Commit 7bd86cc2 authored by Yan, Zheng's avatar Yan, Zheng Committed by David S. Miller
Browse files

ipv4: Cache local output routes 



Commit caacf05e 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: default avatarAlex Shi <alex.shi@intel.com>
Signed-off-by: default avatarYan, Zheng <zheng.z.yan@intel.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent aefe5c00

net/ipv4/route.c

+0 −1
Original line number Diff line number Diff line
@@ -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;

	}