From: sylvain.rochet@finsecur.com (Sylvain Rochet)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2] clocksource: atmel-pit: register as a sched_clock
Date: Wed, 24 Feb 2016 17:20:46 +0100 [thread overview]
Message-ID: <20160224162046.GA28743@finsecur.com> (raw)
In-Reply-To: <1456329882-20709-1-git-send-email-romain.izard.pro@gmail.com>
Hi,
On Wed, Feb 24, 2016 at 05:04:42PM +0100, Romain Izard wrote:
> Register the counter of the Periodic Interval Timer as a possible source
> for sched_clock. Keep the timer running even if the related clockevent
> is disabled.
>
> This provides a better precision than the jiffies-based default. The
> TCB clocksource does not work, as it is registered too late in the
> initialization sequence.
I have mixed feelings about that, but this is probably just a
misunderstanding from my part.
The PIT timer should not be used for systems with PM_SUSPEND enabled and
used because it takes ages to synchronize on resume, how does this patch
affect that ?
Ref: commit ac34ad27fc ("clockevents: Do not suspend/resume if unused")
Sylvain
WARNING: multiple messages have this Message-ID (diff)
From: Sylvain Rochet <sylvain.rochet@finsecur.com>
To: Romain Izard <romain.izard.pro@gmail.com>
Cc: linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
Boris Brezillon <boris.brezillon@free-electrons.com>,
Daniel Lezcano <daniel.lezcano@linaro.org>,
Nicolas Ferre <nicolas.ferre@atmel.com>,
Alexandre Belloni <alexandre.belloni@free-electrons.com>,
Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH v2] clocksource: atmel-pit: register as a sched_clock
Date: Wed, 24 Feb 2016 17:20:46 +0100 [thread overview]
Message-ID: <20160224162046.GA28743@finsecur.com> (raw)
In-Reply-To: <1456329882-20709-1-git-send-email-romain.izard.pro@gmail.com>
Hi,
On Wed, Feb 24, 2016 at 05:04:42PM +0100, Romain Izard wrote:
> Register the counter of the Periodic Interval Timer as a possible source
> for sched_clock. Keep the timer running even if the related clockevent
> is disabled.
>
> This provides a better precision than the jiffies-based default. The
> TCB clocksource does not work, as it is registered too late in the
> initialization sequence.
I have mixed feelings about that, but this is probably just a
misunderstanding from my part.
The PIT timer should not be used for systems with PM_SUSPEND enabled and
used because it takes ages to synchronize on resume, how does this patch
affect that ?
Ref: commit ac34ad27fc ("clockevents: Do not suspend/resume if unused")
Sylvain
next prev parent reply other threads:[~2016-02-24 16:20 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-02-24 16:04 [PATCH v2] clocksource: atmel-pit: register as a sched_clock Romain Izard
2016-02-24 16:04 ` Romain Izard
2016-02-24 16:15 ` Alexandre Belloni
2016-02-24 16:15 ` Alexandre Belloni
2016-02-24 16:20 ` Sylvain Rochet [this message]
2016-02-24 16:20 ` Sylvain Rochet
2016-02-24 16:44 ` Romain Izard
2016-02-24 16:44 ` Romain Izard
2016-02-24 17:13 ` Nicolas Ferre
2016-02-24 17:13 ` Nicolas Ferre
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