RE: [virtio] Re: [virtio-comment] [PATCH requirements 7/7] net-features: Add header data split requirements

[Parav Pandit <parav@nvidia.com>]

> From: David Edmondson <david.edmondson@oracle.com>
> Sent: Monday, August 14, 2023 6:40 PM

> >> > +5. The device should be able to zero pad the header buffer when the
> received
> >> > +   header is shorter than cpu cache line size.
> >>
> >> What's the use case for this (item 5)?
> >
> > Without zero padding, each header write results in a
> > read-modify-write, possibly over PCIe. That can significantly depress
> > throughput.
> 
> Understood. So it could be anything padding, we just want to write a full cache
> line.
Yes. if the data descriptor is partial, need to zero fill too.
I will double check if I covered already or not.

Yet catching up after a break.