From: Arran Cudbard-Bell <a.cudbardb@freeradius.org>
Date: Sat, 6 Nov 2021 14:46:43 +0000 (-0400)
Subject: Remove hot branch in rbtree find_node
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=b19a7ac6737e7a0f0aefb20cd94d9441d0e0eb3c;p=thirdparty%2Ffreeradius-server.git

Remove hot branch in rbtree find_node
---

diff --git a/src/lib/util/rb.c b/src/lib/util/rb.c
index 738aad1080a..68d8c9ae9b0 100644
--- a/src/lib/util/rb.c
+++ b/src/lib/util/rb.c
@@ -557,7 +557,16 @@ static inline CC_HINT(always_inline) fr_rb_node_t *find_node(fr_rb_tree_t const
 
 		if (result == 0) return current;
 
-		current = (result < 0) ? current->left : current->right;
+		/*
+		 *	If result > 0, return the start of the struct
+		 *	i.e. the left branch.
+		 *
+		 *	If result < 0, return struct + sizeof(fr_rb_node_t)
+		 *	i.e. the right branch.
+		 *
+		 *	One fewer branch in the hot loop...
+		 */
+		current = *(fr_rb_node_t **)((uint8_t *)current + ((result > 0) * sizeof(fr_rb_node_t *)));
 	}
 
 	return NULL;
diff --git a/src/lib/util/rb.h b/src/lib/util/rb.h
index 9c26a2ff307..cfcab49945b 100644
--- a/src/lib/util/rb.h
+++ b/src/lib/util/rb.h
@@ -39,9 +39,9 @@ typedef enum {
 } fr_rb_colour_t;
 
 typedef struct fr_rb_node_s fr_rb_node_t;
-struct fr_rb_node_s {
-	fr_rb_node_t		*left;		//!< Left child
-	fr_rb_node_t		*right;		//!< Right child
+struct CC_HINT(packed) fr_rb_node_s {
+	fr_rb_node_t		*left;		//!< Left child - Must occur first in the struct.
+	fr_rb_node_t		*right;		//!< Right child - Must occur second in the struct.
 	fr_rb_node_t		*parent;	//!< Parent
 	void			*data;		//!< data stored in node