From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Date: Wed, 6 Jul 2011 04:44:43 +0000 (-0400)
Subject: rculfhash: use threshold and target
X-Git-Tag: v0.7.0~43^2~228
X-Git-Url: https://git.lttng.org./?a=commitdiff_plain;h=3390d4701e9fec1df68bbfff42cca215b4bfee05;p=userspace-rcu.git

rculfhash: use threshold and target

Accept to target bucket len greater than 1 to diminish the memory
consumption without too much performance impact.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
---

diff --git a/rculfhash.c b/rculfhash.c
index 497a9ea..450b286 100644
--- a/rculfhash.c
+++ b/rculfhash.c
@@ -46,7 +46,8 @@
 #define dbg_printf(args...)
 #endif
 
-#define BUCKET_SIZE_RESIZE_THRESHOLD	4
+#define CHAIN_LEN_TARGET		4
+#define CHAIN_LEN_RESIZE_THRESHOLD	16
 
 #ifndef max
 #define max(a, b)	((a) > (b) ? (a) : (b))
@@ -165,8 +166,9 @@ static
 void check_resize(struct rcu_ht *ht, struct rcu_table *t,
 		  uint32_t chain_len)
 {
-	if (chain_len >= BUCKET_SIZE_RESIZE_THRESHOLD)
-		ht_resize_lazy(ht, t, log2_u32(chain_len));
+	if (chain_len >= CHAIN_LEN_RESIZE_THRESHOLD)
+		ht_resize_lazy(ht, t,
+			log2_u32(chain_len - CHAIN_LEN_TARGET));
 }
 
 static