Re: [RFC PATCH v3] sched/fair: select idle cpu from idle cpumask for task wakeup

[Valentin Schneider]

On 04/11/20 11:52, Li, Aubrey wrote:
> On 2020/11/4 3:27, Valentin Schneider wrote:
>>> +static DEFINE_PER_CPU(bool, cpu_idle_state);
>>
>> I would've expected this to be far less compact than a cpumask, but that's
>> not the story readelf is telling me. Objdump tells me this is recouping
>> some of the padding in .data..percpu, at least with the arm64 defconfig.
>>
>> In any case this ought to be better wrt cacheline bouncing, which I suppose
>> is what we ultimately want here.
>
> Yes, every CPU has a byte, so it may not be less than a cpumask. Probably I can
> put it into struct rq, do you have any better suggestions?
>

Not really, I'm afraid.