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From: Daniel Phillips <phillips@arcor.de>
To: "Martin J. Bligh" <mbligh@aracnet.com>, Oliver Neukum <oliver@neukum.name>,
       Andrew Morton <akpm@digeo.com>, Rob Landley <landley@trommello.org>
Subject: Re: The reason to call it 3.0 is the desktop (was Re: [OT] 2.6 not 3.0 - (NUMA))
Date: Mon, 7 Oct 2002 19:43:17 +0200
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On Sunday 06 October 2002 17:19, Martin J. Bligh wrote:
> > Then there's the issue of application startup. There's not enough
> > read ahead. This is especially sad, as the order of page faults is 
> > at least partially predictable.
> 
> Is the problem really, fundamentally a lack of readahead in the
> kernel? Or is it that your application is huge bloated pig? 

Readahead isn't the only problem, but it is a huge problem.  The current 
readahead model is per-inode, which is very little help with lots of small 
files, especially if they are fragmented or out of order.  There are various 
ways to fix this; they are all difficult[1].  Fortunately, we can call this 
"tuning work" so it can be done during the stable series.

[1] We could teach each filesystem how to read ahead across directories, or 
we could teach the vfs how to do physical readahead.  Choose your poison.

-- 
Daniel
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