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Subject: Re: [PATCH 0/4] Page based O_DIRECT v2
From: "Alan D. Brunelle" <Alan.Brunelle@hp.com>
To: Jens Axboe <jens.axboe@oracle.com>
Cc: linux-kernel@vger.kernel.org, zach.brown@oracle.com, hch@infradead.org
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Date: Wed, 19 Aug 2009 18:23:24 -0400
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On Thu, 2009-08-20 at 00:06 +0200, Jens Axboe wrote:

> 
> Thanks a lot for the test run, Alan. I wonder why writes are down while
> reads are up. One possibility could be a WRITE vs WRITE_ODIRECT
> difference, though I think they should be the same. The patches I posted
> have not been benchmarked at all, it's still very much a work in
> progress. I just wanted to show the general direction that I thought
> would be interesting. So I have done absolutely zero performance
> testing, it's only been tested for whether it still worked or not (to
> some degree :-)...
> 
> I'll poke a bit at it here, too. I want to finish the unplug/wait
> problem first. Is your test case using read/write or readv/writev?
> 

Hi Jens - I just had some extra cycles, so figured what the heck... :-)

Actually, this is using asynchronous direct I/Os (libaio/Linux native
AIO). If I get a chance tomorrow, I'll play with read/write (and/or
readv/writev). 

Alan