linux-kernel - Re: [PATCH] cpufreq, intel_pstate, set max_sysfs_pct and min_sysfs

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Date:	Wed, 07 Oct 2015 16:40:44 -0400
From:	Prarit Bhargava <prarit@...hat.com>
To:	Doug Smythies <dsmythies@...us.net>
CC:	"'Kristen Carlson Accardi'" <kristen@...ux.intel.com>,
	linux-kernel@...r.kernel.org,
	"'Viresh Kumar'" <viresh.kumar@...aro.org>,
	linux-pm@...r.kernel.org, "'Rafael J. Wysocki'" <rjw@...ysocki.net>
Subject: Re: [PATCH] cpufreq, intel_pstate, set max_sysfs_pct and min_sysfs_pct
 on governor switch



On 10/07/2015 02:52 PM, Doug Smythies wrote:
> On 2015.10.07 08:46 Prarit Bhargava wrote:
>> On 10/07/2015 11:40 AM, Doug Smythies wrote:
>>>
>>> Do we agree or disagree that the root issue seems to be (from your test)?:
>>>
>>> \#  echo 100 > /sys/devices/system/cpu/intel_pstate/min_perf_pct
>>>
>>> [   21.483436] store_min_perf_pct[453] min_sysfs_pct = 100
>>> [   21.489373] store_min_perf_pct[456] min_perf_pct = 100
>>> [   21.495203] store_min_perf_pct[459] min_perf_pct = 100
>>> [   21.501050] store_min_perf_pct[462] min_perf_pct = 100
>>
>> Yep, and it appears to be done by default in Fedora & RHEL :/ ... the issue is
>> still the same IMO that min_sysfs_pct & max_sysfs_pct are not cleared on a
>> governor switch.
> 
> Clearing them will break some other things. For example, and as
> shown in my original reply, resume from suspend.
> 
> Why? Because, at least on my computer, the governor is changed to
> "performance" during suspend, and the "powersave" governor is
> restored sometime during resume. The users wants the settings they had
> before the suspend.

Hmm ... okay.  I'm going to try again with a new patch and I'll add an
additional test of starting with the powersave governor, changing the
min_perf_pct, and then doing a suspend/resume.

P.
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