tools/perf/util/callchain.c

   1 /*
   2  * Copyright (C) 2009, 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 "callchain.h"
  19
  20 #define chain_for_each_child(child, parent)     \
  21         list_for_each_entry(child, &parent->children, brothers)
  22
  23 static void
  24 rb_insert_callchain(struct rb_root *root, struct callchain_node *chain,
  25                     enum chain_mode mode)
  26 {
  27         struct rb_node **p = &root->rb_node;
  28         struct rb_node *parent = NULL;
  29         struct callchain_node *rnode;
  30         u64 chain_cumul = cumul_hits(chain);
  31
  32         while (*p) {
  33                 u64 rnode_cumul;
  34
  35                 parent = *p;
  36                 rnode = rb_entry(parent, struct callchain_node, rb_node);
  37                 rnode_cumul = cumul_hits(rnode);
  38
  39                 switch (mode) {
  40                 case CHAIN_FLAT:
  41                         if (rnode->hit < chain->hit)
  42                                 p = &(*p)->rb_left;
  43                         else
  44                                 p = &(*p)->rb_right;
  45                         break;
  46                 case CHAIN_GRAPH_ABS: /* Falldown */
  47                 case CHAIN_GRAPH_REL:
  48                         if (rnode_cumul < chain_cumul)
  49                                 p = &(*p)->rb_left;
  50                         else
  51                                 p = &(*p)->rb_right;
  52                         break;
  53                 case CHAIN_NONE:
  54                 default:
  55                         break;
  56                 }
  57         }
  58
  59         rb_link_node(&chain->rb_node, parent, p);
  60         rb_insert_color(&chain->rb_node, root);
  61 }
  62
  63 static void
  64 __sort_chain_flat(struct rb_root *rb_root, struct callchain_node *node,
  65                   u64 min_hit)
  66 {
  67         struct callchain_node *child;
  68
  69         chain_for_each_child(child, node)
  70                 __sort_chain_flat(rb_root, child, min_hit);
  71
  72         if (node->hit && node->hit >= min_hit)
  73                 rb_insert_callchain(rb_root, node, CHAIN_FLAT);
  74 }
  75
  76 /*
  77  * Once we get every callchains from the stream, we can now
  78  * sort them by hit
  79  */
  80 static void
  81 sort_chain_flat(struct rb_root *rb_root, struct callchain_node *node,
  82                 u64 min_hit, struct callchain_param *param __used)
  83 {
  84         __sort_chain_flat(rb_root, node, min_hit);
  85 }
  86
  87 static void __sort_chain_graph_abs(struct callchain_node *node,
  88                                    u64 min_hit)
  89 {
  90         struct callchain_node *child;
  91
  92         node->rb_root = RB_ROOT;
  93
  94         chain_for_each_child(child, node) {
  95                 __sort_chain_graph_abs(child, min_hit);
  96                 if (cumul_hits(child) >= min_hit)
  97                         rb_insert_callchain(&node->rb_root, child,
  98                                             CHAIN_GRAPH_ABS);
  99         }
 100 }
 101
 102 static void
 103 sort_chain_graph_abs(struct rb_root *rb_root, struct callchain_node *chain_root,
 104                      u64 min_hit, struct callchain_param *param __used)
 105 {
 106         __sort_chain_graph_abs(chain_root, min_hit);
 107         rb_root->rb_node = chain_root->rb_root.rb_node;
 108 }
 109
 110 static void __sort_chain_graph_rel(struct callchain_node *node,
 111                                    double min_percent)
 112 {
 113         struct callchain_node *child;
 114         u64 min_hit;
 115
 116         node->rb_root = RB_ROOT;
 117         min_hit = ceil(node->children_hit * min_percent);
 118
 119         chain_for_each_child(child, node) {
 120                 __sort_chain_graph_rel(child, min_percent);
 121                 if (cumul_hits(child) >= min_hit)
 122                         rb_insert_callchain(&node->rb_root, child,
 123                                             CHAIN_GRAPH_REL);
 124         }
 125 }
 126
 127 static void
 128 sort_chain_graph_rel(struct rb_root *rb_root, struct callchain_node *chain_root,
 129                      u64 min_hit __used, struct callchain_param *param)
 130 {
 131         __sort_chain_graph_rel(chain_root, param->min_percent / 100.0);
 132         rb_root->rb_node = chain_root->rb_root.rb_node;
 133 }
 134
 135 int register_callchain_param(struct callchain_param *param)
 136 {
 137         switch (param->mode) {
 138         case CHAIN_GRAPH_ABS:
 139                 param->sort = sort_chain_graph_abs;
 140                 break;
 141         case CHAIN_GRAPH_REL:
 142                 param->sort = sort_chain_graph_rel;
 143                 break;
 144         case CHAIN_FLAT:
 145                 param->sort = sort_chain_flat;
 146                 break;
 147         case CHAIN_NONE:
 148         default:
 149                 return -1;
 150         }
 151         return 0;
 152 }
 153
 154 /*
 155  * Create a child for a parent. If inherit_children, then the new child
 156  * will become the new parent of it's parent children
 157  */
 158 static struct callchain_node *
 159 create_child(struct callchain_node *parent, bool inherit_children)
 160 {
 161         struct callchain_node *new;
 162
 163         new = malloc(sizeof(*new));
 164         if (!new) {
 165                 perror("not enough memory to create child for code path tree");
 166                 return NULL;
 167         }
 168         new->parent = parent;
 169         INIT_LIST_HEAD(&new->children);
 170         INIT_LIST_HEAD(&new->val);
 171
 172         if (inherit_children) {
 173                 struct callchain_node *next;
 174
 175                 list_splice(&parent->children, &new->children);
 176                 INIT_LIST_HEAD(&parent->children);
 177
 178                 chain_for_each_child(next, new)
 179                         next->parent = new;
 180         }
 181         list_add_tail(&new->brothers, &parent->children);
 182
 183         return new;
 184 }
 185
 186 /*
 187  * Fill the node with callchain values
 188  */
 189 static void
 190 fill_node(struct callchain_node *node, struct ip_callchain *chain,
 191           int start, struct symbol **syms)
 192 {
 193         unsigned int i;
 194
 195         for (i = start; i < chain->nr; i++) {
 196                 struct callchain_list *call;
 197
 198                 call = malloc(sizeof(*call));
 199                 if (!call) {
 200                         perror("not enough memory for the code path tree");
 201                         return;
 202                 }
 203                 call->ip = chain->ips[i];
 204                 call->sym = syms[i];
 205                 list_add_tail(&call->list, &node->val);
 206         }
 207         node->val_nr = chain->nr - start;
 208         if (!node->val_nr)
 209                 pr_warning("Warning: empty node in callchain tree\n");
 210 }
 211
 212 static void
 213 add_child(struct callchain_node *parent, struct ip_callchain *chain,
 214           int start, struct symbol **syms)
 215 {
 216         struct callchain_node *new;
 217
 218         new = create_child(parent, false);
 219         fill_node(new, chain, start, syms);
 220
 221         new->children_hit = 0;
 222         new->hit = 1;
 223 }
 224
 225 /*
 226  * Split the parent in two parts (a new child is created) and
 227  * give a part of its callchain to the created child.
 228  * Then create another child to host the given callchain of new branch
 229  */
 230 static void
 231 split_add_child(struct callchain_node *parent, struct ip_callchain *chain,
 232                 struct callchain_list *to_split, int idx_parents, int idx_local,
 233                 struct symbol **syms)
 234 {
 235         struct callchain_node *new;
 236         struct list_head *old_tail;
 237         unsigned int idx_total = idx_parents + idx_local;
 238
 239         /* split */
 240         new = create_child(parent, true);
 241
 242         /* split the callchain and move a part to the new child */
 243         old_tail = parent->val.prev;
 244         list_del_range(&to_split->list, old_tail);
 245         new->val.next = &to_split->list;
 246         new->val.prev = old_tail;
 247         to_split->list.prev = &new->val;
 248         old_tail->next = &new->val;
 249
 250         /* split the hits */
 251         new->hit = parent->hit;
 252         new->children_hit = parent->children_hit;
 253         parent->children_hit = cumul_hits(new);
 254         new->val_nr = parent->val_nr - idx_local;
 255         parent->val_nr = idx_local;
 256
 257         /* create a new child for the new branch if any */
 258         if (idx_total < chain->nr) {
 259                 parent->hit = 0;
 260                 add_child(parent, chain, idx_total, syms);
 261                 parent->children_hit++;
 262         } else {
 263                 parent->hit = 1;
 264         }
 265 }
 266
 267 static int
 268 __append_chain(struct callchain_node *root, struct ip_callchain *chain,
 269                unsigned int start, struct symbol **syms);
 270
 271 static void
 272 __append_chain_children(struct callchain_node *root, struct ip_callchain *chain,
 273                         struct symbol **syms, unsigned int start)
 274 {
 275         struct callchain_node *rnode;
 276
 277         /* lookup in childrens */
 278         chain_for_each_child(rnode, root) {
 279                 unsigned int ret = __append_chain(rnode, chain, start, syms);
 280
 281                 if (!ret)
 282                         goto inc_children_hit;
 283         }
 284         /* nothing in children, add to the current node */
 285         add_child(root, chain, start, syms);
 286
 287 inc_children_hit:
 288         root->children_hit++;
 289 }
 290
 291 static int
 292 __append_chain(struct callchain_node *root, struct ip_callchain *chain,
 293                unsigned int start, struct symbol **syms)
 294 {
 295         struct callchain_list *cnode;
 296         unsigned int i = start;
 297         bool found = false;
 298
 299         /*
 300          * Lookup in the current node
 301          * If we have a symbol, then compare the start to match
 302          * anywhere inside a function.
 303          */
 304         list_for_each_entry(cnode, &root->val, list) {
 305                 if (i == chain->nr)
 306                         break;
 307                 if (cnode->sym && syms[i]) {
 308                         if (cnode->sym->start != syms[i]->start)
 309                                 break;
 310                 } else if (cnode->ip != chain->ips[i])
 311                         break;
 312                 if (!found)
 313                         found = true;
 314                 i++;
 315         }
 316
 317         /* matches not, relay on the parent */
 318         if (!found)
 319                 return -1;
 320
 321         /* we match only a part of the node. Split it and add the new chain */
 322         if (i - start < root->val_nr) {
 323                 split_add_child(root, chain, cnode, start, i - start, syms);
 324                 return 0;
 325         }
 326
 327         /* we match 100% of the path, increment the hit */
 328         if (i - start == root->val_nr && i == chain->nr) {
 329                 root->hit++;
 330                 return 0;
 331         }
 332
 333         /* We match the node and still have a part remaining */
 334         __append_chain_children(root, chain, syms, i);
 335
 336         return 0;
 337 }
 338
 339 void append_chain(struct callchain_node *root, struct ip_callchain *chain,
 340                   struct symbol **syms)
 341 {
 342         if (!chain->nr)
 343                 return;
 344         __append_chain_children(root, chain, syms, 0);
 345 }