Re: [PATCH V2] sched: Improve load balancing in the presence of idle CPUs

From: Wanpeng Li
Date: Thu Mar 26 2015 - 22:30:28 EST


Hi Preeti,
On Thu, Mar 26, 2015 at 06:32:44PM +0530, Preeti U Murthy wrote:
>
>1. An ILB CPU was chosen from the first numa domain to trigger nohz idle
>load balancing [Given the experiment, upto 6 CPUs per core could be
>potentially idle in this domain.]
>
>2. However the ILB CPU would call load_balance() on itself before
>initiating nohz idle load balancing.
>
>3. Given cores are SMT8, the ILB CPU had enough opportunities to pull
>tasks from its sibling cores to even out load.
>
>4. Now that the ILB CPU was no longer idle, it would abort nohz idle
>load balancing

I don't see abort nohz idle load balancing when ILB CPU was no longer idle
in nohz_idle_balance(), could you explain more in details?

Regards,
Wanpeng Li
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