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