linux-kernel - Re: [PATCH v12 5/9] cpufreq: amd-pstate: implement cpb

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Message-ID: <87plsavoup.fsf@BLR-5CG11610CF.amd.com>
Date: Fri, 21 Jun 2024 11:06:46 +0530
From: Gautham R.Shenoy <gautham.shenoy@....com>
To: Mario Limonciello <mario.limonciello@....com>, Perry Yuan
	<perry.yuan@....com>, <rafael.j.wysocki@...el.com>, <viresh.kumar@...aro.org>
CC: <Xinmei.Huang@....com>, <Xiaojian.Du@....com>, <Li.Meng@....com>,
	<linux-pm@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v12 5/9] cpufreq: amd-pstate: implement cpb_boost sysfs
 entry for boost control

Mario Limonciello <mario.limonciello@....com> writes:

> On 6/19/2024 04:16, Perry Yuan wrote:
>> From: Perry Yuan <Perry.Yuan@....com>
>> 
>> With this new sysfs entry `cpb_boost`created, user can change CPU boost
>> state dynamically under `active`, `guided` and `passive` modes.
>> And the highest perf and frequency will also be updated as the boost
>> state changing.
>
> s/changing/changes/
>
>> 
>> 0): check current boost state
>> cat /sys/devices/system/cpu/amd_pstate/cpb_boost
>> 
>> 1): disable CPU boost
>> sudo bash -c "echo 0 > /sys/devices/system/cpu/amd_pstate/cpb_boost"
>> 
>> 2): enable CPU boost
>> sudo bash -c "echo 1 > /sys/devices/system/cpu/amd_pstate/cpb_boost"

>From the point of view of the functionality this new interface is no
different from

/sys/devices/system/cpu/cpufreq/boost, which is currently suppported for
the passive mode and the guided mode.

Is there anything that prevents us from enabling this interface for the
active mode as well? 

It is easier if we use the common interface because tools such as
cpupower will then not need to fiddle with several different sysfs files
to enable/disable boost.

--
Thanks and Regards
gautham.