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

[Jason Wang]

On 03/15/2016 05:17 PM, address@hidden wrote:
> 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.

I think you need figure out where was the packet dropped first. If the
packet was not dropped by windows guest, you may want to try dropmonitor.

>
> 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(-)
>