Messages in this thread | | | Date | Thu, 9 Aug 2018 16:41:56 +0100 | From | Patrick Bellasi <> | Subject | Re: [PATCH v3 06/14] sched/cpufreq: uclamp: add utilization clamping for RT tasks |
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On 07-Aug 14:54, Quentin Perret wrote: > Hi Patrick,
Hi Quentin!
> On Monday 06 Aug 2018 at 17:39:38 (+0100), Patrick Bellasi wrote: > > diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c > > index a7affc729c25..bb25ef66c2d3 100644 > > --- a/kernel/sched/cpufreq_schedutil.c > > +++ b/kernel/sched/cpufreq_schedutil.c > > @@ -200,6 +200,7 @@ static unsigned int get_next_freq(struct sugov_policy *sg_policy, > > static unsigned long sugov_get_util(struct sugov_cpu *sg_cpu) > > { > > struct rq *rq = cpu_rq(sg_cpu->cpu); > > + unsigned long util_cfs, util_rt; > > unsigned long util, irq, max; > > > > sg_cpu->max = max = arch_scale_cpu_capacity(NULL, sg_cpu->cpu); > > IIUC, not far below this you should still have something like: > > if (rt_rq_is_runnable(&rq->rt)) > return max;
Do you mean that when RT tasks are RUNNABLE we still want to got to MAX? Not sure to understand... since this patch is actually to clamp the RT class...
> So you won't reach the actual clamping code at the end of the function > when a RT task is runnable no?
... mmm... no... this patch is to clamp RT tasks... Am I missing something?
> Also, I always had the feeling that the default for RT should be > util_min == 1024, and then users could decide to lower the bar if they > want to.
Mmm... good point! This would keep the policy unaltered for RT tasks.
I want to keep sched class specific code in uclamp at minimum, but likely this should be achievable by just properly initializing the task-specific util_min for RT tasks, if the original task has UCLAM_NOT_VALID.
> For the specific case of RT, that feels more natural than > applying a max util clamp IMO. What do you think ?
I'll look better into this for the next posting!
Cheers Patrick
-- #include <best/regards.h>
Patrick Bellasi
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