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From: "Michel Dänzer" <michel@daenzer.net>
To: Tejun Heo <tj@kernel.org>
Cc: "Bhaktipriya Shridhar" <bhaktipriya96@gmail.com>,
	"Alex Deucher" <alexander.deucher@amd.com>,
	"Christian König" <christian.koenig@amd.com>,
	dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] drm/radeon: Remove deprecated create_singlethread_workqueue
Date: Thu, 7 Jul 2016 12:32:33 +0900	[thread overview]
Message-ID: <85449fbd-45ba-7eea-8520-d0c19b8af001@daenzer.net> (raw)
In-Reply-To: <20160706134532.GF3262@mtj.duckdns.org>


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On 06.07.2016 22:45, Tejun Heo wrote:
> On Wed, Jul 06, 2016 at 12:12:52PM +0900, Michel Dänzer wrote:
> 
>> Not being very familiar with the workqueue APIs, I'll describe how it's
>> supposed to work from a driver POV, which will hopefully help you guys
>> decide on the most appropriate alloc_workqueue parameters.
>>
>> There is one flip work queue for each hardware CRTC. At most one
>> radeon_flip_work_func item can be queued for any of them at any time.
>> When a radeon_flip_work_func item is queued, it should be executed ASAP
>> (so WQ_HIGHPRI might be appropriate?).
> 
> Hmmm... the only time WQ_HIGHPRI should be used is when it'd otherwise
> require a kthread w/ nice value at -20.  Would that be the case here?
> What are the consequences of the work item getting delayed?

A page flip may be delayed to a later display refresh cycle.


> Also, what kind of delays matter here?  Is it millisec range or micro?

It can be the latter in theory, but normally rather the former.


-- 
Earthling Michel Dänzer               |               http://www.amd.com
Libre software enthusiast             |             Mesa and X developer


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  reply	other threads:[~2016-07-07  4:16 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-07-02 11:03 [PATCH] drm/radeon: Remove deprecated create_singlethread_workqueue Bhaktipriya Shridhar
2016-07-02 13:46 ` Tejun Heo
2016-07-04  3:58   ` Michel Dänzer
2016-07-05 21:06     ` Tejun Heo
2016-07-06  3:12       ` Michel Dänzer
2016-07-06 13:45         ` Tejun Heo
2016-07-07  3:32           ` Michel Dänzer [this message]
2016-07-07  7:43             ` Christian König
2016-07-08  5:52               ` Michel Dänzer
2016-07-12 17:52                 ` Tejun Heo
2016-07-16 11:30                   ` [PATCH v2] " Bhaktipriya Shridhar
2016-07-18 13:21                     ` Christian König
2016-07-19  0:48                     ` Tejun Heo
2016-07-28 16:14                       ` Alex Deucher
  -- strict thread matches above, loose matches on Subject: below --
2016-06-28 17:26 [PATCH] " Bhaktipriya Shridhar
2016-06-28 17:44 ` Bhaktipriya Shridhar

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