From: Tejun Heo <tj@kernel.org>
To: David Howells <dhowells@redhat.com>
Cc: torvalds@linux-foundation.org, mingo@elte.hu,
peterz@infradead.org, awalls@radix.net,
linux-kernel@vger.kernel.org, jeff@garzik.org,
akpm@linux-foundation.org, jens.axboe@oracle.com,
rusty@rustcorp.com.au, cl@linux-foundation.org,
arjan@linux.intel.com, avi@redhat.com, johannes@sipsolutions.net,
andi@firstfloor.org, oleg@redhat.com
Subject: Re: [PATCHSET] workqueue: concurrency managed workqueue, take#4
Date: Sat, 13 Mar 2010 07:55:19 +0900 [thread overview]
Message-ID: <4B9AC657.1090607@kernel.org> (raw)
In-Reply-To: <3491.1268393035@redhat.com>
Hello,
On 03/12/2010 08:23 PM, David Howells wrote:
>> Yes, that's the one of the characteristics of workqueue. For IO bound
>> stuff, it usually is a plus.
>
> Hmmm. So when, say, an FS-Cache index object finishes creating
> itself on disk and then releases all the several thousand data
> objects waiting on that event so that they can then create
> themselves, it will do this by calling queue_work() on each of them
> in turn. I take it this will stack them all up on that one CPU's
> work queue.
Well, you can RR queue them but in general I don't think things like
that would be much of a problem for IO bounded works. If it becomes
bad, scheduler will end up moving the source around and for most
common cases, those group queued works are gonna hit similar code
paths over and over again during their short CPU burn durations so
it's likely to be more efficient. Are you seeing maleffects of cpu
affine work scheduling during fscache load tests?
Thank you for testing.
--
tejun
next prev parent reply other threads:[~2010-03-12 22:54 UTC|newest]
Thread overview: 86+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-02-26 12:22 [PATCHSET] workqueue: concurrency managed workqueue, take#4 Tejun Heo
2010-02-26 12:22 ` [PATCH 01/43] sched: consult online mask instead of active in select_fallback_rq() Tejun Heo
2010-02-26 12:22 ` [PATCH 02/43] sched: rename preempt_notifiers to sched_notifiers and refactor implementation Tejun Heo
2010-02-26 12:22 ` [PATCH 03/43] sched: refactor try_to_wake_up() Tejun Heo
2010-02-26 12:22 ` [PATCH 04/43] sched: implement __set_cpus_allowed() Tejun Heo
2010-02-26 12:22 ` [PATCH 05/43] sched: make sched_notifiers unconditional Tejun Heo
2010-02-26 12:22 ` [PATCH 06/43] sched: add wakeup/sleep sched_notifiers and allow NULL notifier ops Tejun Heo
2010-02-26 12:22 ` [PATCH 07/43] sched: implement try_to_wake_up_local() Tejun Heo
2010-02-28 12:33 ` Oleg Nesterov
2010-03-01 14:22 ` Tejun Heo
2010-02-26 12:22 ` [PATCH 08/43] workqueue: change cancel_work_sync() to clear work->data Tejun Heo
2010-02-26 12:22 ` [PATCH 09/43] acpi: use queue_work_on() instead of binding workqueue worker to cpu0 Tejun Heo
2010-02-26 12:22 ` [PATCH 10/43] stop_machine: reimplement without using workqueue Tejun Heo
2010-02-28 14:11 ` Oleg Nesterov
2010-03-01 15:07 ` Tejun Heo
2010-03-01 15:37 ` Oleg Nesterov
2010-03-01 16:36 ` Tejun Heo
2010-03-01 16:50 ` Oleg Nesterov
2010-03-01 18:02 ` Tejun Heo
2010-02-28 14:34 ` Oleg Nesterov
2010-03-01 15:11 ` Tejun Heo
2010-03-01 15:41 ` Oleg Nesterov
2010-02-26 12:22 ` [PATCH 11/43] workqueue: misc/cosmetic updates Tejun Heo
2010-02-26 12:22 ` [PATCH 12/43] workqueue: merge feature parameters into flags Tejun Heo
2010-02-26 12:22 ` [PATCH 13/43] workqueue: define masks for work flags and conditionalize STATIC flags Tejun Heo
2010-02-26 12:22 ` [PATCH 14/43] workqueue: separate out process_one_work() Tejun Heo
2010-02-26 12:22 ` [PATCH 15/43] workqueue: temporarily disable workqueue tracing Tejun Heo
2010-02-26 12:22 ` [PATCH 16/43] workqueue: kill cpu_populated_map Tejun Heo
2010-02-28 16:00 ` Oleg Nesterov
2010-03-01 15:32 ` Tejun Heo
2010-03-01 15:50 ` Oleg Nesterov
2010-03-01 16:19 ` Tejun Heo
2010-02-26 12:22 ` [PATCH 17/43] workqueue: update cwq alignement Tejun Heo
2010-02-28 17:12 ` Oleg Nesterov
2010-03-01 16:40 ` Tejun Heo
2010-02-26 12:22 ` [PATCH 18/43] workqueue: reimplement workqueue flushing using color coded works Tejun Heo
2010-02-28 20:31 ` Oleg Nesterov
2010-03-01 17:33 ` Tejun Heo
2010-03-01 19:47 ` Oleg Nesterov
2010-02-26 12:22 ` [PATCH 19/43] workqueue: introduce worker Tejun Heo
2010-02-26 12:22 ` [PATCH 20/43] workqueue: reimplement work flushing using linked works Tejun Heo
2010-03-01 14:53 ` Oleg Nesterov
2010-03-01 18:00 ` Tejun Heo
2010-03-01 18:51 ` Oleg Nesterov
2010-02-26 12:22 ` [PATCH 21/43] workqueue: implement per-cwq active work limit Tejun Heo
2010-02-26 12:22 ` [PATCH 22/43] workqueue: reimplement workqueue freeze using max_active Tejun Heo
2010-02-26 12:23 ` [PATCH 23/43] workqueue: introduce global cwq and unify cwq locks Tejun Heo
2010-02-26 12:23 ` [PATCH 24/43] workqueue: implement worker states Tejun Heo
2010-02-26 12:23 ` [PATCH 25/43] workqueue: reimplement CPU hotplugging support using trustee Tejun Heo
2010-02-26 12:23 ` [PATCH 26/43] workqueue: make single thread workqueue shared worker pool friendly Tejun Heo
2010-02-26 12:23 ` [PATCH 27/43] workqueue: add find_worker_executing_work() and track current_cwq Tejun Heo
2010-02-26 12:23 ` [PATCH 28/43] workqueue: carry cpu number in work data once execution starts Tejun Heo
2010-02-28 7:08 ` [PATCH UPDATED " Tejun Heo
2010-02-26 12:23 ` [PATCH 29/43] workqueue: implement WQ_NON_REENTRANT Tejun Heo
2010-02-26 12:23 ` [PATCH 30/43] workqueue: use shared worklist and pool all workers per cpu Tejun Heo
2010-02-26 12:23 ` [PATCH 31/43] workqueue: implement concurrency managed dynamic worker pool Tejun Heo
2010-02-26 12:23 ` [PATCH 32/43] workqueue: increase max_active of keventd and kill current_is_keventd() Tejun Heo
2010-02-26 12:23 ` [PATCH 33/43] workqueue: add system_wq, system_long_wq and system_nrt_wq Tejun Heo
2010-02-26 12:23 ` [PATCH 34/43] workqueue: implement DEBUGFS/workqueue Tejun Heo
2010-02-28 7:13 ` [PATCH UPDATED " Tejun Heo
2010-02-26 12:23 ` [PATCH 35/43] workqueue: implement several utility APIs Tejun Heo
2010-02-28 7:15 ` [PATCH UPDATED " Tejun Heo
2010-02-26 12:23 ` [PATCH 36/43] libata: take advantage of cmwq and remove concurrency limitations Tejun Heo
2010-02-26 12:23 ` [PATCH 37/43] async: use workqueue for worker pool Tejun Heo
2010-02-26 12:23 ` [PATCH 38/43] fscache: convert object to use workqueue instead of slow-work Tejun Heo
2010-02-26 12:23 ` [PATCH 39/43] fscache: convert operation " Tejun Heo
2010-02-26 12:23 ` [PATCH 40/43] fscache: drop references to slow-work Tejun Heo
2010-02-26 12:23 ` [PATCH 41/43] cifs: use workqueue instead of slow-work Tejun Heo
2010-02-28 7:09 ` [PATCH UPDATED " Tejun Heo
2010-02-26 12:23 ` [PATCH 42/43] gfs2: " Tejun Heo
2010-02-28 7:10 ` [PATCH UPDATED " Tejun Heo
2010-02-26 12:23 ` [PATCH 43/43] slow-work: kill it Tejun Heo
2010-02-27 22:52 ` [PATCH] workqueue: Fix build on PowerPC Anton Blanchard
2010-02-28 6:08 ` Tejun Heo
2010-02-28 1:00 ` [PATCH] workqueue: Fix a compile warning in work_busy Anton Blanchard
2010-02-28 6:18 ` Tejun Heo
2010-02-28 1:11 ` [PATCHSET] workqueue: concurrency managed workqueue, take#4 Anton Blanchard
2010-02-28 6:32 ` Tejun Heo
2010-03-10 14:52 ` David Howells
2010-03-12 5:03 ` Tejun Heo
2010-03-12 11:23 ` David Howells
2010-03-12 22:55 ` Tejun Heo [this message]
2010-03-16 14:38 ` David Howells
2010-03-16 16:03 ` Tejun Heo
2010-03-16 17:18 ` David Howells
2010-04-25 8:09 ` [PATCHSET UPDATED] " Tejun Heo
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