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

Vincent Guittot
2018-05-30T09:54:09Z

On 30 May 2018 at 11:40, Patrick Bellasi <patrick.bellasi@arm.com> wrote:
> 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...

yes good point

>
>> }
>>
>> 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