mirror of https://gitee.com/openkylin/linux.git
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
Arnaldo Carvalho de Melo
parent
f11cfc6f29
commit
e369517ce5
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@ -21,12 +21,6 @@
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__thread struct callchain_cursor callchain_cursor;
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#define chain_for_each_child(child, parent) \
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list_for_each_entry(child, &parent->children, siblings)
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#define chain_for_each_child_safe(child, next, parent) \
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list_for_each_entry_safe(child, next, &parent->children, siblings)
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static void
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rb_insert_callchain(struct rb_root *root, struct callchain_node *chain,
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enum chain_mode mode)
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@ -71,10 +65,16 @@ static void
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__sort_chain_flat(struct rb_root *rb_root, struct callchain_node *node,
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u64 min_hit)
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{
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struct rb_node *n;
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struct callchain_node *child;
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chain_for_each_child(child, node)
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n = rb_first(&node->rb_root_in);
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while (n) {
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child = rb_entry(n, struct callchain_node, rb_node_in);
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n = rb_next(n);
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__sort_chain_flat(rb_root, child, min_hit);
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}
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if (node->hit && node->hit >= min_hit)
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rb_insert_callchain(rb_root, node, CHAIN_FLAT);
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@ -94,11 +94,16 @@ sort_chain_flat(struct rb_root *rb_root, struct callchain_root *root,
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static void __sort_chain_graph_abs(struct callchain_node *node,
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u64 min_hit)
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{
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struct rb_node *n;
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struct callchain_node *child;
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node->rb_root = RB_ROOT;
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n = rb_first(&node->rb_root_in);
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while (n) {
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child = rb_entry(n, struct callchain_node, rb_node_in);
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n = rb_next(n);
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chain_for_each_child(child, node) {
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__sort_chain_graph_abs(child, min_hit);
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if (callchain_cumul_hits(child) >= min_hit)
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rb_insert_callchain(&node->rb_root, child,
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@ -117,13 +122,18 @@ sort_chain_graph_abs(struct rb_root *rb_root, struct callchain_root *chain_root,
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static void __sort_chain_graph_rel(struct callchain_node *node,
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double min_percent)
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{
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struct rb_node *n;
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struct callchain_node *child;
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u64 min_hit;
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node->rb_root = RB_ROOT;
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min_hit = ceil(node->children_hit * min_percent);
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chain_for_each_child(child, node) {
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n = rb_first(&node->rb_root_in);
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while (n) {
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child = rb_entry(n, struct callchain_node, rb_node_in);
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n = rb_next(n);
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__sort_chain_graph_rel(child, min_percent);
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if (callchain_cumul_hits(child) >= min_hit)
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rb_insert_callchain(&node->rb_root, child,
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@ -173,19 +183,26 @@ create_child(struct callchain_node *parent, bool inherit_children)
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return NULL;
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}
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new->parent = parent;
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INIT_LIST_HEAD(&new->children);
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INIT_LIST_HEAD(&new->val);
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if (inherit_children) {
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struct callchain_node *next;
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struct rb_node *n;
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struct callchain_node *child;
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list_splice(&parent->children, &new->children);
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INIT_LIST_HEAD(&parent->children);
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new->rb_root_in = parent->rb_root_in;
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parent->rb_root_in = RB_ROOT;
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chain_for_each_child(next, new)
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next->parent = new;
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n = rb_first(&new->rb_root_in);
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while (n) {
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child = rb_entry(n, struct callchain_node, rb_node_in);
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child->parent = new;
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n = rb_next(n);
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}
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/* make it the first child */
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rb_link_node(&new->rb_node_in, NULL, &parent->rb_root_in.rb_node);
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rb_insert_color(&new->rb_node_in, &parent->rb_root_in);
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}
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list_add_tail(&new->siblings, &parent->children);
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return new;
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}
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@ -223,7 +240,7 @@ fill_node(struct callchain_node *node, struct callchain_cursor *cursor)
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}
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}
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static void
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static struct callchain_node *
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add_child(struct callchain_node *parent,
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struct callchain_cursor *cursor,
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u64 period)
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@ -235,6 +252,19 @@ add_child(struct callchain_node *parent,
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new->children_hit = 0;
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new->hit = period;
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return new;
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}
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static s64 match_chain(struct callchain_cursor_node *node,
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struct callchain_list *cnode)
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{
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struct symbol *sym = node->sym;
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if (cnode->ms.sym && sym &&
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callchain_param.key == CCKEY_FUNCTION)
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return cnode->ms.sym->start - sym->start;
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else
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return cnode->ip - node->ip;
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}
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/*
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@ -272,9 +302,33 @@ split_add_child(struct callchain_node *parent,
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/* create a new child for the new branch if any */
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if (idx_total < cursor->nr) {
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struct callchain_node *first;
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struct callchain_list *cnode;
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struct callchain_cursor_node *node;
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struct rb_node *p, **pp;
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parent->hit = 0;
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add_child(parent, cursor, period);
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parent->children_hit += period;
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node = callchain_cursor_current(cursor);
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new = add_child(parent, cursor, period);
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/*
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* This is second child since we moved parent's children
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* to new (first) child above.
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*/
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p = parent->rb_root_in.rb_node;
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first = rb_entry(p, struct callchain_node, rb_node_in);
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cnode = list_first_entry(&first->val, struct callchain_list,
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list);
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if (match_chain(node, cnode) < 0)
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pp = &p->rb_left;
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else
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pp = &p->rb_right;
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rb_link_node(&new->rb_node_in, p, pp);
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rb_insert_color(&new->rb_node_in, &parent->rb_root_in);
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} else {
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parent->hit = period;
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}
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@ -291,16 +345,40 @@ append_chain_children(struct callchain_node *root,
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u64 period)
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{
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struct callchain_node *rnode;
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struct callchain_cursor_node *node;
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struct rb_node **p = &root->rb_root_in.rb_node;
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struct rb_node *parent = NULL;
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node = callchain_cursor_current(cursor);
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if (!node)
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return;
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/* lookup in childrens */
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chain_for_each_child(rnode, root) {
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unsigned int ret = append_chain(rnode, cursor, period);
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while (*p) {
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s64 ret;
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struct callchain_list *cnode;
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if (!ret)
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parent = *p;
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rnode = rb_entry(parent, struct callchain_node, rb_node_in);
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cnode = list_first_entry(&rnode->val, struct callchain_list,
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list);
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/* just check first entry */
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ret = match_chain(node, cnode);
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if (ret == 0) {
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append_chain(rnode, cursor, period);
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goto inc_children_hit;
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}
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if (ret < 0)
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p = &parent->rb_left;
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else
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p = &parent->rb_right;
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}
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/* nothing in children, add to the current node */
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add_child(root, cursor, period);
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rnode = add_child(root, cursor, period);
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rb_link_node(&rnode->rb_node_in, parent, p);
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rb_insert_color(&rnode->rb_node_in, &root->rb_root_in);
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inc_children_hit:
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root->children_hit += period;
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@ -325,28 +403,20 @@ append_chain(struct callchain_node *root,
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*/
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list_for_each_entry(cnode, &root->val, list) {
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struct callchain_cursor_node *node;
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struct symbol *sym;
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node = callchain_cursor_current(cursor);
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if (!node)
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break;
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sym = node->sym;
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if (cnode->ms.sym && sym &&
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callchain_param.key == CCKEY_FUNCTION) {
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if (cnode->ms.sym->start != sym->start)
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break;
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} else if (cnode->ip != node->ip)
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if (match_chain(node, cnode) != 0)
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break;
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if (!found)
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found = true;
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found = true;
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callchain_cursor_advance(cursor);
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}
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/* matches not, relay on the parent */
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/* matches not, relay no the parent */
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if (!found) {
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cursor->curr = curr_snap;
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cursor->pos = start;
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@ -395,8 +465,9 @@ merge_chain_branch(struct callchain_cursor *cursor,
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struct callchain_node *dst, struct callchain_node *src)
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{
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struct callchain_cursor_node **old_last = cursor->last;
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struct callchain_node *child, *next_child;
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struct callchain_node *child;
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struct callchain_list *list, *next_list;
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struct rb_node *n;
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int old_pos = cursor->nr;
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int err = 0;
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@ -412,12 +483,16 @@ merge_chain_branch(struct callchain_cursor *cursor,
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append_chain_children(dst, cursor, src->hit);
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}
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chain_for_each_child_safe(child, next_child, src) {
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n = rb_first(&src->rb_root_in);
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while (n) {
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child = container_of(n, struct callchain_node, rb_node_in);
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n = rb_next(n);
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rb_erase(&child->rb_node_in, &src->rb_root_in);
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err = merge_chain_branch(cursor, dst, child);
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if (err)
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break;
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list_del(&child->siblings);
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free(child);
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}
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@ -21,11 +21,11 @@ enum chain_order {
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struct callchain_node {
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struct callchain_node *parent;
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struct list_head siblings;
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struct list_head children;
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struct list_head val;
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struct rb_node rb_node; /* to sort nodes in an rbtree */
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struct rb_root rb_root; /* sorted tree of children */
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struct rb_node rb_node_in; /* to insert nodes in an rbtree */
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struct rb_node rb_node; /* to sort nodes in an output tree */
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struct rb_root rb_root_in; /* input tree of children */
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struct rb_root rb_root; /* sorted output tree of children */
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unsigned int val_nr;
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u64 hit;
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u64 children_hit;
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@ -86,13 +86,12 @@ extern __thread struct callchain_cursor callchain_cursor;
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static inline void callchain_init(struct callchain_root *root)
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{
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INIT_LIST_HEAD(&root->node.siblings);
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INIT_LIST_HEAD(&root->node.children);
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INIT_LIST_HEAD(&root->node.val);
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root->node.parent = NULL;
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root->node.hit = 0;
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root->node.children_hit = 0;
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root->node.rb_root_in = RB_ROOT;
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root->max_depth = 0;
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}
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