Re: [libvirt] [PATCH] Support for qemu aio drive option

[adding Matthias on cc]

On 05/17/2010 03:07 PM, Chris Lalancette wrote: > On 05/12/2010 11:26 PM, Eric Blake wrote: >> From: Matthias Dahl <mdvirt(a)designassembly.de&gt; >> >> qemu allows the user to choose what io storage api should be used, either the >> default (threads) or native (linux aio) which in the latter case can result in >> better performance. >> > > The implementation looks perfectly reasonable. I'm just concerned that the > concept of what we are doing is too qemu specific, though. Basically, I think > what we are trying to model here is the concept of an I/O backend implementation, > correct? Should we maybe change this to be "<iobackend type='%s'/>", and then > have available enums like: > > aiothreads > aionative > ... > > That way, for other hypervisors that do something different (like VirtualBox, > which just has AIO on/off), we can have additional enums to describe their > behavior. Even further, if a given hypervisor wanted to do something like > "Direct I/O" for the I/O backend (as an example), we could also use this element > to specify that. What do you think? Indeed, having a more-generic attribute "type", where only a subset of known enum values are appropriate per a given hypervisor, makes sense to me.