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Re: [Xen-devel] 100 Hz idle timer on domU?

from [Andrew Theurer]

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To:	Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>
Subject:	Re: [Xen-devel] 100 Hz idle timer on domU?
From:	Andrew Theurer <habanero@xxxxxxxxxx>
Date:	Mon, 23 May 2005 15:29:46 -0500
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On Monday 23 May 2005 15:03, Keir Fraser wrote:
> On 23 May 2005, at 20:07, Andrew Theurer wrote:
> > I just built bk-1.1514 (which oddly enough that version I can't
> > find a reference to on bk-bits anymore, was that changeset backed
> > out?) and I am noticing that domU's cpus are getting timer ticks at
> > 100Hz even when idle.  I know I have observed a "no tick" behavior
> > before.  Was this change intentional?
>
> If it's an SMP domU then it's because we do not do tick holdoff for
> SMP guests. There are unresolved issues with how we interact with the
> RCU mechanisms in Linux 2.6. It is our plan to resolve these and hold
> off ticks for idle SMP guests just as we do for uniproc ones.

OK, saw the changes in time.c and now I understand what's going on, 
thanks.

-Andrew

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