Messages in this thread | | | Date | Fri, 17 Jun 2016 16:28:14 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH 4/4] sched,fair: Fix PELT integrity for new tasks |
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On Fri, Jun 17, 2016 at 04:09:01PM +0200, Vincent Guittot wrote: > > > > Scenario 1: switch to fair class > > > > p->sched_class = fair_class; > > if (queued) > > enqueue_task(p); > > ... > > enqueue_entity() > > enqueue_entity_load_avg() > > migrated = !sa->last_update_time (true) > > if (migrated) > > attach_entity_load_avg() > > check_class_changed() > > switched_from() (!fair) > > switched_to() (fair) > > switched_to_fair() > > attach_entity_load_avg()
> > @@ -733,18 +737,21 @@ void post_init_entity_util_avg(struct sc > > } > > sa->util_sum = sa->util_avg * LOAD_AVG_MAX; > > } > > + > > + update_cfs_rq_load_avg(cfs_rq_clock_task(cfs_rq), cfs_rq, false); > > + attach_entity_load_avg(cfs_rq, se); > > A new RT task will be attached and will contribute to the load until > it decays to 0 > Should we detach it for non cfs task ? We just want to update > last_update_time of RT task to something different from 0
Won't we open up that (scenario 1) hole again? Maybe we can initialize !fair tasks to 0 load and have them ramp up once they get demoted back to fair?
Blergh, I'll go ponder moar.
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