Re: [PATCH 3/3] sched: limit cpu search and rotate search window for scalability

[Subhra Mazumdar]

On 04/24/2018 05:48 AM, Peter Zijlstra wrote:
> On Mon, Apr 23, 2018 at 05:41:16PM -0700, subhra mazumdar wrote:
> > Lower the lower limit of idle cpu search in select_idle_cpu() and also put
> > an upper limit. This helps in scalability of the search by restricting the
> > search window. Also rotating the search window with help of next_cpu
> > ensures any idle cpu is eventually found in case of high load.
> So this patch does 2 (possibly 3) things, that's not good.
During testing I did try with first only restricting the search window.
That alone wasn't enough to give the full benefit, rotating search window
was essential to get best results. I will break this up in next version.