Date: Fri, 26 May 2006 09:25:44 -0700
From: Andrew Morton <akpm@osdl.org>
To: Andi Kleen <ak@suse.de>
Cc: linux-kernel@vger.kernel.org, wfg@mail.ustc.edu.cn, mstone@mathom.us
Subject: Re: [PATCH 00/33] Adaptive read-ahead V12
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References: <348469535.17438@ustc.edu.cn>
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Andi Kleen <ak@suse.de> wrote:
>
> Andrew Morton <akpm@osdl.org> writes:
> > 
> > These are nice-looking numbers, but one wonders.  If optimising readahead
> > makes this much difference to postgresql performance then postgresql should
> > be doing the readahead itself, rather than relying upon the kernel's
> > ability to guess what the application will be doing in the future.  Because
> > surely the database can do a better job of that than the kernel.
> 
> With that argument we should remove all readahead from the kernel? 
> Because it's already trying to guess what the application will do. 
> 
> I suspect it's better to have good readahead code in the kernel
> than in a zillion application.
> 

Wu: "this readahead patch speeds up postgres"

Me: "but postgres could be sped up even more via X"

everyone: "ah, you're saying that's a reason for not altering readahead!".


Would everyone *please* stop being so completely and utterly thick?

Thank you.
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