Re: [RFC PATCH 7/9] housekeeping: Use own boot option, independant from nohz

From: Mike Galbraith
Date: Mon Aug 14 2017 - 14:30:40 EST


On Mon, 2017-08-14 at 13:34 -0400, Luiz Capitulino wrote:
> On Mon, 14 Aug 2017 19:01:09 +0200
>
> > What is the source of the load balancing inducing such latency when a single
> > task is affine to a CPU? If this is idle load balancing, it is now affine to
> > housekeepers. If this is task wakeup then it's suprising because select_task_rq()
> > is optimized toward single CPU affinity.
>
> I guess it was idle load balancing, but I don't remember because this
> was a few years ago. I think this might be reproducible without using
> isolcpus=. I'll give it a try shortly and let you know.

idle_balance() can swamp other noise by a couple orders of magnitude,

-Mike