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From: Tejun Heo <tj@kernel.org>
To: Jens Axboe <jaxboe@fusionio.com>
Cc: Christoph Hellwig <hch@lst.de>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCHSET] backing-dev: replace private thread pool with  workqueue
Date: Tue, 07 Sep 2010 14:36:14 +0200	[thread overview]
Message-ID: <4C8631BE.9030709@kernel.org> (raw)
In-Reply-To: <4C86303A.90601@fusionio.com>

Hello,

On 09/07/2010 02:29 PM, Jens Axboe wrote:
> I agree (with both of you). It's definitely too early to convert it
> over, but if we can in the longer run, it never hurts to get rid of
> code. The writeback threads aren't a typical threadpool, in that the
> threads stick around and only go away when idle for too long. If they
> stick around, you get the same process hammering IO at your device. So
> converting that over to the generic cwq may or may not be at a
> performance cost, it'll definitely have to be tested.

One thing to try is removing WQ_UNBOUND and see how it affects the
performance.  I put WQ_UNBOUND there mainly to keep the behavior about
the same as the current code but given what it does I think it would
probably fare better with workers bound to CPUs.

Thanks.

-- 
tejun

  reply	other threads:[~2010-09-07 12:36 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-09-06 12:46 [PATCHSET] backing-dev: replace private thread pool with workqueue Tejun Heo
2010-09-06 12:46 ` [PATCH 1/5] workqueue: implement workqueue_on_rescuer() Tejun Heo
2010-09-06 12:46 ` [PATCH 2/5] backing-dev: kill unused bdi_writeback->nr Tejun Heo
2010-09-08  8:57   ` Artem Bityutskiy
2010-09-06 12:46 ` [PATCH 3/5] backing-dev: replace private thread pool with workqueue Tejun Heo
2010-09-06 12:46 ` [PATCH 4/5] backing-dev: update trace points Tejun Heo
2010-09-06 12:46 ` [PATCH 5/5] backing-dev: replace sync_supers_tsk/timer with a delayed_work Tejun Heo
2010-09-08  9:00   ` Artem Bityutskiy
2010-09-07 12:16 ` [PATCHSET] backing-dev: replace private thread pool with workqueue Christoph Hellwig
2010-09-07 12:19   ` Tejun Heo
2010-09-07 12:29     ` Jens Axboe
2010-09-07 12:36       ` Tejun Heo [this message]
2010-11-27 16:02         ` Tejun Heo
2010-11-27 18:50           ` Jens Axboe
2010-11-27 20:30             ` Tejun Heo

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