Re: reasons/requirements for some of patches/linux-2.6.16.29/*

["Daniel P. Berrange" <berrange@redhat.com>]

On Fri, Oct 06, 2006 at 08:51:28AM +0100, Jan Beulich wrote:
> >>> Keir Fraser <Keir.Fraser@cl.cam.ac.uk> 06.10.06 09:25 >>>
> >On 6/10/06 8:25 am, "Jan Beulich" <jbeulich@novell.com> wrote:
> >
> >> Could anyone give a description (and reason it is needed for Xen, if that's
> >> not obvious from the description) for each of
> >> 
> >> blktap-aio-16_03_06.patch
> >
> >Not sure. Andrew Warfield or Julian Chesterfield probably will know. I would
> >guess it's probably a backport of AIO changes from a more recent kernel, but
> >I'm not certain about that.
> 
> It's certainly not a backport (i.e. still needed in almost unchanged form in 2.6.18).
> 
> >> net-gso-*.patch
> >
> >Backport of GSO patches from 2.6.17,18,... Done by Herbert Xu as part of his
> >big netfront/back reworking and upgrade. This will mostly go away when we
> >upgrade to 2.6.18.
> 
> I understand that. But what I need is an understanding of why Xen needs this
> right away.

A significant performance increase. Without it, DomU -> Dom0 networking is far 
less than baremetal wirespeed; With it, DomU -> Dom0 networking has parity
with baremetal wirespeed. Herbert's preso at the summit had a few more details

  http://xensource.com/files/summit_3/rdd-tso-xen.pdf

Regards,
Dan
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