OpenCloudOS-Kernel/net/packet
Jason Wang 10a8d94a95 virtio_net: introduce VIRTIO_NET_HDR_F_DATA_VALID
There's no need for the guest to validate the checksum if it have been
validated by host nics. So this patch introduces a new flag -
VIRTIO_NET_HDR_F_DATA_VALID which is used to bypass the checksum
examing in guest. The backend (tap/macvtap) may set this flag when
met skbs with CHECKSUM_UNNECESSARY to save cpu utilization.

No feature negotiation is needed as old driver just ignore this flag.

Iperf shows 12%-30% performance improvement for UDP traffic. For TCP,
when gro is on no difference as it produces skb with partial
checksum. But when gro is disabled, 20% or even higher improvement
could be measured by netperf.

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>
2011-06-11 15:57:47 -07:00
..
Kconfig packet: Kill CONFIG_PACKET_MMAP. 2010-02-05 16:29:48 -08:00
Makefile Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
af_packet.c virtio_net: introduce VIRTIO_NET_HDR_F_DATA_VALID 2011-06-11 15:57:47 -07:00