Re: Delayed acpi frequency governor call

[Viresh Kumar <viresh.kumar@linaro.org>]

On 20-01-17, 16:27, Philipp Miedl wrote:
> This is not my issue. The code I'm referring to can be found in
> cpufreq_governor.c:
> <-->
> if (unlikely(wall_time > (2 * sampling_rate) &&
>        j_cdbs->prev_load)) {

This only confirms that the CPU was idle for sometime.

>   load = j_cdbs->prev_load;
> 
>   /*
>    * Perform a destructive copy, to ensure that we copy
>    * the previous load only once, upon the first wake-up
>    * from idle.
>    */
>   j_cdbs->prev_load = 0;
> } else {
>   load = 100 * (wall_time - idle_time) / wall_time;
>   j_cdbs->prev_load = load;
> }
> <-->
> 
> How can it happen that "unlikely(wall_time > (2 * sampling_rate)" is true
> although the CPU utilization was 5%?

I am not sure how your test works, etc. Maybe try to generate traces for your
CPUs to see if they are going into idle or not. Maybe you are having a hard time
because of SMP platform ?

-- 
viresh