Re: [PATCH v5 03/10] cpufreq/schedutil: add rt utilization tracking

Patrick Bellasi
2018-05-30T09:40:07Z

On 25-May 15:12, Vincent Guittot wrote:
> Add both cfs and rt utilization when selecting an OPP for cfs tasks as rt
> can preempt and steal cfs's running time.
>
> Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
> ---
> kernel/sched/cpufreq_schedutil.c | 14 +++++++++++---
> 1 file changed, 11 insertions(+), 3 deletions(-)
>
> diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c
> index 28592b6..a84b5a5 100644
> --- a/kernel/sched/cpufreq_schedutil.c
> +++ b/kernel/sched/cpufreq_schedutil.c
> @@ -56,6 +56,7 @@ struct sugov_cpu {
> /* The fields below are only needed when sharing a policy: */
> unsigned long util_cfs;
> unsigned long util_dl;
> + unsigned long util_rt;
> unsigned long max;
>
> /* The field below is for single-CPU policies only: */
> @@ -178,14 +179,21 @@ static void sugov_get_util(struct sugov_cpu *sg_cpu)
> sg_cpu->max = arch_scale_cpu_capacity(NULL, sg_cpu->cpu);
> sg_cpu->util_cfs = cpu_util_cfs(rq);
> sg_cpu->util_dl = cpu_util_dl(rq);
> + sg_cpu->util_rt = cpu_util_rt(rq);
> }
>
> static unsigned long sugov_aggregate_util(struct sugov_cpu *sg_cpu)
> {
> struct rq *rq = cpu_rq(sg_cpu->cpu);
> + unsigned long util;
>
> - if (rq->rt.rt_nr_running)
> - return sg_cpu->max;
> + if (rq->rt.rt_nr_running) {
> + util = sg_cpu->max;

Why not just adding the following lines while keeping the return in
for the rq->rt.rt_nr_running case?

> + } else {
> + util = sg_cpu->util_dl;
> + util += sg_cpu->util_cfs;
> + util += sg_cpu->util_rt;
> + }
>
> /*
> * Utilization required by DEADLINE must always be granted while, for
> @@ -197,7 +205,7 @@ static unsigned long sugov_aggregate_util(struct sugov_cpu *sg_cpu)
> * util_cfs + util_dl as requested freq. However, cpufreq is not yet
> * ready for such an interface. So, we only do the latter for now.
> */
> - return min(sg_cpu->max, (sg_cpu->util_dl + sg_cpu->util_cfs));
> + return min(sg_cpu->max, util);

... for the rq->rt.rt_nr_running case we don't really need to min
clamp util = sg_cpu->max with itself...

> }
>
> static void sugov_set_iowait_boost(struct sugov_cpu *sg_cpu, u64 time, unsigned int flags)
> --
> 2.7.4
>

--
#include <best/regards.h>

Patrick Bellasi