Re: [Xen-devel] How expensive is a VM EXIT?

To:	NAHieu <nahieu@xxxxxxxxx>
Subject:	Re: [Xen-devel] How expensive is a VM EXIT?
From:	Keir Fraser <keir.fraser@xxxxxxxxxxxxx>
Date:	Wed, 04 Mar 2009 08:45:46 +0000
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On 04/03/2009 00:15, "NAHieu" <nahieu@xxxxxxxxx> wrote:

> On Wed, Mar 4, 2009 at 1:34 AM, Keir Fraser <keir.fraser@xxxxxxxxxxxxx> wrote:
>> For just the VMEXIT itself, it's probably about 1000-1500 cycles on the
>> latest processors. I haven't measured it very recently though.
>> 
> 
> Could you explain how do you measure the cycles for VMEXIT?

RDTSC in the guest immediately before triggering a VMEXIT and RDTSC in the
hypervisor on entry.

 -- Keir



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Re: [Xen-devel] How expensive is a VM EXIT?