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From: jim owens <jowens@hp.com>
To: Christian Kujau <lists@nerdbynature.de>
Cc: Larry McVoy <lm@bitmover.com>,
	tytso@mit.edu, jfs-discussion@lists.sourceforge.net,
	linux-nilfs@vger.kernel.org, xfs@oss.sgi.com,
	reiserfs-devel@vger.kernel.org,
	Peter Grandi <pg_jf2@jf2.for.sabi.co.UK>,
	ext-users <ext3-users@redhat.com>,
	linux-ext4@vger.kernel.org, linux-btrfs@vger.kernel.org
Subject: Re: [Jfs-discussion] benchmark results
Date: Sat, 26 Dec 2009 11:00:59 -0500	[thread overview]
Message-ID: <4B36333B.3030600@hp.com> (raw)
In-Reply-To: <alpine.DEB.2.01.0912251042540.3483@bogon.housecafe.de>

Christian Kujau wrote:
 
> I was using "sync" to make sure that the data "should" be on the disks 

Good, but not good enough for many tests... info sync

CONFORMING TO
       POSIX.2

NOTES
       On Linux, sync is only guaranteed to  schedule  the  dirty  blocks  for
       writing;  it  can  actually take a short time before all the blocks are
       finally written.

This is consistent with all the feels-like-unix OSes I have used.

And to make it even more random, the hardware (drive/controller)
write cache state needs to be accounted for, and what the filesystem
does if anything to try to ensure device-cache-to-media consistency.

That does not mean I'm saying the tests are invalid or not useful,
only that people need to evaluate "what do they really tell me".

jim

  reply	other threads:[~2009-12-26 16:01 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-12-24 10:31 benchmark results Christian Kujau
2009-12-24 12:06 ` Ryusuke Konishi
2009-12-24 12:59 ` Teran McKinney
2009-12-24 20:01   ` Christian Kujau
2009-12-24 13:05 ` Peter Grandi
2009-12-24 21:27   ` [Jfs-discussion] " tytso
2009-12-24 23:46     ` Evgeniy Polyakov
2009-12-25 16:11       ` tytso
2010-01-04 16:27         ` Chris Mason
2010-01-04 18:57           ` Michael Rubin
2010-01-05  0:41           ` Dave Chinner
2010-01-05 15:31             ` Steven Pratt
2009-12-25  1:52     ` Christian Kujau
2009-12-25 13:19       ` lakshmi pathi
2009-12-25 16:14       ` tytso
2009-12-25 16:22         ` Larry McVoy
2009-12-25 16:33           ` tytso
2009-12-25 18:51           ` Christian Kujau
2009-12-26 16:00             ` jim owens [this message]
2009-12-26 19:06               ` Christian Kujau
2009-12-27 19:50                 ` jim owens
2009-12-27 21:55                   ` Christian Kujau
2009-12-27 22:33                     ` tytso
2009-12-28  1:24                       ` Christian Kujau
2009-12-28 14:08                       ` Larry McVoy
2010-01-15 21:42                         ` Edward Shishkin
2009-12-26 19:19               ` tytso
     [not found]           ` <20091225163341.GE32757@thunk.org>
2009-12-25 18:56             ` Christian Kujau
2009-12-25 19:32               ` Christian Kujau
2010-01-11  1:03           ` Casey Allen Shobe
2010-01-11  1:32             ` Larry McVoy
2009-12-25 18:42         ` Christian Kujau
2009-12-29 11:27 ` Emmanuel Florac

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