Re: [RFC PATCH V2 0/3] sched/fair: Fix nr-running vs delayed-dequeue

[Peter Zijlstra]

On Mon, Mar 03, 2025 at 06:52:38PM +0800, Xuewen Yan wrote:
> Delayed dequeued feature keeps a sleeping sched_entitiy enqueued until its
> lag has elapsed. As a result, it stays also visible in rq->nr_running.
> However, sometimes when using nr-running, we should not consider
> sched-delayed tasks.
> This serie fixes those by adding a helper function which return the
> number of sched-delayed tasks. And when we should get the real runnable
> tasks, we sub the nr-delayed tasks.
> 

Is there an actual performance improvement? Because when a runqueue
looses competition, delayed tasks very quickly dissipate.