Messages in this thread | | | From | Vincent Guittot <> | Date | Fri, 17 Jun 2016 18:14:54 +0200 | Subject | Re: [PATCH 4/4] sched,fair: Fix PELT integrity for new tasks |
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On 17 June 2016 at 18:02, Peter Zijlstra <peterz@infradead.org> wrote: > On Fri, Jun 17, 2016 at 04:28:14PM +0200, Peter Zijlstra wrote: >> 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 ? > > Right, an attach + detach, which basically ends up being: > >> > We just want to update >> > last_update_time of RT task to something different from 0 > > this. That's the same as starting as fair and then doing > switched_from_fair().
Yes that's also a possibility to add a way to call switched_from_fair for non fair task
> > So yes, ho-humm, how to go about doing that bestest. Lemme have a play. >
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