Re: [PATCH 2/9] sched/fair: Add new cfs_rq.h_nr_enqueued

[Peter Zijlstra <peterz@infradead.org>]

On Thu, Nov 28, 2024 at 11:24:45AM +0100, Vincent Guittot wrote:
> On Thu, 28 Nov 2024 at 10:56, Peter Zijlstra <peterz@infradead.org> wrote:
> >
> > On Thu, Nov 28, 2024 at 10:27:43AM +0100, Vincent Guittot wrote:
> > > With delayed dequeued feature, a sleeping sched_entity remains enqueued
> > > in the rq until its lag has elapsed. As a result, it stays also visible
> > > in the statistics that are used to balance the system and in particular
> > > the field h_nr_running when the sched_entity is associated to a task.
> > >
> > > Create a new h_nr_enqueued that tracks all enqueued tasks and restore the
> > > behavior of h_nr_running i.e. tracking the number of fair tasks that want
> > > to run.
> >
> > Isn't h_nr_enqueued := h_nr_running - h_nr_delayed ? Does it really make
> > sense to have another variable that is so trivially computable?
> 
> I changed h_nr_running to track only running tasks and not delayed dequeue

Yes, that was hidden so well, I couldn't even find it on the second
reading :/