On Wed, 17 Feb 2016 17:04:41 +0100 (CET)
Thomas Gleixner <t...@linutronix.de> wrote:
> > >
> > > for_each_online_cpu(i) {
> > > if (topology_physical_package_id(i) ==
> > > package_id)
>
> This is still crap. We really want a proper handling for that which
> does not require these silly for_each_cpu() loops.
>
> That code already has a hotplug notifier, so you can track one online
> cpu in the package like we do in cqm and other facilities.
>
> The first online cpu of a package sets itself as 'owner'. On unplug
> it looks up:
>
> rpl->cpu = cpumask_any_but(topology_core_cpumask(cpu), cpu);
>
> So if this is the last cpu then rpl->cpu becomes nr_cpu_ids.
>
> So that whole nonsense can be avoided completely.
ok, that would work nicely, similar to cqm_pick_event_reader().
thanks for the tip. just fyi, unlike perf cqm, rapl runtime change is
expected to be low frequency.
