linux-kernel - Re: [intel-pstate driver regression] processor frequency very high even if in idle

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Date:	Tue, 29 Mar 2016 19:32:27 +0200
From:	Jörg Otte <jrg.otte@...il.com>
To:	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [intel-pstate driver regression] processor frequency very high
 even if in idle

2016-03-29 19:24 GMT+02:00 Jörg Otte <jrg.otte@...il.com>:
> in v4.5 and earlier intel-pstate downscaled idle processors (load
> 0.1-0.2%) to minumum frequency, in my case 800MHz.
>
> Now in v4.6-rc1 the characteristic has dramatically changed. If in
> idle the processor frequency is more or less a few MHz around 2500Mhz.
> This is the maximum non turbo frequency.
>
> No difference between powersafe or performance governor.
>
> I currently use acpi_cpufreq which works as usual.
>
> Processor:
> Intel(R) Core(TM) i5-4200M CPU @ 2.50GHz (family: 0x6, model: 0x3c,
> stepping: 0x3)
>
> Last known good kernel is: 4.5.0-01127-g9256d5a
> First known bad kernel is: 4.5.0-02535-g09fd671
>
> There is
> commit 277edba Merge tag 'pm+acpi-4.6-rc1-1' of
> git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
> in between, which brought a few changes in intel_pstate.
>
> thanks, Jörg