Re: [PATCH v3 6/8] admin: Add theory of operation for write recording commands

["Michael S. Tsirkin" <mst@redhat.com>]

On Tue, Nov 14, 2023 at 03:34:32PM +0800, Zhu, Lingshan wrote:
> > > So I can't
> > > believe it has good performance overall. Logging via IOMMU or using
> > > shadow virtqueue doesn't need any extra PCI transactions at least.
> > On the other hand they have an extra CPU cost.  Personally if this is
> > coming from a hardware vendor, I am inclined to trust them wrt PCI
> > transactions.  But anyway, discussing this at a high level theoretically
> > is pointless - whoever bothers with actual prototyping for performance
> > testing wins, if no one does I'd expect a back of a napkin estimate
> > to be included.
> if so, Intel has released productions implementing these interfaces years
> ago,
> see live migration in 4.1. IFCVF vDPA Implementation,
> https://doc.dpdk.org/guides-21.11/vdpadevs/ifc.html
> and

That one is based on shadow queue, right? Which I think this shows
is worth supporting.

> But I still believe we are here try our best to work out an industrial spec
> with better quality, to serve broad interest. This is not competition
> between companies,
> and the spec is not a FIFO, not like a early bird can catch all the worm.