[libvirt] [PATCH v2] qemu: Add option to enable/disable IOEventFD feature
Daniel Veillard
veillard at redhat.com
Wed May 18 08:07:30 UTC 2011
On Tue, May 17, 2011 at 03:56:11PM +0100, Daniel P. Berrange wrote:
> On Tue, May 17, 2011 at 04:49:17PM +0200, Michal Privoznik wrote:
> > This feature allows QEMU to achieve higher throughput, but is available
> > only in recent versions. It is accessible via ioeventfd attribute
> > with accepting values 'on', 'off'. Only experienced users needs to set
> > this, because QEMU defaults to 'on', meaning higher performance.
> > Translates into virtio-{blk|net}-pci.ioeventfd option.
[...]
> > + <li>
> > + The optional <code>ioeventfd</code> attribute enables or disables
> > + IOEventFD feature for virtqueue notify. The value can be either
> > + 'on' or 'off'.
> > + <span class="since">Since 0.9.2 (QEMU and KVM only)</span>
>
> This is a qemu specific attribute name & description. IMHO we shouldn't
> be exposing that directly. Who even knows what effect it actually has
> on the guests...
Agreed, what is the semantic of this flag, beside allowing to switch
something in qemu ?
Daniel
--
Daniel Veillard | libxml Gnome XML XSLT toolkit http://xmlsoft.org/
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