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, 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 static void
  32 rb_insert_callchain(struct rb_root *root, struct callchain_node *chain,
  33                     enum chain_mode mode)
  34 {
  35         struct rb_node **p = &root->rb_node;
  36         struct rb_node *parent = NULL;
  37         struct callchain_node *rnode;
  38         u64 chain_cumul = cumul_hits(chain);
  39
  40         while (*p) {
  41                 u64 rnode_cumul;
  42
  43                 parent = *p;
  44                 rnode = rb_entry(parent, struct callchain_node, rb_node);
  45                 rnode_cumul = cumul_hits(rnode);
  46
  47                 switch (mode) {
  48                 case CHAIN_FLAT:
  49                         if (rnode->hit < chain->hit)
  50                                 p = &(*p)->rb_left;
  51                         else
  52                                 p = &(*p)->rb_right;
  53                         break;
  54                 case CHAIN_GRAPH_ABS: /* Falldown */
  55                 case CHAIN_GRAPH_REL:
  56                         if (rnode_cumul < chain_cumul)
  57                                 p = &(*p)->rb_left;
  58                         else
  59                                 p = &(*p)->rb_right;
  60                         break;
  61                 case CHAIN_NONE:
  62                 default:
  63                         break;
  64                 }
  65         }
  66
  67         rb_link_node(&chain->rb_node, parent, p);
  68         rb_insert_color(&chain->rb_node, root);
  69 }
  70
  71 static void
  72 __sort_chain_flat(struct rb_root *rb_root, struct callchain_node *node,
  73                   u64 min_hit)
  74 {
  75         struct callchain_node *child;
  76
  77         chain_for_each_child(child, node)
  78                 __sort_chain_flat(rb_root, child, min_hit);
  79
  80         if (node->hit && node->hit >= min_hit)
  81                 rb_insert_callchain(rb_root, node, CHAIN_FLAT);
  82 }
  83
  84 /*
  85  * Once we get every callchains from the stream, we can now
  86  * sort them by hit
  87  */
  88 static void
  89 sort_chain_flat(struct rb_root *rb_root, struct callchain_node *node,
  90                 u64 min_hit, struct callchain_param *param __used)
  91 {
  92         __sort_chain_flat(rb_root, node, min_hit);
  93 }
  94
  95 static void __sort_chain_graph_abs(struct callchain_node *node,
  96                                    u64 min_hit)
  97 {
  98         struct callchain_node *child;
  99
 100         node->rb_root = RB_ROOT;
 101
 102         chain_for_each_child(child, node) {
 103                 __sort_chain_graph_abs(child, min_hit);
 104                 if (cumul_hits(child) >= min_hit)
 105                         rb_insert_callchain(&node->rb_root, child,
 106                                             CHAIN_GRAPH_ABS);
 107         }
 108 }
 109
 110 static void
 111 sort_chain_graph_abs(struct rb_root *rb_root, struct callchain_node *chain_root,
 112                      u64 min_hit, struct callchain_param *param __used)
 113 {
 114         __sort_chain_graph_abs(chain_root, min_hit);
 115         rb_root->rb_node = chain_root->rb_root.rb_node;
 116 }
 117
 118 static void __sort_chain_graph_rel(struct callchain_node *node,
 119                                    double min_percent)
 120 {
 121         struct callchain_node *child;
 122         u64 min_hit;
 123
 124         node->rb_root = RB_ROOT;
 125         min_hit = ceil(node->children_hit * min_percent);
 126
 127         chain_for_each_child(child, node) {
 128                 __sort_chain_graph_rel(child, min_percent);
 129                 if (cumul_hits(child) >= min_hit)
 130                         rb_insert_callchain(&node->rb_root, child,
 131                                             CHAIN_GRAPH_REL);
 132         }
 133 }
 134
 135 static void
 136 sort_chain_graph_rel(struct rb_root *rb_root, struct callchain_node *chain_root,
 137                      u64 min_hit __used, struct callchain_param *param)
 138 {
 139         __sort_chain_graph_rel(chain_root, param->min_percent / 100.0);
 140         rb_root->rb_node = chain_root->rb_root.rb_node;
 141 }
 142
 143 int register_callchain_param(struct callchain_param *param)
 144 {
 145         switch (param->mode) {
 146         case CHAIN_GRAPH_ABS:
 147                 param->sort = sort_chain_graph_abs;
 148                 break;
 149         case CHAIN_GRAPH_REL:
 150                 param->sort = sort_chain_graph_rel;
 151                 break;
 152         case CHAIN_FLAT:
 153                 param->sort = sort_chain_flat;
 154                 break;
 155         case CHAIN_NONE:
 156         default:
 157                 return -1;
 158         }
 159         return 0;
 160 }
 161
 162 /*
 163  * Create a child for a parent. If inherit_children, then the new child
 164  * will become the new parent of it's parent children
 165  */
 166 static struct callchain_node *
 167 create_child(struct callchain_node *parent, bool inherit_children)
 168 {
 169         struct callchain_node *new;
 170
 171         new = zalloc(sizeof(*new));
 172         if (!new) {
 173                 perror("not enough memory to create child for code path tree");
 174                 return NULL;
 175         }
 176         new->parent = parent;
 177         INIT_LIST_HEAD(&new->children);
 178         INIT_LIST_HEAD(&new->val);
 179
 180         if (inherit_children) {
 181                 struct callchain_node *next;
 182
 183                 list_splice(&parent->children, &new->children);
 184                 INIT_LIST_HEAD(&parent->children);
 185
 186                 chain_for_each_child(next, new)
 187                         next->parent = new;
 188         }
 189         list_add_tail(&new->brothers, &parent->children);
 190
 191         return new;
 192 }
 193
 194
 195 struct resolved_ip {
 196         u64               ip;
 197         struct map_symbol ms;
 198 };
 199
 200 struct resolved_chain {
 201         u64                     nr;
 202         struct resolved_ip      ips[0];
 203 };
 204
 205
 206 /*
 207  * Fill the node with callchain values
 208  */
 209 static void
 210 fill_node(struct callchain_node *node, struct resolved_chain *chain, int start)
 211 {
 212         unsigned int i;
 213
 214         for (i = start; i < chain->nr; i++) {
 215                 struct callchain_list *call;
 216
 217                 call = zalloc(sizeof(*call));
 218                 if (!call) {
 219                         perror("not enough memory for the code path tree");
 220                         return;
 221                 }
 222                 call->ip = chain->ips[i].ip;
 223                 call->ms = chain->ips[i].ms;
 224                 list_add_tail(&call->list, &node->val);
 225         }
 226         node->val_nr = chain->nr - start;
 227         if (!node->val_nr)
 228                 pr_warning("Warning: empty node in callchain tree\n");
 229 }
 230
 231 static void
 232 add_child(struct callchain_node *parent, struct resolved_chain *chain,
 233           int start, u64 period)
 234 {
 235         struct callchain_node *new;
 236
 237         new = create_child(parent, false);
 238         fill_node(new, chain, start);
 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, struct resolved_chain *chain,
 251                 struct callchain_list *to_split, int idx_parents, int idx_local,
 252                 u64 period)
 253 {
 254         struct callchain_node *new;
 255         struct list_head *old_tail;
 256         unsigned int idx_total = idx_parents + idx_local;
 257
 258         /* split */
 259         new = create_child(parent, true);
 260
 261         /* split the callchain and move a part to the new child */
 262         old_tail = parent->val.prev;
 263         list_del_range(&to_split->list, old_tail);
 264         new->val.next = &to_split->list;
 265         new->val.prev = old_tail;
 266         to_split->list.prev = &new->val;
 267         old_tail->next = &new->val;
 268
 269         /* split the hits */
 270         new->hit = parent->hit;
 271         new->children_hit = parent->children_hit;
 272         parent->children_hit = cumul_hits(new);
 273         new->val_nr = parent->val_nr - idx_local;
 274         parent->val_nr = idx_local;
 275
 276         /* create a new child for the new branch if any */
 277         if (idx_total < chain->nr) {
 278                 parent->hit = 0;
 279                 add_child(parent, chain, idx_total, period);
 280                 parent->children_hit += period;
 281         } else {
 282                 parent->hit = period;
 283         }
 284 }
 285
 286 static int
 287 __append_chain(struct callchain_node *root, struct resolved_chain *chain,
 288                unsigned int start, u64 period);
 289
 290 static void
 291 __append_chain_children(struct callchain_node *root,
 292                         struct resolved_chain *chain,
 293                         unsigned int start, u64 period)
 294 {
 295         struct callchain_node *rnode;
 296
 297         /* lookup in childrens */
 298         chain_for_each_child(rnode, root) {
 299                 unsigned int ret = __append_chain(rnode, chain, start, period);
 300
 301                 if (!ret)
 302                         goto inc_children_hit;
 303         }
 304         /* nothing in children, add to the current node */
 305         add_child(root, chain, start, period);
 306
 307 inc_children_hit:
 308         root->children_hit += period;
 309 }
 310
 311 static int
 312 __append_chain(struct callchain_node *root, struct resolved_chain *chain,
 313                unsigned int start, u64 period)
 314 {
 315         struct callchain_list *cnode;
 316         unsigned int i = start;
 317         bool found = false;
 318
 319         /*
 320          * Lookup in the current node
 321          * If we have a symbol, then compare the start to match
 322          * anywhere inside a function.
 323          */
 324         list_for_each_entry(cnode, &root->val, list) {
 325                 struct symbol *sym;
 326
 327                 if (i == chain->nr)
 328                         break;
 329
 330                 sym = chain->ips[i].ms.sym;
 331
 332                 if (cnode->ms.sym && sym) {
 333                         if (cnode->ms.sym->start != sym->start)
 334                                 break;
 335                 } else if (cnode->ip != chain->ips[i].ip)
 336                         break;
 337
 338                 if (!found)
 339                         found = true;
 340                 i++;
 341         }
 342
 343         /* matches not, relay on the parent */
 344         if (!found)
 345                 return -1;
 346
 347         /* we match only a part of the node. Split it and add the new chain */
 348         if (i - start < root->val_nr) {
 349                 split_add_child(root, chain, cnode, start, i - start, period);
 350                 return 0;
 351         }
 352
 353         /* we match 100% of the path, increment the hit */
 354         if (i - start == root->val_nr && i == chain->nr) {
 355                 root->hit += period;
 356                 return 0;
 357         }
 358
 359         /* We match the node and still have a part remaining */
 360         __append_chain_children(root, chain, i, period);
 361
 362         return 0;
 363 }
 364
 365 static void filter_context(struct ip_callchain *old, struct resolved_chain *new,
 366                            struct map_symbol *syms)
 367 {
 368         int i, j = 0;
 369
 370         for (i = 0; i < (int)old->nr; i++) {
 371                 if (old->ips[i] >= PERF_CONTEXT_MAX)
 372                         continue;
 373
 374                 new->ips[j].ip = old->ips[i];
 375                 new->ips[j].ms = syms[i];
 376                 j++;
 377         }
 378
 379         new->nr = j;
 380 }
 381
 382
 383 int append_chain(struct callchain_node *root, struct ip_callchain *chain,
 384                  struct map_symbol *syms, u64 period)
 385 {
 386         struct resolved_chain *filtered;
 387
 388         if (!chain->nr)
 389                 return 0;
 390
 391         filtered = zalloc(sizeof(*filtered) +
 392                           chain->nr * sizeof(struct resolved_ip));
 393         if (!filtered)
 394                 return -ENOMEM;
 395
 396         filter_context(chain, filtered, syms);
 397
 398         if (!filtered->nr)
 399                 goto end;
 400
 401         __append_chain_children(root, filtered, 0, period);
 402 end:
 403         free(filtered);
 404
 405         return 0;
 406 }