linux-kernel - Re: 4.8.1 regression with cpufreq governors

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Message-ID: <20161019140608.GA11766@vireshk-i7>
Date:   Wed, 19 Oct 2016 19:36:08 +0530
From:   Viresh Kumar <viresh.kumar@...aro.org>
To:     "Rafael J. Wysocki" <rjw@...ysocki.net>
Cc:     Tim Walberg <twalberg@...cast.net>, linux-kernel@...r.kernel.org,
        Linux PM list <linux-pm@...r.kernel.org>
Subject: Re: 4.8.1 regression with cpufreq governors

On 18-10-16, 23:10, Rafael J. Wysocki wrote:
> On Monday, October 17, 2016 07:46:06 PM Tim Walberg wrote:
> > May or may not be related to similar reports, but here's what I've just observed
> > on my system. Built a stock kernel from tags/v4.8.1, relevant cpufreq bits:
> > 
> > CONFIG_ACPI_CPU_FREQ_PSS=y
> > CONFIG_CPU_FREQ=y
> > CONFIG_CPU_FREQ_GOV_ATTR_SET=y
> > CONFIG_CPU_FREQ_GOV_COMMON=y
> > CONFIG_CPU_FREQ_STAT=y
> > CONFIG_CPU_FREQ_STAT_DETAILS=y
> > # CONFIG_CPU_FREQ_DEFAULT_GOV_PERFORMANCE is not set
> > # CONFIG_CPU_FREQ_DEFAULT_GOV_POWERSAVE is not set
> > # CONFIG_CPU_FREQ_DEFAULT_GOV_USERSPACE is not set
> > # CONFIG_CPU_FREQ_DEFAULT_GOV_ONDEMAND is not set
> > CONFIG_CPU_FREQ_DEFAULT_GOV_CONSERVATIVE=y
> > # CONFIG_CPU_FREQ_DEFAULT_GOV_SCHEDUTIL is not set
> > CONFIG_CPU_FREQ_GOV_PERFORMANCE=y
> > CONFIG_CPU_FREQ_GOV_POWERSAVE=m
> > CONFIG_CPU_FREQ_GOV_USERSPACE=m
> > CONFIG_CPU_FREQ_GOV_ONDEMAND=m
> > CONFIG_CPU_FREQ_GOV_CONSERVATIVE=y
> > CONFIG_CPU_FREQ_GOV_SCHEDUTIL=m
> > # CONFIG_X86_PCC_CPUFREQ is not set
> > CONFIG_X86_ACPI_CPUFREQ=m
> > CONFIG_X86_ACPI_CPUFREQ_CPB=y
> > 
> > 
> > Conservative is set as default governer, yet when boot completes, all CPUs are
> > pegged at the highest frequency. Changing governor to powersave knocks them all
> > down to the lowest available frequency. Putting them back on conservative (or
> > ondemand) results in no change in frequency, despite generating load. Switching
> > to performance of course kicks them back up to high frequency. Basically, the
> > governors don't seem to be ... governing.
> 
> The "convervative" governor issue seems to be the one fixed recently
> (http://git.kernel.org/cgit/linux/kernel/git/rafael/linux-pm.git/commit/?h=pm-cpufreq&id=abb6627910a1e783c8e034b35b7c80e5e7f98f41).
> 
> I'm not sure why "ondemand" behaves incorrectly for you though.

@Tim: Can you please try this as well:

https://marc.info/?l=linux-kernel&m=147624218132250&w=2

Subject: [PATCH V2] cpufreq: skip invalid entries when searching the frequency

-- 
viresh