1 /* 2 * Copyright (C) 2009-2011, Frederic Weisbecker <fweisbec (at) 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 "hist.h" 19 #include "util.h" 20 #include "callchain.h" 21 22 #ifdef __APPLE__ 23 struct callchain_cursor callchain_cursor; 24 #else 25 __thread struct callchain_cursor callchain_cursor; 26 #endif 27 28 #define chain_for_each_child(child, parent) \ 29 list_for_each_entry(child, &parent->children, siblings) 30 31 #define chain_for_each_child_safe(child, next, parent) \ 32 list_for_each_entry_safe(child, next, &parent->children, siblings) 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 = callchain_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 = callchain_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 __maybe_unused) 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 (callchain_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 __maybe_unused) 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 (callchain_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 __maybe_unused, 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 callchain_register_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->siblings, &parent->children); 193 194 return new; 195 } 196 197 198 /* 199 * Fill the node with callchain values 200 */ 201 static void 202 fill_node(struct callchain_node *node, struct callchain_cursor *cursor) 203 { 204 struct callchain_cursor_node *cursor_node; 205 206 node->val_nr = cursor->nr - cursor->pos; 207 if (!node->val_nr) 208 pr_warning("Warning: empty node in callchain tree\n"); 209 210 cursor_node = callchain_cursor_current(cursor); 211 212 while (cursor_node) { 213 struct callchain_list *call; 214 215 call = zalloc(sizeof(*call)); 216 if (!call) { 217 perror("not enough memory for the code path tree"); 218 return; 219 } 220 call->ip = cursor_node->ip; 221 call->ms.sym = cursor_node->sym; 222 call->ms.map = cursor_node->map; 223 list_add_tail(&call->list, &node->val); 224 225 callchain_cursor_advance(cursor); 226 cursor_node = callchain_cursor_current(cursor); 227 } 228 } 229 230 static void 231 add_child(struct callchain_node *parent, 232 struct callchain_cursor *cursor, 233 u64 period) 234 { 235 struct callchain_node *new; 236 237 new = create_child(parent, false); 238 fill_node(new, cursor); 239 240 new->children_hit = 0; 241 new->hit = period; 242 } 243 244 /* 245 * Split the parent in two parts (a new child is created) and 246 * give a part of its callchain to the created child. 247 * Then create another child to host the given callchain of new branch 248 */ 249 static void 250 split_add_child(struct callchain_node *parent, 251 struct callchain_cursor *cursor, 252 struct callchain_list *to_split, 253 u64 idx_parents, u64 idx_local, u64 period) 254 { 255 struct callchain_node *new; 256 struct list_head *old_tail; 257 unsigned int idx_total = idx_parents + idx_local; 258 259 /* split */ 260 new = create_child(parent, true); 261 262 /* split the callchain and move a part to the new child */ 263 old_tail = parent->val.prev; 264 list_del_range(&to_split->list, old_tail); 265 new->val.next = &to_split->list; 266 new->val.prev = old_tail; 267 to_split->list.prev = &new->val; 268 old_tail->next = &new->val; 269 270 /* split the hits */ 271 new->hit = parent->hit; 272 new->children_hit = parent->children_hit; 273 parent->children_hit = callchain_cumul_hits(new); 274 new->val_nr = parent->val_nr - idx_local; 275 parent->val_nr = idx_local; 276 277 /* create a new child for the new branch if any */ 278 if (idx_total < cursor->nr) { 279 parent->hit = 0; 280 add_child(parent, cursor, period); 281 parent->children_hit += period; 282 } else { 283 parent->hit = period; 284 } 285 } 286 287 static int 288 append_chain(struct callchain_node *root, 289 struct callchain_cursor *cursor, 290 u64 period); 291 292 static void 293 append_chain_children(struct callchain_node *root, 294 struct callchain_cursor *cursor, 295 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, cursor, period); 302 303 if (!ret) 304 goto inc_children_hit; 305 } 306 /* nothing in children, add to the current node */ 307 add_child(root, cursor, period); 308 309 inc_children_hit: 310 root->children_hit += period; 311 } 312 313 static int 314 append_chain(struct callchain_node *root, 315 struct callchain_cursor *cursor, 316 u64 period) 317 { 318 struct callchain_cursor_node *curr_snap = cursor->curr; 319 struct callchain_list *cnode; 320 u64 start = cursor->pos; 321 bool found = false; 322 u64 matches; 323 324 /* 325 * Lookup in the current node 326 * If we have a symbol, then compare the start to match 327 * anywhere inside a function, unless function 328 * mode is disabled. 329 */ 330 list_for_each_entry(cnode, &root->val, list) { 331 struct callchain_cursor_node *node; 332 struct symbol *sym; 333 334 node = callchain_cursor_current(cursor); 335 if (!node) 336 break; 337 338 sym = node->sym; 339 340 if (cnode->ms.sym && sym && 341 callchain_param.key == CCKEY_FUNCTION) { 342 if (cnode->ms.sym->start != sym->start) 343 break; 344 } else if (cnode->ip != node->ip) 345 break; 346 347 if (!found) 348 found = true; 349 350 callchain_cursor_advance(cursor); 351 } 352 353 /* matches not, relay on the parent */ 354 if (!found) { 355 cursor->curr = curr_snap; 356 cursor->pos = start; 357 return -1; 358 } 359 360 matches = cursor->pos - start; 361 362 /* we match only a part of the node. Split it and add the new chain */ 363 if (matches < root->val_nr) { 364 split_add_child(root, cursor, cnode, start, matches, period); 365 return 0; 366 } 367 368 /* we match 100% of the path, increment the hit */ 369 if (matches == root->val_nr && cursor->pos == cursor->nr) { 370 root->hit += period; 371 return 0; 372 } 373 374 /* We match the node and still have a part remaining */ 375 append_chain_children(root, cursor, period); 376 377 return 0; 378 } 379 380 int callchain_append(struct callchain_root *root, 381 struct callchain_cursor *cursor, 382 u64 period) 383 { 384 if (!cursor->nr) 385 return 0; 386 387 callchain_cursor_commit(cursor); 388 389 append_chain_children(&root->node, cursor, period); 390 391 if (cursor->nr > root->max_depth) 392 root->max_depth = cursor->nr; 393 394 return 0; 395 } 396 397 static int 398 merge_chain_branch(struct callchain_cursor *cursor, 399 struct callchain_node *dst, struct callchain_node *src) 400 { 401 struct callchain_cursor_node **old_last = cursor->last; 402 struct callchain_node *child, *next_child; 403 struct callchain_list *list, *next_list; 404 int old_pos = cursor->nr; 405 int err = 0; 406 407 list_for_each_entry_safe(list, next_list, &src->val, list) { 408 callchain_cursor_append(cursor, list->ip, 409 list->ms.map, list->ms.sym); 410 list_del(&list->list); 411 free(list); 412 } 413 414 if (src->hit) { 415 callchain_cursor_commit(cursor); 416 append_chain_children(dst, cursor, src->hit); 417 } 418 419 chain_for_each_child_safe(child, next_child, src) { 420 err = merge_chain_branch(cursor, dst, child); 421 if (err) 422 break; 423 424 list_del(&child->siblings); 425 free(child); 426 } 427 428 cursor->nr = old_pos; 429 cursor->last = old_last; 430 431 return err; 432 } 433 434 int callchain_merge(struct callchain_cursor *cursor, 435 struct callchain_root *dst, struct callchain_root *src) 436 { 437 return merge_chain_branch(cursor, &dst->node, &src->node); 438 } 439 440 int callchain_cursor_append(struct callchain_cursor *cursor, 441 u64 ip, struct map *map, struct symbol *sym) 442 { 443 struct callchain_cursor_node *node = *cursor->last; 444 445 if (!node) { 446 node = calloc(1, sizeof(*node)); 447 if (!node) 448 return -ENOMEM; 449 450 *cursor->last = node; 451 } 452 453 node->ip = ip; 454 node->map = map; 455 node->sym = sym; 456 457 cursor->nr++; 458 459 cursor->last = &node->next; 460 461 return 0; 462 } 463
