summaryrefslogtreecommitdiff
path: root/net/ipv4/ip_gre.c
diff options
context:
space:
mode:
authorEric Dumazet <eric.dumazet@gmail.com>2010-09-27 23:05:47 +0000
committerDavid S. Miller <davem@davemloft.net>2010-09-29 13:25:38 -0700
commitb790e01aee74c23a5d92576177934f13aa51f718 (patch)
treec0868448408c40d2a6f70ae2326556798620d272 /net/ipv4/ip_gre.c
parent8df40d1033d64597dcf1efd4f7547e817f7a953b (diff)
ip_gre: lockless xmit
GRE tunnels can benefit from lockless xmits, using NETIF_F_LLTX Note: If tunnels are created with the "oseq" option, LLTX is not enabled : Even using an atomic_t o_seq, we would increase chance for packets being out of order at receiver. Bench on a 16 cpus machine (dual E5540 cpus), 16 threads sending 10000000 UDP frames via one gre tunnel (size:200 bytes per frame) Before patch : real 3m0.094s user 0m9.365s sys 47m50.103s After patch: real 0m29.756s user 0m11.097s sys 7m33.012s Last problem to solve is the contention on dst : 38660.00 21.4% __ip_route_output_key vmlinux 20786.00 11.5% dst_release vmlinux 14191.00 7.8% __xfrm_lookup vmlinux 12410.00 6.9% ip_finish_output vmlinux 4540.00 2.5% ip_push_pending_frames vmlinux 4427.00 2.4% ip_append_data vmlinux 4265.00 2.4% __alloc_skb vmlinux 4140.00 2.3% __ip_local_out vmlinux 3991.00 2.2% dev_queue_xmit vmlinux Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/ip_gre.c')
-rw-r--r--net/ipv4/ip_gre.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c
index a1b5d5e03064..035db6350037 100644
--- a/net/ipv4/ip_gre.c
+++ b/net/ipv4/ip_gre.c
@@ -1557,6 +1557,10 @@ static int ipgre_newlink(struct net *src_net, struct net_device *dev, struct nla
if (!tb[IFLA_MTU])
dev->mtu = mtu;
+ /* Can use a lockless transmit, unless we generate output sequences */
+ if (!(nt->parms.o_flags & GRE_SEQ))
+ dev->features |= NETIF_F_LLTX;
+
err = register_netdevice(dev);
if (err)
goto out;