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 __thread struct callchain_cursor callchain_cursor;
  22
  23 bool ip_callchain__valid(struct ip_callchain *chain,
  24                          const union perf_event *event)
  25 {
  26         unsigned int chain_size = event->header.size;
  27         chain_size -= (unsigned long)&event->ip.__more_data - (unsigned long)event;
  28         return chain->nr * sizeof(u64) <= chain_size;
  29 }
  30
  31 #define chain_for_each_child(child, parent)     \
  32         list_for_each_entry(child, &parent->children, siblings)
  33
  34 #define chain_for_each_child_safe(child, next, parent)  \
  35         list_for_each_entry_safe(child, next, &parent->children, siblings)
  36
  37 static void
  38 rb_insert_callchain(struct rb_root *root, struct callchain_node *chain,
  39                     enum chain_mode mode)
  40 {
  41         struct rb_node **p = &root->rb_node;
  42         struct rb_node *parent = NULL;
  43         struct callchain_node *rnode;
  44         u64 chain_cumul = callchain_cumul_hits(chain);
  45
  46         while (*p) {
  47                 u64 rnode_cumul;
  48
  49                 parent = *p;
  50                 rnode = rb_entry(parent, struct callchain_node, rb_node);
  51                 rnode_cumul = callchain_cumul_hits(rnode);
  52
  53                 switch (mode) {
  54                 case CHAIN_FLAT:
  55                         if (rnode->hit < chain->hit)
  56                                 p = &(*p)->rb_left;
  57                         else
  58                                 p = &(*p)->rb_right;
  59                         break;
  60                 case CHAIN_GRAPH_ABS: /* Falldown */
  61                 case CHAIN_GRAPH_REL:
  62                         if (rnode_cumul < chain_cumul)
  63                                 p = &(*p)->rb_left;
  64                         else
  65                                 p = &(*p)->rb_right;
  66                         break;
  67                 case CHAIN_NONE:
  68                 default:
  69                         break;
  70                 }
  71         }
  72
  73         rb_link_node(&chain->rb_node, parent, p);
  74         rb_insert_color(&chain->rb_node, root);
  75 }
  76
  77 static void
  78 __sort_chain_flat(struct rb_root *rb_root, struct callchain_node *node,
  79                   u64 min_hit)
  80 {
  81         struct callchain_node *child;
  82
  83         chain_for_each_child(child, node)
  84                 __sort_chain_flat(rb_root, child, min_hit);
  85
  86         if (node->hit && node->hit >= min_hit)
  87                 rb_insert_callchain(rb_root, node, CHAIN_FLAT);
  88 }
  89
  90 /*
  91  * Once we get every callchains from the stream, we can now
  92  * sort them by hit
  93  */
  94 static void
  95 sort_chain_flat(struct rb_root *rb_root, struct callchain_root *root,
  96                 u64 min_hit, struct callchain_param *param __maybe_unused)
  97 {
  98         __sort_chain_flat(rb_root, &root->node, min_hit);
  99 }
 100
 101 static void __sort_chain_graph_abs(struct callchain_node *node,
 102                                    u64 min_hit)
 103 {
 104         struct callchain_node *child;
 105
 106         node->rb_root = RB_ROOT;
 107
 108         chain_for_each_child(child, node) {
 109                 __sort_chain_graph_abs(child, min_hit);
 110                 if (callchain_cumul_hits(child) >= min_hit)
 111                         rb_insert_callchain(&node->rb_root, child,
 112                                             CHAIN_GRAPH_ABS);
 113         }
 114 }
 115
 116 static void
 117 sort_chain_graph_abs(struct rb_root *rb_root, struct callchain_root *chain_root,
 118                      u64 min_hit, struct callchain_param *param __maybe_unused)
 119 {
 120         __sort_chain_graph_abs(&chain_root->node, min_hit);
 121         rb_root->rb_node = chain_root->node.rb_root.rb_node;
 122 }
 123
 124 static void __sort_chain_graph_rel(struct callchain_node *node,
 125                                    double min_percent)
 126 {
 127         struct callchain_node *child;
 128         u64 min_hit;
 129
 130         node->rb_root = RB_ROOT;
 131         min_hit = ceil(node->children_hit * min_percent);
 132
 133         chain_for_each_child(child, node) {
 134                 __sort_chain_graph_rel(child, min_percent);
 135                 if (callchain_cumul_hits(child) >= min_hit)
 136                         rb_insert_callchain(&node->rb_root, child,
 137                                             CHAIN_GRAPH_REL);
 138         }
 139 }
 140
 141 static void
 142 sort_chain_graph_rel(struct rb_root *rb_root, struct callchain_root *chain_root,
 143                      u64 min_hit __maybe_unused, struct callchain_param *param)
 144 {
 145         __sort_chain_graph_rel(&chain_root->node, param->min_percent / 100.0);
 146         rb_root->rb_node = chain_root->node.rb_root.rb_node;
 147 }
 148
 149 int callchain_register_param(struct callchain_param *param)
 150 {
 151         switch (param->mode) {
 152         case CHAIN_GRAPH_ABS:
 153                 param->sort = sort_chain_graph_abs;
 154                 break;
 155         case CHAIN_GRAPH_REL:
 156                 param->sort = sort_chain_graph_rel;
 157                 break;
 158         case CHAIN_FLAT:
 159                 param->sort = sort_chain_flat;
 160                 break;
 161         case CHAIN_NONE:
 162         default:
 163                 return -1;
 164         }
 165         return 0;
 166 }
 167
 168 /*
 169  * Create a child for a parent. If inherit_children, then the new child
 170  * will become the new parent of it's parent children
 171  */
 172 static struct callchain_node *
 173 create_child(struct callchain_node *parent, bool inherit_children)
 174 {
 175         struct callchain_node *new;
 176
 177         new = zalloc(sizeof(*new));
 178         if (!new) {
 179                 perror("not enough memory to create child for code path tree");
 180                 return NULL;
 181         }
 182         new->parent = parent;
 183         INIT_LIST_HEAD(&new->children);
 184         INIT_LIST_HEAD(&new->val);
 185
 186         if (inherit_children) {
 187                 struct callchain_node *next;
 188
 189                 list_splice(&parent->children, &new->children);
 190                 INIT_LIST_HEAD(&parent->children);
 191
 192                 chain_for_each_child(next, new)
 193                         next->parent = new;
 194         }
 195         list_add_tail(&new->siblings, &parent->children);
 196
 197         return new;
 198 }
 199
 200
 201 /*
 202  * Fill the node with callchain values
 203  */
 204 static void
 205 fill_node(struct callchain_node *node, struct callchain_cursor *cursor)
 206 {
 207         struct callchain_cursor_node *cursor_node;
 208
 209         node->val_nr = cursor->nr - cursor->pos;
 210         if (!node->val_nr)
 211                 pr_warning("Warning: empty node in callchain tree\n");
 212
 213         cursor_node = callchain_cursor_current(cursor);
 214
 215         while (cursor_node) {
 216                 struct callchain_list *call;
 217
 218                 call = zalloc(sizeof(*call));
 219                 if (!call) {
 220                         perror("not enough memory for the code path tree");
 221                         return;
 222                 }
 223                 call->ip = cursor_node->ip;
 224                 call->ms.sym = cursor_node->sym;
 225                 call->ms.map = cursor_node->map;
 226                 list_add_tail(&call->list, &node->val);
 227
 228                 callchain_cursor_advance(cursor);
 229                 cursor_node = callchain_cursor_current(cursor);
 230         }
 231 }
 232
 233 static void
 234 add_child(struct callchain_node *parent,
 235           struct callchain_cursor *cursor,
 236           u64 period)
 237 {
 238         struct callchain_node *new;
 239
 240         new = create_child(parent, false);
 241         fill_node(new, cursor);
 242
 243         new->children_hit = 0;
 244         new->hit = period;
 245 }
 246
 247 /*
 248  * Split the parent in two parts (a new child is created) and
 249  * give a part of its callchain to the created child.
 250  * Then create another child to host the given callchain of new branch
 251  */
 252 static void
 253 split_add_child(struct callchain_node *parent,
 254                 struct callchain_cursor *cursor,
 255                 struct callchain_list *to_split,
 256                 u64 idx_parents, u64 idx_local, u64 period)
 257 {
 258         struct callchain_node *new;
 259         struct list_head *old_tail;
 260         unsigned int idx_total = idx_parents + idx_local;
 261
 262         /* split */
 263         new = create_child(parent, true);
 264
 265         /* split the callchain and move a part to the new child */
 266         old_tail = parent->val.prev;
 267         list_del_range(&to_split->list, old_tail);
 268         new->val.next = &to_split->list;
 269         new->val.prev = old_tail;
 270         to_split->list.prev = &new->val;
 271         old_tail->next = &new->val;
 272
 273         /* split the hits */
 274         new->hit = parent->hit;
 275         new->children_hit = parent->children_hit;
 276         parent->children_hit = callchain_cumul_hits(new);
 277         new->val_nr = parent->val_nr - idx_local;
 278         parent->val_nr = idx_local;
 279
 280         /* create a new child for the new branch if any */
 281         if (idx_total < cursor->nr) {
 282                 parent->hit = 0;
 283                 add_child(parent, cursor, period);
 284                 parent->children_hit += period;
 285         } else {
 286                 parent->hit = period;
 287         }
 288 }
 289
 290 static int
 291 append_chain(struct callchain_node *root,
 292              struct callchain_cursor *cursor,
 293              u64 period);
 294
 295 static void
 296 append_chain_children(struct callchain_node *root,
 297                       struct callchain_cursor *cursor,
 298                       u64 period)
 299 {
 300         struct callchain_node *rnode;
 301
 302         /* lookup in childrens */
 303         chain_for_each_child(rnode, root) {
 304                 unsigned int ret = append_chain(rnode, cursor, period);
 305
 306                 if (!ret)
 307                         goto inc_children_hit;
 308         }
 309         /* nothing in children, add to the current node */
 310         add_child(root, cursor, period);
 311
 312 inc_children_hit:
 313         root->children_hit += period;
 314 }
 315
 316 static int
 317 append_chain(struct callchain_node *root,
 318              struct callchain_cursor *cursor,
 319              u64 period)
 320 {
 321         struct callchain_cursor_node *curr_snap = cursor->curr;
 322         struct callchain_list *cnode;
 323         u64 start = cursor->pos;
 324         bool found = false;
 325         u64 matches;
 326
 327         /*
 328          * Lookup in the current node
 329          * If we have a symbol, then compare the start to match
 330          * anywhere inside a function.
 331          */
 332         list_for_each_entry(cnode, &root->val, list) {
 333                 struct callchain_cursor_node *node;
 334                 struct symbol *sym;
 335
 336                 node = callchain_cursor_current(cursor);
 337                 if (!node)
 338                         break;
 339
 340                 sym = node->sym;
 341
 342                 if (cnode->ms.sym && sym) {
 343                         if (cnode->ms.sym->start != sym->start)
 344                                 break;
 345                 } else if (cnode->ip != node->ip)
 346                         break;
 347
 348                 if (!found)
 349                         found = true;
 350
 351                 callchain_cursor_advance(cursor);
 352         }
 353
 354         /* matches not, relay on the parent */
 355         if (!found) {
 356                 cursor->curr = curr_snap;
 357                 cursor->pos = start;
 358                 return -1;
 359         }
 360
 361         matches = cursor->pos - start;
 362
 363         /* we match only a part of the node. Split it and add the new chain */
 364         if (matches < root->val_nr) {
 365                 split_add_child(root, cursor, cnode, start, matches, period);
 366                 return 0;
 367         }
 368
 369         /* we match 100% of the path, increment the hit */
 370         if (matches == root->val_nr && cursor->pos == cursor->nr) {
 371                 root->hit += period;
 372                 return 0;
 373         }
 374
 375         /* We match the node and still have a part remaining */
 376         append_chain_children(root, cursor, period);
 377
 378         return 0;
 379 }
 380
 381 int callchain_append(struct callchain_root *root,
 382                      struct callchain_cursor *cursor,
 383                      u64 period)
 384 {
 385         if (!cursor->nr)
 386                 return 0;
 387
 388         callchain_cursor_commit(cursor);
 389
 390         append_chain_children(&root->node, cursor, period);
 391
 392         if (cursor->nr > root->max_depth)
 393                 root->max_depth = cursor->nr;
 394
 395         return 0;
 396 }
 397
 398 static int
 399 merge_chain_branch(struct callchain_cursor *cursor,
 400                    struct callchain_node *dst, struct callchain_node *src)
 401 {
 402         struct callchain_cursor_node **old_last = cursor->last;
 403         struct callchain_node *child, *next_child;
 404         struct callchain_list *list, *next_list;
 405         int old_pos = cursor->nr;
 406         int err = 0;
 407
 408         list_for_each_entry_safe(list, next_list, &src->val, list) {
 409                 callchain_cursor_append(cursor, list->ip,
 410                                         list->ms.map, list->ms.sym);
 411                 list_del(&list->list);
 412                 free(list);
 413         }
 414
 415         if (src->hit) {
 416                 callchain_cursor_commit(cursor);
 417                 append_chain_children(dst, cursor, src->hit);
 418         }
 419
 420         chain_for_each_child_safe(child, next_child, src) {
 421                 err = merge_chain_branch(cursor, dst, child);
 422                 if (err)
 423                         break;
 424
 425                 list_del(&child->siblings);
 426                 free(child);
 427         }
 428
 429         cursor->nr = old_pos;
 430         cursor->last = old_last;
 431
 432         return err;
 433 }
 434
 435 int callchain_merge(struct callchain_cursor *cursor,
 436                     struct callchain_root *dst, struct callchain_root *src)
 437 {
 438         return merge_chain_branch(cursor, &dst->node, &src->node);
 439 }
 440
 441 int callchain_cursor_append(struct callchain_cursor *cursor,
 442                             u64 ip, struct map *map, struct symbol *sym)
 443 {
 444         struct callchain_cursor_node *node = *cursor->last;
 445
 446         if (!node) {
 447                 node = calloc(sizeof(*node), 1);
 448                 if (!node)
 449                         return -ENOMEM;
 450
 451                 *cursor->last = node;
 452         }
 453
 454         node->ip = ip;
 455         node->map = map;
 456         node->sym = sym;
 457
 458         cursor->nr++;
 459
 460         cursor->last = &node->next;
 461
 462         return 0;
 463 }