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Re: [Xen-devel] Poor HVM performance with 8 vcpus

To: Juergen Gross <juergen.gross@xxxxxxxxxxxxxx>
Subject: Re: [Xen-devel] Poor HVM performance with 8 vcpus
From: Gianluca Guida <gianluca.guida@xxxxxxxxxxxxx>
Date: Wed, 14 Oct 2009 12:35:41 +0100
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On Wed, Oct 14, 2009 at 9:16 AM, Juergen Gross
<juergen.gross@xxxxxxxxxxxxxx> wrote:
> Gianluca,
>
> as the performance of BS2000 seems to be hit by OOS optimization, I'm
> thinking of making a patch to disable this feature by a domain parameter.
>
> Is there a way to do this without having to change all places where the
> #if statements are placed?
> I think there should be some central routines where adding an "if" could
> be enough (setting oos_active to 0 seems not to be enough, I fear).

It should be. oos_active set to zero (if you prevent the shadow code
to set it to 1 when we enable paging) will prevent any page to go OOS.
This is exactly what Tim's suggestion was.

Have you tried it?

Thanks,
Gianluca

-- 
It was a type of people I did not know, I found them very strange and
they did not inspire confidence at all. Later I learned that I had been
introduced to electronic engineers.
                                                  E. W. Dijkstra

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