Re: Re: [kvm-devel] [PATCH 1/3] Refactor AIO interface to allow other AIO implementations

Anthony Liguori
2008-04-18T15:23:31Z

Jamie Lokier wrote:
>> I've basically got a choice of making libvirt always ad '-aio linux'
>> or never add it at all. My inclination is to the latter since it is
>> compatible with existing QEMU which has no -aio option. Presumably
>> '-aio linux' is intended to provide some performance benefit so it'd
>> be nice to use it. If we can't express some criteria under which it
>> should be turned on, I can't enable it; where as if you can express
>> some criteria, then QEMU should apply them automatically.
>>
>
> I'm of the view that '-aio auto' would be a really good option - and
> when it's proven itself, it should be the default. It could work on
> all QEMU hosts: it would pick synchronous IO when there is nothing else.
>

Right now, not specifying the -aio option is equivalent to your proposed
-aio auto.

I guess I should include an info aio to let the user know what type of
aio they are using. We can add selection criteria later but
semantically, not specifying an explicit -aio option allows QEMU to
choose whichever one it thinks is best.

Regards,

Anthony Liguori