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, 8 insertions, 8 deletions

diff --git a/tools/perf/ui/browsers/hists.c b/tools/perf/ui/browsers/hists.c
index b32f505a7608..85790a4d1842 100644
--- a/tools/perf/ui/browsers/hists.c
+++ b/tools/perf/ui/browsers/hists.c
@@ -49,7 +49,7 @@ static int hist_browser__get_folding(struct hist_browser *browser)
 	struct hists *hists = browser->hists;
 	int unfolded_rows = 0;
 
-	for (nd = rb_first(&hists->entries);
+	for (nd = rb_first_cached(&hists->entries);
 	     (nd = hists__filter_entries(nd, browser->min_pcnt)) != NULL;
 	     nd = rb_hierarchy_next(nd)) {
 		struct hist_entry *he =
@@ -267,7 +267,7 @@ static int hierarchy_count_rows(struct hist_browser *hb, struct hist_entry *he,
 	if (he->has_no_entry)
 		return 1;
 
-	node = rb_first(&he->hroot_out);
+	node = rb_first_cached(&he->hroot_out);
 	while (node) {
 		float percent;
 
@@ -372,7 +372,7 @@ static void hist_entry__init_have_children(struct hist_entry *he)
 		he->has_children = !RB_EMPTY_ROOT(&he->sorted_chain);
 		callchain__init_have_children(&he->sorted_chain);
 	} else {
-		he->has_children = !RB_EMPTY_ROOT(&he->hroot_out);
+		he->has_children = !RB_EMPTY_ROOT(&he->hroot_out.rb_root);
 	}
 
 	he->init_have_children = true;
@@ -508,7 +508,7 @@ static int hierarchy_set_folding(struct hist_browser *hb, struct hist_entry *he,
 	struct hist_entry *child;
 	int n = 0;
 
-	for (nd = rb_first(&he->hroot_out); nd; nd = rb_next(nd)) {
+	for (nd = rb_first_cached(&he->hroot_out); nd; nd = rb_next(nd)) {
 		child = rb_entry(nd, struct hist_entry, rb_node);
 		percent = hist_entry__get_percent_limit(child);
 		if (!child->filtered && percent >= hb->min_pcnt)
@@ -566,7 +566,7 @@ __hist_browser__set_folding(struct hist_browser *browser, bool unfold)
 	struct rb_node *nd;
 	struct hist_entry *he;
 
-	nd = rb_first(&browser->hists->entries);
+	nd = rb_first_cached(&browser->hists->entries);
 	while (nd) {
 		he = rb_entry(nd, struct hist_entry, rb_node);
 
@@ -1738,7 +1738,7 @@ static void ui_browser__hists_init_top(struct ui_browser *browser)
 		struct hist_browser *hb;
 
 		hb = container_of(browser, struct hist_browser, b);
-		browser->top = rb_first(&hb->hists->entries);
+		browser->top = rb_first_cached(&hb->hists->entries);
 	}
 }
 
@@ -2649,7 +2649,7 @@ add_socket_opt(struct hist_browser *browser, struct popup_action *act,
 static void hist_browser__update_nr_entries(struct hist_browser *hb)
 {
 	u64 nr_entries = 0;
-	struct rb_node *nd = rb_first(&hb->hists->entries);
+	struct rb_node *nd = rb_first_cached(&hb->hists->entries);
 
 	if (hb->min_pcnt == 0 && !symbol_conf.report_hierarchy) {
 		hb->nr_non_filtered_entries = hb->hists->nr_non_filtered_entries;
@@ -2669,7 +2669,7 @@ static void hist_browser__update_percent_limit(struct hist_browser *hb,
 					       double percent)
 {
 	struct hist_entry *he;
-	struct rb_node *nd = rb_first(&hb->hists->entries);
+	struct rb_node *nd = rb_first_cached(&hb->hists->entries);
 	u64 total = hists__total_period(hb->hists);
 	u64 min_callchain_hits = total * (percent / 100);