[PATCH 4/7] perf util: Use cached rbtree for rblists

From: Davidlohr Bueso
Date: Sun Nov 26 2017 - 21:34:58 EST


At the cost of an extra pointer, we can avoid the O(logN) cost
of finding the first element in the tree (smallest node), which
is something required for any of the strlist or intlist traversals
(XXX_for_each_entry()). There are a number of users in perf of
these (particularly strlists), including probes, and buildid.

Signed-off-by: Davidlohr Bueso <dbueso@xxxxxxx>
---
tools/perf/util/intlist.h | 2 +-
tools/perf/util/metricgroup.c | 2 +-
tools/perf/util/rblist.c | 30 ++++++++++++++++++------------
tools/perf/util/rblist.h | 2 +-
tools/perf/util/stat-shadow.c | 2 +-
tools/perf/util/strlist.h | 2 +-
6 files changed, 23 insertions(+), 17 deletions(-)

diff --git a/tools/perf/util/intlist.h b/tools/perf/util/intlist.h
index 85bab8735fa9..5c19ee001299 100644
--- a/tools/perf/util/intlist.h
+++ b/tools/perf/util/intlist.h
@@ -45,7 +45,7 @@ static inline unsigned int intlist__nr_entries(const struct intlist *ilist)
/* For intlist iteration */
static inline struct int_node *intlist__first(struct intlist *ilist)
{
- struct rb_node *rn = rb_first(&ilist->rblist.entries);
+ struct rb_node *rn = rb_first_cached(&ilist->rblist.entries);
return rn ? rb_entry(rn, struct int_node, rb_node) : NULL;
}
static inline struct int_node *intlist__next(struct int_node *in)
diff --git a/tools/perf/util/metricgroup.c b/tools/perf/util/metricgroup.c
index 0ddd9c199227..59a08a9eebb9 100644
--- a/tools/perf/util/metricgroup.c
+++ b/tools/perf/util/metricgroup.c
@@ -350,7 +350,7 @@ void metricgroup__print(bool metrics, bool metricgroups, char *filter,
else if (metrics && !raw)
printf("\nMetrics:\n\n");

- for (node = rb_first(&groups.entries); node; node = next) {
+ for (node = rb_first_cached(&groups.entries); node; node = next) {
struct mep *me = container_of(node, struct mep, nd);

if (metricgroups)
diff --git a/tools/perf/util/rblist.c b/tools/perf/util/rblist.c
index 0dfe27d99458..8256545344ed 100644
--- a/tools/perf/util/rblist.c
+++ b/tools/perf/util/rblist.c
@@ -13,8 +13,9 @@

int rblist__add_node(struct rblist *rblist, const void *new_entry)
{
- struct rb_node **p = &rblist->entries.rb_node;
+ struct rb_node **p = &rblist->entries.rb_root.rb_node;
struct rb_node *parent = NULL, *new_node;
+ bool leftmost = true;

while (*p != NULL) {
int rc;
@@ -24,9 +25,10 @@ int rblist__add_node(struct rblist *rblist, const void *new_entry)
rc = rblist->node_cmp(parent, new_entry);
if (rc > 0)
p = &(*p)->rb_left;
- else if (rc < 0)
+ else if (rc < 0) {
p = &(*p)->rb_right;
- else
+ leftmost = false;
+ } else
return -EEXIST;
}

@@ -35,7 +37,7 @@ int rblist__add_node(struct rblist *rblist, const void *new_entry)
return -ENOMEM;

rb_link_node(new_node, parent, p);
- rb_insert_color(new_node, &rblist->entries);
+ rb_insert_color_cached(new_node, &rblist->entries, leftmost);
++rblist->nr_entries;

return 0;
@@ -43,7 +45,7 @@ int rblist__add_node(struct rblist *rblist, const void *new_entry)

void rblist__remove_node(struct rblist *rblist, struct rb_node *rb_node)
{
- rb_erase(rb_node, &rblist->entries);
+ rb_erase_cached(rb_node, &rblist->entries);
--rblist->nr_entries;
rblist->node_delete(rblist, rb_node);
}
@@ -52,8 +54,9 @@ static struct rb_node *__rblist__findnew(struct rblist *rblist,
const void *entry,
bool create)
{
- struct rb_node **p = &rblist->entries.rb_node;
+ struct rb_node **p = &rblist->entries.rb_root.rb_node;
struct rb_node *parent = NULL, *new_node = NULL;
+ bool leftmost = true;

while (*p != NULL) {
int rc;
@@ -63,9 +66,10 @@ static struct rb_node *__rblist__findnew(struct rblist *rblist,
rc = rblist->node_cmp(parent, entry);
if (rc > 0)
p = &(*p)->rb_left;
- else if (rc < 0)
+ else if (rc < 0) {
p = &(*p)->rb_right;
- else
+ leftmost = false;
+ } else
return parent;
}

@@ -73,7 +77,8 @@ static struct rb_node *__rblist__findnew(struct rblist *rblist,
new_node = rblist->node_new(rblist, entry);
if (new_node) {
rb_link_node(new_node, parent, p);
- rb_insert_color(new_node, &rblist->entries);
+ rb_insert_color_cached(new_node,
+ &rblist->entries, leftmost);
++rblist->nr_entries;
}
}
@@ -94,7 +99,7 @@ struct rb_node *rblist__findnew(struct rblist *rblist, const void *entry)
void rblist__init(struct rblist *rblist)
{
if (rblist != NULL) {
- rblist->entries = RB_ROOT;
+ rblist->entries = RB_ROOT_CACHED;
rblist->nr_entries = 0;
}

@@ -104,7 +109,7 @@ void rblist__init(struct rblist *rblist)
void rblist__delete(struct rblist *rblist)
{
if (rblist != NULL) {
- struct rb_node *pos, *next = rb_first(&rblist->entries);
+ struct rb_node *pos, *next = rb_first_cached(&rblist->entries);

while (next) {
pos = next;
@@ -119,7 +124,8 @@ struct rb_node *rblist__entry(const struct rblist *rblist, unsigned int idx)
{
struct rb_node *node;

- for (node = rb_first(&rblist->entries); node; node = rb_next(node)) {
+ for (node = rb_first_cached(&rblist->entries);
+ node; node = rb_next(node)) {
if (!idx--)
return node;
}
diff --git a/tools/perf/util/rblist.h b/tools/perf/util/rblist.h
index 4c8638a22571..4b16fc48a46d 100644
--- a/tools/perf/util/rblist.h
+++ b/tools/perf/util/rblist.h
@@ -20,7 +20,7 @@
*/

struct rblist {
- struct rb_root entries;
+ struct rb_root_cached entries;
unsigned int nr_entries;

int (*node_cmp)(struct rb_node *rbn, const void *entry);
diff --git a/tools/perf/util/stat-shadow.c b/tools/perf/util/stat-shadow.c
index 855e35cbb1dc..a7ed1180d878 100644
--- a/tools/perf/util/stat-shadow.c
+++ b/tools/perf/util/stat-shadow.c
@@ -164,7 +164,7 @@ void perf_stat__reset_shadow_stats(void)
memset(runtime_smi_num_stats, 0, sizeof(runtime_smi_num_stats));
memset(runtime_aperf_stats, 0, sizeof(runtime_aperf_stats));

- next = rb_first(&runtime_saved_values.entries);
+ next = rb_first_cached(&runtime_saved_values.entries);
while (next) {
pos = next;
next = rb_next(pos);
diff --git a/tools/perf/util/strlist.h b/tools/perf/util/strlist.h
index d58f1e08b170..7e82c71dcc42 100644
--- a/tools/perf/util/strlist.h
+++ b/tools/perf/util/strlist.h
@@ -57,7 +57,7 @@ static inline unsigned int strlist__nr_entries(const struct strlist *slist)
/* For strlist iteration */
static inline struct str_node *strlist__first(struct strlist *slist)
{
- struct rb_node *rn = rb_first(&slist->rblist.entries);
+ struct rb_node *rn = rb_first_cached(&slist->rblist.entries);
return rn ? rb_entry(rn, struct str_node, rb_node) : NULL;
}
static inline struct str_node *strlist__next(struct str_node *sn)
--
2.13.6