perf hist: Use cached rbtrees

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 heavily required for histograms. Specifically, the following
are converted to rb_root_cached, and users accordingly:

hist::entries_in_array
hist::entries_in
hist::entries
hist::entries_collapsed
hist_entry::hroot_in
hist_entry::hroot_out

Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lkml.kernel.org/r/20181206191819.30182-7-dave@stgolabs.net
[ Added some missing conversions to rb_first_cached() ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 112 insertions, 87 deletions

diff --git a/tools/perf/util/hist.c b/tools/perf/util/hist.c
index 8aad8330e392..9e7a8e044a0a 100644
--- a/tools/perf/util/hist.c
+++ b/tools/perf/util/hist.c
@@ -209,7 +209,7 @@ void hists__calc_col_len(struct hists *hists, struct hist_entry *h)
 
 void hists__output_recalc_col_len(struct hists *hists, int max_rows)
 {
-	struct rb_node *next = rb_first(&hists->entries);
+	struct rb_node *next = rb_first_cached(&hists->entries);
 	struct hist_entry *n;
 	int row = 0;
 
@@ -296,7 +296,7 @@ static bool hists__decay_entry(struct hists *hists, struct hist_entry *he)
 
 	if (!he->leaf) {
 		struct hist_entry *child;
-		struct rb_node *node = rb_first(&he->hroot_out);
+		struct rb_node *node = rb_first_cached(&he->hroot_out);
 		while (node) {
 			child = rb_entry(node, struct hist_entry, rb_node);
 			node = rb_next(node);
@@ -311,8 +311,8 @@ static bool hists__decay_entry(struct hists *hists, struct hist_entry *he)
 
 static void hists__delete_entry(struct hists *hists, struct hist_entry *he)
 {
-	struct rb_root *root_in;
-	struct rb_root *root_out;
+	struct rb_root_cached *root_in;
+	struct rb_root_cached *root_out;
 
 	if (he->parent_he) {
 		root_in  = &he->parent_he->hroot_in;
@@ -325,8 +325,8 @@ static void hists__delete_entry(struct hists *hists, struct hist_entry *he)
 		root_out = &hists->entries;
 	}
 
-	rb_erase(&he->rb_node_in, root_in);
-	rb_erase(&he->rb_node, root_out);
+	rb_erase_cached(&he->rb_node_in, root_in);
+	rb_erase_cached(&he->rb_node, root_out);
 
 	--hists->nr_entries;
 	if (!he->filtered)
@@ -337,7 +337,7 @@ static void hists__delete_entry(struct hists *hists, struct hist_entry *he)
 
 void hists__decay_entries(struct hists *hists, bool zap_user, bool zap_kernel)
 {
-	struct rb_node *next = rb_first(&hists->entries);
+	struct rb_node *next = rb_first_cached(&hists->entries);
 	struct hist_entry *n;
 
 	while (next) {
@@ -353,7 +353,7 @@ void hists__decay_entries(struct hists *hists, bool zap_user, bool zap_kernel)
 
 void hists__delete_entries(struct hists *hists)
 {
-	struct rb_node *next = rb_first(&hists->entries);
+	struct rb_node *next = rb_first_cached(&hists->entries);
 	struct hist_entry *n;
 
 	while (next) {
@@ -435,8 +435,8 @@ static int hist_entry__init(struct hist_entry *he,
 	}
 	INIT_LIST_HEAD(&he->pairs.node);
 	thread__get(he->thread);
-	he->hroot_in  = RB_ROOT;
-	he->hroot_out = RB_ROOT;
+	he->hroot_in  = RB_ROOT_CACHED;
+	he->hroot_out = RB_ROOT_CACHED;
 
 	if (!symbol_conf.report_hierarchy)
 		he->leaf = true;
@@ -513,8 +513,9 @@ static struct hist_entry *hists__findnew_entry(struct hists *hists,
 	int64_t cmp;
 	u64 period = entry->stat.period;
 	u64 weight = entry->stat.weight;
+	bool leftmost = true;
 
-	p = &hists->entries_in->rb_node;
+	p = &hists->entries_in->rb_root.rb_node;
 
 	while (*p != NULL) {
 		parent = *p;
@@ -557,8 +558,10 @@ static struct hist_entry *hists__findnew_entry(struct hists *hists,
 
 		if (cmp < 0)
 			p = &(*p)->rb_left;
-		else
+		else {
 			p = &(*p)->rb_right;
+			leftmost = false;
+		}
 	}
 
 	he = hist_entry__new(entry, sample_self);
@@ -570,7 +573,7 @@ static struct hist_entry *hists__findnew_entry(struct hists *hists,
 	hists->nr_entries++;
 
 	rb_link_node(&he->rb_node_in, parent, p);
-	rb_insert_color(&he->rb_node_in, hists->entries_in);
+	rb_insert_color_cached(&he->rb_node_in, hists->entries_in, leftmost);
 out:
 	if (sample_self)
 		he_stat__add_cpumode_period(&he->stat, al->cpumode, period);
@@ -1279,16 +1282,17 @@ static void hist_entry__apply_hierarchy_filters(struct hist_entry *he)
 }
 
 static struct hist_entry *hierarchy_insert_entry(struct hists *hists,
-						 struct rb_root *root,
+						 struct rb_root_cached *root,
 						 struct hist_entry *he,
 						 struct hist_entry *parent_he,
 						 struct perf_hpp_list *hpp_list)
 {
-	struct rb_node **p = &root->rb_node;
+	struct rb_node **p = &root->rb_root.rb_node;
 	struct rb_node *parent = NULL;
 	struct hist_entry *iter, *new;
 	struct perf_hpp_fmt *fmt;
 	int64_t cmp;
+	bool leftmost = true;
 
 	while (*p != NULL) {
 		parent = *p;
@@ -1308,8 +1312,10 @@ static struct hist_entry *hierarchy_insert_entry(struct hists *hists,
 
 		if (cmp < 0)
 			p = &parent->rb_left;
-		else
+		else {
 			p = &parent->rb_right;
+			leftmost = false;
+		}
 	}
 
 	new = hist_entry__new(he, true);
@@ -1343,12 +1349,12 @@ static struct hist_entry *hierarchy_insert_entry(struct hists *hists,
 	}
 
 	rb_link_node(&new->rb_node_in, parent, p);
-	rb_insert_color(&new->rb_node_in, root);
+	rb_insert_color_cached(&new->rb_node_in, root, leftmost);
 	return new;
 }
 
 static int hists__hierarchy_insert_entry(struct hists *hists,
-					 struct rb_root *root,
+					 struct rb_root_cached *root,
 					 struct hist_entry *he)
 {
 	struct perf_hpp_list_node *node;
@@ -1395,13 +1401,14 @@ static int hists__hierarchy_insert_entry(struct hists *hists,
 }
 
 static int hists__collapse_insert_entry(struct hists *hists,
-					struct rb_root *root,
+					struct rb_root_cached *root,
 					struct hist_entry *he)
 {
-	struct rb_node **p = &root->rb_node;
+	struct rb_node **p = &root->rb_root.rb_node;
 	struct rb_node *parent = NULL;
 	struct hist_entry *iter;
 	int64_t cmp;
+	bool leftmost = true;
 
 	if (symbol_conf.report_hierarchy)
 		return hists__hierarchy_insert_entry(hists, root, he);
@@ -1432,19 +1439,21 @@ static int hists__collapse_insert_entry(struct hists *hists,
 
 		if (cmp < 0)
 			p = &(*p)->rb_left;
-		else
+		else {
 			p = &(*p)->rb_right;
+			leftmost = false;
+		}
 	}
 	hists->nr_entries++;
 
 	rb_link_node(&he->rb_node_in, parent, p);
-	rb_insert_color(&he->rb_node_in, root);
+	rb_insert_color_cached(&he->rb_node_in, root, leftmost);
 	return 1;
 }
 
-struct rb_root *hists__get_rotate_entries_in(struct hists *hists)
+struct rb_root_cached *hists__get_rotate_entries_in(struct hists *hists)
 {
-	struct rb_root *root;
+	struct rb_root_cached *root;
 
 	pthread_mutex_lock(&hists->lock);
 
@@ -1467,7 +1476,7 @@ static void hists__apply_filters(struct hists *hists, struct hist_entry *he)
 
 int hists__collapse_resort(struct hists *hists, struct ui_progress *prog)
 {
-	struct rb_root *root;
+	struct rb_root_cached *root;
 	struct rb_node *next;
 	struct hist_entry *n;
 	int ret;
@@ -1479,7 +1488,7 @@ int hists__collapse_resort(struct hists *hists, struct ui_progress *prog)
 
 	root = hists__get_rotate_entries_in(hists);
 
-	next = rb_first(root);
+	next = rb_first_cached(root);
 
 	while (next) {
 		if (session_done())
@@ -1487,7 +1496,7 @@ int hists__collapse_resort(struct hists *hists, struct ui_progress *prog)
 		n = rb_entry(next, struct hist_entry, rb_node_in);
 		next = rb_next(&n->rb_node_in);
 
-		rb_erase(&n->rb_node_in, root);
+		rb_erase_cached(&n->rb_node_in, root);
 		ret = hists__collapse_insert_entry(hists, &hists->entries_collapsed, n);
 		if (ret < 0)
 			return -1;
@@ -1558,7 +1567,7 @@ static void hierarchy_recalc_total_periods(struct hists *hists)
 	struct rb_node *node;
 	struct hist_entry *he;
 
-	node = rb_first(&hists->entries);
+	node = rb_first_cached(&hists->entries);
 
 	hists->stats.total_period = 0;
 	hists->stats.total_non_filtered_period = 0;
@@ -1578,13 +1587,14 @@ static void hierarchy_recalc_total_periods(struct hists *hists)
 	}
 }
 
-static void hierarchy_insert_output_entry(struct rb_root *root,
+static void hierarchy_insert_output_entry(struct rb_root_cached *root,
 					  struct hist_entry *he)
 {
-	struct rb_node **p = &root->rb_node;
+	struct rb_node **p = &root->rb_root.rb_node;
 	struct rb_node *parent = NULL;
 	struct hist_entry *iter;
 	struct perf_hpp_fmt *fmt;
+	bool leftmost = true;
 
 	while (*p != NULL) {
 		parent = *p;
@@ -1592,12 +1602,14 @@ static void hierarchy_insert_output_entry(struct rb_root *root,
 
 		if (hist_entry__sort(he, iter) > 0)
 			p = &parent->rb_left;
-		else
+		else {
 			p = &parent->rb_right;
+			leftmost = false;
+		}
 	}
 
 	rb_link_node(&he->rb_node, parent, p);
-	rb_insert_color(&he->rb_node, root);
+	rb_insert_color_cached(&he->rb_node, root, leftmost);
 
 	/* update column width of dynamic entry */
 	perf_hpp_list__for_each_sort_list(he->hpp_list, fmt) {
@@ -1608,16 +1620,16 @@ static void hierarchy_insert_output_entry(struct rb_root *root,
 
 static void hists__hierarchy_output_resort(struct hists *hists,
 					   struct ui_progress *prog,
-					   struct rb_root *root_in,
-					   struct rb_root *root_out,
+					   struct rb_root_cached *root_in,
+					   struct rb_root_cached *root_out,
 					   u64 min_callchain_hits,
 					   bool use_callchain)
 {
 	struct rb_node *node;
 	struct hist_entry *he;
 
-	*root_out = RB_ROOT;
-	node = rb_first(root_in);
+	*root_out = RB_ROOT_CACHED;
+	node = rb_first_cached(root_in);
 
 	while (node) {
 		he = rb_entry(node, struct hist_entry, rb_node_in);
@@ -1660,15 +1672,16 @@ static void hists__hierarchy_output_resort(struct hists *hists,
 	}
 }
 
-static void __hists__insert_output_entry(struct rb_root *entries,
+static void __hists__insert_output_entry(struct rb_root_cached *entries,
 					 struct hist_entry *he,
 					 u64 min_callchain_hits,
 					 bool use_callchain)
 {
-	struct rb_node **p = &entries->rb_node;
+	struct rb_node **p = &entries->rb_root.rb_node;
 	struct rb_node *parent = NULL;
 	struct hist_entry *iter;
 	struct perf_hpp_fmt *fmt;
+	bool leftmost = true;
 
 	if (use_callchain) {
 		if (callchain_param.mode == CHAIN_GRAPH_REL) {
@@ -1689,12 +1702,14 @@ static void __hists__insert_output_entry(struct rb_root *entries,
 
 		if (hist_entry__sort(he, iter) > 0)
 			p = &(*p)->rb_left;
-		else
+		else {
 			p = &(*p)->rb_right;
+			leftmost = false;
+		}
 	}
 
 	rb_link_node(&he->rb_node, parent, p);
-	rb_insert_color(&he->rb_node, entries);
+	rb_insert_color_cached(&he->rb_node, entries, leftmost);
 
 	perf_hpp_list__for_each_sort_list(&perf_hpp_list, fmt) {
 		if (perf_hpp__is_dynamic_entry(fmt) &&
@@ -1706,7 +1721,7 @@ static void __hists__insert_output_entry(struct rb_root *entries,
 static void output_resort(struct hists *hists, struct ui_progress *prog,
 			  bool use_callchain, hists__resort_cb_t cb)
 {
-	struct rb_root *root;
+	struct rb_root_cached *root;
 	struct rb_node *next;
 	struct hist_entry *n;
 	u64 callchain_total;
@@ -1736,8 +1751,8 @@ static void output_resort(struct hists *hists, struct ui_progress *prog,
 	else
 		root = hists->entries_in;
 
-	next = rb_first(root);
-	hists->entries = RB_ROOT;
+	next = rb_first_cached(root);
+	hists->entries = RB_ROOT_CACHED;
 
 	while (next) {
 		n = rb_entry(next, struct hist_entry, rb_node_in);
@@ -1798,7 +1813,7 @@ struct rb_node *rb_hierarchy_last(struct rb_node *node)
 	struct hist_entry *he = rb_entry(node, struct hist_entry, rb_node);
 
 	while (can_goto_child(he, HMD_NORMAL)) {
-		node = rb_last(&he->hroot_out);
+		node = rb_last(&he->hroot_out.rb_root);
 		he = rb_entry(node, struct hist_entry, rb_node);
 	}
 	return node;
@@ -1809,7 +1824,7 @@ struct rb_node *__rb_hierarchy_next(struct rb_node *node, enum hierarchy_move_di
 	struct hist_entry *he = rb_entry(node, struct hist_entry, rb_node);
 
 	if (can_goto_child(he, hmd))
-		node = rb_first(&he->hroot_out);
+		node = rb_first_cached(&he->hroot_out);
 	else
 		node = rb_next(node);
 
@@ -1847,7 +1862,7 @@ bool hist_entry__has_hierarchy_children(struct hist_entry *he, float limit)
 	if (he->leaf)
 		return false;
 
-	node = rb_first(&he->hroot_out);
+	node = rb_first_cached(&he->hroot_out);
 	child = rb_entry(node, struct hist_entry, rb_node);
 
 	while (node && child->filtered) {
@@ -1965,7 +1980,7 @@ static void hists__filter_by_type(struct hists *hists, int type, filter_fn_t fil
 	hists__reset_filter_stats(hists);
 	hists__reset_col_len(hists);
 
-	for (nd = rb_first(&hists->entries); nd; nd = rb_next(nd)) {
+	for (nd = rb_first_cached(&hists->entries); nd; nd = rb_next(nd)) {
 		struct hist_entry *h = rb_entry(nd, struct hist_entry, rb_node);
 
 		if (filter(hists, h))
@@ -1975,13 +1990,15 @@ static void hists__filter_by_type(struct hists *hists, int type, filter_fn_t fil
 	}
 }
 
-static void resort_filtered_entry(struct rb_root *root, struct hist_entry *he)
+static void resort_filtered_entry(struct rb_root_cached *root,
+				  struct hist_entry *he)
 {
-	struct rb_node **p = &root->rb_node;
+	struct rb_node **p = &root->rb_root.rb_node;
 	struct rb_node *parent = NULL;
 	struct hist_entry *iter;
-	struct rb_root new_root = RB_ROOT;
+	struct rb_root_cached new_root = RB_ROOT_CACHED;
 	struct rb_node *nd;
+	bool leftmost = true;
 
 	while (*p != NULL) {
 		parent = *p;
@@ -1989,22 +2006,24 @@ static void resort_filtered_entry(struct rb_root *root, struct hist_entry *he)
 
 		if (hist_entry__sort(he, iter) > 0)
 			p = &(*p)->rb_left;
-		else
+		else {
 			p = &(*p)->rb_right;
+			leftmost = false;
+		}
 	}
 
 	rb_link_node(&he->rb_node, parent, p);
-	rb_insert_color(&he->rb_node, root);
+	rb_insert_color_cached(&he->rb_node, root, leftmost);
 
 	if (he->leaf || he->filtered)
 		return;
 
-	nd = rb_first(&he->hroot_out);
+	nd = rb_first_cached(&he->hroot_out);
 	while (nd) {
 		struct hist_entry *h = rb_entry(nd, struct hist_entry, rb_node);
 
 		nd = rb_next(nd);
-		rb_erase(&h->rb_node, &he->hroot_out);
+		rb_erase_cached(&h->rb_node, &he->hroot_out);
 
 		resort_filtered_entry(&new_root, h);
 	}
@@ -2015,14 +2034,14 @@ static void resort_filtered_entry(struct rb_root *root, struct hist_entry *he)
 static void hists__filter_hierarchy(struct hists *hists, int type, const void *arg)
 {
 	struct rb_node *nd;
-	struct rb_root new_root = RB_ROOT;
+	struct rb_root_cached new_root = RB_ROOT_CACHED;
 
 	hists->stats.nr_non_filtered_samples = 0;
 
 	hists__reset_filter_stats(hists);
 	hists__reset_col_len(hists);
 
-	nd = rb_first(&hists->entries);
+	nd = rb_first_cached(&hists->entries);
 	while (nd) {
 		struct hist_entry *h = rb_entry(nd, struct hist_entry, rb_node);
 		int ret;
@@ -2066,12 +2085,12 @@ static void hists__filter_hierarchy(struct hists *hists, int type, const void *a
 	 * resort output after applying a new filter since filter in a lower
 	 * hierarchy can change periods in a upper hierarchy.
 	 */
-	nd = rb_first(&hists->entries);
+	nd = rb_first_cached(&hists->entries);
 	while (nd) {
 		struct hist_entry *h = rb_entry(nd, struct hist_entry, rb_node);
 
 		nd = rb_next(nd);
-		rb_erase(&h->rb_node, &hists->entries);
+		rb_erase_cached(&h->rb_node, &hists->entries);
 
 		resort_filtered_entry(&new_root, h);
 	}
@@ -2140,18 +2159,19 @@ void hists__inc_nr_samples(struct hists *hists, bool filtered)
 static struct hist_entry *hists__add_dummy_entry(struct hists *hists,
 						 struct hist_entry *pair)
 {
-	struct rb_root *root;
+	struct rb_root_cached *root;
 	struct rb_node **p;
 	struct rb_node *parent = NULL;
 	struct hist_entry *he;
 	int64_t cmp;
+	bool leftmost = true;
 
 	if (hists__has(hists, need_collapse))
 		root = &hists->entries_collapsed;
 	else
 		root = hists->entries_in;
 
-	p = &root->rb_node;
+	p = &root->rb_root.rb_node;
 
 	while (*p != NULL) {
 		parent = *p;
@@ -2164,8 +2184,10 @@ static struct hist_entry *hists__add_dummy_entry(struct hists *hists,
 
 		if (cmp < 0)
 			p = &(*p)->rb_left;
-		else
+		else {
 			p = &(*p)->rb_right;
+			leftmost = false;
+		}
 	}
 
 	he = hist_entry__new(pair, true);
@@ -2175,7 +2197,7 @@ static struct hist_entry *hists__add_dummy_entry(struct hists *hists,
 		if (symbol_conf.cumulate_callchain)
 			memset(he->stat_acc, 0, sizeof(he->stat));
 		rb_link_node(&he->rb_node_in, parent, p);
-		rb_insert_color(&he->rb_node_in, root);
+		rb_insert_color_cached(&he->rb_node_in, root, leftmost);
 		hists__inc_stats(hists, he);
 		he->dummy = true;
 	}
@@ -2184,15 +2206,16 @@ out:
 }
 
 static struct hist_entry *add_dummy_hierarchy_entry(struct hists *hists,
-						    struct rb_root *root,
+						    struct rb_root_cached *root,
 						    struct hist_entry *pair)
 {
 	struct rb_node **p;
 	struct rb_node *parent = NULL;
 	struct hist_entry *he;
 	struct perf_hpp_fmt *fmt;
+	bool leftmost = true;
 
-	p = &root->rb_node;
+	p = &root->rb_root.rb_node;
 	while (*p != NULL) {
 		int64_t cmp = 0;
 
@@ -2209,14 +2232,16 @@ static struct hist_entry *add_dummy_hierarchy_entry(struct hists *hists,
 
 		if (cmp < 0)
 			p = &parent->rb_left;
-		else
+		else {
 			p = &parent->rb_right;
+			leftmost = false;
+		}
 	}
 
 	he = hist_entry__new(pair, true);
 	if (he) {
 		rb_link_node(&he->rb_node_in, parent, p);
-		rb_insert_color(&he->rb_node_in, root);
+		rb_insert_color_cached(&he->rb_node_in, root, leftmost);
 
 		he->dummy = true;
 		he->hists = hists;
@@ -2233,9 +2258,9 @@ static struct hist_entry *hists__find_entry(struct hists *hists,
 	struct rb_node *n;
 
 	if (hists__has(hists, need_collapse))
-		n = hists->entries_collapsed.rb_node;
+		n = hists->entries_collapsed.rb_root.rb_node;
 	else
-		n = hists->entries_in->rb_node;
+		n = hists->entries_in->rb_root.rb_node;
 
 	while (n) {
 		struct hist_entry *iter = rb_entry(n, struct hist_entry, rb_node_in);
@@ -2252,10 +2277,10 @@ static struct hist_entry *hists__find_entry(struct hists *hists,
 	return NULL;
 }
 
-static struct hist_entry *hists__find_hierarchy_entry(struct rb_root *root,
+static struct hist_entry *hists__find_hierarchy_entry(struct rb_root_cached *root,
 						      struct hist_entry *he)
 {
-	struct rb_node *n = root->rb_node;
+	struct rb_node *n = root->rb_root.rb_node;
 
 	while (n) {
 		struct hist_entry *iter;
@@ -2280,13 +2305,13 @@ static struct hist_entry *hists__find_hierarchy_entry(struct rb_root *root,
 	return NULL;
 }
 
-static void hists__match_hierarchy(struct rb_root *leader_root,
-				   struct rb_root *other_root)
+static void hists__match_hierarchy(struct rb_root_cached *leader_root,
+				   struct rb_root_cached *other_root)
 {
 	struct rb_node *nd;
 	struct hist_entry *pos, *pair;
 
-	for (nd = rb_first(leader_root); nd; nd = rb_next(nd)) {
+	for (nd = rb_first_cached(leader_root); nd; nd = rb_next(nd)) {
 		pos  = rb_entry(nd, struct hist_entry, rb_node_in);
 		pair = hists__find_hierarchy_entry(other_root, pos);
 
@@ -2302,7 +2327,7 @@ static void hists__match_hierarchy(struct rb_root *leader_root,
  */
 void hists__match(struct hists *leader, struct hists *other)
 {
-	struct rb_root *root;
+	struct rb_root_cached *root;
 	struct rb_node *nd;
 	struct hist_entry *pos, *pair;
 
@@ -2317,7 +2342,7 @@ void hists__match(struct hists *leader, struct hists *other)
 	else
 		root = leader->entries_in;
 
-	for (nd = rb_first(root); nd; nd = rb_next(nd)) {
+	for (nd = rb_first_cached(root); nd; nd = rb_next(nd)) {
 		pos  = rb_entry(nd, struct hist_entry, rb_node_in);
 		pair = hists__find_entry(other, pos);
 
@@ -2328,13 +2353,13 @@ void hists__match(struct hists *leader, struct hists *other)
 
 static int hists__link_hierarchy(struct hists *leader_hists,
 				 struct hist_entry *parent,
-				 struct rb_root *leader_root,
-				 struct rb_root *other_root)
+				 struct rb_root_cached *leader_root,
+				 struct rb_root_cached *other_root)
 {
 	struct rb_node *nd;
 	struct hist_entry *pos, *leader;
 
-	for (nd = rb_first(other_root); nd; nd = rb_next(nd)) {
+	for (nd = rb_first_cached(other_root); nd; nd = rb_next(nd)) {
 		pos = rb_entry(nd, struct hist_entry, rb_node_in);
 
 		if (hist_entry__has_pairs(pos)) {
@@ -2377,7 +2402,7 @@ static int hists__link_hierarchy(struct hists *leader_hists,
  */
 int hists__link(struct hists *leader, struct hists *other)
 {
-	struct rb_root *root;
+	struct rb_root_cached *root;
 	struct rb_node *nd;
 	struct hist_entry *pos, *pair;
 
@@ -2393,7 +2418,7 @@ int hists__link(struct hists *leader, struct hists *other)
 	else
 		root = other->entries_in;
 
-	for (nd = rb_first(root); nd; nd = rb_next(nd)) {
+	for (nd = rb_first_cached(root); nd; nd = rb_next(nd)) {
 		pos = rb_entry(nd, struct hist_entry, rb_node_in);
 
 		if (!hist_entry__has_pairs(pos)) {
@@ -2566,10 +2591,10 @@ int perf_hist_config(const char *var, const char *value)
 int __hists__init(struct hists *hists, struct perf_hpp_list *hpp_list)
 {
 	memset(hists, 0, sizeof(*hists));
-	hists->entries_in_array[0] = hists->entries_in_array[1] = RB_ROOT;
+	hists->entries_in_array[0] = hists->entries_in_array[1] = RB_ROOT_CACHED;
 	hists->entries_in = &hists->entries_in_array[0];
-	hists->entries_collapsed = RB_ROOT;
-	hists->entries = RB_ROOT;
+	hists->entries_collapsed = RB_ROOT_CACHED;
+	hists->entries = RB_ROOT_CACHED;
 	pthread_mutex_init(&hists->lock, NULL);
 	hists->socket_filter = -1;
 	hists->hpp_list = hpp_list;
@@ -2577,14 +2602,14 @@ int __hists__init(struct hists *hists, struct perf_hpp_list *hpp_list)
 	return 0;
 }
 
-static void hists__delete_remaining_entries(struct rb_root *root)
+static void hists__delete_remaining_entries(struct rb_root_cached *root)
 {
 	struct rb_node *node;
 	struct hist_entry *he;
 
-	while (!RB_EMPTY_ROOT(root)) {
-		node = rb_first(root);
-		rb_erase(node, root);
+	while (!RB_EMPTY_ROOT(&root->rb_root)) {
+		node = rb_first_cached(root);
+		rb_erase_cached(node, root);
 
 		he = rb_entry(node, struct hist_entry, rb_node_in);
 		hist_entry__delete(he);