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Date: Wed, 1 Apr 2009 22:26:00 +0100
From: Matthew Garrett <mjg59@srcf.ucam.org>
To: Ray Lee <ray-lk@madrabbit.org>
Cc: Theodore Tso <tytso@mit.edu>, Sitsofe Wheeler <sitsofe@yahoo.com>,
       "Andreas T.Auer" <andreas.t.auer_lkml_73537@ursus.ath.cx>,
       Alberto Gonzalez <info@gnebu.es>,
       Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: Ext4 and the "30 second window of death"
Message-ID: <20090401212600.GA18301@srcf.ucam.org>
References: <200903311452.05210.info@gnebu.es> <20090331134547.GJ13356@mit.edu> <200904010002.47077.info@gnebu.es> <49D2A5AB.1090704@ursus.ath.cx> <20090401015010.GB4529@mit.edu> <20090401052050.GA20456@sucs.org> <20090401151219.GA12285@srcf.ucam.org> <20090401173521.GA15423@mit.edu> <20090401174336.GA14726@srcf.ucam.org> <2c0942db0904011421w58c0c2dyb70235fb739cbd30@mail.gmail.com>
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On Wed, Apr 01, 2009 at 02:21:43PM -0700, Ray Lee wrote:
> On Wed, Apr 1, 2009 at 10:43 AM, Matthew Garrett <mjg59@srcf.ucam.org> wrote:
> > I've got absolutely no idea why anyone would want fsync() to stop
> > meaning "Put my data on the disk please".
> 
> Some guy named Andrew used to run a kernel with 'return 0' at the top
> of fsync and fdatasync: http://lkml.org/lkml/2007/4/27/88
> 
> It's that the latency penalty of apps using *sync() on common hardware
> sucks. That's all, and finding a way to fix that would make this
> entire thread go away, I think.

And also disk spinups.
-- 
Matthew Garrett | mjg59@srcf.ucam.org
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