Re: [PATCH v2 2/2] cpufreq: schedutil: Optimize operations with single max CPU capacity

[Lukasz Luba]

On 12/8/22 04:09, Viresh Kumar wrote:
> On 07-12-22, 10:17, 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@xxxxxxx>
> > ---
> >   kernel/sched/cpufreq_schedutil.c | 22 +++++++++++-----------
> >   1 file changed, 11 insertions(+), 11 deletions(-)
>
> Looks okay to me.
>
> Acked-by: Viresh Kumar <viresh.kumar@xxxxxxxxxx>

Thank you Viresh!

As Rafael said, it will wait after 6.2-rc1 is out.

Regards,
Lukasz