sit: enable lockless xmits
authorEric Dumazet <eric.dumazet@gmail.com>
Tue, 28 Sep 2010 02:53:41 +0000 (02:53 +0000)
committerDavid S. Miller <davem@davemloft.net>
Wed, 29 Sep 2010 20:25:37 +0000 (13:25 -0700)
SIT 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 sit tunnel (size:220 bytes per frame)

Before patch :

real 3m15.399s
user 0m9.185s
sys 51m55.403s

75029.00 87.5% _raw_spin_lock            vmlinux
 1090.00  1.3% dst_release               vmlinux
  902.00  1.1% dev_queue_xmit            vmlinux
  627.00  0.7% sock_wfree                vmlinux
  613.00  0.7% ip6_push_pending_frames   ipv6.ko
  505.00  0.6% __ip_route_output_key     vmlinux

After patch:

real 1m1.387s
user 0m12.489s
sys 15m58.868s

28239.00 23.3% dst_release               vmlinux
13570.00 11.2% ip6_push_pending_frames   ipv6.ko
13118.00 10.8% ip6_append_data           ipv6.ko
 7995.00  6.6% __ip_route_output_key     vmlinux
 7924.00  6.5% sk_dst_check              vmlinux
 5015.00  4.1% udpv6_sendmsg             ipv6.ko
 3594.00  3.0% sock_alloc_send_pskb      vmlinux
 3135.00  2.6% sock_wfree                vmlinux
 3055.00  2.5% ip6_sk_dst_lookup         ipv6.ko
 2473.00  2.0% ip_finish_output          vmlinux

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
net/ipv6/sit.c

index 2cb6460..d770178 100644 (file)
@@ -1140,6 +1140,7 @@ static void ipip6_tunnel_setup(struct net_device *dev)
        dev->iflink             = 0;
        dev->addr_len           = 4;
        dev->features           |= NETIF_F_NETNS_LOCAL;
+       dev->features           |= NETIF_F_LLTX;
 }
 
 static int ipip6_tunnel_init(struct net_device *dev)