From: Maxime Ripard <maxime.ripard@bootlin.com>
To: Philipp Rossak <embed3d@gmail.com>
Cc: linux@armlinux.org.uk, wens@csie.org, davem@davemloft.net,
arnd@arndb.de, mchehab@kernel.org, clabbe.montjoie@gmail.com,
rask@formelder.dk, krzk@kernel.org, sean@mess.org,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, linux-sunxi@googlegroups.com
Subject: Re: [RFC PATCH] ARM: configs: sunxi: Set ondemand govenor as default
Date: Tue, 27 Feb 2018 08:12:11 +0100 [thread overview]
Message-ID: <20180227071211.4c5okbwcp5qjx4ok@flea> (raw)
In-Reply-To: <15992664-76be-2584-0f8d-424eadc23925@gmail.com>
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On Mon, Feb 26, 2018 at 10:29:29PM +0100, Philipp Rossak wrote:
>
>
> On 19.02.2018 09:10, Maxime Ripard wrote:
> > On Sat, Feb 17, 2018 at 03:22:35PM +0100, Philipp Rossak wrote:
> > > Right now the performance govenor is the default frequency govenor on
> > > sunxi devices. This causes some general problems.
> > > When the cpu is idle the cpu runs with its maximum frequency.
> > > This causes a higher cpu temperature in the idle state. When the cpu is
> > > now under load the cpu gets with that higher idle temperature now faster
> > > to its thermal limits.
> > > An other big problem of the performace govenor is the missing
> > > thermal throttling. Some tests with cpuburn resulted in a system crash
> > > when the soc reached its thermal limits since no thermal throttling
> > > occurred.
> >
> > This won't change anything with cpuburn. While cpuburn will be
> > running, ondemand will increase the frequency of the cores to the
> > maximum frequency, putting yourself in the exact same situation.
>
> I see here a totally different behavior on the hardware (Bananapi M2, A31s).
> First ondemand increases the cpu frequency, when the maximum temperature is
> reached, then it throttles down the cpu step by step to its minimum.
This is the thermal throttling, not the cpufreq governor.
Maxime
--
Maxime Ripard, Bootlin (formerly Free Electrons)
Embedded Linux and Kernel engineering
https://bootlin.com
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prev parent reply other threads:[~2018-02-27 7:12 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-17 14:22 [RFC PATCH] ARM: configs: sunxi: Set ondemand govenor as default Philipp Rossak
2018-02-19 8:10 ` Maxime Ripard
2018-02-26 21:29 ` Philipp Rossak
2018-02-27 7:12 ` Maxime Ripard [this message]
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