linux-kernel - Re: [Xen-devel] Is: axe read_tscp pvops call. Was: Re: [RFC] ACPI S3 and Xen (suprisingly small\!).

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Message-ID: <alpine.DEB.2.02.1210181737390.2689@kaball.uk.xensource.com>
Date:	Thu, 18 Oct 2012 17:44:22 +0100
From:	Stefano Stabellini <stefano.stabellini@...citrix.com>
To:	Borislav Petkov <bp@...en8.de>
CC:	Dan Magenheimer <dan.magenheimer@...cle.com>,
	"H. Peter Anvin" <hpa@...or.com>,
	Konrad Wilk <konrad.wilk@...cle.com>,
	"linux-acpi@...r.kernel.org" <linux-acpi@...r.kernel.org>,
	"x86@...nel.org" <x86@...nel.org>,
	"xen-devel@...ts.xensource.com" <xen-devel@...ts.xensource.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"lenb@...nel.org" <lenb@...nel.org>
Subject: Re: [Xen-devel] Is: axe read_tscp pvops call. Was: Re: [RFC] ACPI
 S3 and Xen (suprisingly small\!).

On Thu, 18 Oct 2012, Borislav Petkov wrote:
> On Thu, Oct 18, 2012 at 08:56:40AM -0700, Dan Magenheimer wrote:
> > I agree the whole idea of paravirtualization is a hack, but it is a
> > hack to workaround some poor architectural design decisions many years
> > ago by Intel processor designers who should have known better. Go yell
> > at them.
> >
> > Worse, the rdtscp instruction was a poor design decision by AMD
> > processor designers to hack around tsc skew problems. Go yell at them
> > too.
> >
> > And both Intel and AMD chose to perpetuate the problem with a
> > complicated VT/SVM implementation that will never perform as well as
> > native. At least they tried ;-)
> 
> Looks like xen people seem to know better so maybe they should design
> their own processor, add xen support for it and leave the linux kernel
> alone so that both camps can finally get on with their lives.

I know that it is obvious but it is worth stating it in clear letters:

these are Dan's personal opinions and by no means represent the position
of the Xen community as a whole on this topic.

I, for one, have no idea what he is talking about.
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