1 /* 2 * Copyright (C) 2009-2010, 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 bool ip_callchain__valid(struct ip_callchain *chain, const event_t *event) 22 { 23 unsigned int chain_size = event->header.size; 24 chain_size -= (unsigned long)&event->ip.__more_data - (unsigned long)event; 25 return chain->nr * sizeof(u64) <= chain_size; 26 } 27 28 #define chain_for_each_child(child, parent) \ 29 list_for_each_entry(child, &parent->children, brothers) 30 31 #define chain_for_each_child_safe(child, next, parent) \ 32 list_for_each_entry_safe(child, next, &parent->children, brothers) 33 34 static void 35 rb_insert_callchain(struct rb_root *root, struct callchain_node *chain, 36 enum chain_mode mode) 37 { 38 struct rb_node **p = &root->rb_node; 39 struct rb_node *parent = NULL; 40 struct callchain_node *rnode; 41 u64 chain_cumul = cumul_hits(chain); 42 43 while (*p) { 44 u64 rnode_cumul; 45 46 parent = *p; 47 rnode = rb_entry(parent, struct callchain_node, rb_node); 48 rnode_cumul = cumul_hits(rnode); 49 50 switch (mode) { 51 case CHAIN_FLAT: 52 if (rnode->hit < chain->hit) 53 p = &(*p)->rb_left; 54 else 55 p = &(*p)->rb_right; 56 break; 57 case CHAIN_GRAPH_ABS: /* Falldown */ 58 case CHAIN_GRAPH_REL: 59 if (rnode_cumul < chain_cumul) 60 p = &(*p)->rb_left; 61 else 62 p = &(*p)->rb_right; 63 break; 64 case CHAIN_NONE: 65 default: 66 break; 67 } 68 } 69 70 rb_link_node(&chain->rb_node, parent, p); 71 rb_insert_color(&chain->rb_node, root); 72 } 73 74 static void 75 __sort_chain_flat(struct rb_root *rb_root, struct callchain_node *node, 76 u64 min_hit) 77 { 78 struct callchain_node *child; 79 80 chain_for_each_child(child, node) 81 __sort_chain_flat(rb_root, child, min_hit); 82 83 if (node->hit && node->hit >= min_hit) 84 rb_insert_callchain(rb_root, node, CHAIN_FLAT); 85 } 86 87 /* 88 * Once we get every callchains from the stream, we can now 89 * sort them by hit 90 */ 91 static void 92 sort_chain_flat(struct rb_root *rb_root, struct callchain_root *root, 93 u64 min_hit, struct callchain_param *param __used) 94 { 95 __sort_chain_flat(rb_root, &root->node, min_hit); 96 } 97 98 static void __sort_chain_graph_abs(struct callchain_node *node, 99 u64 min_hit) 100 { 101 struct callchain_node *child; 102 103 node->rb_root = RB_ROOT; 104 105 chain_for_each_child(child, node) { 106 __sort_chain_graph_abs(child, min_hit); 107 if (cumul_hits(child) >= min_hit) 108 rb_insert_callchain(&node->rb_root, child, 109 CHAIN_GRAPH_ABS); 110 } 111 } 112 113 static void 114 sort_chain_graph_abs(struct rb_root *rb_root, struct callchain_root *chain_root, 115 u64 min_hit, struct callchain_param *param __used) 116 { 117 __sort_chain_graph_abs(&chain_root->node, min_hit); 118 rb_root->rb_node = chain_root->node.rb_root.rb_node; 119 } 120 121 static void __sort_chain_graph_rel(struct callchain_node *node, 122 double min_percent) 123 { 124 struct callchain_node *child; 125 u64 min_hit; 126 127 node->rb_root = RB_ROOT; 128 min_hit = ceil(node->children_hit * min_percent); 129 130 chain_for_each_child(child, node) { 131 __sort_chain_graph_rel(child, min_percent); 132 if (cumul_hits(child) >= min_hit) 133 rb_insert_callchain(&node->rb_root, child, 134 CHAIN_GRAPH_REL); 135 } 136 } 137 138 static void 139 sort_chain_graph_rel(struct rb_root *rb_root, struct callchain_root *chain_root, 140 u64 min_hit __used, struct callchain_param *param) 141 { 142 __sort_chain_graph_rel(&chain_root->node, param->min_percent / 100.0); 143 rb_root->rb_node = chain_root->node.rb_root.rb_node; 144 } 145 146 int register_callchain_param(struct callchain_param *param) 147 { 148 switch (param->mode) { 149 case CHAIN_GRAPH_ABS: 150 param->sort = sort_chain_graph_abs; 151 break; 152 case CHAIN_GRAPH_REL: 153 param->sort = sort_chain_graph_rel; 154 break; 155 case CHAIN_FLAT: 156 param->sort = sort_chain_flat; 157 break; 158 case CHAIN_NONE: 159 default: 160 return -1; 161 } 162 return 0; 163 } 164 165 /* 166 * Create a child for a parent. If inherit_children, then the new child 167 * will become the new parent of it's parent children 168 */ 169 static struct callchain_node * 170 create_child(struct callchain_node *parent, bool inherit_children) 171 { 172 struct callchain_node *new; 173 174 new = zalloc(sizeof(*new)); 175 if (!new) { 176 perror("not enough memory to create child for code path tree"); 177 return NULL; 178 } 179 new->parent = parent; 180 INIT_LIST_HEAD(&new->children); 181 INIT_LIST_HEAD(&new->val); 182 183 if (inherit_children) { 184 struct callchain_node *next; 185 186 list_splice(&parent->children, &new->children); 187 INIT_LIST_HEAD(&parent->children); 188 189 chain_for_each_child(next, new) 190 next->parent = new; 191 } 192 list_add_tail(&new->brothers, &parent->children); 193 194 return new; 195 } 196 197 198 struct resolved_ip { 199 u64 ip; 200 struct map_symbol ms; 201 }; 202 203 struct resolved_chain { 204 u64 nr; 205 struct resolved_ip ips[0]; 206 }; 207 208 209 /* 210 * Fill the node with callchain values 211 */ 212 static void 213 fill_node(struct callchain_node *node, struct resolved_chain *chain, int start) 214 { 215 unsigned int i; 216 217 for (i = start; i < chain->nr; i++) { 218 struct callchain_list *call; 219 220 call = zalloc(sizeof(*call)); 221 if (!call) { 222 perror("not enough memory for the code path tree"); 223 return; 224 } 225 call->ip = chain->ips[i].ip; 226 call->ms = chain->ips[i].ms; 227 list_add_tail(&call->list, &node->val); 228 } 229 node->val_nr = chain->nr - start; 230 if (!node->val_nr) 231 pr_warning("Warning: empty node in callchain tree\n"); 232 } 233 234 static void 235 add_child(struct callchain_node *parent, struct resolved_chain *chain, 236 int start, u64 period) 237 { 238 struct callchain_node *new; 239 240 new = create_child(parent, false); 241 fill_node(new, chain, start); 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, struct resolved_chain *chain, 254 struct callchain_list *to_split, int idx_parents, int idx_local, 255 u64 period) 256 { 257 struct callchain_node *new; 258 struct list_head *old_tail; 259 unsigned int idx_total = idx_parents + idx_local; 260 261 /* split */ 262 new = create_child(parent, true); 263 264 /* split the callchain and move a part to the new child */ 265 old_tail = parent->val.prev; 266 list_del_range(&to_split->list, old_tail); 267 new->val.next = &to_split->list; 268 new->val.prev = old_tail; 269 to_split->list.prev = &new->val; 270 old_tail->next = &new->val; 271 272 /* split the hits */ 273 new->hit = parent->hit; 274 new->children_hit = parent->children_hit; 275 parent->children_hit = cumul_hits(new); 276 new->val_nr = parent->val_nr - idx_local; 277 parent->val_nr = idx_local; 278 279 /* create a new child for the new branch if any */ 280 if (idx_total < chain->nr) { 281 parent->hit = 0; 282 add_child(parent, chain, idx_total, period); 283 parent->children_hit += period; 284 } else { 285 parent->hit = period; 286 } 287 } 288 289 static int 290 append_chain(struct callchain_node *root, struct resolved_chain *chain, 291 unsigned int start, u64 period); 292 293 static void 294 append_chain_children(struct callchain_node *root, struct resolved_chain *chain, 295 unsigned int start, u64 period) 296 { 297 struct callchain_node *rnode; 298 299 /* lookup in childrens */ 300 chain_for_each_child(rnode, root) { 301 unsigned int ret = append_chain(rnode, chain, start, period); 302 303 if (!ret) 304 goto inc_children_hit; 305 } 306 /* nothing in children, add to the current node */ 307 add_child(root, chain, start, period); 308 309 inc_children_hit: 310 root->children_hit += period; 311 } 312 313 static int 314 append_chain(struct callchain_node *root, struct resolved_chain *chain, 315 unsigned int start, u64 period) 316 { 317 struct callchain_list *cnode; 318 unsigned int i = start; 319 bool found = false; 320 321 /* 322 * Lookup in the current node 323 * If we have a symbol, then compare the start to match 324 * anywhere inside a function. 325 */ 326 list_for_each_entry(cnode, &root->val, list) { 327 struct symbol *sym; 328 329 if (i == chain->nr) 330 break; 331 332 sym = chain->ips[i].ms.sym; 333 334 if (cnode->ms.sym && sym) { 335 if (cnode->ms.sym->start != sym->start) 336 break; 337 } else if (cnode->ip != chain->ips[i].ip) 338 break; 339 340 if (!found) 341 found = true; 342 i++; 343 } 344 345 /* matches not, relay on the parent */ 346 if (!found) 347 return -1; 348 349 /* we match only a part of the node. Split it and add the new chain */ 350 if (i - start < root->val_nr) { 351 split_add_child(root, chain, cnode, start, i - start, period); 352 return 0; 353 } 354 355 /* we match 100% of the path, increment the hit */ 356 if (i - start == root->val_nr && i == chain->nr) { 357 root->hit += period; 358 return 0; 359 } 360 361 /* We match the node and still have a part remaining */ 362 append_chain_children(root, chain, i, period); 363 364 return 0; 365 } 366 367 static void filter_context(struct ip_callchain *old, struct resolved_chain *new, 368 struct map_symbol *syms) 369 { 370 int i, j = 0; 371 372 for (i = 0; i < (int)old->nr; i++) { 373 if (old->ips[i] >= PERF_CONTEXT_MAX) 374 continue; 375 376 new->ips[j].ip = old->ips[i]; 377 new->ips[j].ms = syms[i]; 378 j++; 379 } 380 381 new->nr = j; 382 } 383 384 385 int callchain_append(struct callchain_root *root, struct ip_callchain *chain, 386 struct map_symbol *syms, u64 period) 387 { 388 struct resolved_chain *filtered; 389 390 if (!chain->nr) 391 return 0; 392 393 filtered = zalloc(sizeof(*filtered) + 394 chain->nr * sizeof(struct resolved_ip)); 395 if (!filtered) 396 return -ENOMEM; 397 398 filter_context(chain, filtered, syms); 399 400 if (!filtered->nr) 401 goto end; 402 403 append_chain_children(&root->node, filtered, 0, period); 404 405 if (filtered->nr > root->max_depth) 406 root->max_depth = filtered->nr; 407 end: 408 free(filtered); 409 410 return 0; 411 } 412 413 static int 414 merge_chain_branch(struct callchain_node *dst, struct callchain_node *src, 415 struct resolved_chain *chain) 416 { 417 struct callchain_node *child, *next_child; 418 struct callchain_list *list, *next_list; 419 int old_pos = chain->nr; 420 int err = 0; 421 422 list_for_each_entry_safe(list, next_list, &src->val, list) { 423 chain->ips[chain->nr].ip = list->ip; 424 chain->ips[chain->nr].ms = list->ms; 425 chain->nr++; 426 list_del(&list->list); 427 free(list); 428 } 429 430 if (src->hit) 431 append_chain_children(dst, chain, 0, src->hit); 432 433 chain_for_each_child_safe(child, next_child, src) { 434 err = merge_chain_branch(dst, child, chain); 435 if (err) 436 break; 437 438 list_del(&child->brothers); 439 free(child); 440 } 441 442 chain->nr = old_pos; 443 444 return err; 445 } 446 447 int callchain_merge(struct callchain_root *dst, struct callchain_root *src) 448 { 449 struct resolved_chain *chain; 450 int err; 451 452 chain = malloc(sizeof(*chain) + 453 src->max_depth * sizeof(struct resolved_ip)); 454 if (!chain) 455 return -ENOMEM; 456 457 chain->nr = 0; 458 459 err = merge_chain_branch(&dst->node, &src->node, chain); 460 461 free(chain); 462 463 return err; 464 } 465