RE: [Xen-devel] [PATCH] x86, cpuidle: remove assertion on X86_FEATURE_TSC_RELIABLE

[Dan Magenheimer <dan.magenheimer@xxxxxxxxxx>]

> From: Tian, Kevin [mailto:kevin.tian@xxxxxxxxx]
> Subject: RE: [Xen-devel] [PATCH] x86, cpuidle: remove assertion on
> X86_FEATURE_TSC_RELIABLE
> 
> > From: Keir Fraser [mailto:keir.xen@xxxxxxxxx]
> >
> > Nevertheless, I feel I'm playing devil's advocate here and batting on
> DanM's
> > side for something I don't consider a major issue. If someone wants
> to clean
> > this up and come up with (possibly different and new) documented and
> > consistently applied semantics for these TSC feature flags, please go
> ahead and
> > propose it. And we'll see who comes out to care and bat against it.
> 
> I'll take a further look to understand it and then may send out a
> cleanup patch later.

Hi Kevin --

Welcome back to xen-devel (after a two-year hiatus?)

I'm not keeping up with xen-devel as frequently as I was in the past,
so please cc me directly if you propose different semantics.

> How about a system without NONSTOP_TSC, but with deep cstate disabled?
> This case we could still deem it as reliable.

IIRC, this is not true on a multi-socket motherboard.  Even though
each socket has NONSTOP_TSC, they are using different crystals, correct?

Thanks,
Dan


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel