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: Thu, 13 Oct 2011 22:18:35 +0200 [thread overview]
Message-ID: <20111013201835.GD27363@quack.suse.cz> (raw)
In-Reply-To: <20111013143939.GA9691@localhost>
On Thu 13-10-11 22:39:39, Wu Fengguang wrote:
> > > + long pause = 1;
> > > + long max_pause = dirty_writeback_interval ?
> > > + msecs_to_jiffies(dirty_writeback_interval * 10) :
> > > + HZ;
> >
> > It's better not to put the flusher to sleeps more than 10ms, so that
> > when the condition changes, we don't risk making the storage idle for
> > too long time.
>
> Yeah, the one big regression case
>
> 3.1.0-rc8-ioless6a+ 3.1.0-rc8-ioless6-requeue6+
> ------------------------ ------------------------
> 47.07 -15.5% 39.78 thresh=1M/xfs-2dd-4k-8p-4096M-1M:10-X
>
> is exactly caused by the large sleep: the attached graphs are showing
> one period of no-progress on the number of written pages.
Thanks for the tests! Interesting. Do you have trace file from that run?
I see the writeback stalled for 20s or so which is more than
dirty_writeback_centisecs so I think something more complicated must have
happened.
Honza
--
Jan Kara <jack@suse.cz>
SUSE Labs, CR
next prev parent reply other threads:[~2011-10-13 20:18 UTC|newest]
Thread overview: 43+ 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 [this message]
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
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 --
2011-10-05 17:58 [PATCH 0/2] Avoid putting of writeback of inodes for too long (v3) Jan Kara
2011-10-05 17:58 ` [PATCH 1/2] writeback: Improve busyloop prevention Jan Kara
2011-09-08 0:44 Jan Kara
2011-09-08 0:57 ` Wu Fengguang
2011-09-08 13:49 ` Jan Kara
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