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

[Wei Xu]

On 2016年03月18日 13:21, Jason Wang wrote:
> On 03/18/2016 12:24 PM, Wei Xu wrote:
> > On 2016年03月18日 10:22, Jason Wang wrote:
> > > On 03/18/2016 12:57 AM, Wei Xu wrote:
> > > > On 2016年03月17日 23:44, Michael S. Tsirkin wrote:
> > > > > On Thu, Mar 17, 2016 at 11:21:28PM +0800, Wei Xu wrote:
> > > > > > On 2016年03月17日 14:47, Jason Wang wrote:
> > > > > > > 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.
> > > > > > Yes, there is something wrong with my previous description, i add
> > > > > > some debug
> > > > > > code and did new test, the packets are received by
> > > > > > virtio_net_receive() and
> > > > > > are finished putting to the vring with no error and sent to win guest
> > > > > > already, but wireshark on win guest doesn't get it, because the test
> > > > > > case
> > > > > > did some hacking on the filter, it installed another lightweight
> > > > > > filter, i'm
> > > > > > not sure how these packets go in the guest, maybe they are
> > > > > > received but
> > > > > > dropped by driver or stack, etc.
> > > > > Add some debug output in the driver, rebuild it and see packets
> > > > > as they are received and passed up the stack.
> > > > Yes, but this is to win guest, i tried to build a windows debug binary
> > > > but failed, is there any possible missing path in virtio between
> > > > pushed it to vring and notified the guest successfully? i'm sure at
> > > > this by debugging it with gdb.
> > > Is the packet always dropped or does it help if you turn off some
> > > configuration (e.g checksum offloads) works?
> > Yes, only the test packets are dropped, there is no checksum for ipv6
> > header,
> > i remembered i disabled checksum offloads and changed other features(RSS)
> > in the guest but it doesn't help, is there any other tunable values
> > for qemu?
> -device virtio-net-pci,? can gives you all the properties.
ok, thanks a lot.