Commit 153f0943 authored Sep 28, 2010 by Eric Dumazet Committed by David S. Miller Sep 29, 2010

ipip: enable lockless xmits



IPIP tunnels can benefit from lockless xmits, using NETIF_F_LLTX

Bench on a 16 cpus machine (dual E5540 cpus), 16 threads sending
10000000 UDP frames via one ipip tunnel (size:200 bytes per frame)

Before patch :
real	2m53.321s
user	0m10.277s
sys	46m0.597s

After patch:
real	0m32.063s
user	0m9.237s
sys	8m16.255s

Last problem to solve is the contention on dst :

16118.00 28.3% __ip_route_output_key         vmlinux
 6135.00 10.8% dst_release                   vmlinux
 3220.00  5.6% ip_finish_output              vmlinux
 2149.00  3.8% ip_route_output_flow          vmlinux
 1575.00  2.8% ip_append_data                vmlinux
 1481.00  2.6% ip_push_pending_frames        vmlinux
 1349.00  2.4% __xfrm_lookup                 vmlinux
 1216.00  2.1% csum_partial_copy_generic     vmlinux
 1208.00  2.1% udp_sendmsg                   vmlinux

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent b790e01a

net/ipv4/ipip.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -767,6 +767,7 @@ static void ipip_tunnel_setup(struct net_device *dev)
		dev->iflink = 0;
		dev->addr_len = 4;
		dev->features \|= NETIF_F_NETNS_LOCAL;
		dev->features \|= NETIF_F_LLTX;
		dev->priv_flags &= ~IFF_XMIT_DST_RELEASE;
		}

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