/*
* Copyright (C) 2009, Frederic Weisbecker <fweisbec@gmail.com>
*
* Handle the callchains from the stream in an ad-hoc radix tree and then
* sort them in an rbtree.
*
* Using a radix for code path provides a fast retrieval and factorizes
* memory use. Also that lets us use the paths in a hierarchical graph view.
*
*/
#include <stdlib.h>
#include <stdio.h>
#include <stdbool.h>
#include <errno.h>
#include <math.h>
#include "callchain.h"
#define chain_for_each_child(child, parent) \
list_for_each_entry(child, &parent->children, brothers)
static void
rb_insert_callchain(struct rb_root *root, struct callchain_node *chain,
enum chain_mode mode)
{
struct rb_node **p = &root->rb_node;
struct rb_node *parent = NULL;
struct callchain_node *rnode;
u64 chain_cumul = cumul_hits(chain);
while (*p) {
u64 rnode_cumul;
parent = *p;
rnode = rb_entry(parent, struct callchain_node, rb_node);
rnode_cumul = cumul_hits(rnode);
switch (mode) {
case CHAIN_FLAT:
if (rnode->hit < chain->hit)
p = &(*p)->rb_left;
else
p = &(*p)->rb_right;
break;
case CHAIN_GRAPH_ABS: /* Falldown */
case CHAIN_GRAPH_REL:
if (rnode_cumul < chain_cumul)
p = &(*p)->rb_left;
else
p = &(*p)->rb_right;
break;
default:
break;
}
}
rb_link_node(&chain->rb_node, parent, p);
rb_insert_color(&chain->rb_node, root);
}
static void
__sort_chain_flat(struct rb_root *rb_root, struct callchain_node *node,
u64 min_hit)
{
struct callchain_node *child;
chain_for_each_child(child, node)
__sort_chain_flat(rb_root, child, min_hit);
if (node->hit && node->hit >= min_hit)
rb_insert_callchain(rb_root, node, CHAIN_FLAT);
}
/*
* Once we get every callchains from the stream, we can now
* sort them by hit
*/
static void
sort_chain_flat(struct rb_root *rb_root, struct callchain_node *node,
u64 min_hit, struct callchain_param *param __used)
{
__sort_chain_flat(rb_root, node, min_hit);
}
static void __sort_chain_graph_abs(struct callchain_node *node,
u64 min_hit)
{
struct callchain_node *child;
node->rb_root = RB_ROOT;
chain_for_each_child(child, node) {
__sort_chain_graph_abs(child, min_hit);
if (cumul_hits(child) >= min_hit)
rb_insert_callchain(&node->rb_root, child,
CHAIN_GRAPH_ABS);
}
}
static void
sort_chain_graph_abs(struct rb_root *rb_root, struct callchain_node *chain_root,
u64 min_hit, struct callchain_param *param __used)
{
__sort_chain_graph_abs(chain_root, min_hit);
rb_root->rb_node = chain_root->rb_root.rb_node;
}
static void __sort_chain_graph_rel(struct callchain_node *node,
double min_percent)
{
struct callchain_node *child;
u64 min_hit;
node->rb_root = RB_ROOT;
min_hit = ceil(node->children_hit * min_percent);
chain_for_each_child(child, node) {
__sort_chain_graph_rel(child, min_percent);
if (cumul_hits(child) >= min_hit)
rb_insert_callchain(&node->rb_root, child,
CHAIN_GRAPH_REL);
}
}
static void
sort_chain_graph_rel(struct rb_root *rb_root, struct callchain_node *chain_root,
u64 min_hit __used, struct callchain_param *param)
{
__sort_chain_graph_rel(chain_root, param->min_percent / 100.0);
rb_root->rb_node = chain_root->rb_root.rb_node;
}
int register_callchain_param(struct callchain_param *param)
{
switch (param->mode) {
case CHAIN_GRAPH_ABS:
param->sort = sort_chain_graph_abs;
break;
case CHAIN_GRAPH_REL:
param->sort = sort_chain_graph_rel;
break;
case CHAIN_FLAT:
param->sort = sort_chain_flat;
break;
default:
return -1;
}
return 0;
}
/*
* Create a child for a parent. If inherit_children, then the new child
* will become the new parent of it's parent children
*/
static struct callchain_node *
create_child(struct callchain_node *parent, bool inherit_children)
{
struct callchain_node *new;
new = malloc(sizeof(*new));
if (!new) {
perror("not enough memory to create child for code path tree");
return NULL;
}
new->parent = parent;
INIT_LIST_HEAD(&new->children);
INIT_LIST_HEAD(&new->val);
if (inherit_children) {
struct callchain_node *next;
list_splice(&parent->children, &new->children);
INIT_LIST_HEAD(&parent->children);
chain_for_each_child(next, new)
next->parent = new;
}
list_add_tail(&new->brothers, &parent->children);
return new;
}
/*
* Fill the node with callchain values
*/
static void
fill_node(struct callchain_node *node, struct ip_callchain *chain,
int start, struct symbol **syms)
{
unsigned int i;
for (i = start; i < chain->nr; i++) {
struct callchain_list *call;
call = malloc(sizeof(*call));
if (!call) {
perror("not enough memory for the code path tree");
return;
}
call->ip = chain->ips[i];
call->sym = syms[i];
list_add_tail(&call->list, &node->val);
}
node->val_nr = chain->nr - start;
if (!node->val_nr)
printf("Warning: empty node in callchain tree\n");
}
static void
add_child(struct callchain_node *parent, struct ip_callchain *chain,
int start, struct symbol **syms)
{
struct callchain_node *new;
new = create_child(parent, false);
fill_node(new, chain, start, syms);
new->children_hit = 0;
new->hit = 1;
}
/*
* Split the parent in two parts (a new child is created) and
* give a part of its callchain to the created child.
* Then create another child to host the given callchain of new branch
*/
static void
split_add_child(struct callchain_node *parent, struct ip_callchain *chain,
struct callchain_list *to_split, int idx_parents, int idx_local,
struct symbol **syms)
{
struct callchain_node *new;
struct list_head *old_tail;
unsigned int idx_total = idx_parents + idx_local;
/* split */
new = create_child(parent, true);
/* split the callchain and move a part to the new child */
old_tail = parent->val.prev;
list_del_range(&to_split->list, old_tail);
new->val.next = &to_split->list;
new->val.prev = old_tail;
to_split->list.prev = &new->val;
old_tail->next = &new->val;
/* split the hits */
new->hit = parent->hit;
new->children_hit = parent->children_hit;
parent->children_hit = cumul_hits(new);
new->val_nr = parent->val_nr - idx_local;
parent->val_nr = idx_local;
/* create a new child for the new branch if any */
if (idx_total < chain->nr) {
parent->hit = 0;
add_child(parent, chain, idx_total, syms);
parent->children_hit++;
} else {
parent->hit = 1;
}
}
static int
__append_chain(struct callchain_node *root, struct ip_callchain *chain,
unsigned int start, struct symbol **syms);
static void
__append_chain_children(struct callchain_node *root, struct ip_callchain *chain,
struct symbol **syms, unsigned int start)
{
struct callchain_node *rnode;
/* lookup in childrens */
chain_for_each_child(rnode, root) {
unsigned int ret = __append_chain(rnode, chain, start, syms);
if (!ret)
goto inc_children_hit;
}
/* nothing in children, add to the current node */
add_child(root, chain, start, syms);
inc_children_hit:
root->children_hit++;
}
static int
__append_chain(struct callchain_node *root, struct ip_callchain *chain,
unsigned int start, struct symbol **syms)
{
struct callchain_list *cnode;
unsigned int i = start;
bool found = false;
/*
* Lookup in the current node
* If we have a symbol, then compare the start to match
* anywhere inside a function.
*/
list_for_each_entry(cnode, &root->val, list) {
if (i == chain->nr)
break;
if (cnode->sym && syms[i]) {
if (cnode->sym->start != syms[i]->start)
break;
} else if (cnode->ip != chain->ips[i])
break;
if (!found)
found = true;
i++;
}
/* matches not, relay on the parent */
if (!found)
return -1;
/* we match only a part of the node. Split it and add the new chain */
if (i - start < root->val_nr) {
split_add_child(root, chain, cnode, start, i - start, syms);
return 0;
}
/* we match 100% of the path, increment the hit */
if (i - start == root->val_nr && i == chain->nr) {
root->hit++;
return 0;
}
/* We match the node and still have a part remaining */
__append_chain_children(root, chain, syms, i);
return 0;
}
void append_chain(struct callchain_node *root, struct ip_callchain *chain,
struct symbol **syms)
{
if (!chain->nr)
return;
__append_chain_children(root, chain, syms, 0);
}
