Re: [PATCH v6 06/11] cpufreq/schedutil: use dl utilization tracking

[Juri Lelli]

Hi Vincent,

On 08/06/18 14:09, Vincent Guittot wrote:
> Now that we have both the dl class bandwidth requirement and the dl class
> utilization, we can detect when CPU is fully used so we should run at max.
> Otherwise, we keep using the dl bandwidth requirement to define the
> utilization of the CPU
> 
> Cc: Ingo Molnar <mingo@xxxxxxxxxx>
> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
> Signed-off-by: Vincent Guittot <vincent.guittot@xxxxxxxxxx>
> ---

[...]

> @@ -190,20 +192,24 @@ static unsigned long sugov_aggregate_util(struct sugov_cpu *sg_cpu)
>  	if (rq->rt.rt_nr_running)
>  		return sg_cpu->max;
>  
> -	util = sg_cpu->util_dl;
> -	util += sg_cpu->util_cfs;
> +	util = sg_cpu->util_cfs;
>  	util += sg_cpu->util_rt;
>  
> +	if ((util + sg_cpu->util_dl) >= sg_cpu->max)
> +		return sg_cpu->max;
> +

Mmm, won't we run at max (or reach max) with a, say, 100ms/500ms DL task
running alone?

Best,

- Juri