Re: xen on i7-12700: works with cet-no-ibt !!

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

On Wed, Sep 18, 2024 at 07:53:29AM -0400, Greg Troxel wrote:
> Brad Spencer <brad%anduin.eldar.org@localhost> writes:
> 
> > Greg Troxel <gdt%lexort.com@localhost> writes:
> >
> > [snip]
> >
> >> It looks like the dom0-pv vs bare metal slowdown is still huge, 70.1s
> >> for PV vs 27.6s for bare metal.
> >
> > This may be expected to some extent.  A hit pretty much has to happen
> > and it may be mostly a matter of whether or not it can be tolerated.  I
> > try to run very little on my DOM0 guests, if at all possible.
> 
> Sure, but running at 90% is one thing compared to 39%.
> 
> I had not previously realized how slow PV systems were.
> 
> I'm running benchmarks on a computer with VMX/VT-d/EPT/HAP and which
> thus can run PVH and PVHVM guests, and will post that.  I don't want to
> conclude this seriously, but I am starting to think one can bin into old
> and new, and that
>  
>  PV is 30% ish on very old hardware
>  PV is 40% ish on newish hardware
> 
>  PVH is 66% on new hardware
> 
>  HVM is atrocious on very old hardware
>  (nonpv)HVM is 65% on modern hardware
>  PVHVM is 80% on modern hardware

Why do you think PVHVM is faster than PVH ? I'd expect the opposite actually

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