Re: [PATCH] sched/fair: Reschedule the cfs_rq when current is ineligible

[Peter Zijlstra]

On Sat, May 25, 2024 at 08:41:28AM +0200, Mike Galbraith wrote:

> -	if (pick_eevdf(cfs_rq) == pse)
> -		goto preempt;
> -
> -	return;
> +	if (pick_eevdf(cfs_rq) == se)
> +		return;

Right, this will preempt more.

This is probably going to make Prateek's case worse though. Then again,
I was already leaning to towards not making his stronger slice
protection default, because it simply hurts too much elsewhere.

Still, his observation that placing tasks can move V left which in turn
can cause the just scheduled in current non-eligible and cause
over-scheduling is valid -- just not sure what to do about it yet.