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Date: Sun, 20 Apr 2008 16:49:43 +0100
From: Jamie Lokier <jamie@shareable.org>
Subject: Re: [kvm-devel] [Qemu-devel] Re: [PATCH 1/3] Refactor AIO interface
	to allow other AIO implementations
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To: qemu-devel@nongnu.org
Cc: kvm-devel@lists.sourceforge.net, Anthony Liguori <aliguori@us.ibm.com>, Marcelo Tosatti <mtosatti@redhat.com>

Avi Kivity wrote:
> For the majority of deployments posix aio should be sufficient.  The few 
> that need something else can use Linux aio.

Does that mean "for the majority of deployments, the slow version is
sufficient.  The few that care about performance can use Linux AIO?"

I'm under the impression that the entire and only point of Linux AIO
is that it's faster than POSIX AIO on Linux.

> Of course, a managed environment can use Linux aio unconditionally if 
> knows the kernel has all the needed goodies.

Does that mean "a managed environment can have some code which check
the host kernel version + filesystem type holding the VM image, to
conditionally enable Linux AIO?"  (Since if you care about
performance, which is the sole reason for using Linux AIO, you
wouldn't want to enable Linux AIO on any host in your cluster where it
will trash performance.)

Just wondering.

Thanks,
-- Jamie