Re: [PATCH RFC 1/2] sched: Minimize the idle cpu selection race window.

[Mike Galbraith]

On Tue, 2017-11-28 at 10:34 +0100, Uladzislau Rezki wrote:
> On Fri, Nov 24, 2017 at 07:46:30PM +0100, Mike Galbraith wrote:
> 
> > My view is you're barking up the wrong tree: you're making the idle
> > data SIS is using more accurate, but I question the benefit.  That it
> > makes an imperfect placement decision occasionally due to raciness is
> > nearly meaningless compared to the cost of frequent bounce.

> Before sitting down and start testing, i just illustrated how we can
> apply claim_wake_up to ilb asking community a specific view on it:
> drawbacks, pros/cons, proposals etc.

Even if you make the thing atomic, what is ILB supposed to do, look
over its shoulder every step of the way and sh*t it's pants if somebody
touches claim_wake_up as it's about to or just after it did something?

If you intend to make all of LB race free, good luck.

	-Mike