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Subject: Re: [PATCH v3 4/7] thermal/drivers/tegra: Add driver for Tegra30
 thermal sensor
To:     Vincent Guittot <vincent.guittot@linaro.org>,
        Viresh Kumar <viresh.kumar@linaro.org>
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From:   Dmitry Osipenko <digetx@gmail.com>
Message-ID: <96bf59af-20b6-b706-5ff0-fe70f9eba827@gmail.com>
Date:   Wed, 16 Jun 2021 11:39:49 +0300
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16.06.2021 11:30, Vincent Guittot пишет:
> On Wed, 16 Jun 2021 at 10:03, Viresh Kumar <viresh.kumar@linaro.org> wrote:
>>
>> +Vincent.
>>
>> On 15-06-21, 22:32, Dmitry Osipenko wrote:
>>> IIUC, the cpufreq already should be prepared for the case where firmware
>>> may override frequency. Viresh, could you please clarify what are the
>>> possible implications of the frequency overriding?
>>
>> The only implication is software would think hardware is running at
>> some other frequency, while it is not. Not sure if something may break
>> as a result of this.
>>
>> The scheduler's view of CPUs will not be same though, i.e. scheduler
>> will see capacity as X, while in reality it has changed to Y.
> 
> thermal_pressure is used by scheduler to balance the load between CPUs
> according to the actual max frequency. If the thermal pressure doesn't
> reflect reality, scheduler will end up enqueuing too many  tasks on a
> throttle CPU.

What if all CPUs are throttled equally and running on the same
frequency, will throttling have any effect on the scheduler decisions?