tools/perf/util/callchain.c

   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 "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 = 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 __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 (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 __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 (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 __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 /*
 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.
 328          */
 329         list_for_each_entry(cnode, &root->val, list) {
 330                 struct callchain_cursor_node *node;
 331                 struct symbol *sym;
 332
 333                 node = callchain_cursor_current(cursor);
 334                 if (!node)
 335                         break;
 336
 337                 sym = node->sym;
 338
 339                 if (cnode->ms.sym && sym) {
 340                         if (cnode->ms.sym->start != sym->start)
 341                                 break;
 342                 } else if (cnode->ip != node->ip)
 343                         break;
 344
 345                 if (!found)
 346                         found = true;
 347
 348                 callchain_cursor_advance(cursor);
 349         }
 350
 351         /* matches not, relay on the parent */
 352         if (!found) {
 353                 cursor->curr = curr_snap;
 354                 cursor->pos = start;
 355                 return -1;
 356         }
 357
 358         matches = cursor->pos - start;
 359
 360         /* we match only a part of the node. Split it and add the new chain */
 361         if (matches < root->val_nr) {
 362                 split_add_child(root, cursor, cnode, start, matches, period);
 363                 return 0;
 364         }
 365
 366         /* we match 100% of the path, increment the hit */
 367         if (matches == root->val_nr && cursor->pos == cursor->nr) {
 368                 root->hit += period;
 369                 return 0;
 370         }
 371
 372         /* We match the node and still have a part remaining */
 373         append_chain_children(root, cursor, period);
 374
 375         return 0;
 376 }
 377
 378 int callchain_append(struct callchain_root *root,
 379                      struct callchain_cursor *cursor,
 380                      u64 period)
 381 {
 382         if (!cursor->nr)
 383                 return 0;
 384
 385         callchain_cursor_commit(cursor);
 386
 387         append_chain_children(&root->node, cursor, period);
 388
 389         if (cursor->nr > root->max_depth)
 390                 root->max_depth = cursor->nr;
 391
 392         return 0;
 393 }
 394
 395 static int
 396 merge_chain_branch(struct callchain_cursor *cursor,
 397                    struct callchain_node *dst, struct callchain_node *src)
 398 {
 399         struct callchain_cursor_node **old_last = cursor->last;
 400         struct callchain_node *child, *next_child;
 401         struct callchain_list *list, *next_list;
 402         int old_pos = cursor->nr;
 403         int err = 0;
 404
 405         list_for_each_entry_safe(list, next_list, &src->val, list) {
 406                 callchain_cursor_append(cursor, list->ip,
 407                                         list->ms.map, list->ms.sym);
 408                 list_del(&list->list);
 409                 free(list);
 410         }
 411
 412         if (src->hit) {
 413                 callchain_cursor_commit(cursor);
 414                 append_chain_children(dst, cursor, src->hit);
 415         }
 416
 417         chain_for_each_child_safe(child, next_child, src) {
 418                 err = merge_chain_branch(cursor, dst, child);
 419                 if (err)
 420                         break;
 421
 422                 list_del(&child->brothers);
 423                 free(child);
 424         }
 425
 426         cursor->nr = old_pos;
 427         cursor->last = old_last;
 428
 429         return err;
 430 }
 431
 432 int callchain_merge(struct callchain_cursor *cursor,
 433                     struct callchain_root *dst, struct callchain_root *src)
 434 {
 435         return merge_chain_branch(cursor, &dst->node, &src->node);
 436 }
 437
 438 int callchain_cursor_append(struct callchain_cursor *cursor,
 439                             u64 ip, struct map *map, struct symbol *sym)
 440 {
 441         struct callchain_cursor_node *node = *cursor->last;
 442
 443         if (!node) {
 444                 node = calloc(sizeof(*node), 1);
 445                 if (!node)
 446                         return -ENOMEM;
 447
 448                 *cursor->last = node;
 449         }
 450
 451         node->ip = ip;
 452         node->map = map;
 453         node->sym = sym;
 454
 455         cursor->nr++;
 456
 457         cursor->last = &node->next;
 458
 459         return 0;
 460 }