From 7bd86cc282a458b66c41e3f6676de6656c99b8db Mon Sep 17 00:00:00 2001 From: "Yan, Zheng" Date: Sun, 12 Aug 2012 20:09:59 +0000 Subject: [PATCH] ipv4: Cache local output routes Commit caacf05e5ad1abf causes big drop of UDP loop back performance. The cause of the regression is that we do not cache the local output routes. Each time we send a datagram from unconnected UDP socket, the kernel allocates a dst_entry and adds it to the rt_uncached_list. It creates lock contention on the rt_uncached_lock. Reported-by: Alex Shi Signed-off-by: Yan, Zheng Signed-off-by: David S. Miller --- net/ipv4/route.c | 1 - 1 file changed, 1 deletion(-) diff --git a/net/ipv4/route.c b/net/ipv4/route.c index e4ba974..fd9ecb5 100644 --- a/net/ipv4/route.c +++ b/net/ipv4/route.c @@ -2028,7 +2028,6 @@ struct rtable *__ip_route_output_key(struct net *net, struct flowi4 *fl4) } dev_out = net->loopback_dev; fl4->flowi4_oif = dev_out->ifindex; - res.fi = NULL; flags |= RTCF_LOCAL; goto make_route; } -- 2.7.4