Re: [PATCH v5 08/10] cpufreq/schedutil: take into account interrupt

Juri Lelli
2018-05-28T13:54:11Z

Hi Vincent,

On 25/05/18 15:12, Vincent Guittot wrote:
> The time spent under interrupt can be significant but it is not reflected
> in the utilization of CPU when deciding to choose an OPP. Now that we have
> access to this metric, schedutil can take it into account when selecting
> the OPP for a CPU.
> The CPU utilization is :
> irq util_avg + (1 - irq util_avg / max capacity ) * /Sum rq util_avg

IIUC the code below you actually propose that

util = [(max_cap - util_irq) * util_rq] / max_cap + util_irq

where

util_rq = /Sum rq util_avg
util_irq = irq util_avg

So, which one is what you have in mind? Or am I wrong? :)

[...]

> static unsigned long sugov_aggregate_util(struct sugov_cpu *sg_cpu)
> @@ -190,9 +192,17 @@ static unsigned long sugov_aggregate_util(struct sugov_cpu *sg_cpu)
> if (rq->rt.rt_nr_running) {
> util = sg_cpu->max;
> } else {
> + /* Sum rq utilization*/
> util = sg_cpu->util_dl;
> util += sg_cpu->util_cfs;
> util += sg_cpu->util_rt;
> +
> + /* Weight rq's utilization to the normal context */
> + util *= (sg_cpu->max - sg_cpu->util_irq);
> + util /= sg_cpu->max;
> +
> + /* Add interrupt utilization */
> + util += sg_cpu->util_irq;

Thanks,

- Juri