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From: Rik van Riel <riel@surriel.com>
To: Dietmar Eggemann <dietmar.eggemann@arm.com>,
	linux-kernel@vger.kernel.org
Cc: kernel-team@fb.com, pjt@google.com, peterz@infradead.org,
	mingo@redhat.com, morten.rasmussen@arm.com, tglx@linutronix.de,
	mgorman@techsingularity.net, vincent.guittot@linaro.org
Subject: Re: [PATCH 13/15] sched,fair: propagate sum_exec_runtime up the hierarchy
Date: Wed, 28 Aug 2019 09:14:54 -0400	[thread overview]
Message-ID: <a35dd83b9ecadf4e136b588d7696a23e36ff2e9a.camel@surriel.com> (raw)
In-Reply-To: <f940abf6-3020-014c-74d7-d9be334e201c@arm.com>

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On Wed, 2019-08-28 at 09:51 +0200, Dietmar Eggemann wrote:
> On 22/08/2019 04:17, Rik van Riel wrote:
> > Now that enqueue_task_fair and dequeue_task_fair no longer iterate
> > up
> > the hierarchy all the time, a method to lazily propagate
> > sum_exec_runtime
> > up the hierarchy is necessary.
> > 
> > Once a tick, propagate the newly accumulated exec_runtime up the
> > hierarchy,
> > and feed it into CFS bandwidth control.
> > 
> > Remove the pointless call to account_cfs_rq_runtime from
> > update_curr,
> > which is always called with a root cfs_rq.
> 
> But what about the call to account_cfs_rq_runtime() in
> set_curr_task_fair()? Here you always call it with the root cfs_rq.
> Shouldn't this be called also in a loop over all se's until !se-
> >parent
> (like in propagate_exec_runtime() further below).

I believe that call should be only on the cgroup
cfs_rq, with account_cfs_rq_runtime figuring out
whether more runtime needs to be obtained from
further up in the hierarchy.

By default we should probably work under the assumption
that account_cfs_rq_runtime() will succeed at the current
level, and no gymnastics are required to obtain CPU time.

-- 
All Rights Reversed.

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  reply	other threads:[~2019-08-28 13:15 UTC|newest]

Thread overview: 46+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-22  2:17 [PATCH RFC v4 0/15] sched,fair: flatten CPU controller runqueues Rik van Riel
2019-08-22  2:17 ` [PATCH 01/15] sched: introduce task_se_h_load helper Rik van Riel
2019-08-23 18:13   ` Dietmar Eggemann
2019-08-24  0:05     ` Rik van Riel
2019-08-22  2:17 ` [PATCH 02/15] sched: change /proc/sched_debug fields Rik van Riel
2019-08-22  2:17 ` [PATCH 03/15] sched,fair: redefine runnable_load_avg as the sum of task_h_load Rik van Riel
2019-08-28 13:50   ` Vincent Guittot
2019-08-28 14:47     ` Rik van Riel
2019-08-28 15:02       ` Vincent Guittot
2019-08-22  2:17 ` [PATCH 04/15] sched,fair: move runnable_load_avg to cfs_rq Rik van Riel
2019-08-22  2:17 ` [PATCH 05/15] sched,fair: remove cfs_rqs from leaf_cfs_rq_list bottom up Rik van Riel
2019-08-28 14:09   ` Vincent Guittot
2019-08-22  2:17 ` [PATCH 06/15] sched,cfs: use explicit cfs_rq of parent se helper Rik van Riel
2019-08-28 13:53   ` Vincent Guittot
2019-08-28 15:28     ` Rik van Riel
2019-08-28 16:34       ` Vincent Guittot
2019-08-22  2:17 ` [PATCH 07/15] sched,cfs: fix zero length timeslice calculation Rik van Riel
2019-08-28 16:59   ` Vincent Guittot
2019-08-22  2:17 ` [PATCH 08/15] sched,fair: simplify timeslice length code Rik van Riel
2019-08-28 17:32   ` Vincent Guittot
2019-08-28 23:18     ` Rik van Riel
2019-08-29 14:02       ` Vincent Guittot
2019-08-29 16:00         ` Rik van Riel
2019-08-30  6:41           ` Vincent Guittot
2019-08-30 15:01             ` Rik van Riel
2019-09-02  7:51               ` Vincent Guittot
2019-09-02 17:47                 ` Rik van Riel
2019-08-22  2:17 ` [PATCH 09/15] sched,fair: refactor enqueue/dequeue_entity Rik van Riel
2019-09-03 15:38   ` Vincent Guittot
2019-09-03 20:27     ` Rik van Riel
2019-09-04  6:44       ` Vincent Guittot
2019-08-22  2:17 ` [PATCH 10/15] sched,fair: add helper functions for flattened runqueue Rik van Riel
2019-08-22  2:17 ` [PATCH 11/15] sched,fair: flatten hierarchical runqueues Rik van Riel
2019-08-23 18:14   ` Dietmar Eggemann
2019-08-24  1:16     ` Rik van Riel
2019-08-22  2:17 ` [PATCH 12/15] sched,fair: flatten update_curr functionality Rik van Riel
2019-08-27 10:37   ` Dietmar Eggemann
2019-08-22  2:17 ` [PATCH 13/15] sched,fair: propagate sum_exec_runtime up the hierarchy Rik van Riel
2019-08-28  7:51   ` Dietmar Eggemann
2019-08-28 13:14     ` Rik van Riel [this message]
2019-08-29 17:20       ` Dietmar Eggemann
2019-08-29 18:06         ` Rik van Riel
2019-08-22  2:17 ` [PATCH 14/15] sched,fair: ramp up task_se_h_weight quickly Rik van Riel
2019-08-22  2:17 ` [PATCH 15/15] sched,fair: scale vdiff in wakeup_preempt_entity Rik van Riel
2019-09-02 10:53 ` [PATCH RFC v4 0/15] sched,fair: flatten CPU controller runqueues Dietmar Eggemann
2019-09-03  1:44   ` Rik van Riel

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