val.next = &to_split->list; |
269 | new->val.prev = old_tail; |
270 | to_split->list.prev = &new->val; |
271 | old_tail->next = &new->val; |
272 | |
273 | /* split the hits */ |
274 | new->hit = parent->hit; |
275 | new->children_hit = parent->children_hit; |
276 | parent->children_hit = callchain_cumul_hits(new); |
277 | new->val_nr = parent->val_nr - idx_local; |
278 | parent->val_nr = idx_local; |
279 | |
280 | /* create a new child for the new branch if any */ |
281 | if (idx_total < cursor->nr) { |
282 | parent->hit = 0; |
283 | add_child(parent, cursor, period); |
284 | parent->children_hit += period; |
285 | } else { |
286 | parent->hit = period; |
287 | } |
288 | } |
289 | |
290 | static int |
291 | append_chain(struct callchain_node *root, |
292 | struct callchain_cursor *cursor, |
293 | u64 period); |
294 | |
295 | static void |
296 | append_chain_children(struct callchain_node *root, |
297 | struct callchain_cursor *cursor, |
298 | u64 period) |
299 | { |
300 | struct callchain_node *rnode; |
301 | |
302 | /* lookup in childrens */ |
303 | chain_for_each_child(rnode, root) { |
304 | unsigned int ret = append_chain(rnode, cursor, period); |
305 | |
306 | if (!ret) |
307 | goto inc_children_hit; |
308 | } |
309 | /* nothing in children, add to the current node */ |
310 | add_child(root, cursor, period); |
311 | |
312 | inc_children_hit: |
313 | root->children_hit += period; |
314 | } |
315 | |
316 | static int |
317 | append_chain(struct callchain_node *root, |
318 | struct callchain_cursor *cursor, |
319 | u64 period) |
320 | { |
321 | struct callchain_cursor_node *curr_snap = cursor->curr; |
322 | struct callchain_list *cnode; |
323 | u64 start = cursor->pos; |
324 | bool found = false; |
325 | u64 matches; |
326 | |
327 | /* |
328 | * Lookup in the current node |
329 | * If we have a symbol, then compare the start to match |
330 | * anywhere inside a function. |
331 | */ |
332 | list_for_each_entry(cnode, &root->val, list) { |
333 | struct callchain_cursor_node *node; |
334 | struct symbol *sym; |
335 | |
336 | node = callchain_cursor_current(cursor); |
337 | if (!node) |
338 | break; |
339 | |
340 | sym = node->sym; |
341 | |
342 | if (cnode->ms.sym && sym) { |
343 | if (cnode->ms.sym->start != sym->start) |
344 | break; |
345 | } else if (cnode->ip != node->ip) |
346 | break; |
347 | |
348 | if (!found) |
349 | found = true; |
350 | |
351 | callchain_cursor_advance(cursor); |
352 | } |
353 | |
354 | /* matches not, relay on the parent */ |
355 | if (!found) { |
356 | cursor->curr = curr_snap; |
357 | cursor->pos = start; |
358 | return -1; |
359 | } |
360 | |
361 | matches = cursor->pos - start; |
362 | |
363 | /* we match only a part of the node. Split it and add the new chain */ |
364 | if (matches < root->val_nr) { |
365 | split_add_child(root, cursor, cnode, start, matches, period); |
366 | return 0; |
367 | } |
368 | |
369 | /* we match 100% of the path, increment the hit */ |
370 | if (matches == root->val_nr && cursor->pos == cursor->nr) { |
371 | root->hit += period; |
372 | return 0; |
373 | } |
374 | |
375 | /* We match the node and still have a part remaining */ |
376 | append_chain_children(root, cursor, period); |
377 | |
378 | return 0; |
379 | } |
380 | |
381 | int callchain_append(struct callchain_root *root, |
382 | struct callchain_cursor *cursor, |
383 | u64 period) |
384 | { |
385 | if (!cursor->nr) |
386 | return 0; |
387 | |
388 | callchain_cursor_commit(cursor); |
389 | |
390 | append_chain_children(&root->node, cursor, period); |
391 | |
392 | if (cursor->nr > root->max_depth) |
393 | root->max_depth = cursor->nr; |
394 | |
395 | return 0; |
396 | } |
397 | |
398 | static int |
399 | merge_chain_branch(struct callchain_cursor *cursor, |
400 | struct callchain_node *dst, struct callchain_node *src) |
401 | { |
402 | struct callchain_cursor_node **old_last = cursor->last; |
403 | struct callchain_node *child, *next_child; |
404 | struct callchain_list *list, *next_list; |
405 | int old_pos = cursor->nr; |
406 | int err = 0; |
407 | |
408 | list_for_each_entry_safe(list, next_list, &src->val, list) { |
409 | callchain_cursor_append(cursor, list->ip, |
410 | list->ms.map, list->ms.sym); |
411 | list_del(&list->list); |
412 | free(list); |
413 | } |
414 | |
415 | if (src->hit) { |
416 | callchain_cursor_commit(cursor); |
417 | append_chain_children(dst, cursor, src->hit); |
418 | } |
419 | |
420 | chain_for_each_child_safe(child, next_child, src) { |
421 | err = merge_chain_branch(cursor, dst, child); |
422 | if (err) |
423 | break; |
424 | |
425 | list_del(&child->siblings); |
426 | free(child); |
427 | } |
428 | |
429 | cursor->nr = old_pos; |
430 | cursor->last = old_last; |
431 | |
432 | return err; |
433 | } |
434 | |
435 | int callchain_merge(struct callchain_cursor *cursor, |
436 | struct callchain_root *dst, struct callchain_root *src) |
437 | { |
438 | return merge_chain_branch(cursor, &dst->node, &src->node); |
439 | } |
440 | |
441 | int callchain_cursor_append(struct callchain_cursor *cursor, |
442 | u64 ip, struct map *map, struct symbol *sym) |
443 | { |
444 | struct callchain_cursor_node *node = *cursor->last; |
445 | |
446 | if (!node) { |
447 | node = calloc(sizeof(*node), 1); |
448 | if (!node) |
449 | return -ENOMEM; |
450 | |
451 | *cursor->last = node; |
452 | } |
453 | |
454 | node->ip = ip; |
455 | node->map = map; |
456 | node->sym = sym; |
457 | |
458 | cursor->nr++; |
459 | |
460 | cursor->last = &node->next; |
461 | |
462 | return 0; |
463 | } |
464 |
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Tags:
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