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Date: Tue, 4 Oct 2005 00:24:51 -0500
From: Troy Benjegerdes <hozer@hozed.org>
Subject: Re: [Qemu-devel] [patch] non-blocking disk IO
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To: qemu-devel@nongnu.org

> 
> If you anyway plan on having Posix AIO support then go for the Posix AIO 
> interface. The performance reasons why Linux AIO exists is very unlikely 
> to be an issue to qemu as you need to be quite I/O intensive to see any 
> performance difference.

Ideally, we should be able to use a Posix AIO support libary that uses
native Linux AIO underneath.

What we want is to be able to have the guest OS request some DMA
I/O operation, and have qemu be able to use AIO so that the actual disk
hardware can dump the data directly in the pages the userspace process
on the guest OS ends up wanting it in, avoiding several expensive memcopy
and context switch operations.