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Subject: Re: [PATCH][KVM][retry 3] Add support for Pause Filtering to AMD
 SVM
From: Peter Zijlstra <peterz@infradead.org>
To: Avi Kivity <avi@redhat.com>
Cc: Mark Langsdorf <mark.langsdorf@amd.com>,
       Joerg Roedel <joerg.roedel@amd.com>, kvm@vger.kernel.org,
       linux-kernel@vger.kernel.org
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Date: Wed, 20 May 2009 10:42:34 +0200
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On Wed, 2009-05-20 at 11:38 +0300, Avi Kivity wrote:
> Peter Zijlstra wrote:
> > That said, I still thoroughly dislike this whole approach.
> >   
> 
> Can you explain why?  We have a thread that has detected that it's 
> spinning.  Keeping on spinning is a waste of cpu time.  Why not let 
> something else use the cpu?

Because its a polling interface. I much prefer it if we were to get a
wakeup notification when the vcpu holding the lock releases it.