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Date: Mon, 03 Dec 2007 15:38:27 -0600
From: Anthony Liguori <anthony@codemonkey.ws>
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Subject: Re: [Qemu-devel] [PATCH 2/2 v2] Direct IDE I/O
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To: qemu-devel@nongnu.org

Gerd Hoffmann wrote:
>   Hi,
>
>   
>> BTW, if everyone thinks it could be a good idea I can port block-raw.c
>> to use linux kernel AIO (without removing POSIX AIO support, of course)
>>     
>
> IMHO it would be a much better idea to kill the aio interface altogether
> and instead make the block drivers reentrant.  Then you can use
> (multiple) posix threads to run the I/O async if you want.
>   

Threads are a poor substitute for a proper AIO interface.  linux-aio 
gives you everything you could possibly want in an interface since it 
allows you to submit multiple vectored operations in a single syscall, 
use an fd to signal request completion, complete multiple requests in a 
single syscall, and inject barriers via fdsync.

Regards,

Anthony Liguori

> cheers,
>   Gerd
>
>
>
>
>
>