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Date: Thu, 25 Mar 2010 12:07:41 +0200
From: "Michael S. Tsirkin" <mst@redhat.com>
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Subject: [Qemu-devel] Re: [PATCH v3 1/1] Shared memory uio_pci driver
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To: Avi Kivity <avi@redhat.com>
Cc: Cam Macdonell <cam@cs.ualberta.ca>, qemu-devel@nongnu.org, kvm@vger.kernel.org, virtualization@lists.linux-foundation.org

On Thu, Mar 25, 2010 at 11:58:30AM +0200, Avi Kivity wrote:
> On 03/25/2010 11:44 AM, Michael S. Tsirkin wrote:
>> On Thu, Mar 25, 2010 at 11:40:09AM +0200, Avi Kivity wrote:
>>    
>>> On 03/25/2010 11:15 AM, Michael S. Tsirkin wrote:
>>>      
>>>> - Why are you using 32 bit long memory accesses for interrupts?
>>>>     16 bit IO eould be enough and it's faster. This what virtio-pci does.
>>>>
>>>>
>>>>        
>>> Why is 16 bit io faster?
>>>      
>> Something to do with need for emulation to get address/data
>> for pci memory accesses?
>>    
>
> pio is definitely faster than mmio (all that is needed is to set one bit  
> on the BAR).  But 32 vs. 16 makes no difference.

Right. That's what I meant.

> -- 
> error compiling committee.c: too many arguments to function