Re: [PATCH 6/8] cpufreq/schedutil: sum per-sched class utilization

From: Peter Zijlstra
Date: Tue Mar 15 2016 - 17:32:40 EST


On Sun, Mar 13, 2016 at 10:22:10PM -0700, Michael Turquette wrote:

> +static unsigned long sugov_sum_total_util(struct sugov_cpu *sg_cpu)
> +{
> + enum sched_class_util sc;
> +
> + /* sum the utilization of all sched classes */
> + sg_cpu->total_util = 0;
> + for (sc = 0; sc < nr_util_types; sc++)
> + sg_cpu->total_util += sg_cpu->util[sc];
> +
> + return sg_cpu->total_util;
> +}

> @@ -153,7 +172,7 @@ static unsigned int sugov_next_freq(struct sugov_policy *sg_policy,
> if ((s64)delta_ns > NSEC_PER_SEC / HZ)
> continue;
>
> - j_util = j_sg_cpu->util;
> + j_util = j_sg_cpu->total_util;
> j_max = j_sg_cpu->max;
> if (j_util > j_max)
> return max_f;

So while not strictly wrong, I think we can do so much better.

Changelog doesn't mention anything useful, like that this is indeed very
rough and what we really should be doing etc..