From: Peter Zijlstra <peterz@infradead.org>
To: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Yuyang Du <yuyang.du@intel.com>, Ingo Molnar <mingo@kernel.org>,
linux-kernel <linux-kernel@vger.kernel.org>,
Mike Galbraith <umgwanakikbuti@gmail.com>,
Benjamin Segall <bsegall@google.com>,
Paul Turner <pjt@google.com>,
Morten Rasmussen <morten.rasmussen@arm.com>,
Dietmar Eggemann <dietmar.eggemann@arm.com>,
Matt Fleming <matt@codeblueprint.co.uk>
Subject: Re: [PATCH 4/4] sched,fair: Fix PELT integrity for new tasks
Date: Fri, 17 Jun 2016 16:28:14 +0200 [thread overview]
Message-ID: <20160617142814.GT30154@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <CAKfTPtAUtteP0V5-1u2n0YFDdFbZfwSqigHjOfM32Vbw3iAPbg@mail.gmail.com>
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.
next prev parent reply other threads:[~2016-06-17 14:28 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-17 12:01 [PATCH 0/4] sched/fair: Fix PELT wobblies Peter Zijlstra
2016-06-17 12:01 ` [PATCH 1/4] sched: Optimize fork() paths Peter Zijlstra
2016-06-17 12:01 ` [PATCH 2/4] sched/fair: Fix PELT integrity for new groups Peter Zijlstra
2016-06-17 13:51 ` Vincent Guittot
2016-06-17 12:01 ` [PATCH 3/4] sched,cgroup: Fix cpu_cgroup_fork() Peter Zijlstra
2016-06-17 13:58 ` Vincent Guittot
2016-06-17 14:06 ` Peter Zijlstra
2016-06-17 12:01 ` [PATCH 4/4] sched,fair: Fix PELT integrity for new tasks Peter Zijlstra
2016-06-17 14:09 ` Vincent Guittot
2016-06-17 14:28 ` Peter Zijlstra [this message]
2016-06-17 16:02 ` Peter Zijlstra
2016-06-17 16:14 ` Vincent Guittot
2016-06-17 16:18 ` Peter Zijlstra
2016-06-19 22:55 ` Yuyang Du
2016-06-20 9:23 ` Vincent Guittot
2016-06-20 9:52 ` Peter Zijlstra
2016-06-20 10:07 ` Vincent Guittot
2016-06-21 11:43 ` Peter Zijlstra
2016-06-21 12:36 ` Vincent Guittot
2016-06-21 12:47 ` Peter Zijlstra
2016-06-21 12:56 ` Vincent Guittot
2016-06-20 11:35 ` Dietmar Eggemann
2016-06-20 12:35 ` Vincent Guittot
2016-06-20 14:49 ` Dietmar Eggemann
2016-06-21 8:41 ` Peter Zijlstra
2016-06-21 4:51 ` Yuyang Du
2016-06-24 13:03 ` Peter Zijlstra
2016-08-09 23:19 ` Yuyang Du
2016-06-21 13:17 ` Peter Zijlstra
2016-06-21 13:29 ` Vincent Guittot
2016-06-22 11:46 ` Peter Zijlstra
2016-06-23 15:35 ` Dietmar Eggemann
2016-06-23 17:15 ` Peter Zijlstra
2016-06-20 14:27 ` Peter Zijlstra
2016-06-23 11:19 ` Peter Zijlstra
2016-08-01 7:30 ` Wanpeng Li
2016-08-01 9:31 ` Mike Galbraith
2016-08-01 9:56 ` Wanpeng Li
2016-08-01 11:52 ` Mike Galbraith
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