[PATCH v4 4/5] cpufreq: qcom-cpufreq-hw: Use new thermal pressure update function

Lukasz Luba lukasz.luba at arm.com
Tue Nov 16 00:28:53 PST 2021


Hi Thara,

On 11/15/21 11:39 PM, Thara Gopinath wrote:
> 
> 
> On 11/15/21 3:57 PM, Thara Gopinath wrote:
>>
>>
>> On 11/9/21 2:57 PM, Lukasz Luba wrote:
>>> Thermal pressure provides a new API, which allows to use CPU frequency
>>> as an argument. That removes the need of local conversion to capacity.
>>> Use this new API and remove old local conversion code.
>>>
>>> The new arch_update_thermal_pressure() also accepts boost frequencies,
>>> which solves issue in the driver code with wrong reduced capacity
>>> calculation. The reduced capacity was calculated wrongly due to
>>> 'policy->cpuinfo.max_freq' used as a divider. The value present there 
>>> was
>>> actually the boost frequency. Thus, even a normal maximum frequency 
>>> value
>>> which corresponds to max CPU capacity (arch_scale_cpu_capacity(cpu_id))
>>> is not able to remove the capping.
> 
> Also I failed to mention that, currently freq_factor is initialized as 
> cpuinfo.max_freq / 1000 which means again all the issues you mentioned 
> below can be hit, if some cpufreq driver decides to set boost at init.
> I have sent a patch earlier today to fix this.

Yes, you are right.

> 
> https://lore.kernel.org/linux-arm-msm/20211115201010.68567-1-thara.gopinath@linaro.org/T/#u 
> 
> 

Looking at the change, it makes sense. I'll try to respond to that
patch.

Thank you for looking into this issue.

Regards,
Lukasz



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