linux/tools/perf/util/callchain.c
Ingo Molnar 83a0944fa9 perf: Enable more compiler warnings
Related to a shadowed variable bug fix Valdis Kletnieks noticed
that perf does not get built with -Wshadow, which could have
helped us avoid the bug.

So enable -Wshadow and also enable the following warnings on
perf builds, in addition to the already enabled -Wall -Wextra
-std=gnu99 warnings:

 -Wcast-align
 -Wformat=2
 -Wshadow
 -Winit-self
 -Wpacked
 -Wredundant-decls
 -Wstack-protector
 -Wstrict-aliasing=3
 -Wswitch-default
 -Wswitch-enum
 -Wno-system-headers
 -Wundef
 -Wvolatile-register-var
 -Wwrite-strings
 -Wbad-function-cast
 -Wmissing-declarations
 -Wmissing-prototypes
 -Wnested-externs
 -Wold-style-definition
 -Wstrict-prototypes
 -Wdeclaration-after-statement

And change/fix the perf code to build cleanly under GCC 4.3.2.

The list of warnings enablement is rather arbitrary: it's based
on my (quick) reading of the GCC manpages and trying them on
perf.

I categorized the warnings based on individually enabling them
and looking whether they trigger something in the perf build.
If i liked those warnings (i.e. if they trigger for something
that arguably could be improved) i enabled the warning.

If the warnings seemed to come from language laywers spamming
the build with tons of nuisance warnings i generally kept them
off. Most of the sign conversion related warnings were in
this category. (A second patch enabling some of the sign
warnings might be welcome - sign bugs can be nasty.)

I also kept warnings that seem to make sense from their manpage
description and which produced no actual warnings on our code
base. These warnings might still be turned off if they end up
being a nuisance.

I also left out a few warnings that are not supported in older
compilers.

[ Note that these changes might break the build on older
  compilers i did not test, or on non-x86 architectures that
  produce different warnings, so more testing would be welcome. ]

Reported-by: Valdis.Kletnieks@vt.edu
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-08-16 10:47:47 +02:00

345 lines
8.1 KiB
C

/*
* 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;
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_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;
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 = 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);
}