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 "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 = 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 = 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 (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 (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 struct resolved_ip {
 199         u64               ip;
 200         struct map_symbol ms;
 201 };
 202
 203 struct resolved_chain {
 204         u64                     nr;
 205         struct resolved_ip      ips[0];
 206 };
 207
 208
 209 /*
 210  * Fill the node with callchain values
 211  */
 212 static void
 213 fill_node(struct callchain_node *node, struct resolved_chain *chain, int start)
 214 {
 215         unsigned int i;
 216
 217         for (i = start; i < chain->nr; i++) {
 218                 struct callchain_list *call;
 219
 220                 call = zalloc(sizeof(*call));
 221                 if (!call) {
 222                         perror("not enough memory for the code path tree");
 223                         return;
 224                 }
 225                 call->ip = chain->ips[i].ip;
 226                 call->ms = chain->ips[i].ms;
 227                 list_add_tail(&call->list, &node->val);
 228         }
 229         node->val_nr = chain->nr - start;
 230         if (!node->val_nr)
 231                 pr_warning("Warning: empty node in callchain tree\n");
 232 }
 233
 234 static void
 235 add_child(struct callchain_node *parent, struct resolved_chain *chain,
 236           int start, u64 period)
 237 {
 238         struct callchain_node *new;
 239
 240         new = create_child(parent, false);
 241         fill_node(new, chain, start);
 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, struct resolved_chain *chain,
 254                 struct callchain_list *to_split, int idx_parents, int idx_local,
 255                 u64 period)
 256 {
 257         struct callchain_node *new;
 258         struct list_head *old_tail;
 259         unsigned int idx_total = idx_parents + idx_local;
 260
 261         /* split */
 262         new = create_child(parent, true);
 263
 264         /* split the callchain and move a part to the new child */
 265         old_tail = parent->val.prev;
 266         list_del_range(&to_split->list, old_tail);
 267         new->val.next = &to_split->list;
 268         new->val.prev = old_tail;
 269         to_split->list.prev = &new->val;
 270         old_tail->next = &new->val;
 271
 272         /* split the hits */
 273         new->hit = parent->hit;
 274         new->children_hit = parent->children_hit;
 275         parent->children_hit = cumul_hits(new);
 276         new->val_nr = parent->val_nr - idx_local;
 277         parent->val_nr = idx_local;
 278
 279         /* create a new child for the new branch if any */
 280         if (idx_total < chain->nr) {
 281                 parent->hit = 0;
 282                 add_child(parent, chain, idx_total, period);
 283                 parent->children_hit += period;
 284         } else {
 285                 parent->hit = period;
 286         }
 287 }
 288
 289 static int
 290 append_chain(struct callchain_node *root, struct resolved_chain *chain,
 291              unsigned int start, u64 period);
 292
 293 static void
 294 append_chain_children(struct callchain_node *root, struct resolved_chain *chain,
 295                       unsigned int start, 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, chain, start, period);
 302
 303                 if (!ret)
 304                         goto inc_children_hit;
 305         }
 306         /* nothing in children, add to the current node */
 307         add_child(root, chain, start, period);
 308
 309 inc_children_hit:
 310         root->children_hit += period;
 311 }
 312
 313 static int
 314 append_chain(struct callchain_node *root, struct resolved_chain *chain,
 315              unsigned int start, u64 period)
 316 {
 317         struct callchain_list *cnode;
 318         unsigned int i = start;
 319         bool found = false;
 320
 321         /*
 322          * Lookup in the current node
 323          * If we have a symbol, then compare the start to match
 324          * anywhere inside a function.
 325          */
 326         list_for_each_entry(cnode, &root->val, list) {
 327                 struct symbol *sym;
 328
 329                 if (i == chain->nr)
 330                         break;
 331
 332                 sym = chain->ips[i].ms.sym;
 333
 334                 if (cnode->ms.sym && sym) {
 335                         if (cnode->ms.sym->start != sym->start)
 336                                 break;
 337                 } else if (cnode->ip != chain->ips[i].ip)
 338                         break;
 339
 340                 if (!found)
 341                         found = true;
 342                 i++;
 343         }
 344
 345         /* matches not, relay on the parent */
 346         if (!found)
 347                 return -1;
 348
 349         /* we match only a part of the node. Split it and add the new chain */
 350         if (i - start < root->val_nr) {
 351                 split_add_child(root, chain, cnode, start, i - start, period);
 352                 return 0;
 353         }
 354
 355         /* we match 100% of the path, increment the hit */
 356         if (i - start == root->val_nr && i == chain->nr) {
 357                 root->hit += period;
 358                 return 0;
 359         }
 360
 361         /* We match the node and still have a part remaining */
 362         append_chain_children(root, chain, i, period);
 363
 364         return 0;
 365 }
 366
 367 static void filter_context(struct ip_callchain *old, struct resolved_chain *new,
 368                            struct map_symbol *syms)
 369 {
 370         int i, j = 0;
 371
 372         for (i = 0; i < (int)old->nr; i++) {
 373                 if (old->ips[i] >= PERF_CONTEXT_MAX)
 374                         continue;
 375
 376                 new->ips[j].ip = old->ips[i];
 377                 new->ips[j].ms = syms[i];
 378                 j++;
 379         }
 380
 381         new->nr = j;
 382 }
 383
 384
 385 int callchain_append(struct callchain_root *root, struct ip_callchain *chain,
 386                      struct map_symbol *syms, u64 period)
 387 {
 388         struct resolved_chain *filtered;
 389
 390         if (!chain->nr)
 391                 return 0;
 392
 393         filtered = zalloc(sizeof(*filtered) +
 394                           chain->nr * sizeof(struct resolved_ip));
 395         if (!filtered)
 396                 return -ENOMEM;
 397
 398         filter_context(chain, filtered, syms);
 399
 400         if (!filtered->nr)
 401                 goto end;
 402
 403         append_chain_children(&root->node, filtered, 0, period);
 404
 405         if (filtered->nr > root->max_depth)
 406                 root->max_depth = filtered->nr;
 407 end:
 408         free(filtered);
 409
 410         return 0;
 411 }
 412
 413 static int
 414 merge_chain_branch(struct callchain_node *dst, struct callchain_node *src,
 415                    struct resolved_chain *chain)
 416 {
 417         struct callchain_node *child, *next_child;
 418         struct callchain_list *list, *next_list;
 419         int old_pos = chain->nr;
 420         int err = 0;
 421
 422         list_for_each_entry_safe(list, next_list, &src->val, list) {
 423                 chain->ips[chain->nr].ip = list->ip;
 424                 chain->ips[chain->nr].ms = list->ms;
 425                 chain->nr++;
 426                 list_del(&list->list);
 427                 free(list);
 428         }
 429
 430         if (src->hit)
 431                 append_chain_children(dst, chain, 0, src->hit);
 432
 433         chain_for_each_child_safe(child, next_child, src) {
 434                 err = merge_chain_branch(dst, child, chain);
 435                 if (err)
 436                         break;
 437
 438                 list_del(&child->brothers);
 439                 free(child);
 440         }
 441
 442         chain->nr = old_pos;
 443
 444         return err;
 445 }
 446
 447 int callchain_merge(struct callchain_root *dst, struct callchain_root *src)
 448 {
 449         struct resolved_chain *chain;
 450         int err;
 451
 452         chain = malloc(sizeof(*chain) +
 453                        src->max_depth * sizeof(struct resolved_ip));
 454         if (!chain)
 455                 return -ENOMEM;
 456
 457         chain->nr = 0;
 458
 459         err = merge_chain_branch(&dst->node, &src->node, chain);
 460
 461         free(chain);
 462
 463         return err;
 464 }