I think patch should be useful as it helps performance a lot during high
flow load. I have some numbers if you are interested.
--- net/ipv4/Kconfig.orig 2003-12-09 14:00:14.000000000 +0100
+++ net/ipv4/Kconfig 2003-12-09 14:51:27.000000000 +0100
@@ -75,6 +75,19 @@
If unsure, say N.
+ bool "IP: large routing hash"
+ Say yes to increase the number of dst hash buckets. Most likely you
+ are running a server or router with lots of flows. Saying yes
+ will increase used dst hash 8 times typically from 16Kbytes to 128
+ Kbytes on a 256Mbytes system.
+ dst hash is otherwise tunable via /proc/sys/net/ipv4/route/
+ Monitoring can be done with rtstat utility this comes with iproute2.
+ If unsure, say N.
bool "IP: use netfilter MARK value as routing key"
depends on IP_MULTIPLE_TABLES && NETFILTER
--- net/ipv4/route.c.orig 2003-12-09 13:59:57.000000000 +0100
+++ net/ipv4/route.c 2003-12-09 14:49:48.000000000 +0100
@@ -2747,6 +2747,9 @@
goal = num_physpages >> (26 - PAGE_SHIFT);
+ goal <<= 3;
for (order = 0; (1UL << order) < goal; order++)
/* NOTHING */;