netdev - Re: [PATCH net 1/4] ice: Create a separate kthread to handle ptp extts work

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Message-ID: <Y5EvYXK9V+BSU4pS@hoboy.vegasvil.org>
Date:   Wed, 7 Dec 2022 16:27:13 -0800
From:   Richard Cochran <richardcochran@...il.com>
To:     Tony Nguyen <anthony.l.nguyen@...el.com>
Cc:     davem@...emloft.net, kuba@...nel.org, pabeni@...hat.com,
        edumazet@...gle.com,
        Anatolii Gerasymenko <anatolii.gerasymenko@...el.com>,
        netdev@...r.kernel.org, Gurucharan G <gurucharanx.g@...el.com>
Subject: Re: [PATCH net 1/4] ice: Create a separate kthread to handle ptp
 extts work

On Wed, Dec 07, 2022 at 01:10:37PM -0800, Tony Nguyen wrote:
> From: Anatolii Gerasymenko <anatolii.gerasymenko@...el.com>
> 
> ice_ptp_extts_work() and ice_ptp_periodic_work() are both scheduled on
> the same kthread_worker pf.ptp.kworker. But, ice_ptp_periodic_work()
> sends messages to AQ and waits for responses. This causes
> ice_ptp_extts_work() to be blocked while waiting to be scheduled. This
> causes problems with the reading of the incoming signal timestamps,
> which disrupts a 100 Hz signal.
> 
> Create an additional kthread_worker pf.ptp.kworker_extts to service only
> ice_ptp_extts_work() as soon as possible.

Looks like this driver isn't using the do_aux_work callback.  That
would provide a kthread worker for free.  Why not use that?

Thanks,
Richard