[Qemu-devel] Re: [PATCH v3 1/1] Shared memory uio_pci driver

[Avi Kivity]

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.

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error compiling committee.c: too many arguments to function