From: Jan Kara <jack@suse.cz>
To: Wu Fengguang <fengguang.wu@intel.com>
Cc: Jan Kara <jack@suse.cz>,
"linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
Christoph Hellwig <hch@infradead.org>,
Dave Chinner <david@fromorbit.com>
Subject: Re: [PATCH 1/2] writeback: Improve busyloop prevention
Date: Wed, 7 Dec 2011 11:13:46 +0100 [thread overview]
Message-ID: <20111207101346.GA4622@quack.suse.cz> (raw)
In-Reply-To: <20111205080243.GA14799@localhost>
Hello Fengguang,
On Mon 05-12-11 16:02:43, Wu Fengguang wrote:
> On Thu, Nov 10, 2011 at 10:50:44PM +0800, Jan Kara wrote:
> > On Wed 09-11-11 00:52:07, Jan Kara wrote:
> > > > wfg@bee /export/writeback% ./compare.rb -v jsize -e io_wkB_s thresh*/*-ioless-full-next-20111102+ thresh*/*-20111102+
> > > > 3.1.0-ioless-full-next-20111102+ 3.1.0-ioless-full-bg-all-next-20111102+
> > > > ------------------------ ------------------------
> > > > 36231.89 -3.8% 34855.10 thresh=1000M/ext3-100dd-4k-8p-4096M-1000M:10-X
> > > > 41115.07 -12.7% 35886.36 thresh=1000M/ext3-10dd-4k-8p-4096M-1000M:10-X
> > > > 48025.75 -14.3% 41146.57 thresh=1000M/ext3-1dd-4k-8p-4096M-1000M:10-X
> > > > 47684.35 -6.4% 44644.30 thresh=1000M/ext4-100dd-4k-8p-4096M-1000M:10-X
> > > > 54015.86 -4.0% 51851.01 thresh=1000M/ext4-10dd-4k-8p-4096M-1000M:10-X
> > > > 55320.03 -2.6% 53867.63 thresh=1000M/ext4-1dd-4k-8p-4096M-1000M:10-X
> > > > 37400.51 +1.6% 38012.57 thresh=100M/ext3-10dd-4k-8p-4096M-100M:10-X
> > > > 45317.31 -4.5% 43272.16 thresh=100M/ext3-1dd-4k-8p-4096M-100M:10-X
> > > > 40552.64 +0.8% 40884.60 thresh=100M/ext3-2dd-4k-8p-4096M-100M:10-X
> > > > 44271.29 -5.6% 41789.76 thresh=100M/ext4-10dd-4k-8p-4096M-100M:10-X
> > > > 54334.22 -3.5% 52435.69 thresh=100M/ext4-1dd-4k-8p-4096M-100M:10-X
> > > > 52563.67 -6.1% 49341.84 thresh=100M/ext4-2dd-4k-8p-4096M-100M:10-X
> > > > 45027.95 -1.0% 44599.37 thresh=10M/ext3-1dd-4k-8p-4096M-10M:10-X
> > > > 42478.40 +0.3% 42608.48 thresh=10M/ext3-2dd-4k-8p-4096M-10M:10-X
> > > > 35178.47 -0.2% 35103.56 thresh=10M/ext4-10dd-4k-8p-4096M-10M:10-X
> > > > 54079.64 -0.5% 53834.85 thresh=10M/ext4-1dd-4k-8p-4096M-10M:10-X
> > > > 49982.11 -0.4% 49803.44 thresh=10M/ext4-2dd-4k-8p-4096M-10M:10-X
> > > > 783579.17 -3.8% 753937.28 TOTAL io_wkB_s
> > > Here I can see some noticeable drops in the realistic thresh=100M case
> > > (case thresh=1000M is unrealistic but it still surprise me that there are
> > > drops as well). I'll try to reproduce your results so that I can look into
> > > this more effectively.
> > So I've run a test on a machine with 1G of memory, thresh=184M (so
> > something similar to your 4G-1G test). I've used tiobench using 10 threads,
> > each thread writing 1.6G file. I have run the test 10 times to get an idea
> > of fluctuations. The result is:
> > without patch with patch
> > AVG STDDEV AVG STDDEV
> > 199.884820 +- 1.32268 200.466003 +- 0.377405
> >
> > The numbers are time-to-completion so lower is better. Summary is: No
> > statistically meaningful difference. I'll run more tests with different
> > dirty thresholds to see whether I won't be able to observe some
> > difference...
>
> I carried out some tests on ext3/ext4 before/after patch. Most tests
> are repeated for 3 times so as to get an idea about the variations.
>
> The ":jsize=8" notion means "-J size=8" in action.
>
> The overall deltas are -0.3% for ext4 and -3.3% for ext3. I noticed
> that the regressions mostly happen for the "-J size=8" cases. For
> normal mkfs, ext4 actually sees +2.5% increase and ext3 sees only
> -0.8% drop.
>
> I don't find any misbehaves in the graphs.
> So in general I think the test results are acceptable.
Thanks for running the tests. I looked through the results and given the
variation I would be happy with them. Will you merge the patch or should I
resend it?
Honza
--
Jan Kara <jack@suse.cz>
SUSE Labs, CR
next prev parent reply other threads:[~2011-12-07 10:13 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-10-12 20:57 [PATCH 0/2 v4] writeback: Improve busyloop prevention and inode requeueing Jan Kara
2011-10-12 20:57 ` [PATCH 1/2] writeback: Improve busyloop prevention Jan Kara
2011-10-13 14:26 ` Wu Fengguang
2011-10-13 20:13 ` Jan Kara
2011-10-14 7:18 ` Christoph Hellwig
2011-10-14 19:31 ` Chris Mason
[not found] ` <20111013143939.GA9691@localhost>
2011-10-13 20:18 ` Jan Kara
2011-10-14 16:00 ` Wu Fengguang
2011-10-14 16:28 ` Wu Fengguang
2011-10-18 0:51 ` Jan Kara
2011-10-18 14:35 ` Wu Fengguang
2011-10-19 11:56 ` Jan Kara
2011-10-19 13:25 ` Wu Fengguang
2011-10-19 13:30 ` Wu Fengguang
2011-10-19 13:35 ` Wu Fengguang
2011-10-20 12:09 ` Wu Fengguang
2011-10-20 12:33 ` Wu Fengguang
2011-10-20 13:39 ` Wu Fengguang
2011-10-20 22:26 ` Jan Kara
2011-10-22 4:20 ` Wu Fengguang
2011-10-24 15:45 ` Jan Kara
[not found] ` <20111027063133.GA10146@localhost>
2011-10-27 20:31 ` Jan Kara
[not found] ` <20111101134231.GA31718@localhost>
2011-11-01 21:53 ` Jan Kara
2011-11-02 17:25 ` Wu Fengguang
[not found] ` <20111102185603.GA4034@localhost>
2011-11-03 1:51 ` Jan Kara
2011-11-03 14:52 ` Wu Fengguang
[not found] ` <20111104152054.GA11577@localhost>
2011-11-08 23:52 ` Jan Kara
2011-11-09 13:51 ` Wu Fengguang
2011-11-10 14:50 ` Jan Kara
2011-12-05 8:02 ` Wu Fengguang
2011-12-07 10:13 ` Jan Kara [this message]
2011-12-07 11:45 ` Wu Fengguang
[not found] ` <20111027064745.GA14017@localhost>
2011-10-27 20:50 ` Jan Kara
2011-10-20 9:46 ` Christoph Hellwig
2011-10-20 15:32 ` Jan Kara
2011-10-15 12:41 ` Wu Fengguang
2011-10-12 20:57 ` [PATCH 2/2] writeback: Replace some redirty_tail() calls with requeue_io() Jan Kara
2011-10-13 14:30 ` Wu Fengguang
2011-10-13 14:15 ` [PATCH 0/2 v4] writeback: Improve busyloop prevention and inode requeueing Wu Fengguang
-- strict thread matches above, loose matches on Subject: below --
2011-09-08 0:44 [PATCH 1/2] writeback: Improve busyloop prevention Jan Kara
2011-09-08 0:57 ` Wu Fengguang
2011-09-08 13:49 ` Jan Kara
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