Re: [PATCH] cpufreq: schedutil: Optimize operations with single max CPU capacity

[Lukasz Luba <lukasz.luba@arm.com>]

On 12/6/22 10:16, Viresh Kumar wrote:
> On 06-12-22, 10:10, Lukasz Luba wrote:
>> The max CPU capacity is the same for all CPUs sharing frequency domain
>> and thus 'policy' object. There is a way to avoid heavy operations
>> in a loop for each CPU by leveraging this knowledge. Thus, simplify
>> the looping code in the sugov_next_freq_shared() and drop heavy
>> multiplications. Instead, use simple max() to get the highest utilization
>> from these CPUs. This is useful for platforms with many (4 or 6) little
>> CPUs.
>>
>> The max CPU capacity must be fetched every time we are called, due to
>> difficulties during the policy setup, where we are not able to get the
>> normalized CPU capacity at the right time.
>>
>> The stored value in sugov_policy::max is also than used in
>> sugov_iowait_apply() to calculate the right boost. Thus, that field is
>> useful to have in that sugov_policy struct.
>>
>> Signed-off-by: Lukasz Luba <lukasz.luba@arm.com>
> 
> Can you please divide this into two patches, one for just moving max
> and one for looping optimization ? Else we may end up reverting
> everything once again.
> 

OK, I can do that. Thanks for having a look!