From: Jamie Lokier <jamie@shareable.org>
To: Ric Wheeler <ricwheeler@gmail.com>
Cc: Theodore Tso <tytso@mit.edu>,
Chris Mason <chris.mason@oracle.com>,
Andrew Morton <akpm@linux-foundation.org>,
Eric Sandeen <sandeen@redhat.com>,
linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH 0/4] (RESEND) ext3[34] barrier changes
Date: Tue, 20 May 2008 15:42:34 +0100 [thread overview]
Message-ID: <20080520144233.GA16676@shareable.org> (raw)
In-Reply-To: <4830420D.4080608@gmail.com>
Ric Wheeler wrote:
> I will have to figure out to get this kind of test going without all
> of my big EMC toys ;-)
Fwiw, you can test correctness by running a nested VM-in-VM guest
which simulates disk write cache and flush operations (which flush to
the host kernel). I believe recent QEMU/KVM has this as an option.
Data written by the innermost guest will reside in the middle kernel's
write cache.
Disk cache flush commands from the innermost kernel will cause the
middle kernel to write dirty sectors to the outer kernel. Killing the
outermost host process is roughly equivalent to pulling the plug on a
real machine, but faster and without hurting real hardware.
This might not tell you much about performance, but you should be able
to run a lot of repeatable filesystem barrier tests this way.
-- Jamie
next prev parent reply other threads:[~2008-05-20 14:42 UTC|newest]
Thread overview: 80+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-05-16 19:02 [PATCH 0/4] (RESEND) ext3[34] barrier changes Eric Sandeen
2008-05-16 19:05 ` [PATCH 1/4] ext3: enable barriers by default Eric Sandeen
2008-05-19 8:58 ` Pavel Machek
2008-05-16 19:07 ` [PATCH 2/4] ext3: call blkdev_issue_flush on fsync Eric Sandeen
2008-05-16 22:15 ` Jamie Lokier
2008-05-16 19:08 ` [PATCH 3/4] ext4: enable barriers by default Eric Sandeen
2008-05-16 19:09 ` [PATCH 4/4] ext4: call blkdev_issue_flush on fsync Eric Sandeen
2008-05-20 2:34 ` Theodore Tso
2008-05-20 15:43 ` Jamie Lokier
2008-05-20 15:52 ` Eric Sandeen
2008-05-20 20:14 ` Jens Axboe
2008-05-20 19:54 ` Jens Axboe
2008-05-20 22:02 ` Jamie Lokier
2008-05-21 7:30 ` Jens Axboe
2008-05-16 20:05 ` [PATCH 0/4] (RESEND) ext3[34] barrier changes Andrew Morton
2008-05-16 20:53 ` Eric Sandeen
2008-05-16 20:58 ` Andrew Morton
2008-05-16 21:45 ` Jamie Lokier
2008-05-16 22:03 ` Eric Sandeen
2008-05-16 22:09 ` Jamie Lokier
2008-05-16 22:03 ` Jamie Lokier
2008-05-16 22:21 ` Eric Sandeen
2008-05-16 22:53 ` Jamie Lokier
2008-05-17 0:20 ` Theodore Tso
2008-05-17 0:35 ` Andrew Morton
2008-05-17 13:43 ` Theodore Tso
2008-05-17 17:59 ` Andreas Dilger
2008-05-17 20:44 ` Theodore Tso
2008-05-20 14:45 ` Jamie Lokier
2008-05-18 0:48 ` Chris Mason
2008-05-18 1:36 ` Theodore Tso
2008-05-18 14:49 ` Ric Wheeler
2008-05-20 14:42 ` Jamie Lokier [this message]
2008-05-20 23:48 ` Jamie Lokier
[not found] ` <4830420D.4080608__28835.4277647615$1211137279$gmane$org@gmail.com>
2008-05-18 19:59 ` Andi Kleen
2008-05-18 16:07 ` Ric Wheeler
2008-05-20 23:44 ` Jamie Lokier
2008-05-18 20:03 ` Andi Kleen
2008-05-19 0:43 ` Theodore Tso
2008-05-19 2:29 ` Eric Sandeen
2008-05-19 4:11 ` Andrew Morton
2008-05-19 17:16 ` Chris Mason
2008-05-19 18:39 ` Chris Mason
2008-05-19 22:39 ` Jan Kara
2008-05-20 0:29 ` Chris Mason
2008-05-20 3:29 ` Timothy Shimmin
2008-05-20 12:04 ` Chris Mason
2008-05-20 8:25 ` Jens Axboe
2008-05-20 12:17 ` Chris Mason
2008-05-21 11:22 ` Pavel Machek
2008-05-21 12:32 ` Theodore Tso
2008-05-21 18:03 ` Andrew Morton
2008-05-21 18:15 ` Eric Sandeen
2008-05-21 19:43 ` Jamie Lokier
2008-05-21 18:29 ` Theodore Tso
2008-05-21 18:49 ` Andrew Morton
2008-05-21 19:42 ` Jamie Lokier
2008-05-21 19:36 ` Jamie Lokier
2008-05-21 19:40 ` Chris Mason
2008-05-21 19:54 ` Jamie Lokier
2008-05-20 14:58 ` Jamie Lokier
2008-05-21 22:30 ` Daniel Phillips
2008-05-20 23:35 ` Jamie Lokier
2008-05-19 0:28 ` Theodore Tso
2008-05-20 15:13 ` Jamie Lokier
2008-05-21 20:25 ` Greg Smith
2008-05-16 22:30 ` Jamie Lokier
2008-05-18 19:54 ` Andi Kleen
2008-05-19 13:26 ` Chris Mason
2008-05-19 14:46 ` Theodore Tso
2008-05-20 2:51 ` [PATCH, RFC] ext4: Fix use of write barrier in commit logic Theodore Tso
2008-05-20 15:23 ` Jamie Lokier
2008-05-23 18:33 ` [PATCH 0/4] (RESEND) ext3[34] barrier changes Ric Wheeler
2008-05-20 15:36 ` Jamie Lokier
2008-05-20 16:02 ` Chris Mason
2008-05-20 16:27 ` Jamie Lokier
2008-05-20 17:08 ` Chris Mason
2008-05-20 22:26 ` Jamie Lokier
2008-05-19 9:04 ` Pavel Machek
2008-05-29 13:36 ` Eric Sandeen
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