From: Tejun Heo <tj@kernel.org>
To: Heiner Kallweit <hkallweit1@gmail.com>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Jani Nikula <jani.nikula@linux.intel.com>,
Joonas Lahtinen <joonas.lahtinen@linux.intel.com>,
Rodrigo Vivi <rodrigo.vivi@intel.com>,
Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>,
intel-gfx@lists.freedesktop.org
Subject: Re: WQ_UNBOUND warning since recent workqueue refactoring
Date: Wed, 30 Aug 2023 07:51:13 -1000 [thread overview]
Message-ID: <ZO-BkaGuVCgdr3wc@slm.duckdns.org> (raw)
In-Reply-To: <f7e21caa-e98d-e5b5-932a-fe12d27fde9b@gmail.com>
Hello,
(cc'ing i915 folks)
On Wed, Aug 30, 2023 at 04:57:42PM +0200, Heiner Kallweit wrote:
> Recently I started to see the following warning on linux-next and presumably
> this may be related to the refactoring of the workqueue core code.
>
> [ 56.900223] workqueue: output_poll_execute [drm_kms_helper] hogged CPU for >10000us 4 times, consider switching to WQ_UNBOUND
> [ 56.923226] workqueue: i915_hpd_poll_init_work [i915] hogged CPU for >10000us 4 times, consider switching to WQ_UNBOUND
> [ 97.860430] workqueue: output_poll_execute [drm_kms_helper] hogged CPU for >10000us 8 times, consider switching to WQ_UNBOUND
> [ 97.884453] workqueue: i915_hpd_poll_init_work [i915] hogged CPU for >10000us 8 times, consider switching to WQ_UNBOUND
>
> Adding WQ_UNBOUND to these queues didn't change the behavior.
That should have made them go away as the code path isn't active at all for
WQ_UNBOUND workqueues. Can you please double check?
> Maybe relevant: I run the affected system headless.
i915 folks, workqueue recently added debug warnings which trigger when a
per-cpu work item hogs the CPU for too long - 10ms in this case. This is
problematic because such work item can stall other per-cpu work items.
* Is it expected for the above two work functions to occupy the CPU for over
10ms repeatedly?
* If so, can we make them use an unbound workqueue instead?
Thanks.
--
tejun
next prev parent reply other threads:[~2023-08-30 19:30 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-08-30 14:57 WQ_UNBOUND warning since recent workqueue refactoring Heiner Kallweit
2023-08-30 17:51 ` Tejun Heo [this message]
2023-08-30 18:56 ` [Intel-gfx] " Imre Deak
2023-08-30 19:47 ` Heiner Kallweit
2023-08-30 19:54 ` Heiner Kallweit
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