linux-kernel - Re: [PATCH 0/3] cpufreq: scmi: Add boost frequency support

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Date: Wed, 28 Feb 2024 00:14:57 +0530
From: Sibi Sankar <quic_sibis@...cinc.com>
To: Dietmar Eggemann <dietmar.eggemann@....com>,
        Sudeep Holla
	<sudeep.holla@....com>,
        Viresh Kumar <viresh.kumar@...aro.org>
CC: <cristian.marussi@....com>, <rafael@...nel.org>,
        <morten.rasmussen@....com>, <lukasz.luba@....com>, <sboyd@...nel.org>,
        <linux-arm-kernel@...ts.infradead.org>, <linux-pm@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>, <quic_mdtipton@...cinc.com>,
        <linux-arm-msm@...r.kernel.org>, <nm@...com>
Subject: Re: [PATCH 0/3] cpufreq: scmi: Add boost frequency support



On 2/15/24 20:27, Dietmar Eggemann wrote:
> On 13/02/2024 08:35, Sibi Sankar wrote:
>>
>>
>> On 1/31/24 20:37, Dietmar Eggemann wrote:
>>> On 23/01/2024 11:15, Sudeep Holla wrote:
>>>> On Tue, Jan 23, 2024 at 11:38:27AM +0530, Viresh Kumar wrote:
>>>>> On 17-01-24, 16:34, Sibi Sankar wrote:
> 
> [...]
> 

[...]

>>> BTW, what's the use case you have in mind for this feature? Is it to cap
>>> high OPPs for CPUs in a certain CPUfreq policy?
>>
>> Yeah, that's exactly the use case for X1E. Boost frequencies defined in
>> the SoC are achievable by only one CPU in a cluster i.e. either the
>> other CPUs in the same cluster should be in low power mode or offline.
>> So it's mostly for book keeping i.e. we wouldn't to intimate incorrectly
>> that the CPUs are running at max possible frequency when it's actually
>> running at a lower frequency.
> 
> I see.
> 
> What about the issue with the settings of the global and the per-policy
> 'boost' file?
> 
> On my Juno-r0 the initial boost values are:
> 
> (1) Initial setting:
> 
> root@...o:/sys/devices/system/cpu/cpufreq# cat boost policy*/boost
> 1
> 0
> 0
> 
> Should they not all be 1 ?
> 
> 
> (2) Disabling system-wide boost
> 
> root@...o:/sys/devices/system/cpu/cpufreq# echo 0 > boost
> 
> Here I see 'cpufreq_pressure > 0' for all CPUs.
> 
> 
> (3) Enabling system-wide boost
> 
> root@...o:/sys/devices/system/cpu/cpufreq# echo 1 > boost
> 
> And here 'cpufreq_pressure == 0' for all CPUs.
> 
> 
> (4) Disabling boost for policy0.
> 
> root@...o:/sys/devices/system/cpu/cpufreq# echo 0 > policy0/boost
> 
> root@...o:/sys/devices/system/cpu/cpufreq# cat boost policy*/boost
> 1
> 0
> 1
> 
> Here nothing happened. But I was expecting to see 'cpufreq_pressure > 0'
> for CPUs of policy0:
> 

https://patchwork.kernel.org/project/linux-arm-msm/cover/20240227165309.620422-1-quic_sibis@quicinc.com/

Finally got some time to fix this, I've posted out the fix and re-spun
the series as well. This should fix the default values of per-policy
boost flags as well.

-Sibi

> root@...o:/sys/devices/system/cpu/cpufreq# cat policy0/affected_cpus
> 0 3 4 5