linux-kernel - Re: 4.8.1 regression with cpufreq governors

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Date:   Wed, 19 Oct 2016 15:06:10 -0500
From:   Tim Walberg <twalberg@...cast.net>
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>,
        Viresh Kumar <viresh.kumar@...aro.org>
Subject: Re: 4.8.1 regression with cpufreq governors

This indeed turned out to be the fix.

On 10/18/2016 23:10 +0200, 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.
>>	
>>	Thanks,
>>	Rafael
End of included message



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