Commit deac911c authored by Frederic Weisbecker's avatar Frederic Weisbecker Committed by Ingo Molnar
Browse files

perf_counter tools: Various fixes for callchains 



The symbol resolving has of course revealed some bugs in the
callchain tree handling. This patch fixes some of them,
including:

- inherit the children from the parents while splitting a node
- fix list range moving
- fix indexes setting in callchains
- create a child on the current node if the path doesn't match in
  the existent children (was only done on the root)
- compare using symbols when possible so that we can match a function
  using any ip inside by referring to its start address.

The practical effects are:

- remove double callchains
- fix upside down or any random order of callchains
- fix wrong paths
- fix bad hits and percentage accounts

Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Anton Blanchard <anton@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
LKML-Reference: <1246419315-9968-4-git-send-email-fweisbec@gmail.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 4424961a

tools/perf/util/callchain.c

+90 −32
Original line number Diff line number Diff line
@@ -4,6 +4,9 @@ 
 * 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>
@@ -14,7 +17,8 @@ 
#include "callchain.h"





static void rb_insert_callchain(struct rb_root *root, struct callchain_node *chain)

static void

rb_insert_callchain(struct rb_root *root, struct callchain_node *chain)

{

	struct rb_node **p = &root->rb_node;

	struct rb_node *parent = NULL;
@@ -49,7 +53,12 @@ void sort_chain_to_rbtree(struct rb_root *rb_root, struct callchain_node *node) 
		rb_insert_callchain(rb_root, node);

}



static struct callchain_node *create_child(struct callchain_node *parent)

/*

 * 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;
@@ -61,14 +70,27 @@ static struct callchain_node *create_child(struct callchain_node *parent) 
	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);



		list_for_each_entry(next, &new->children, brothers)

			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)

fill_node(struct callchain_node *node, struct ip_callchain *chain,

	  int start, struct symbol **syms)

{

	int i;
@@ -84,54 +106,80 @@ fill_node(struct callchain_node *node, struct ip_callchain *chain, int start, 
		call->sym = syms[i];

		list_add_tail(&call->list, &node->val);

	}

	node->val_nr = i - start;

	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,

		      struct symbol **syms)

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);

	fill_node(new, chain, parent->val_nr, syms);

	new = create_child(parent, false);

	fill_node(new, chain, start, syms);



	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, struct symbol **syms)

		struct callchain_list *to_split, int idx_parents, int idx_local,

		struct symbol **syms)

{

	struct callchain_node *new;

	struct list_head *old_tail;

	int idx_total = idx_parents + idx_local;



	/* split */

	new = create_child(parent);

	list_move_tail(&to_split->list, &new->val);

	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;

	parent->hit = 0;

	parent->val_nr = idx;

	new->val_nr = parent->val_nr - idx_local;

	parent->val_nr = idx_local;



	/* create the new one */

	add_child(parent, chain, syms);

	/* 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);

	} else {

		parent->hit = 1;

	}

}



static int

__append_chain(struct callchain_node *root, struct ip_callchain *chain,

	       int start, struct symbol **syms);



static int

static void

__append_chain_children(struct callchain_node *root, struct ip_callchain *chain,

			struct symbol **syms)

			struct symbol **syms, int start)

{

	struct callchain_node *rnode;



	/* lookup in childrens */

	list_for_each_entry(rnode, &root->children, brothers) {

		int ret = __append_chain(rnode, chain, root->val_nr, syms);

		int ret = __append_chain(rnode, chain, start, syms);

		if (!ret)

			return 0;

			return;

	}

	return -1;

	/* nothing in children, add to the current node */

	add_child(root, chain, start, syms);

}



static int
@@ -142,14 +190,22 @@ __append_chain(struct callchain_node *root, struct ip_callchain *chain, 
	int i = start;

	bool found = false;



	/* lookup in the current node */

	/*

	 * 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 (cnode->ip != chain->ips[i++])

		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;

		if (i == chain->nr)

			break;

		i++;

	}



	/* matches not, relay on the parent */
@@ -157,23 +213,25 @@ __append_chain(struct callchain_node *root, struct ip_callchain *chain, 
		return -1;



	/* we match only a part of the node. Split it and add the new chain */

	if (i < root->val_nr) {

		split_add_child(root, chain, cnode, i, syms);

	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 == root->val_nr) {

	if (i - start == root->val_nr && i == chain->nr) {

		root->hit++;

		return 0;

	}



	return __append_chain_children(root, chain, syms);

	/* 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 (__append_chain_children(root, chain, syms) == -1)

		add_child(root, chain, syms);

	__append_chain_children(root, chain, syms, 0);

}