linux-kernel - Re: [PATCH v3 0/5] Refactor thermal pressure update to avoid code duplication

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Message-ID: <83bab944-cc89-bdf9-e187-7d61a2494935@kali.org>
Date:   Tue, 9 Nov 2021 13:09:47 -0600
From:   Steev Klimaszewski <steev@...i.org>
To:     Lukasz Luba <lukasz.luba@....com>
Cc:     Thara Gopinath <thara.gopinath@...aro.org>,
        linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org,
        linux-arm-msm@...r.kernel.org, sudeep.holla@....com,
        will@...nel.org, catalin.marinas@....com, linux@...linux.org.uk,
        gregkh@...uxfoundation.org, rafael@...nel.org,
        viresh.kumar@...aro.org, amitk@...nel.org,
        daniel.lezcano@...aro.org, amit.kachhap@...il.com,
        bjorn.andersson@...aro.org, agross@...nel.org
Subject: Re: [PATCH v3 0/5] Refactor thermal pressure update to avoid code
 duplication

Hi Lukasz,
>>
>
> I think I have figure out what is going on with the issue that
> you've reported. On this rockchip platform you are probably using
> step-wise thermal governor, which tries to decrease/increase
> max allowed frequency step-by-step walking through the sorted
> frequencies. So it would always set the thermal pressure to 0
> when the thermal throttling is gone.
> On the Qcom platform there is a different policy in HW/FW which
> controls thermal and it can simple remove clamping 'instantly'
> and allow all frequencies also the boost one. The highest possible
> frequency is passed then to the this thermal pressure machinery.
> So we see the warning that the boost frequency value is trying to
> be passed to this arch_update_thermal_pressure(), but we ignore
> such big frequency value and unfortunately do not clean the previously
> set thermal pressure. Then the scheduler still sees the reduced
> capacity on that CPU and cannot request higher frequencies.
>
> The v4 patch would allow to pass the boost frequencies values, so
> the issue would be solved.
>
> Regards,
> Lukasz

Sounds good, I look forward to testing v4 :)

-- steev