tools/perf/util/callchain.c

   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 "callchain.h"
  19
  20 bool ip_callchain__valid(struct ip_callchain *chain, event_t *event)
  21 {
  22         unsigned int chain_size = event->header.size;
  23         chain_size -= (unsigned long)&event->ip.__more_data - (unsigned long)event;
  24         return chain->nr * sizeof(u64) <= chain_size;
  25 }
  26
  27 #define chain_for_each_child(child, parent)     \
  28         list_for_each_entry(child, &parent->children, brothers)
  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 = 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 = 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_node *node,
  89                 u64 min_hit, struct callchain_param *param __used)
  90 {
  91         __sort_chain_flat(rb_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 (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_node *chain_root,
 111                      u64 min_hit, struct callchain_param *param __used)
 112 {
 113         __sort_chain_graph_abs(chain_root, min_hit);
 114         rb_root->rb_node = chain_root->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 (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_node *chain_root,
 136                      u64 min_hit __used, struct callchain_param *param)
 137 {
 138         __sort_chain_graph_rel(chain_root, param->min_percent / 100.0);
 139         rb_root->rb_node = chain_root->rb_root.rb_node;
 140 }
 141
 142 int register_callchain_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 = malloc(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->brothers, &parent->children);
 189
 190         return new;
 191 }
 192
 193
 194 struct resolved_ip {
 195         u64               ip;
 196         struct map_symbol ms;
 197 };
 198
 199 struct resolved_chain {
 200         u64                     nr;
 201         struct resolved_ip      ips[0];
 202 };
 203
 204
 205 /*
 206  * Fill the node with callchain values
 207  */
 208 static void
 209 fill_node(struct callchain_node *node, struct resolved_chain *chain, int start)
 210 {
 211         unsigned int i;
 212
 213         for (i = start; i < chain->nr; i++) {
 214                 struct callchain_list *call;
 215
 216                 call = malloc(sizeof(*call));
 217                 if (!call) {
 218                         perror("not enough memory for the code path tree");
 219                         return;
 220                 }
 221                 call->ip = chain->ips[i].ip;
 222                 call->ms = chain->ips[i].ms;
 223                 list_add_tail(&call->list, &node->val);
 224         }
 225         node->val_nr = chain->nr - start;
 226         if (!node->val_nr)
 227                 pr_warning("Warning: empty node in callchain tree\n");
 228 }
 229
 230 static void
 231 add_child(struct callchain_node *parent, struct resolved_chain *chain,
 232           int start)
 233 {
 234         struct callchain_node *new;
 235
 236         new = create_child(parent, false);
 237         fill_node(new, chain, start);
 238
 239         new->children_hit = 0;
 240         new->hit = 1;
 241 }
 242
 243 /*
 244  * Split the parent in two parts (a new child is created) and
 245  * give a part of its callchain to the created child.
 246  * Then create another child to host the given callchain of new branch
 247  */
 248 static void
 249 split_add_child(struct callchain_node *parent, struct resolved_chain *chain,
 250                 struct callchain_list *to_split, int idx_parents, int idx_local)
 251 {
 252         struct callchain_node *new;
 253         struct list_head *old_tail;
 254         unsigned int idx_total = idx_parents + idx_local;
 255
 256         /* split */
 257         new = create_child(parent, true);
 258
 259         /* split the callchain and move a part to the new child */
 260         old_tail = parent->val.prev;
 261         list_del_range(&to_split->list, old_tail);
 262         new->val.next = &to_split->list;
 263         new->val.prev = old_tail;
 264         to_split->list.prev = &new->val;
 265         old_tail->next = &new->val;
 266
 267         /* split the hits */
 268         new->hit = parent->hit;
 269         new->children_hit = parent->children_hit;
 270         parent->children_hit = cumul_hits(new);
 271         new->val_nr = parent->val_nr - idx_local;
 272         parent->val_nr = idx_local;
 273
 274         /* create a new child for the new branch if any */
 275         if (idx_total < chain->nr) {
 276                 parent->hit = 0;
 277                 add_child(parent, chain, idx_total);
 278                 parent->children_hit++;
 279         } else {
 280                 parent->hit = 1;
 281         }
 282 }
 283
 284 static int
 285 __append_chain(struct callchain_node *root, struct resolved_chain *chain,
 286                unsigned int start);
 287
 288 static void
 289 __append_chain_children(struct callchain_node *root,
 290                         struct resolved_chain *chain,
 291                         unsigned int start)
 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, chain, start);
 298
 299                 if (!ret)
 300                         goto inc_children_hit;
 301         }
 302         /* nothing in children, add to the current node */
 303         add_child(root, chain, start);
 304
 305 inc_children_hit:
 306         root->children_hit++;
 307 }
 308
 309 static int
 310 __append_chain(struct callchain_node *root, struct resolved_chain *chain,
 311                unsigned int start)
 312 {
 313         struct callchain_list *cnode;
 314         unsigned int i = start;
 315         bool found = false;
 316
 317         /*
 318          * Lookup in the current node
 319          * If we have a symbol, then compare the start to match
 320          * anywhere inside a function.
 321          */
 322         list_for_each_entry(cnode, &root->val, list) {
 323                 struct symbol *sym;
 324
 325                 if (i == chain->nr)
 326                         break;
 327
 328                 sym = chain->ips[i].ms.sym;
 329
 330                 if (cnode->ms.sym && sym) {
 331                         if (cnode->ms.sym->start != sym->start)
 332                                 break;
 333                 } else if (cnode->ip != chain->ips[i].ip)
 334                         break;
 335
 336                 if (!found)
 337                         found = true;
 338                 i++;
 339         }
 340
 341         /* matches not, relay on the parent */
 342         if (!found)
 343                 return -1;
 344
 345         /* we match only a part of the node. Split it and add the new chain */
 346         if (i - start < root->val_nr) {
 347                 split_add_child(root, chain, cnode, start, i - start);
 348                 return 0;
 349         }
 350
 351         /* we match 100% of the path, increment the hit */
 352         if (i - start == root->val_nr && i == chain->nr) {
 353                 root->hit++;
 354                 return 0;
 355         }
 356
 357         /* We match the node and still have a part remaining */
 358         __append_chain_children(root, chain, i);
 359
 360         return 0;
 361 }
 362
 363 static void filter_context(struct ip_callchain *old, struct resolved_chain *new,
 364                            struct map_symbol *syms)
 365 {
 366         int i, j = 0;
 367
 368         for (i = 0; i < (int)old->nr; i++) {
 369                 if (old->ips[i] >= PERF_CONTEXT_MAX)
 370                         continue;
 371
 372                 new->ips[j].ip = old->ips[i];
 373                 new->ips[j].ms = syms[i];
 374                 j++;
 375         }
 376
 377         new->nr = j;
 378 }
 379
 380
 381 int append_chain(struct callchain_node *root, struct ip_callchain *chain,
 382                  struct map_symbol *syms)
 383 {
 384         struct resolved_chain *filtered;
 385
 386         if (!chain->nr)
 387                 return 0;
 388
 389         filtered = malloc(sizeof(*filtered) +
 390                           chain->nr * sizeof(struct resolved_ip));
 391         if (!filtered)
 392                 return -ENOMEM;
 393
 394         filter_context(chain, filtered, syms);
 395
 396         if (!filtered->nr)
 397                 goto end;
 398
 399         __append_chain_children(root, filtered, 0);
 400 end:
 401         free(filtered);
 402
 403         return 0;
 404 }