To: Cyrus Massoumi <cyrusm@gmx.net>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>, Diego Calleja <diegocg@gmail.com>,
       Stephen Cuppett <cuppett@gmail.com>, linux-kernel@vger.kernel.org,
       mingo@elte.hu, a.p.zijlstra@chello.nl
Subject: Re: Performance versus FreeBSD 7.0
From: Andi Kleen <andi@firstfloor.org>
References: <316a20a40802290538g55c4171y7cdbcb3a9c1d0f1b@mail.gmail.com>
	<20080229155408.116fa5a1.diegocg@gmail.com>
	<200803040004.52299.nickpiggin@yahoo.com.au>
	<47CC4B3F.8060405@gmx.net>
Date: Tue, 04 Mar 2008 00:23:59 +0100
In-Reply-To: <47CC4B3F.8060405@gmx.net> (Cyrus Massoumi's message of "Mon\, 03 Mar 2008 20\:02\:23 +0100")
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Cyrus Massoumi <cyrusm@gmx.net> writes:
>
> IIRC, going to fine-grained file locking gave them a huge boost in
> this particular benchmark (and maybe others).

What locking? You mean their equivalent of i_mutex? There are 
already file systems on Linux that don't use it significantly
for write.

> As I said on lwn.net Peter Zijlstra posted a patch to break the global
> file list lock about a year ago [1], but I don't think it was ever
> merged. Here [2] are some numbers for the patchset.

The file_list_lock is only for open/close which MySQL is very unlikely
to do in its fast path. You're totally on the wrong path here I think.

-Andi
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