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>,
Dave Chinner <david@fromorbit.com>,
Christoph Hellwig <hch@infradead.org>,
Chris Mason <chris.mason@oracle.com>
Subject: Re: [PATCH 2/2] writeback: Replace some redirty_tail() calls with requeue_io()
Date: Mon, 10 Oct 2011 13:21:33 +0200 [thread overview]
Message-ID: <20111010112133.GA3944@quack.suse.cz> (raw)
In-Reply-To: <20111008040036.GA30069@localhost>
Hi Fengguang,
On Sat 08-10-11 12:00:36, Wu Fengguang wrote:
> The test results look not good: btrfs is heavily impacted and the
> other filesystems are slightly impacted.
>
> I'll send you the detailed logs in private emails (too large for the
> mailing list). Basically I noticed many writeback_wait traces that never
> appear w/o this patch.
OK, thanks for running these tests. I'll have a look at detailed logs.
I guess the difference can be caused by changes in redirty/requeue logic in
the second patch (the changes in the first patch could possibly make
several writeback_wait events from one event but never could introduce new
events).
I guess I'll also try to reproduce the problem since it should be pretty
easy when you see such a huge regression even with 1 dd process on btrfs
filesystem.
> In the btrfs cases that see larger regressions, I see large fluctuations
> in the writeout bandwidth and long disk idle periods. It's still a bit
> puzzling how all these happen..
Yes, I don't understand it yet either...
Honza
>
> 3.1.0-rc8-ioless6+ 3.1.0-rc8-ioless6-requeue+
> ------------------------ ------------------------
> 59.39 -82.9% 10.13 thresh=100M/btrfs-10dd-4k-8p-4096M-100M:10-X
> 58.68 -80.3% 11.54 thresh=100M/btrfs-1dd-4k-8p-4096M-100M:10-X
> 58.92 -80.0% 11.76 thresh=100M/btrfs-2dd-4k-8p-4096M-100M:10-X
> 38.02 -1.0% 37.65 thresh=100M/ext3-10dd-4k-8p-4096M-100M:10-X
> 45.20 +1.7% 45.96 thresh=100M/ext3-1dd-4k-8p-4096M-100M:10-X
> 42.50 -0.8% 42.14 thresh=100M/ext3-2dd-4k-8p-4096M-100M:10-X
> 47.50 -2.5% 46.32 thresh=100M/ext4-10dd-4k-8p-4096M-100M:10-X
> 58.18 -3.0% 56.41 thresh=100M/ext4-1dd-4k-8p-4096M-100M:10-X
> 55.79 -2.1% 54.63 thresh=100M/ext4-2dd-4k-8p-4096M-100M:10-X
> 44.89 -19.3% 36.23 thresh=100M/xfs-10dd-4k-8p-4096M-100M:10-X
> 58.06 -4.2% 55.64 thresh=100M/xfs-1dd-4k-8p-4096M-100M:10-X
> 51.94 -1.1% 51.35 thresh=100M/xfs-2dd-4k-8p-4096M-100M:10-X
> 60.29 -35.9% 38.63 thresh=1G/btrfs-100dd-4k-8p-4096M-1024M:10-X
> 58.80 -33.2% 39.25 thresh=1G/btrfs-10dd-4k-8p-4096M-1024M:10-X
> 58.53 -21.5% 45.93 thresh=1G/btrfs-1dd-4k-8p-4096M-1024M:10-X
> 31.96 -4.7% 30.44 thresh=1G/ext3-100dd-4k-8p-4096M-1024M:10-X
> 36.19 -1.0% 35.82 thresh=1G/ext3-10dd-4k-8p-4096M-1024M:10-X
> 45.03 -2.7% 43.80 thresh=1G/ext3-1dd-4k-8p-4096M-1024M:10-X
> 51.47 -2.6% 50.14 thresh=1G/ext4-100dd-4k-8p-4096M-1024M:10-X
> 56.19 -1.0% 55.64 thresh=1G/ext4-10dd-4k-8p-4096M-1024M:10-X
> 58.41 -1.0% 57.84 thresh=1G/ext4-1dd-4k-8p-4096M-1024M:10-X
> 43.44 -8.4% 39.77 thresh=1G/xfs-100dd-4k-8p-4096M-1024M:10-X
> 49.83 -3.3% 48.18 thresh=1G/xfs-10dd-4k-8p-4096M-1024M:10-X
> 52.70 -0.8% 52.26 thresh=1G/xfs-1dd-4k-8p-4096M-1024M:10-X
> 57.12 -85.5% 8.27 thresh=8M/btrfs-10dd-4k-8p-4096M-8M:10-X
> 59.29 -84.7% 9.05 thresh=8M/btrfs-1dd-4k-8p-4096M-8M:10-X
> 59.23 -84.9% 8.97 thresh=8M/btrfs-2dd-4k-8p-4096M-8M:10-X
> 33.63 -3.3% 32.51 thresh=8M/ext3-10dd-4k-8p-4096M-8M:10-X
> 48.30 -4.7% 46.03 thresh=8M/ext3-1dd-4k-8p-4096M-8M:10-X
> 46.77 -4.5% 44.69 thresh=8M/ext3-2dd-4k-8p-4096M-8M:10-X
> 36.58 -2.2% 35.77 thresh=8M/ext4-10dd-4k-8p-4096M-8M:10-X
> 57.35 -0.3% 57.16 thresh=8M/ext4-1dd-4k-8p-4096M-8M:10-X
> 52.82 -1.5% 52.04 thresh=8M/ext4-2dd-4k-8p-4096M-8M:10-X
> 32.19 -4.5% 30.74 thresh=8M/xfs-10dd-4k-8p-4096M-8M:10-X
> 55.86 -1.4% 55.09 thresh=8M/xfs-1dd-4k-8p-4096M-8M:10-X
> 48.96 -33.1% 32.74 thresh=8M/xfs-2dd-4k-8p-4096M-8M:10-X
> 1810.02 -22.1% 1410.49 TOTAL
>
> Thanks,
> Fengguang
--
Jan Kara <jack@suse.cz>
SUSE Labs, CR
next prev parent reply other threads:[~2011-10-10 11:21 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-09-08 0:44 [PATCH 1/2] writeback: Improve busyloop prevention Jan Kara
2011-09-08 0:44 ` [PATCH 2/2] writeback: Replace some redirty_tail() calls with requeue_io() Jan Kara
2011-09-08 1:22 ` Wu Fengguang
2011-09-08 15:03 ` Jan Kara
2011-09-18 14:07 ` Wu Fengguang
2011-10-05 17:39 ` Jan Kara
2011-10-07 13:43 ` Wu Fengguang
2011-10-07 14:22 ` Jan Kara
2011-10-07 14:29 ` Wu Fengguang
2011-10-07 14:45 ` Jan Kara
2011-10-07 15:29 ` Wu Fengguang
2011-10-08 4:00 ` Wu Fengguang
2011-10-08 11:52 ` Wu Fengguang
2011-10-08 13:49 ` Wu Fengguang
2011-10-09 0:27 ` Wu Fengguang
2011-10-09 8:44 ` Wu Fengguang
2011-10-10 11:21 ` Jan Kara [this message]
2011-10-10 11:31 ` Wu Fengguang
2011-10-10 23:30 ` Jan Kara
2011-10-11 2:36 ` Wu Fengguang
2011-10-11 21:53 ` Jan Kara
2011-10-12 2:44 ` Wu Fengguang
2011-10-12 19:34 ` Jan Kara
2011-09-08 0:57 ` [PATCH 1/2] writeback: Improve busyloop prevention Wu Fengguang
2011-09-08 13:49 ` Jan Kara
-- strict thread matches above, loose matches on Subject: below --
2011-10-05 17:58 [PATCH 0/2] Avoid putting of writeback of inodes for too long (v3) Jan Kara
2011-10-05 17:58 ` [PATCH 2/2] writeback: Replace some redirty_tail() calls with requeue_io() Jan Kara
2011-10-12 20:57 [PATCH 0/2 v4] writeback: Improve busyloop prevention and inode requeueing Jan Kara
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
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