Re: [RFC PATCH 0/8] sched/fair: Propagate load balancing stats up the sched domain hierarchy

[Peter Zijlstra]

On Thu, Mar 13, 2025 at 09:37:38AM +0000, K Prateek Nayak wrote:
> tl;dr
> 
> This prototype is currently limited in the sense that it can only reuse
> statistics for busy load balancing. Reusing stats for newidle load
> balancing specifically ran into issues elaborated below.

Right, it makes sense for busy load balance, newidle I think:

> David had proposed SHARED_RUNQ [4] to improve on the shortcomings of
> newidle balance for Meta's production workloads.

we need to look at this again. Something around the EEVDF merge made the
thing unhappy -- if we figure out what and fix it, I think this makes
more sense than trying to optimize the current scheme for newidle.

newidle really is about getting *any* work fast, which is a totally
different game than the regular busy balancing.

Anyway, I'll try and have a look through the patches.