Re: [PATCH 7/9] sched/fair: Do not try to migrate delayed dequeue task

[Peter Zijlstra]

On Thu, Nov 28, 2024 at 11:03:44AM +0100, Vincent Guittot wrote:
> On Thu, 28 Nov 2024 at 10:49, Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:
> >
> > On Thu, Nov 28, 2024 at 10:27:48AM +0100, Vincent Guittot wrote:
> > > Migrating a delayed dequeued task doesn't help in balancing the number
> > > of runnable tasks in the system.
> >
> > But it can help balance the weight; furthermore, by moving them to a
> > lighter queue, they'll get picked sooner and disappear sooner.
> 
> When groups are not overloaded, we don't compare load but only running
> tasks t balance them across cpus
> 
> It's only when both src and dst groups are overloaded that we look at
> the load and the weight
> 
> >
> > Perhaps make it: p->se.sched_delayed && !env->sd->nr_balance_failed ?
> 
> So we could take into account which type of migration with
> env->migration_type == migrate_load

Yeah that makes sense.