Re: Utility of PV on non-obsolete hardware

[Manuel Bouyer <bouyer%antioche.eu.org@localhost>]

On Sat, Jun 01, 2019 at 06:12:02PM +0200, Maxime Villard wrote:
> > Unfortunately (for several reasons) I cannot lead this process right now
> > but again, if you take the initiative, I am happy to review and test
> > changes.
> 
> Even then, I don't see any reason to keep XenPV, given that XenPVHVM/XenPVH
> will cover everything. And I don't see any reason to go through the effort of
> splitting everything in order to keep XenPV for ... no other reason than the
> sake of keeping XenPV.

It's also to support older NetBSD or linux releases ...

> 
> Also, I think it is no surprise that our PV implementation is really slow.
> After ten years we still don't have SMP support, there are a lot of gross
> splvm() calls that are hard to justify, there are many hypercalls we don't
> combine, there is a lot of cache false sharing in the structures, and there
> are in short many things that overall betray a glaring lack of any kind of
> optimization in our PV code.

Of course we support SMP in PV. This is not PV which prevents using SMP in
dom0, but the support for dom0 ops (i.e. the Xen management tools)

-- 
Manuel Bouyer <bouyer%antioche.eu.org@localhost>
     NetBSD: 26 ans d'experience feront toujours la difference
--