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From: Tejun Heo <tj@kernel.org>
To: Andi Kleen <andi@firstfloor.org>
Cc: jeff@garzik.org, mingo@elte.hu, linux-kernel@vger.kernel.org,
	akpm@linux-foundation.org, jens.axboe@oracle.com,
	rusty@rustcorp.com.au, cl@linux-foundation.org,
	dhowells@redhat.com, ar@firstfloor.org
Subject: Re: [PATCH 19/19] workqueue: implement concurrency managed workqueue
Date: Fri, 02 Oct 2009 21:09:22 +0900	[thread overview]
Message-ID: <4AC5ED72.7090201@kernel.org> (raw)
In-Reply-To: <87ws3esk1m.fsf@basil.nowhere.org>

Hello, Andi.

Andi Kleen wrote:
> Tejun Heo <tj@kernel.org> writes:
> 
>> Currently each workqueue has its own dedicated worker pool.  This
>> causes the following problems.
> 
> I definitely like the basic idea (without having read all the code so
> far).  Thanks for doing that work. On large systems the number of
> kernel threads around can be mind boggling, and it will also get rid
> of bizarreness like the ps2mouse thread.
> 
> I wonder have you ever thought about exposing this to user space too?
> It can face similar problems for parallelization.

Yeah, some similar mechanism could be useful to manage userland worker
pool too but determining what to export would be the difficult
question.  Events when all of certain groups of threads are blocked
could be useful and cpu idleness is too.

One thing is that for userspace there's already pretty thick layer of
abstraction in place and having this type of bare metal mechanism
might not buy much.  In most cases, monitoring system parameters
periodically and supplying a bit of extra threads should be able to
achieve about the same result.  Do you have anything specific on your
mind?

Thanks.

-- 
tejun

  reply	other threads:[~2009-10-02 12:10 UTC|newest]

Thread overview: 90+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-10-01  8:08 [RFC PATCHSET] workqueue: implement concurrency managed workqueue Tejun Heo
2009-10-01  8:09 ` [PATCH 01/19] freezer: don't get over-anxious while waiting Tejun Heo
2009-10-01 18:36   ` Pavel Machek
2009-10-01 21:04     ` Rafael J. Wysocki
2009-10-02 10:56       ` Tejun Heo
2009-10-02 10:56         ` Tejun Heo
2009-10-02 19:47       ` Oren Laadan
2009-10-02 19:47       ` Oren Laadan
2009-10-02 21:04         ` Matt Helsley
2009-10-02 21:21           ` Rafael J. Wysocki
2009-10-02 21:21           ` Rafael J. Wysocki
2009-10-03  0:43             ` Tejun Heo
2009-10-03  0:43             ` Tejun Heo
2009-10-03 19:36               ` Rafael J. Wysocki
2009-10-03 19:36                 ` Rafael J. Wysocki
2009-10-02 21:04         ` Matt Helsley
2009-10-01 21:04     ` Rafael J. Wysocki
2009-10-01  8:09 ` [PATCH 02/19] scheduler: implement sched_class_equal() Tejun Heo
2009-10-01  8:09 ` [PATCH 03/19] scheduler: implement workqueue scheduler class Tejun Heo
2009-10-01 16:57   ` Linus Torvalds
2009-10-01 18:48     ` Ingo Molnar
2009-10-01 19:00       ` Avi Kivity
2009-10-01 19:11         ` Linus Torvalds
2009-10-01 19:23           ` Ingo Molnar
2009-10-01 20:03             ` Linus Torvalds
2009-10-01 19:15         ` Ingo Molnar
2009-10-01 19:06       ` Linus Torvalds
2009-10-02 12:23     ` Tejun Heo
2009-10-01  8:09 ` [PATCH 04/19] scheduler: implement force_cpus_allowed_ptr() Tejun Heo
2009-10-01  8:09 ` [PATCH 05/19] kthread: implement kthread_data() Tejun Heo
2009-10-01  8:09 ` [PATCH 06/19] acpi: use queue_work_on() instead of binding workqueue worker to cpu0 Tejun Heo
2009-10-01  8:09 ` [PATCH 07/19] stop_machine: reimplement without using workqueue Tejun Heo
2009-10-06  9:36   ` Rusty Russell
2009-10-06 23:42     ` Tejun Heo
2009-10-01  8:09 ` [PATCH 08/19] workqueue: misc/cosmetic updates Tejun Heo
2009-10-01  8:09 ` [PATCH 09/19] workqueue: merge feature parametesr into flags Tejun Heo
2009-10-01  8:09 ` [PATCH 10/19] workqueue: update cwq alignement and make one more flag bit available Tejun Heo
2009-10-01  8:09 ` [PATCH 11/19] workqueue: define both bit position and mask for work flags Tejun Heo
2009-10-01  8:09 ` [PATCH 12/19] workqueue: separate out process_one_work() Tejun Heo
2009-10-01  8:09 ` [PATCH 13/19] workqueue: temporarily disable workqueue tracing Tejun Heo
2009-10-01  8:09 ` [PATCH 14/19] workqueue: (TEMPORARY) kill singlethread variant Tejun Heo
2009-10-01  8:09 ` [PATCH 15/19] workqueue: reimplement workqueue flushing using color coded works Tejun Heo
2009-10-01 17:03   ` Linus Torvalds
2009-10-01 17:11     ` Tejun Heo
2009-10-01 17:16       ` Tejun Heo
2009-10-01  8:09 ` [PATCH 16/19] workqueue: introduce worker Tejun Heo
2009-10-01  8:09 ` [PATCH 17/19] workqueue: reimplement work flushing using linked works Tejun Heo
2009-10-01  8:09 ` [PATCH 18/19] workqueue: reimplement workqueue freeze using cwq->frozen_works queue Tejun Heo
2009-10-01  8:09 ` [PATCH 19/19] workqueue: implement concurrency managed workqueue Tejun Heo
2009-10-01 14:49   ` Andrew Morton
2009-10-01 15:12     ` Ingo Molnar
2009-10-01 16:34     ` Tejun Heo
2009-10-04  8:49     ` Peter Zijlstra
2009-10-01 17:12   ` Linus Torvalds
2009-10-01 17:22     ` Tejun Heo
2009-10-01 17:55       ` Linus Torvalds
2009-10-02  0:42   ` Andi Kleen
2009-10-02 12:09     ` Tejun Heo [this message]
2009-10-03  2:59       ` Andi Kleen
2009-10-02 14:28   ` Frédéric Weisbecker
2009-10-01  8:24 ` [RFC PATCHSET] " Jens Axboe
2009-10-01 16:36   ` Tejun Heo
2009-10-01  8:24 ` Jens Axboe
2009-10-01 16:25   ` Tejun Heo
2009-10-01  8:40 ` Ingo Molnar
2009-10-01  8:47   ` Jens Axboe
2009-10-01  9:01     ` Ingo Molnar
2009-10-01  9:05       ` Jens Axboe
2009-10-01  9:11   ` Avi Kivity
2009-10-01  9:22     ` Avi Kivity
2009-10-01 16:55     ` Tejun Heo
2009-10-01 17:06       ` Avi Kivity
2009-10-01 16:43   ` Tejun Heo
2009-10-01 12:53 ` David Howells
2009-10-02 11:44   ` Tejun Heo
2009-10-02 12:45     ` Stefan Richter
2009-10-02 15:38   ` David Howells
2009-10-03  5:07     ` Tejun Heo
2009-10-01 12:57 ` [PATCH 06/19] acpi: use queue_work_on() instead of binding workqueue worker to cpu0 David Howells
2009-10-01 17:07   ` Tejun Heo
2009-10-01 13:05 ` [PATCH 10/19] workqueue: update cwq alignement and make one more flag bit available David Howells
2009-10-01 16:15   ` Jeff Garzik
2009-10-01 16:20   ` David Howells
2009-10-01 16:30     ` Tejun Heo
2009-10-01 16:39   ` Alan Cox
2009-10-01 18:45   ` Ben Pfaff
2009-10-02 11:56     ` Tejun Heo
2009-10-01 13:15 ` [PATCH 19/19] workqueue: implement concurrency managed workqueue David Howells
2009-10-02 12:03   ` Tejun Heo
2009-10-04  8:41 ` [RFC PATCHSET] " Peter Zijlstra

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