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 "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 }