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

[Wei Xu <wexu@redhat.com>]

----- Original Message -----
From: "Michael S. Tsirkin" <mst@redhat.com>
To: wexu@redhat.com
Cc: victork@redhat.com, jasowang@redhat.com, yvugenfi@redhat.com, qemu-devel@nongnu.org, marcel@redhat.com, dfleytma@redhat.com
Sent: Tuesday, March 15, 2016 6:01:12 PM
Subject: Re: [Qemu-devel] [ Patch 0/2] Support Receive-Segment-Offload(RSC) for WHQL test of Window guest

On Tue, Mar 15, 2016 at 05:17:02PM +0800, wexu@redhat.com wrote:
> From: Wei Xu <wexu@redhat.com>
> 
> 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.

So at this point this is still an RFC, pls label as such
in the subject.
Also, commit log of each patch should also include info on
how to activate a feature.

OK, thanks mst.

thanks!

> 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