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Date: Wed, 26 Jul 2006 09:45:36 +0200
From: Jens Axboe <qemu@kernel.dk>
Subject: Re: [Qemu-devel] Re: high CPU load / async IO?
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To: qemu-devel@nongnu.org

On Tue, Jul 25 2006, Fabrice Bellard wrote:
> Jens Axboe wrote:
> >On Tue, Jul 25 2006, Sven K=F6hler wrote:
> >
> >>>>>So the current thread-based async dma patch is really just the
> >>>>>wrong long term solution.  A more long term solution is likely in
> >>>>>the works.  It requires quite a bit of code modification though.
> >>>>
> >>>>I see. So in other words:
> >>>>
> >>>>don't ask for simple async I/O now. The more complex and flexible
> >>>>sollution will follow soon.
> >>>
> >>>Yes, hopefully really soon.
> >>
> >>So i will wait patiently :-)
> >
> >
> >Is anyone actively working on this, or is it just speculation? I'd
> >greatly prefer (and might do, if no one is working on it and Fabrice
> >would take it) do a libaio version, since that'll for sure perform
> >the best on Linux. But a posixaio version might be saner, as that
> >should work on other operating systems as well.
> >
> >Fabrice, can you let people know what you would prefer?
>=20
> I am working on an implementation and the first version will use the
> posix aio and possibly the Windows ReadFile/WriteFile overlapped I/Os.
> Anthony Liguori got a pre version of the code, but it is not
> commitable yet.

Sounds good, so at least it's on its way :-)
It's on of those big items left on the TODO, so will be good to see go
in. Then one should implement an ahci host controller for queued command
support next...

--=20
Jens Axboe