lkml.org 
[lkml]   [2020]   [Jan]   [24]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 1/3] sched/fair: Add asymmetric CPU capacity wakeup scan
Hey Valentin,

On Friday 24 Jan 2020 at 12:42:53 (+0000), Valentin Schneider wrote:
> +/*
> + * Scan the asym_capacity domain for idle CPUs; pick the first idle one on which
> + * the task fits.
> + */
> +static int select_idle_capacity(struct task_struct *p, int target)
> +{
> + struct cpumask *cpus = this_cpu_cpumask_var_ptr(select_idle_mask);
> + struct sched_domain *sd;
> + int cpu;
> +
> + if (!static_branch_unlikely(&sched_asym_cpucapacity))
> + return -1;
> +
> + sd = rcu_dereference(per_cpu(sd_asym_cpucapacity, target));
> + if (!sd)
> + return -1;
> +

You might want 'sync_entity_load_avg(&p->se)' here no ?
find_idlest_cpu() and wake_cap() need one, but since we're going to use
them, you'll want to sync here too I think.


> + cpumask_and(cpus, sched_domain_span(sd), p->cpus_ptr);
> +
> + for_each_cpu_wrap(cpu, cpus, target) {
> + if (!available_idle_cpu(cpu))
> + continue;
> + if (!task_fits_capacity(p, capacity_of(cpu)))
> + continue;
> +
> + return cpu;
> + }

If we found an idle CPU, but not one big enough, should we still go
ahead and choose it ? Misfit / idle balance will fix that later when a
big CPU does become available.

> +
> + return -1;
> +}
> +

Thanks,
Quentin

\
 
 \ /
  Last update: 2020-01-24 13:59    [W:0.338 / U:0.028 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site