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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: Keir Fraser <keir.fraser@xxxxxxxxxxxxx>
Date: Wed, 14 Oct 2009 09:35:49 +0100
Cc: Gianluca Guida <Gianluca.Guida@xxxxxxxxxxxxx>, "xen-devel@xxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxx>
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On 14/10/2009 09:16, "Juergen Gross" <juergen.gross@xxxxxxxxxxxxxx> wrote:

> 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).
> 
> Do you have any hint?

How about disabling it for domains with more than four VCPUs? Have you
measured performance with OOS for 1-4 VCPU guests? This is perhaps not
something that needs to be baked into guest configs.

 -- Keir



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