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From: Jens Axboe <axboe@suse.de>
To: "Mudama, Eric" <eric_mudama@Maxtor.com>
Cc: Greg Stark <gsstark@mit.edu>,
	Linux Kernel <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] ide write barrier support
Date: Fri, 17 Oct 2003 08:46:45 +0200	[thread overview]
Message-ID: <20031017064645.GX1128@suse.de> (raw)
In-Reply-To: <785F348679A4D5119A0C009027DE33C105CDB2C5@mcoexc04.mlm.maxtor.com>

On Thu, Oct 16 2003, Mudama, Eric wrote:
> 
> On Tue, Oct 14 2003, Greg Stark wrote:
> > Jens Axboe <axboe@suse.de> writes:
> > > There's also the case of files opened with O_SYNC. Would inserting a
> > > write barrier after every write to such a file destroy performance?
> > 
> > If it's mainly sequential io, then no it won't destroy performance. It
> > will be lower than without the cache flush of course.
> 
> If you flush a cache after every command in a sequential write, yes, you'll
> destroy performance.  How much you destroy it is a function of command size
> relative to track size, and the RPM of the drive.

Yes you are right, my logic was a bit backwards. But you don't have to
issue a flush after every write, thankfully. But lets still not forget
that performance means nothing if integrity isn't guarenteed.

-- 
Jens Axboe


  parent reply	other threads:[~2003-10-17  6:46 UTC|newest]

Thread overview: 39+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2003-10-16 16:51 [PATCH] ide write barrier support Mudama, Eric
2003-10-16 20:43 ` Greg Stark
2003-10-17  6:44   ` Jens Axboe
2003-10-17  6:46 ` Jens Axboe [this message]
     [not found] <IXzh.61g.5@gated-at.bofh.it>
2003-10-21 19:24 ` Anton Ertl
  -- strict thread matches above, loose matches on Subject: below --
2003-10-17 18:42 Mudama, Eric
2003-10-17 17:59 Manfred Spraul
2003-10-17 18:06 ` Jens Axboe
2003-10-21  0:47   ` Matthias Andree
2003-10-17 16:07 Mudama, Eric
2003-10-17 18:08 ` Jens Axboe
2003-10-16 20:51 Mudama, Eric
2003-10-17  6:48 ` Jens Axboe
2003-10-13 14:08 Jens Axboe
2003-10-13 15:23 ` Jeff Garzik
2003-10-13 15:35   ` Jens Axboe
2003-10-13 15:37     ` Jens Axboe
2003-10-13 22:39 ` Matthias Andree
2003-10-14  0:16   ` Jeff Garzik
2003-10-16 10:36     ` Jens Axboe
2003-10-16 10:46       ` Jeff Garzik
2003-10-16 10:48         ` Jens Axboe
2003-10-13 23:07 ` Andrew Morton
2003-10-14  6:48   ` Jens Axboe
2003-10-15  3:40 ` Greg Stark
2003-10-16  7:10   ` Jens Axboe
2003-10-20 17:10 ` Daniel Phillips
2003-10-20 19:56   ` Jens Axboe
2003-10-20 23:46     ` Daniel Phillips
2003-10-21  5:40       ` Jens Axboe
2003-10-23 16:22         ` Daniel Phillips
2003-10-23 16:23           ` Jens Axboe
2003-10-23 17:20             ` Daniel Phillips
2003-10-23 23:21               ` Nick Piggin
2003-10-26 21:06                 ` Daniel Phillips
2003-10-27 10:29                   ` Lars Marowsky-Bree
2003-10-27 21:35                     ` Daniel Phillips
2003-10-24  9:36               ` Helge Hafting
2003-10-26 15:38                 ` Daniel Phillips

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