Messages in this thread Patch in this message | | | Date | Fri, 7 Feb 2020 10:38:54 +0530 | From | Pavan Kondeti <> | Subject | Re: [PATCH v4 1/4] sched/fair: Add asymmetric CPU capacity wakeup scan |
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On Thu, Feb 06, 2020 at 07:19:54PM +0000, Valentin Schneider wrote: > From: Morten Rasmussen <morten.rasmussen@arm.com> >
<snip>
> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > index fe4e0d7753756..9a5a6e9d2375e 100644 > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -5894,6 +5894,40 @@ static int select_idle_cpu(struct task_struct *p, struct sched_domain *sd, int t > return cpu; > } > > +/* > + * Scan the asym_capacity domain for idle CPUs; pick the first idle one on which > + * the task fits. If no CPU is big enough, but there are idle ones, try to > + * maximize capacity. > + */ > +static int > +select_idle_capacity(struct task_struct *p, struct sched_domain *sd, int target) > +{ > + unsigned long best_cap = 0; > + int cpu, best_cpu = -1; > + struct cpumask *cpus; > + > + sync_entity_load_avg(&p->se); > + > + cpus = this_cpu_cpumask_var_ptr(select_idle_mask); > + cpumask_and(cpus, sched_domain_span(sd), p->cpus_ptr); > + > + for_each_cpu_wrap(cpu, cpus, target) { > + unsigned long cpu_cap = capacity_of(cpu); > + > + if (!available_idle_cpu(cpu) && !sched_idle_cpu(cpu)) > + continue; > + if (task_fits_capacity(p, cpu_cap)) > + return cpu; > + > + if (cpu_cap > best_cap) { > + best_cap = cpu_cap; > + best_cpu = cpu; > + } > + } > + > + return best_cpu; > +} > + > /* > * Try and locate an idle core/thread in the LLC cache domain. > */ > @@ -5902,6 +5936,28 @@ static int select_idle_sibling(struct task_struct *p, int prev, int target) > struct sched_domain *sd; > int i, recent_used_cpu; > > + /* > + * For asymmetric CPU capacity systems, our domain of interest is > + * sd_asym_cpucapacity rather than sd_llc. > + */ > + if (static_branch_unlikely(&sched_asym_cpucapacity)) { > + sd = rcu_dereference(per_cpu(sd_asym_cpucapacity, target)); > + /* > + * On an asymmetric CPU capacity system where an exclusive > + * cpuset defines a symmetric island (i.e. one unique > + * capacity_orig value through the cpuset), the key will be set > + * but the CPUs within that cpuset will not have a domain with > + * SD_ASYM_CPUCAPACITY. These should follow the usual symmetric > + * capacity path. > + */ > + if (!sd) > + goto symmetric; > + > + i = select_idle_capacity(p, sd, target); > + return ((unsigned)i < nr_cpumask_bits) ? i : target; > + } > + > +symmetric: > if (available_idle_cpu(target) || sched_idle_cpu(target)) > return target; > > -- > 2.24.0 >
Looks good to me.
Thanks, Pavan
-- Qualcomm India Private Limited, on behalf of Qualcomm Innovation Center, Inc. Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project.
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