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Date: Thu, 10 Jun 2010 05:59:03 +0300
From: Avi Kivity <avi@redhat.com>
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Subject: [Qemu-devel] Re: [RFC] Moving the kvm ioapic, pic,
	and pit back to userspace
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To: "Dong, Eddie" <eddie.dong@intel.com>
Cc: qemu-devel <qemu-devel@nongnu.org>, KVM list <kvm@vger.kernel.org>

On 06/10/2010 05:37 AM, Dong, Eddie wrote:
> Avi Kivity wrote:
>    
>> On 06/09/2010 06:59 PM, Dong, Eddie wrote:
>>      
>>> Besides VF IO interrupt and timer interrupt introduced performance
>>> overhead risk,
>>>        
>> VF usually uses MSI
>>      
> Typo, I mean PV IO.
>    

That also uses MSI these days.

> A VF interrupt usually happens in 4-8KHZ. How about the virtio?
> I assume virtio will be widely used together w/ leagcy guest with INTx mode.
>    

True, but in time it will be replaced by MSI.

Note without vhost virtio is also in userspace, so there are lots of 
exits anyway for the status register.

-- 
I have a truly marvellous patch that fixes the bug which this
signature is too narrow to contain.