[libvirt] [PATCH] qemu: domain I/O asynchronous handling

[Daniel Veillard]

On Tue, Jun 14, 2011 at 11:14:40AM -0600, Eric Blake wrote:
> On 06/14/2011 11:04 AM, Daniel P. Berrange wrote:
> > On Tue, Jun 14, 2011 at 06:18:17PM +0200, Michal Privoznik wrote:
> >> For virtio disks and interfaces, qemu allows users to enable or disable
> >> ioeventfd feature. This means, qemu can execute domain code, while
> >> another thread waits for I/O event. Basically, in some cases it is win,
> >> in some loss. This feature is available via 'asyncio' attribute in disk
> >> and interface <driver> element. It accepts 'on' and 'off'. Leaving this
> >> attribute out defaults to hypervisor decision.
> > 
> > I think this is rather misleading. AFAIK, ioeventfd has absolutely
> > nothing todo with async I/O.
> > 
> > There is already a completely different QEMU command line flag
> > which toggles between the two QEMU async I/O implementations,
> > which is set via the 'io=' attribute.
> > 
> > So I don't think we can seriously use 'asyncio' for this new
> > feature.
> 
> Hmm, we're at a bit of a conflict here; DV didn't like the name
> 'ioeventfd' as being too hypervisor-specific, and danpb things 'asyncio'
> is not quite the right term.
> 
> The rest of the patch is fine, but we need to settle on the attribute
> name that everyone can live with.

  go for 'ioeventfd' it's very specific but that's normal after all,

Daniel

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