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


  • To: Keir Fraser <keir.fraser@xxxxxxxxxxxxx>
  • From: NAHieu <nahieu@xxxxxxxxx>
  • Date: Wed, 4 Mar 2009 09:15:02 +0900
  • Cc: "xen-devel@xxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxx>
  • Delivery-date: Tue, 03 Mar 2009 16:15:36 -0800
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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?

Thanks,
H


>  -- Keir
> - Show quoted text -
> On 03/03/2009 15:35, "Emre Can Sezer" <ecsezer@xxxxxxxx> wrote:
>
>> Hi,
>>
>> I've been trying to get a ballpark number on how expensive a VM EXIT is
>> in terms of clock cycles. I'm also interested in how slow a TLB miss is.
>> The only reference I was able to find was 13000 cycles for VM EXIT and
>> around several hundred cycles for a TLB miss and a complete walk of page
>> tables. Does anyone know from the top of their head or is there a
>> reference you can share?
>>
>> Thanks in advance.
>>
>> John
>>
>>
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>> Xen-devel mailing list
>> Xen-devel@xxxxxxxxxxxxxxxxxxx
>> http://lists.xensource.com/xen-devel
>
>
>
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