[Qemu-devel] [ Patch 0/2] Support Receive-Segment-Offload(RSC) for WHQL test of Window guest

[wexu]

From: Wei Xu <address@hidden>

Fixed issues based on rfc patch v2:
1. Removed big param list, replace it with 'NetRscUnit' 
2. Different virtio header size
3. Modify callback function to direct call.
4. Needn't check the failure of g_malloc()
5. Other code format adjustment, macro naming, etc 

This patch is to support WHQL test for Windows guest, while this feature also
benifits other guest works as a kernel 'gro' like feature with userspace 
implementation.
Feature information:
  http://msdn.microsoft.com/en-us/library/windows/hardware/jj853324

Both IPv4 and IPv6 are supported, though performance with userspace virtio
is slow than vhost-net, there is about 1x to 3x performance improvement to
userspace virtio, this is done by turning this feature on and disable
'tso/gso/gro' on corresponding tap interface and guest interface, while get
less improment with all these feature on.

Test steps:
Although this feature is mainly used for window guest, i used linux guest to 
help test
the feature, to make things simple, i used 3 steps to test the patch as i moved 
on.
1. With a tcp socket client/server pair running on 2 linux guest, thus i can 
control
the traffic and debugging the code as i want.
2. Netperf on linux guest test the throughput.
3. WHQL test with 2 Windows guests.

Current status:
IPv4 pass all the above tests.
IPv6 just passed test step 1 and 2 as described ahead, the virtio nic cannot
receive any packet in WHQL test, looks like the test traffic is not sent from
on the support machine, test device can access both host and another linux
guest, tried a lot of ways to work it out but failed, maybe debug from windows
guest driver side can help figuring it out.

Note:
A 'MessageDevice' nic chose as 'Realtek' will panic the system sometimes during 
setup,
this can be figured out by replacing it with an 'e1000' nic.

Todo:
More sanity check and tcp 'ecn' and 'window' scale test.

Wei Xu (2):
  virtio-net rsc: support coalescing ipv4 tcp traffic
  virtio-net rsc: support coalescing ipv6 tcp traffic

 hw/net/virtio-net.c            | 602 ++++++++++++++++++++++++++++++++++++++++-
 include/hw/virtio/virtio-net.h |   1 +
 include/hw/virtio/virtio.h     |  75 +++++
 3 files changed, 677 insertions(+), 1 deletion(-)

-- 
2.5.0