From: Matthew Wilcox <matthew@wil.cx>
To: Szabolcs Szakacsits <szaka@ntfs-3g.org>,
Andrew Morton <akpm@linux-foundation.org>,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
xfs@oss.sgi.com
Subject: Re: XFS vs Elevators (was Re: [PATCH RFC] nilfs2: continuous snapshotting file system)
Date: Thu, 21 Aug 2008 05:53:10 -0600 [thread overview]
Message-ID: <20080821115310.GP8318@parisc-linux.org> (raw)
In-Reply-To: <20080821060418.GC5706@disturbed>
On Thu, Aug 21, 2008 at 04:04:18PM +1000, Dave Chinner wrote:
> One thing I just found out - my old *laptop* is 4-5x faster than the
> 10krpm scsi disk behind an old cciss raid controller. I'm wondering
> if the long delays in dispatch is caused by an interaction with CTQ
> but I can't change it on the cciss raid controllers. Are you using
> ctq/ncq on your machine? If so, can you reduce the depth to
> something less than 4 and see what difference that makes?
I don't think that's going to make a difference when using CFQ. I did
some tests that showed that CFQ would never issue more than one IO at a
time to a drive. This was using sixteen userspace threads, each doing a
4k direct I/O to the same location. When using noop, I would get 70k
IOPS and when using CFQ I'd get around 40k IOPS.
--
Matthew Wilcox Intel Open Source Technology Centre
"Bill, look, we understand that you're interested in selling us this
operating system, but compare it to ours. We can't possibly take such
a retrograde step."
next prev parent reply other threads:[~2008-08-21 11:52 UTC|newest]
Thread overview: 70+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-08-20 2:45 [PATCH RFC] nilfs2: continuous snapshotting file system Ryusuke Konishi
2008-08-20 7:43 ` Andrew Morton
2008-08-20 8:22 ` Pekka Enberg
2008-08-20 18:47 ` Ryusuke Konishi
2008-08-20 16:13 ` Ryusuke Konishi
2008-08-20 21:25 ` Szabolcs Szakacsits
2008-08-20 21:39 ` Andrew Morton
2008-08-20 21:48 ` Szabolcs Szakacsits
2008-08-21 2:12 ` Dave Chinner
2008-08-21 2:46 ` Szabolcs Szakacsits
2008-08-21 5:15 ` XFS vs Elevators (was Re: [PATCH RFC] nilfs2: continuous snapshotting file system) Dave Chinner
2008-08-21 6:00 ` gus3
2008-08-21 6:14 ` Dave Chinner
2008-08-21 7:00 ` Nick Piggin
2008-08-21 8:53 ` Dave Chinner
2008-08-21 9:33 ` Nick Piggin
2008-08-21 17:08 ` Dave Chinner
2008-08-21 17:08 ` Dave Chinner
2008-08-22 2:29 ` Nick Piggin
2008-08-22 2:29 ` Nick Piggin
2008-08-25 1:59 ` Dave Chinner
2008-08-25 4:32 ` Nick Piggin
2008-08-25 12:01 ` Jamie Lokier
2008-08-25 12:01 ` Jamie Lokier
2008-08-26 3:07 ` Dave Chinner
2008-08-26 3:50 ` david
2008-08-27 1:20 ` Dave Chinner
2008-08-27 21:54 ` david
2008-08-28 1:08 ` Dave Chinner
2008-08-21 14:52 ` Chris Mason
2008-08-21 14:52 ` Chris Mason
2008-08-21 6:04 ` Dave Chinner
2008-08-21 8:07 ` Aaron Carroll
2008-08-21 8:25 ` Dave Chinner
2008-08-21 11:02 ` Martin Steigerwald
2008-08-21 15:00 ` Martin Steigerwald
2008-08-21 15:00 ` Martin Steigerwald
2008-08-21 17:10 ` Szabolcs Szakacsits
2008-08-21 17:33 ` Szabolcs Szakacsits
2008-08-22 2:24 ` Dave Chinner
2008-08-22 6:49 ` Martin Steigerwald
2008-08-22 6:49 ` Martin Steigerwald
2008-08-22 12:44 ` Szabolcs Szakacsits
2008-08-23 12:52 ` Szabolcs Szakacsits
2008-08-21 11:53 ` Matthew Wilcox [this message]
2008-08-21 15:56 ` Dave Chinner
2008-08-21 12:51 ` [PATCH RFC] nilfs2: continuous snapshotting file system Chris Mason
2008-08-26 10:16 ` Jörn Engel
2008-08-26 16:54 ` Ryusuke Konishi
2008-08-27 18:13 ` Jörn Engel
2008-08-27 18:13 ` Jörn Engel
2008-08-27 18:19 ` Jörn Engel
2008-08-27 18:19 ` Jörn Engel
2008-08-29 6:29 ` Ryusuke Konishi
2008-08-29 8:40 ` Arnd Bergmann
2008-08-29 10:51 ` konishi.ryusuke
2008-08-29 11:04 ` Jörn Engel
2008-08-29 10:45 ` Jörn Engel
2008-08-29 10:45 ` Jörn Engel
2008-08-29 16:37 ` Ryusuke Konishi
2008-08-29 16:37 ` Ryusuke Konishi
2008-08-29 19:16 ` Jörn Engel
2008-08-29 19:16 ` Jörn Engel
2008-09-01 12:25 ` Ryusuke Konishi
2008-09-01 12:25 ` Ryusuke Konishi
2008-08-20 9:47 ` Andi Kleen
2008-08-21 4:57 ` Ryusuke Konishi
-- strict thread matches above, loose matches on Subject: below --
2008-08-21 11:05 XFS vs Elevators (was Re: [PATCH RFC] nilfs2: continuous snapshotting file system) Martin Knoblauch
2008-08-21 11:05 ` Martin Knoblauch
2008-08-21 15:59 ` Dave Chinner
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