Re: [PATCH v3 04/25] clocksource: Add Owl timer

From	Thomas Gleixner <tglx@linutronix.de>
Newsgroups	linux.kernel
Subject	Re: [PATCH v3 04/25] clocksource: Add Owl timer
Date	2017-02-28 21:40 +0100
Message-ID	<tfWIV-Ym-5@gated-at.bofh.it> (permalink)
References	(1 earlier) <tfJVp-Kr-31@gated-at.bofh.it> <tfTrI-7ry-19@gated-at.bofh.it> <tfTrI-7ry-17@gated-at.bofh.it> <tfU4p-7JC-11@gated-at.bofh.it> <tfUxr-897-3@gated-at.bofh.it>
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On Tue, 28 Feb 2017, Andreas Färber wrote:
> This is a callback, which I thought is re-entrant.

It's not reentrant at least not on the same CPU. On a SMP machine this
function might be called concurrently on several cores (assumed that the
whole thing is replicated across cores).

> VAL changes when the timer is running, and CTL changes every time we
> enable the timer. We could call _reset() here, but then we would be
> initializing CMP twice, which again would be less performant then just
> setting the registers to their final values directly.

Makes sense.

Thanks,

	tglx

Thread

[PATCH v3 04/25] clocksource: Add Owl timer Andreas Färber <afaerber@suse.de> - 2017-02-28 08:00 +0100
  Re: [PATCH v3 04/25] clocksource: Add Owl timer Andreas Färber <afaerber@suse.de> - 2017-02-28 18:10 +0100
    Re: [PATCH v3 04/25] clocksource: Add Owl timer Daniel Lezcano <daniel.lezcano@linaro.org> - 2017-02-28 18:50 +0100
      Re: [PATCH v3 04/25] clocksource: Add Owl timer Andreas Färber <afaerber@suse.de> - 2017-02-28 19:20 +0100
        Re: [PATCH v3 04/25] clocksource: Add Owl timer Thomas Gleixner <tglx@linutronix.de> - 2017-02-28 21:40 +0100
      Re: [PATCH v3 04/25] clocksource: Add Owl timer Thomas Gleixner <tglx@linutronix.de> - 2017-02-28 20:40 +0100
  Re: [PATCH v3 04/25] clocksource: Add Owl timer Daniel Lezcano <daniel.lezcano@linaro.org> - 2017-02-28 20:00 +0100

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