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
  17 #include "callchain.h"
  18
  19 #define chain_for_each_child(child, parent)     \
  20         list_for_each_entry(child, &parent->children, brothers)
  21
  22 static void
  23 rb_insert_callchain(struct rb_root *root, struct callchain_node *chain,
  24                     enum chain_mode mode)
  25 {
  26         struct rb_node **p = &root->rb_node;
  27         struct rb_node *parent = NULL;
  28         struct callchain_node *rnode;
  29         u64 chain_cumul = cumul_hits(chain);
  30
  31         while (*p) {
  32                 u64 rnode_cumul;
  33
  34                 parent = *p;
  35                 rnode = rb_entry(parent, struct callchain_node, rb_node);
  36                 rnode_cumul = cumul_hits(rnode);
  37
  38                 switch (mode) {
  39                 case CHAIN_FLAT:
  40                         if (rnode->hit < chain->hit)
  41                                 p = &(*p)->rb_left;
  42                         else
  43                                 p = &(*p)->rb_right;
  44                         break;
  45                 case CHAIN_GRAPH_ABS: /* Falldown */
  46                 case CHAIN_GRAPH_REL:
  47                         if (rnode_cumul < chain_cumul)
  48                                 p = &(*p)->rb_left;
  49                         else
  50                                 p = &(*p)->rb_right;
  51                         break;
  52                 default:
  53                         break;
  54                 }
  55         }
  56
  57         rb_link_node(&chain->rb_node, parent, p);
  58         rb_insert_color(&chain->rb_node, root);
  59 }
  60
  61 static void
  62 __sort_chain_flat(struct rb_root *rb_root, struct callchain_node *node,
  63                   u64 min_hit)
  64 {
  65         struct callchain_node *child;
  66
  67         chain_for_each_child(child, node)
  68                 __sort_chain_flat(rb_root, child, min_hit);
  69
  70         if (node->hit && node->hit >= min_hit)
  71                 rb_insert_callchain(rb_root, node, CHAIN_FLAT);
  72 }
  73
  74 /*
  75  * Once we get every callchains from the stream, we can now
  76  * sort them by hit
  77  */
  78 static void
  79 sort_chain_flat(struct rb_root *rb_root, struct callchain_node *node,
  80                 u64 min_hit, struct callchain_param *param __used)
  81 {
  82         __sort_chain_flat(rb_root, node, min_hit);
  83 }
  84
  85 static void __sort_chain_graph_abs(struct callchain_node *node,
  86                                    u64 min_hit)
  87 {
  88         struct callchain_node *child;
  89
  90         node->rb_root = RB_ROOT;
  91
  92         chain_for_each_child(child, node) {
  93                 __sort_chain_graph_abs(child, min_hit);
  94                 if (cumul_hits(child) >= min_hit)
  95                         rb_insert_callchain(&node->rb_root, child,
  96                                             CHAIN_GRAPH_ABS);
  97         }
  98 }
  99
 100 static void
 101 sort_chain_graph_abs(struct rb_root *rb_root, struct callchain_node *chain_root,
 102                      u64 min_hit, struct callchain_param *param __used)
 103 {
 104         __sort_chain_graph_abs(chain_root, min_hit);
 105         rb_root->rb_node = chain_root->rb_root.rb_node;
 106 }
 107
 108 static void __sort_chain_graph_rel(struct callchain_node *node,
 109                                    double min_percent)
 110 {
 111         struct callchain_node *child;
 112         u64 min_hit;
 113
 114         node->rb_root = RB_ROOT;
 115         min_hit = node->children_hit * min_percent / 100.0;
 116
 117         chain_for_each_child(child, node) {
 118                 __sort_chain_graph_rel(child, min_percent);
 119                 if (cumul_hits(child) >= min_hit)
 120                         rb_insert_callchain(&node->rb_root, child,
 121                                             CHAIN_GRAPH_REL);
 122         }
 123 }
 124
 125 static void
 126 sort_chain_graph_rel(struct rb_root *rb_root, struct callchain_node *chain_root,
 127                      u64 min_hit __used, struct callchain_param *param)
 128 {
 129         __sort_chain_graph_rel(chain_root, param->min_percent);
 130         rb_root->rb_node = chain_root->rb_root.rb_node;
 131 }
 132
 133 int register_callchain_param(struct callchain_param *param)
 134 {
 135         switch (param->mode) {
 136         case CHAIN_GRAPH_ABS:
 137                 param->sort = sort_chain_graph_abs;
 138                 break;
 139         case CHAIN_GRAPH_REL:
 140                 param->sort = sort_chain_graph_rel;
 141                 break;
 142         case CHAIN_FLAT:
 143                 param->sort = sort_chain_flat;
 144                 break;
 145         default:
 146                 return -1;
 147         }
 148         return 0;
 149 }
 150
 151 /*
 152  * Create a child for a parent. If inherit_children, then the new child
 153  * will become the new parent of it's parent children
 154  */
 155 static struct callchain_node *
 156 create_child(struct callchain_node *parent, bool inherit_children)
 157 {
 158         struct callchain_node *new;
 159
 160         new = malloc(sizeof(*new));
 161         if (!new) {
 162                 perror("not enough memory to create child for code path tree");
 163                 return NULL;
 164         }
 165         new->parent = parent;
 166         INIT_LIST_HEAD(&new->children);
 167         INIT_LIST_HEAD(&new->val);
 168
 169         if (inherit_children) {
 170                 struct callchain_node *next;
 171
 172                 list_splice(&parent->children, &new->children);
 173                 INIT_LIST_HEAD(&parent->children);
 174
 175                 chain_for_each_child(next, new)
 176                         next->parent = new;
 177         }
 178         list_add_tail(&new->brothers, &parent->children);
 179
 180         return new;
 181 }
 182
 183 /*
 184  * Fill the node with callchain values
 185  */
 186 static void
 187 fill_node(struct callchain_node *node, struct ip_callchain *chain,
 188           int start, struct symbol **syms)
 189 {
 190         unsigned int i;
 191
 192         for (i = start; i < chain->nr; i++) {
 193                 struct callchain_list *call;
 194
 195                 call = malloc(sizeof(*call));
 196                 if (!call) {
 197                         perror("not enough memory for the code path tree");
 198                         return;
 199                 }
 200                 call->ip = chain->ips[i];
 201                 call->sym = syms[i];
 202                 list_add_tail(&call->list, &node->val);
 203         }
 204         node->val_nr = chain->nr - start;
 205         if (!node->val_nr)
 206                 printf("Warning: empty node in callchain tree\n");
 207 }
 208
 209 static void
 210 add_child(struct callchain_node *parent, struct ip_callchain *chain,
 211           int start, struct symbol **syms)
 212 {
 213         struct callchain_node *new;
 214
 215         new = create_child(parent, false);
 216         fill_node(new, chain, start, syms);
 217
 218         new->children_hit = 0;
 219         new->hit = 1;
 220 }
 221
 222 /*
 223  * Split the parent in two parts (a new child is created) and
 224  * give a part of its callchain to the created child.
 225  * Then create another child to host the given callchain of new branch
 226  */
 227 static void
 228 split_add_child(struct callchain_node *parent, struct ip_callchain *chain,
 229                 struct callchain_list *to_split, int idx_parents, int idx_local,
 230                 struct symbol **syms)
 231 {
 232         struct callchain_node *new;
 233         struct list_head *old_tail;
 234         unsigned int idx_total = idx_parents + idx_local;
 235
 236         /* split */
 237         new = create_child(parent, true);
 238
 239         /* split the callchain and move a part to the new child */
 240         old_tail = parent->val.prev;
 241         list_del_range(&to_split->list, old_tail);
 242         new->val.next = &to_split->list;
 243         new->val.prev = old_tail;
 244         to_split->list.prev = &new->val;
 245         old_tail->next = &new->val;
 246
 247         /* split the hits */
 248         new->hit = parent->hit;
 249         new->children_hit = parent->children_hit;
 250         parent->children_hit = cumul_hits(new);
 251         new->val_nr = parent->val_nr - idx_local;
 252         parent->val_nr = idx_local;
 253
 254         /* create a new child for the new branch if any */
 255         if (idx_total < chain->nr) {
 256                 parent->hit = 0;
 257                 add_child(parent, chain, idx_total, syms);
 258                 parent->children_hit++;
 259         } else {
 260                 parent->hit = 1;
 261         }
 262 }
 263
 264 static int
 265 __append_chain(struct callchain_node *root, struct ip_callchain *chain,
 266                unsigned int start, struct symbol **syms);
 267
 268 static void
 269 __append_chain_children(struct callchain_node *root, struct ip_callchain *chain,
 270                         struct symbol **syms, unsigned int start)
 271 {
 272         struct callchain_node *rnode;
 273
 274         /* lookup in childrens */
 275         chain_for_each_child(rnode, root) {
 276                 unsigned int ret = __append_chain(rnode, chain, start, syms);
 277
 278                 if (!ret)
 279                         goto inc_children_hit;
 280         }
 281         /* nothing in children, add to the current node */
 282         add_child(root, chain, start, syms);
 283
 284 inc_children_hit:
 285         root->children_hit++;
 286 }
 287
 288 static int
 289 __append_chain(struct callchain_node *root, struct ip_callchain *chain,
 290                unsigned int start, struct symbol **syms)
 291 {
 292         struct callchain_list *cnode;
 293         unsigned int i = start;
 294         bool found = false;
 295
 296         /*
 297          * Lookup in the current node
 298          * If we have a symbol, then compare the start to match
 299          * anywhere inside a function.
 300          */
 301         list_for_each_entry(cnode, &root->val, list) {
 302                 if (i == chain->nr)
 303                         break;
 304                 if (cnode->sym && syms[i]) {
 305                         if (cnode->sym->start != syms[i]->start)
 306                                 break;
 307                 } else if (cnode->ip != chain->ips[i])
 308                         break;
 309                 if (!found)
 310                         found = true;
 311                 i++;
 312         }
 313
 314         /* matches not, relay on the parent */
 315         if (!found)
 316                 return -1;
 317
 318         /* we match only a part of the node. Split it and add the new chain */
 319         if (i - start < root->val_nr) {
 320                 split_add_child(root, chain, cnode, start, i - start, syms);
 321                 return 0;
 322         }
 323
 324         /* we match 100% of the path, increment the hit */
 325         if (i - start == root->val_nr && i == chain->nr) {
 326                 root->hit++;
 327                 return 0;
 328         }
 329
 330         /* We match the node and still have a part remaining */
 331         __append_chain_children(root, chain, syms, i);
 332
 333         return 0;
 334 }
 335
 336 void append_chain(struct callchain_node *root, struct ip_callchain *chain,
 337                   struct symbol **syms)
 338 {
 339         if (!chain->nr)
 340                 return;
 341         __append_chain_children(root, chain, syms, 0);
 342 }