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Subject: Re: VM performance issue in KVM guests.
From: Peter Zijlstra <peterz@infradead.org>
To: Avi Kivity <avi@redhat.com>
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Date: Thu, 15 Apr 2010 15:33:18 +0200
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On Thu, 2010-04-15 at 11:18 +0300, Avi Kivity wrote:
> 
> Certainly that has even greater potential for Linux guests.  Note that 
> we spin on mutexes now, so we need to prevent preemption while the lock 
> owner is running. 

either that, or disable spinning on (para) virt kernels. Para virt
kernels could possibly extend the thing by also checking to see if the
owner's vcpu is running.