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