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perf callchain: Convert children list to rbtree 

Current collapse stage has a scalability problem which can be reproduced
easily with a parallel kernel build.

This is because it needs to traverse every children of callchains
linearly during the collapse/merge stage.

Converting it to a rbtree reduced the overhead significantly.

On my 400MB perf.data file which recorded with make -j32 kernel build:

  $ time perf --no-pager report --stdio > /dev/null

before:
  real	6m22.073s
  user	6m18.683s
  sys	0m0.706s

after:
  real	0m20.780s
  user	0m19.962s
  sys	0m0.689s

During the perf report the overhead on append_chain_children went down
from 96.69% to 18.16%:

  -  18.16%  perf  perf                [.] append_chain_children
     - append_chain_children
        - 77.48% append_chain_children
           + 69.79% merge_chain_branch
           - 22.96% append_chain_children
              + 67.44% merge_chain_branch
              + 30.15% append_chain_children
              + 2.41% callchain_append
           + 7.25% callchain_append
        + 12.26% callchain_append
        + 10.22% merge_chain_branch
  +  11.58%  perf  perf                [.] dso__find_symbol
  +   8.02%  perf  perf                [.] sort__comm_cmp
  +   5.48%  perf  libc-2.17.so        [.] malloc_consolidate

Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1381468543-25334-2-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Namhyung Kim 2013-10-11 14:15:36 +09:00 committed by Arnaldo Carvalho de Melo
parent f11cfc6f29
commit e369517ce5
2 changed files with 116 additions and 42 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

147
tools/perf/util/callchain.c
View File

@ -21,12 +21,6 @@
__thread struct callchain_cursor callchain_cursor; __thread struct callchain_cursor callchain_cursor;
#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 static void
rb_insert_callchain(struct rb_root *root, struct callchain_node *chain, rb_insert_callchain(struct rb_root *root, struct callchain_node *chain,
enum chain_mode mode) enum chain_mode mode)
@ -71,10 +65,16 @@ static void
__sort_chain_flat(struct rb_root *rb_root, struct callchain_node *node, __sort_chain_flat(struct rb_root *rb_root, struct callchain_node *node,
u64 min_hit) u64 min_hit)
{ {
struct rb_node *n;
struct callchain_node *child; struct callchain_node *child;
chain_for_each_child(child, node) n = rb_first(&node->rb_root_in);
while (n) {
child = rb_entry(n, struct callchain_node, rb_node_in);
n = rb_next(n);
__sort_chain_flat(rb_root, child, min_hit); __sort_chain_flat(rb_root, child, min_hit);
}
if (node->hit && node->hit >= min_hit) if (node->hit && node->hit >= min_hit)
rb_insert_callchain(rb_root, node, CHAIN_FLAT); rb_insert_callchain(rb_root, node, CHAIN_FLAT);
@ -94,11 +94,16 @@ sort_chain_flat(struct rb_root *rb_root, struct callchain_root *root,
static void __sort_chain_graph_abs(struct callchain_node *node, static void __sort_chain_graph_abs(struct callchain_node *node,
u64 min_hit) u64 min_hit)
{ {
struct rb_node *n;
struct callchain_node *child; struct callchain_node *child;
node->rb_root = RB_ROOT; node->rb_root = RB_ROOT;
n = rb_first(&node->rb_root_in);
while (n) {
child = rb_entry(n, struct callchain_node, rb_node_in);
n = rb_next(n);
chain_for_each_child(child, node) {
__sort_chain_graph_abs(child, min_hit); __sort_chain_graph_abs(child, min_hit);
if (callchain_cumul_hits(child) >= min_hit) if (callchain_cumul_hits(child) >= min_hit)
rb_insert_callchain(&node->rb_root, child, rb_insert_callchain(&node->rb_root, child,
@ -117,13 +122,18 @@ sort_chain_graph_abs(struct rb_root *rb_root, struct callchain_root *chain_root,
static void __sort_chain_graph_rel(struct callchain_node *node, static void __sort_chain_graph_rel(struct callchain_node *node,
double min_percent) double min_percent)
{ {
struct rb_node *n;
struct callchain_node *child; struct callchain_node *child;
u64 min_hit; u64 min_hit;
node->rb_root = RB_ROOT; node->rb_root = RB_ROOT;
min_hit = ceil(node->children_hit * min_percent); min_hit = ceil(node->children_hit * min_percent);
chain_for_each_child(child, node) { n = rb_first(&node->rb_root_in);
while (n) {
child = rb_entry(n, struct callchain_node, rb_node_in);
n = rb_next(n);
__sort_chain_graph_rel(child, min_percent); __sort_chain_graph_rel(child, min_percent);
if (callchain_cumul_hits(child) >= min_hit) if (callchain_cumul_hits(child) >= min_hit)
rb_insert_callchain(&node->rb_root, child, rb_insert_callchain(&node->rb_root, child,
@ -173,19 +183,26 @@ create_child(struct callchain_node *parent, bool inherit_children)
return NULL; return NULL;
} }
new->parent = parent; new->parent = parent;
INIT_LIST_HEAD(&new->children);
INIT_LIST_HEAD(&new->val); INIT_LIST_HEAD(&new->val);
if (inherit_children) { if (inherit_children) {
struct callchain_node *next; struct rb_node *n;
struct callchain_node *child;
list_splice(&parent->children, &new->children); new->rb_root_in = parent->rb_root_in;
INIT_LIST_HEAD(&parent->children); parent->rb_root_in = RB_ROOT;
chain_for_each_child(next, new) n = rb_first(&new->rb_root_in);
next->parent = new; while (n) {
child = rb_entry(n, struct callchain_node, rb_node_in);
child->parent = new;
n = rb_next(n);
}
/* make it the first child */
rb_link_node(&new->rb_node_in, NULL, &parent->rb_root_in.rb_node);
rb_insert_color(&new->rb_node_in, &parent->rb_root_in);
} }
list_add_tail(&new->siblings, &parent->children);
return new; return new;
} }
@ -223,7 +240,7 @@ fill_node(struct callchain_node *node, struct callchain_cursor *cursor)
} }
} }
static void static struct callchain_node *
add_child(struct callchain_node *parent, add_child(struct callchain_node *parent,
struct callchain_cursor *cursor, struct callchain_cursor *cursor,
u64 period) u64 period)
@ -235,6 +252,19 @@ add_child(struct callchain_node *parent,
new->children_hit = 0; new->children_hit = 0;
new->hit = period; new->hit = period;
return new;
}
static s64 match_chain(struct callchain_cursor_node *node,
struct callchain_list *cnode)
{
struct symbol *sym = node->sym;
if (cnode->ms.sym && sym &&
callchain_param.key == CCKEY_FUNCTION)
return cnode->ms.sym->start - sym->start;
else
return cnode->ip - node->ip;
} }
/* /*
@ -272,9 +302,33 @@ split_add_child(struct callchain_node *parent,
/* create a new child for the new branch if any */ /* create a new child for the new branch if any */
if (idx_total < cursor->nr) { if (idx_total < cursor->nr) {
struct callchain_node *first;
struct callchain_list *cnode;
struct callchain_cursor_node *node;
struct rb_node *p, **pp;
parent->hit = 0; parent->hit = 0;
add_child(parent, cursor, period);
parent->children_hit += period; parent->children_hit += period;
node = callchain_cursor_current(cursor);
new = add_child(parent, cursor, period);
/*
* This is second child since we moved parent's children
* to new (first) child above.
*/
p = parent->rb_root_in.rb_node;
first = rb_entry(p, struct callchain_node, rb_node_in);
cnode = list_first_entry(&first->val, struct callchain_list,
list);
if (match_chain(node, cnode) < 0)
pp = &p->rb_left;
else
pp = &p->rb_right;
rb_link_node(&new->rb_node_in, p, pp);
rb_insert_color(&new->rb_node_in, &parent->rb_root_in);
} else { } else {
parent->hit = period; parent->hit = period;
} }
@ -291,16 +345,40 @@ append_chain_children(struct callchain_node *root,
u64 period) u64 period)
{ {
struct callchain_node *rnode; struct callchain_node *rnode;
struct callchain_cursor_node *node;
struct rb_node **p = &root->rb_root_in.rb_node;
struct rb_node *parent = NULL;
node = callchain_cursor_current(cursor);
if (!node)
return;
/* lookup in childrens */ /* lookup in childrens */
chain_for_each_child(rnode, root) { while (*p) {
unsigned int ret = append_chain(rnode, cursor, period); s64 ret;
struct callchain_list *cnode;
if (!ret) parent = *p;
rnode = rb_entry(parent, struct callchain_node, rb_node_in);
cnode = list_first_entry(&rnode->val, struct callchain_list,
list);
/* just check first entry */
ret = match_chain(node, cnode);
if (ret == 0) {
append_chain(rnode, cursor, period);
goto inc_children_hit; goto inc_children_hit;
}
if (ret < 0)
p = &parent->rb_left;
else
p = &parent->rb_right;
} }
/* nothing in children, add to the current node */ /* nothing in children, add to the current node */
add_child(root, cursor, period); rnode = add_child(root, cursor, period);
rb_link_node(&rnode->rb_node_in, parent, p);
rb_insert_color(&rnode->rb_node_in, &root->rb_root_in);
inc_children_hit: inc_children_hit:
root->children_hit += period; root->children_hit += period;
@ -325,28 +403,20 @@ append_chain(struct callchain_node *root,
*/ */
list_for_each_entry(cnode, &root->val, list) { list_for_each_entry(cnode, &root->val, list) {
struct callchain_cursor_node *node; struct callchain_cursor_node *node;
struct symbol *sym;
node = callchain_cursor_current(cursor); node = callchain_cursor_current(cursor);
if (!node) if (!node)
break; break;
sym = node->sym; if (match_chain(node, cnode) != 0)
if (cnode->ms.sym && sym &&
callchain_param.key == CCKEY_FUNCTION) {
if (cnode->ms.sym->start != sym->start)
break;
} else if (cnode->ip != node->ip)
break; break;
if (!found) found = true;
found = true;
callchain_cursor_advance(cursor); callchain_cursor_advance(cursor);
} }
/* matches not, relay on the parent */ /* matches not, relay no the parent */
if (!found) { if (!found) {
cursor->curr = curr_snap; cursor->curr = curr_snap;
cursor->pos = start; cursor->pos = start;
@ -395,8 +465,9 @@ merge_chain_branch(struct callchain_cursor *cursor,
struct callchain_node *dst, struct callchain_node *src) struct callchain_node *dst, struct callchain_node *src)
{ {
struct callchain_cursor_node **old_last = cursor->last; struct callchain_cursor_node **old_last = cursor->last;
struct callchain_node *child, *next_child; struct callchain_node *child;
struct callchain_list *list, *next_list; struct callchain_list *list, *next_list;
struct rb_node *n;
int old_pos = cursor->nr; int old_pos = cursor->nr;
int err = 0; int err = 0;
@ -412,12 +483,16 @@ merge_chain_branch(struct callchain_cursor *cursor,
append_chain_children(dst, cursor, src->hit); append_chain_children(dst, cursor, src->hit);
} }
chain_for_each_child_safe(child, next_child, src) { n = rb_first(&src->rb_root_in);
while (n) {
child = container_of(n, struct callchain_node, rb_node_in);
n = rb_next(n);
rb_erase(&child->rb_node_in, &src->rb_root_in);
err = merge_chain_branch(cursor, dst, child); err = merge_chain_branch(cursor, dst, child);
if (err) if (err)
break; break;
list_del(&child->siblings);
free(child); free(child);
} }

11
tools/perf/util/callchain.h
View File

@ -21,11 +21,11 @@ enum chain_order {
struct callchain_node { struct callchain_node {
struct callchain_node *parent; struct callchain_node *parent;
struct list_head siblings;
struct list_head children;
struct list_head val; struct list_head val;
struct rb_node rb_node; /* to sort nodes in an rbtree */ struct rb_node rb_node_in; /* to insert nodes in an rbtree */
struct rb_root rb_root; /* sorted tree of children */ struct rb_node rb_node; /* to sort nodes in an output tree */
struct rb_root rb_root_in; /* input tree of children */
struct rb_root rb_root; /* sorted output tree of children */
unsigned int val_nr; unsigned int val_nr;
u64 hit; u64 hit;
u64 children_hit; u64 children_hit;
@ -86,13 +86,12 @@ extern __thread struct callchain_cursor callchain_cursor;
static inline void callchain_init(struct callchain_root *root) static inline void callchain_init(struct callchain_root *root)
{ {
INIT_LIST_HEAD(&root->node.siblings);
INIT_LIST_HEAD(&root->node.children);
INIT_LIST_HEAD(&root->node.val); INIT_LIST_HEAD(&root->node.val);
root->node.parent = NULL; root->node.parent = NULL;
root->node.hit = 0; root->node.hit = 0;
root->node.children_hit = 0; root->node.children_hit = 0;
root->node.rb_root_in = RB_ROOT;
root->max_depth = 0; root->max_depth = 0;
} }