Messages in this thread | | | Subject | Re: [PATCH 1/2] sched/fair: Take thermal pressure into account while estimating energy | From | Lukasz Luba <> | Date | Wed, 2 Jun 2021 16:35:25 +0100 |
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Hi Quentin,
On 6/2/21 4:00 PM, Quentin Perret wrote: > Hi Lukasz, > > On Wednesday 02 Jun 2021 at 14:56:08 (+0100), Lukasz Luba wrote: >> compute_energy(struct task_struct *p, int dst_cpu, struct perf_domain *pd) >> { >> struct cpumask *pd_mask = perf_domain_span(pd); >> - unsigned long cpu_cap = arch_scale_cpu_capacity(cpumask_first(pd_mask)); >> + unsigned long _cpu_cap = arch_scale_cpu_capacity(cpumask_first(pd_mask)); >> unsigned long max_util = 0, sum_util = 0; >> + unsigned long cpu_cap = _cpu_cap; >> int cpu; >> >> /* >> @@ -6558,6 +6559,14 @@ compute_energy(struct task_struct *p, int dst_cpu, struct perf_domain *pd) >> cpu_util_next(cpu, p, -1) + task_util_est(p); >> } >> >> + /* >> + * Take the thermal pressure from non-idle CPUs. They have >> + * most up-to-date information. For idle CPUs thermal pressure >> + * signal is not updated so often. >> + */ >> + if (!idle_cpu(cpu)) >> + cpu_cap = _cpu_cap - thermal_load_avg(cpu_rq(cpu)); > > This messes up the irq time scaling no? Maybe move the capping in this
You are talking about scale_irq_capacity() which shrinks the util by some percentage of irq time. It might be different, by some fraction (e.g. 8/9 vs 9/10) compared to SchedUtil view, which passes 'raw' arch capacity. It then adds the irq part, but still to this slightly different base util.
> function instead of relying on effective_cpu_util() to do it for you?
Agree, since it would be more 'aligned' with how SchedUtil calls effective_cpu_util(). I will clamp the returned value.
Thanks for pointing this out.
Regards, Lukasz
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