Re: [libvirt] [PATCH] qemu: domain I/O asynchronous handling
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.
Regards,
Daniel
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