Messages in this thread | | | Date | Tue, 27 Feb 2018 08:12:11 +0100 | From | Maxime Ripard <> | Subject | Re: [RFC PATCH] ARM: configs: sunxi: Set ondemand govenor as default |
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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 [unhandled content-type:application/pgp-signature] | |