Commit c0317998 authored Apr 10, 2013 by Jason Wang Committed by David S. Miller Apr 11, 2013

tuntap: initialize vlan_features



The vlan_features was zero which prevents vlan GSO packets to be transmitted to
userspace. This is suboptimal so enable this by initialize vlan_features for
tuntap.

Netperf shows better performance of guest receiving since vlan TSO works for
tuntap:

before:
netperf -H 192.168.5.4
MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.5.4 ()
port 0 AF_INET : demo
Recv   Send    Send
Socket Socket  Message  Elapsed
Size   Size    Size     Time     Throughput
bytes  bytes   bytes    secs.    10^6bits/sec

 87380  16384  16384    10.01    2786.67

after:
netperf -H 192.168.5.4
MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.5.4 ()
port 0 AF_INET : demo
Recv   Send    Send
Socket Socket  Message  Elapsed
Size   Size    Size     Time     Throughput
bytes  bytes   bytes    secs.    10^6bits/sec

 87380  16384  16384    10.00    8085.49

Signed-off-by: Jason Wang <jasowang@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 4fda8302

drivers/net/tun.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -1656,6 +1656,7 @@ static int tun_set_iff(struct net net, struct file file, struct ifreq *ifr)
		dev->hw_features = NETIF_F_SG \| NETIF_F_FRAGLIST \|
		TUN_USER_FEATURES;
		dev->features = dev->hw_features;
		dev->vlan_features = dev->features;

		INIT_LIST_HEAD(&tun->disabled);
		err = tun_attach(tun, file);

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