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| author | Eric Dumazet <eric.dumazet@gmail.com> | 2010-09-27 23:05:47 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2010-09-29 13:25:38 -0700 |
| commit | b790e01aee74c23a5d92576177934f13aa51f718 (patch) | |
| tree | c0868448408c40d2a6f70ae2326556798620d272 /net | |
| parent | 8df40d1033d64597dcf1efd4f7547e817f7a953b (diff) | |
| download | blackbird-op-linux-b790e01aee74c23a5d92576177934f13aa51f718.tar.gz blackbird-op-linux-b790e01aee74c23a5d92576177934f13aa51f718.zip | |
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')
| -rw-r--r-- | net/ipv4/ip_gre.c | 4 |
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; |
