linux/tools/perf/util/callchain.c

462 lines
10 KiB
C

/*
* Copyright (C) 2009-2011, 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 "util.h"
#include "callchain.h"
bool ip_callchain__valid(struct ip_callchain *chain,
const union perf_event *event)
{
unsigned int chain_size = event->header.size;
chain_size -= (unsigned long)&event->ip.__more_data - (unsigned long)event;
return chain->nr * sizeof(u64) <= chain_size;
}
#define chain_for_each_child(child, parent) \
list_for_each_entry(child, &parent->children, siblings)
#define chain_for_each_child_safe(child, next, parent) \
list_for_each_entry_safe(child, next, &parent->children, siblings)
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 = callchain_cumul_hits(chain);
while (*p) {
u64 rnode_cumul;
parent = *p;
rnode = rb_entry(parent, struct callchain_node, rb_node);
rnode_cumul = callchain_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;
case CHAIN_NONE:
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_root *root,
u64 min_hit, struct callchain_param *param __used)
{
__sort_chain_flat(rb_root, &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 (callchain_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_root *chain_root,
u64 min_hit, struct callchain_param *param __used)
{
__sort_chain_graph_abs(&chain_root->node, min_hit);
rb_root->rb_node = chain_root->node.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 (callchain_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_root *chain_root,
u64 min_hit __used, struct callchain_param *param)
{
__sort_chain_graph_rel(&chain_root->node, param->min_percent / 100.0);
rb_root->rb_node = chain_root->node.rb_root.rb_node;
}
int callchain_register_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;
case CHAIN_NONE:
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 = zalloc(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->siblings, &parent->children);
return new;
}
/*
* Fill the node with callchain values
*/
static void
fill_node(struct callchain_node *node, struct callchain_cursor *cursor)
{
struct callchain_cursor_node *cursor_node;
node->val_nr = cursor->nr - cursor->pos;
if (!node->val_nr)
pr_warning("Warning: empty node in callchain tree\n");
cursor_node = callchain_cursor_current(cursor);
while (cursor_node) {
struct callchain_list *call;
call = zalloc(sizeof(*call));
if (!call) {
perror("not enough memory for the code path tree");
return;
}
call->ip = cursor_node->ip;
call->ms.sym = cursor_node->sym;
call->ms.map = cursor_node->map;
list_add_tail(&call->list, &node->val);
callchain_cursor_advance(cursor);
cursor_node = callchain_cursor_current(cursor);
}
}
static void
add_child(struct callchain_node *parent,
struct callchain_cursor *cursor,
u64 period)
{
struct callchain_node *new;
new = create_child(parent, false);
fill_node(new, cursor);
new->children_hit = 0;
new->hit = period;
}
/*
* 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 callchain_cursor *cursor,
struct callchain_list *to_split,
u64 idx_parents, u64 idx_local, u64 period)
{
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 = callchain_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 < cursor->nr) {
parent->hit = 0;
add_child(parent, cursor, period);
parent->children_hit += period;
} else {
parent->hit = period;
}
}
static int
append_chain(struct callchain_node *root,
struct callchain_cursor *cursor,
u64 period);
static void
append_chain_children(struct callchain_node *root,
struct callchain_cursor *cursor,
u64 period)
{
struct callchain_node *rnode;
/* lookup in childrens */
chain_for_each_child(rnode, root) {
unsigned int ret = append_chain(rnode, cursor, period);
if (!ret)
goto inc_children_hit;
}
/* nothing in children, add to the current node */
add_child(root, cursor, period);
inc_children_hit:
root->children_hit += period;
}
static int
append_chain(struct callchain_node *root,
struct callchain_cursor *cursor,
u64 period)
{
struct callchain_cursor_node *curr_snap = cursor->curr;
struct callchain_list *cnode;
u64 start = cursor->pos;
bool found = false;
u64 matches;
/*
* 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) {
struct callchain_cursor_node *node;
struct symbol *sym;
node = callchain_cursor_current(cursor);
if (!node)
break;
sym = node->sym;
if (cnode->ms.sym && sym) {
if (cnode->ms.sym->start != sym->start)
break;
} else if (cnode->ip != node->ip)
break;
if (!found)
found = true;
callchain_cursor_advance(cursor);
}
/* matches not, relay on the parent */
if (!found) {
cursor->curr = curr_snap;
cursor->pos = start;
return -1;
}
matches = cursor->pos - start;
/* we match only a part of the node. Split it and add the new chain */
if (matches < root->val_nr) {
split_add_child(root, cursor, cnode, start, matches, period);
return 0;
}
/* we match 100% of the path, increment the hit */
if (matches == root->val_nr && cursor->pos == cursor->nr) {
root->hit += period;
return 0;
}
/* We match the node and still have a part remaining */
append_chain_children(root, cursor, period);
return 0;
}
int callchain_append(struct callchain_root *root,
struct callchain_cursor *cursor,
u64 period)
{
if (!cursor->nr)
return 0;
callchain_cursor_commit(cursor);
append_chain_children(&root->node, cursor, period);
if (cursor->nr > root->max_depth)
root->max_depth = cursor->nr;
return 0;
}
static int
merge_chain_branch(struct callchain_cursor *cursor,
struct callchain_node *dst, struct callchain_node *src)
{
struct callchain_cursor_node **old_last = cursor->last;
struct callchain_node *child, *next_child;
struct callchain_list *list, *next_list;
int old_pos = cursor->nr;
int err = 0;
list_for_each_entry_safe(list, next_list, &src->val, list) {
callchain_cursor_append(cursor, list->ip,
list->ms.map, list->ms.sym);
list_del(&list->list);
free(list);
}
if (src->hit) {
callchain_cursor_commit(cursor);
append_chain_children(dst, cursor, src->hit);
}
chain_for_each_child_safe(child, next_child, src) {
err = merge_chain_branch(cursor, dst, child);
if (err)
break;
list_del(&child->siblings);
free(child);
}
cursor->nr = old_pos;
cursor->last = old_last;
return err;
}
int callchain_merge(struct callchain_cursor *cursor,
struct callchain_root *dst, struct callchain_root *src)
{
return merge_chain_branch(cursor, &dst->node, &src->node);
}
int callchain_cursor_append(struct callchain_cursor *cursor,
u64 ip, struct map *map, struct symbol *sym)
{
struct callchain_cursor_node *node = *cursor->last;
if (!node) {
node = calloc(sizeof(*node), 1);
if (!node)
return -ENOMEM;
*cursor->last = node;
}
node->ip = ip;
node->map = map;
node->sym = sym;
cursor->nr++;
cursor->last = &node->next;
return 0;
}