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