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 static void 32 rb_insert_callchain(struct rb_root *root, struct callchain_node *chain, 33 enum chain_mode mode) 34 { 35 struct rb_node **p = &root->rb_node; 36 struct rb_node *parent = NULL; 37 struct callchain_node *rnode; 38 u64 chain_cumul = cumul_hits(chain); 39 40 while (*p) { 41 u64 rnode_cumul; 42 43 parent = *p; 44 rnode = rb_entry(parent, struct callchain_node, rb_node); 45 rnode_cumul = cumul_hits(rnode); 46 47 switch (mode) { 48 case CHAIN_FLAT: 49 if (rnode->hit < chain->hit) 50 p = &(*p)->rb_left; 51 else 52 p = &(*p)->rb_right; 53 break; 54 case CHAIN_GRAPH_ABS: /* Falldown */ 55 case CHAIN_GRAPH_REL: 56 if (rnode_cumul < chain_cumul) 57 p = &(*p)->rb_left; 58 else 59 p = &(*p)->rb_right; 60 break; 61 case CHAIN_NONE: 62 default: 63 break; 64 } 65 } 66 67 rb_link_node(&chain->rb_node, parent, p); 68 rb_insert_color(&chain->rb_node, root); 69 } 70 71 static void 72 __sort_chain_flat(struct rb_root *rb_root, struct callchain_node *node, 73 u64 min_hit) 74 { 75 struct callchain_node *child; 76 77 chain_for_each_child(child, node) 78 __sort_chain_flat(rb_root, child, min_hit); 79 80 if (node->hit && node->hit >= min_hit) 81 rb_insert_callchain(rb_root, node, CHAIN_FLAT); 82 } 83 84 /* 85 * Once we get every callchains from the stream, we can now 86 * sort them by hit 87 */ 88 static void 89 sort_chain_flat(struct rb_root *rb_root, struct callchain_node *node, 90 u64 min_hit, struct callchain_param *param __used) 91 { 92 __sort_chain_flat(rb_root, node, min_hit); 93 } 94 95 static void __sort_chain_graph_abs(struct callchain_node *node, 96 u64 min_hit) 97 { 98 struct callchain_node *child; 99 100 node->rb_root = RB_ROOT; 101 102 chain_for_each_child(child, node) { 103 __sort_chain_graph_abs(child, min_hit); 104 if (cumul_hits(child) >= min_hit) 105 rb_insert_callchain(&node->rb_root, child, 106 CHAIN_GRAPH_ABS); 107 } 108 } 109 110 static void 111 sort_chain_graph_abs(struct rb_root *rb_root, struct callchain_node *chain_root, 112 u64 min_hit, struct callchain_param *param __used) 113 { 114 __sort_chain_graph_abs(chain_root, min_hit); 115 rb_root->rb_node = chain_root->rb_root.rb_node; 116 } 117 118 static void __sort_chain_graph_rel(struct callchain_node *node, 119 double min_percent) 120 { 121 struct callchain_node *child; 122 u64 min_hit; 123 124 node->rb_root = RB_ROOT; 125 min_hit = ceil(node->children_hit * min_percent); 126 127 chain_for_each_child(child, node) { 128 __sort_chain_graph_rel(child, min_percent); 129 if (cumul_hits(child) >= min_hit) 130 rb_insert_callchain(&node->rb_root, child, 131 CHAIN_GRAPH_REL); 132 } 133 } 134 135 static void 136 sort_chain_graph_rel(struct rb_root *rb_root, struct callchain_node *chain_root, 137 u64 min_hit __used, struct callchain_param *param) 138 { 139 __sort_chain_graph_rel(chain_root, param->min_percent / 100.0); 140 rb_root->rb_node = chain_root->rb_root.rb_node; 141 } 142 143 int register_callchain_param(struct callchain_param *param) 144 { 145 switch (param->mode) { 146 case CHAIN_GRAPH_ABS: 147 param->sort = sort_chain_graph_abs; 148 break; 149 case CHAIN_GRAPH_REL: 150 param->sort = sort_chain_graph_rel; 151 break; 152 case CHAIN_FLAT: 153 param->sort = sort_chain_flat; 154 break; 155 case CHAIN_NONE: 156 default: 157 return -1; 158 } 159 return 0; 160 } 161 162 /* 163 * Create a child for a parent. If inherit_children, then the new child 164 * will become the new parent of it's parent children 165 */ 166 static struct callchain_node * 167 create_child(struct callchain_node *parent, bool inherit_children) 168 { 169 struct callchain_node *new; 170 171 new = zalloc(sizeof(*new)); 172 if (!new) { 173 perror("not enough memory to create child for code path tree"); 174 return NULL; 175 } 176 new->parent = parent; 177 INIT_LIST_HEAD(&new->children); 178 INIT_LIST_HEAD(&new->val); 179 180 if (inherit_children) { 181 struct callchain_node *next; 182 183 list_splice(&parent->children, &new->children); 184 INIT_LIST_HEAD(&parent->children); 185 186 chain_for_each_child(next, new) 187 next->parent = new; 188 } 189 list_add_tail(&new->brothers, &parent->children); 190 191 return new; 192 } 193 194 195 struct resolved_ip { 196 u64 ip; 197 struct map_symbol ms; 198 }; 199 200 struct resolved_chain { 201 u64 nr; 202 struct resolved_ip ips[0]; 203 }; 204 205 206 /* 207 * Fill the node with callchain values 208 */ 209 static void 210 fill_node(struct callchain_node *node, struct resolved_chain *chain, int start) 211 { 212 unsigned int i; 213 214 for (i = start; i < chain->nr; i++) { 215 struct callchain_list *call; 216 217 call = zalloc(sizeof(*call)); 218 if (!call) { 219 perror("not enough memory for the code path tree"); 220 return; 221 } 222 call->ip = chain->ips[i].ip; 223 call->ms = chain->ips[i].ms; 224 list_add_tail(&call->list, &node->val); 225 } 226 node->val_nr = chain->nr - start; 227 if (!node->val_nr) 228 pr_warning("Warning: empty node in callchain tree\n"); 229 } 230 231 static void 232 add_child(struct callchain_node *parent, struct resolved_chain *chain, 233 int start, u64 period) 234 { 235 struct callchain_node *new; 236 237 new = create_child(parent, false); 238 fill_node(new, chain, start); 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, struct resolved_chain *chain, 251 struct callchain_list *to_split, int idx_parents, int idx_local, 252 u64 period) 253 { 254 struct callchain_node *new; 255 struct list_head *old_tail; 256 unsigned int idx_total = idx_parents + idx_local; 257 258 /* split */ 259 new = create_child(parent, true); 260 261 /* split the callchain and move a part to the new child */ 262 old_tail = parent->val.prev; 263 list_del_range(&to_split->list, old_tail); 264 new->val.next = &to_split->list; 265 new->val.prev = old_tail; 266 to_split->list.prev = &new->val; 267 old_tail->next = &new->val; 268 269 /* split the hits */ 270 new->hit = parent->hit; 271 new->children_hit = parent->children_hit; 272 parent->children_hit = cumul_hits(new); 273 new->val_nr = parent->val_nr - idx_local; 274 parent->val_nr = idx_local; 275 276 /* create a new child for the new branch if any */ 277 if (idx_total < chain->nr) { 278 parent->hit = 0; 279 add_child(parent, chain, idx_total, period); 280 parent->children_hit += period; 281 } else { 282 parent->hit = period; 283 } 284 } 285 286 static int 287 __append_chain(struct callchain_node *root, struct resolved_chain *chain, 288 unsigned int start, u64 period); 289 290 static void 291 __append_chain_children(struct callchain_node *root, 292 struct resolved_chain *chain, 293 unsigned int start, u64 period) 294 { 295 struct callchain_node *rnode; 296 297 /* lookup in childrens */ 298 chain_for_each_child(rnode, root) { 299 unsigned int ret = __append_chain(rnode, chain, start, period); 300 301 if (!ret) 302 goto inc_children_hit; 303 } 304 /* nothing in children, add to the current node */ 305 add_child(root, chain, start, period); 306 307 inc_children_hit: 308 root->children_hit += period; 309 } 310 311 static int 312 __append_chain(struct callchain_node *root, struct resolved_chain *chain, 313 unsigned int start, u64 period) 314 { 315 struct callchain_list *cnode; 316 unsigned int i = start; 317 bool found = false; 318 319 /* 320 * Lookup in the current node 321 * If we have a symbol, then compare the start to match 322 * anywhere inside a function. 323 */ 324 list_for_each_entry(cnode, &root->val, list) { 325 struct symbol *sym; 326 327 if (i == chain->nr) 328 break; 329 330 sym = chain->ips[i].ms.sym; 331 332 if (cnode->ms.sym && sym) { 333 if (cnode->ms.sym->start != sym->start) 334 break; 335 } else if (cnode->ip != chain->ips[i].ip) 336 break; 337 338 if (!found) 339 found = true; 340 i++; 341 } 342 343 /* matches not, relay on the parent */ 344 if (!found) 345 return -1; 346 347 /* we match only a part of the node. Split it and add the new chain */ 348 if (i - start < root->val_nr) { 349 split_add_child(root, chain, cnode, start, i - start, period); 350 return 0; 351 } 352 353 /* we match 100% of the path, increment the hit */ 354 if (i - start == root->val_nr && i == chain->nr) { 355 root->hit += period; 356 return 0; 357 } 358 359 /* We match the node and still have a part remaining */ 360 __append_chain_children(root, chain, i, period); 361 362 return 0; 363 } 364 365 static void filter_context(struct ip_callchain *old, struct resolved_chain *new, 366 struct map_symbol *syms) 367 { 368 int i, j = 0; 369 370 for (i = 0; i < (int)old->nr; i++) { 371 if (old->ips[i] >= PERF_CONTEXT_MAX) 372 continue; 373 374 new->ips[j].ip = old->ips[i]; 375 new->ips[j].ms = syms[i]; 376 j++; 377 } 378 379 new->nr = j; 380 } 381 382 383 int append_chain(struct callchain_node *root, struct ip_callchain *chain, 384 struct map_symbol *syms, u64 period) 385 { 386 struct resolved_chain *filtered; 387 388 if (!chain->nr) 389 return 0; 390 391 filtered = zalloc(sizeof(*filtered) + 392 chain->nr * sizeof(struct resolved_ip)); 393 if (!filtered) 394 return -ENOMEM; 395 396 filter_context(chain, filtered, syms); 397 398 if (!filtered->nr) 399 goto end; 400 401 __append_chain_children(root, filtered, 0, period); 402 end: 403 free(filtered); 404 405 return 0; 406 } 407