From: "Martin K. Petersen" <martin.petersen@oracle.com>
To: Dave Chinner <david@fromorbit.com>
Cc: "Darrick J. Wong" <djwong@us.ibm.com>,
Andreas Dilger <adilger@dilger.ca>, Jens Axboe <axboe@kernel.dk>,
linux-kernel <linux-kernel@vger.kernel.org>,
"linux-fsdevel\@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
Mingming Cao <mcao@us.ibm.com>,
linux-scsi <linux-scsi@vger.kernel.org>
Subject: Re: [RFC] block integrity: Fix write after checksum calculation problem
Date: Wed, 23 Feb 2011 11:24:50 -0500 [thread overview]
Message-ID: <yq1vd0awwfh.fsf@sermon.lab.mkp.net> (raw)
In-Reply-To: <20110222225351.GG3166@dastard> (Dave Chinner's message of "Wed, 23 Feb 2011 09:53:51 +1100")
>>>>> "Dave" == Dave Chinner <david@fromorbit.com> writes:
>> Agreed. I too am curious to study which circumstances favor copying
>> vs blocking.
Dave> IMO blocking is generally preferable in high throughput threaded
Dave> workloads as there is always another thread that can do useful
Dave> work while we wait for IO to complete. Most use cases for DIF
Dave> center around high throughput environments....
Yeah.
A while back I did a bunch of tests with a liberal amount of
wait_on_page_writeback() calls added to (I think) ext2, ext3, and
XFS. For my regular workloads there was no measurable change (kernel
builds, random database and I/O tests). I'm sure we'll unearth some apps
that will suffer when DI is on but so far I'm not too worried about
blocking in the data path.
My main concern is wrt. metadata because that's where extN really
hurts. Simple test: Unpack a kernel tarball and watch the directory
block fireworks. Given how frequently those buffers get hit I'm sure
blocking would cause performance to tank completely. I looked into
fixing this in ext2 but I had to stop because my eyes were bleeding.
--
Martin K. Petersen Oracle Linux Engineering
next prev parent reply other threads:[~2011-02-23 16:27 UTC|newest]
Thread overview: 67+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-02-22 2:00 Darrick J. Wong
2011-02-22 5:45 ` Boaz Harrosh
2011-02-22 11:42 ` Jan Kara
2011-02-22 13:02 ` Chris Mason
2011-02-22 19:13 ` Boaz Harrosh
2011-03-04 20:51 ` Darrick J. Wong
2011-03-04 20:53 ` Christoph Hellwig
2011-02-22 16:13 ` Andreas Dilger
2011-02-22 16:40 ` Martin K. Petersen
2011-02-22 19:45 ` Darrick J. Wong
2011-02-22 22:53 ` Dave Chinner
2011-02-23 16:24 ` Martin K. Petersen [this message]
2011-02-23 23:47 ` Dave Chinner
2011-02-24 16:43 ` Jan Kara
2011-02-28 8:49 ` Christoph Hellwig
2011-02-22 16:45 ` Martin K. Petersen
2011-02-23 20:24 ` Joel Becker
2011-02-23 20:35 ` Chris Mason
2011-02-23 21:42 ` Joel Becker
2011-02-24 16:47 ` Jan Kara
2011-02-24 17:37 ` Chris Mason
2011-02-24 18:27 ` Darrick J. Wong
2011-02-28 12:54 ` Chris Mason
2011-03-04 21:07 ` Darrick J. Wong
2011-03-04 22:22 ` Andreas Dilger
2011-03-07 19:11 ` Darrick J. Wong
2011-03-07 21:12 ` Chris Mason
2011-03-08 4:56 ` Dave Chinner
2011-03-10 23:57 ` Darrick J. Wong
2011-03-11 16:34 ` Chris Mason
2011-03-11 18:51 ` Darrick J. Wong
2011-03-19 0:07 ` Darrick J. Wong
2011-03-19 2:28 ` Andreas Dilger
2011-03-22 19:23 ` Darrick J. Wong
2011-03-22 21:54 ` Jan Kara
2011-03-21 14:04 ` Jan Kara
2011-03-21 14:24 ` Chris Mason
2011-03-21 16:43 ` Jan Kara
2011-04-06 23:29 ` Darrick J. Wong
2011-04-07 16:44 ` Darrick J. Wong
2011-04-07 16:57 ` Jan Kara
2011-04-08 20:31 ` Darrick J. Wong
2011-04-11 16:42 ` Jeff Layton
2011-04-11 17:41 ` Chris Mason
2011-04-11 18:25 ` Christoph Hellwig
2011-04-11 18:38 ` Chris Mason
2011-04-12 0:46 ` Mingming Cao
2011-04-12 0:57 ` Christoph Hellwig
2011-04-14 0:48 ` Mingming Cao
2011-04-22 0:02 ` [RFC v2] block integrity: Stabilize(?) pages during writeback Darrick J. Wong
2011-04-22 12:50 ` Chris Mason
2011-04-22 20:34 ` Jan Kara
2011-04-26 0:37 ` Darrick J. Wong
2011-04-26 11:33 ` Chris Mason
2011-05-03 1:59 ` Darrick J. Wong
2011-05-04 1:26 ` Darrick J. Wong
2011-04-26 11:37 ` Jan Kara
2011-05-04 17:37 ` [PATCH v3 0/3] data integrity: Stabilize pages during writeback for ext4 Darrick J. Wong
2011-05-04 18:46 ` Christoph Hellwig
2011-05-04 19:21 ` Chris Mason
2011-05-04 20:00 ` Darrick J. Wong
2011-05-04 23:57 ` Darrick J. Wong
2011-05-05 15:26 ` Jan Kara
2011-05-04 17:39 ` [PATCH v3 1/3] ext4: Clean up some wait_on_page_writeback calls Darrick J. Wong
2011-05-04 17:41 ` [PATCH v3 2/3] ext4: Wait for writeback to complete while making pages writable Darrick J. Wong
2011-05-04 17:42 ` [PATCH v3 3/3] mm: Wait for writeback when grabbing pages to begin a write Darrick J. Wong
2011-05-04 18:48 ` Christoph Hellwig
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