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From: Vincent Guittot <vincent.guittot@linaro.org>
To: Tejun Heo <tj@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@redhat.com>,
	linux-kernel <linux-kernel@vger.kernel.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Mike Galbraith <efault@gmx.de>, Paul Turner <pjt@google.com>,
	Chris Mason <clm@fb.com>,
	kernel-team@fb.com
Subject: Re: [PATCH 2/2] sched/fair: Always propagate runnable_load_avg
Date: Thu, 4 May 2017 21:02:39 +0200	[thread overview]
Message-ID: <CAKfTPtAEwFMbobPDXTShBezZhwvxkNPTMWfb3BUfiExaCaq9pg@mail.gmail.com> (raw)
In-Reply-To: <20170504174341.GC7288@htj.duckdns.org>

Hi Tejun,

On 4 May 2017 at 19:43, Tejun Heo <tj@kernel.org> wrote:
> Hello,
>
> On Thu, May 04, 2017 at 10:19:46AM +0200, Vincent Guittot wrote:
>> > schbench inside a cgroup and have some base load, it is actually
>> > expected to show worse latency.  You need to give higher weight to the
>> > cgroup matching the number of active threads (to be accruate, scaled
>> > by duty cycle but shouldn't matter too much in practice).
>>
>> I don't have to change anything cgroup weight with mainline to get
>> good number which means that the base load which is quite close to
>> null, is probably not the problem
>
> So, while that *could* be the case, it could also be the baseline
> incorrectly favoring the nested cfs_rqs over other tasks because of
> the nested runnables being inflated with blocked load avgs.  I think
> it'd be a good idea to test with matching weight to put things on the
> even ground.

In the trace i have uploaded, you will see that regressions happen
whereas there is no other runnable threads around so it's not a matter
of background activities that disturbs schbench

Thanks
Vincent

>
> Thanks.
>
> --
> tejun

  reply	other threads:[~2017-05-04 19:03 UTC|newest]

Thread overview: 69+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-04-24 20:13 [RFC PATCHSET] sched/fair: fix load balancer behavior when cgroup is in use Tejun Heo
2017-04-24 20:14 ` [PATCH 1/2] sched/fair: Fix how load gets propagated from cfs_rq to its sched_entity Tejun Heo
2017-04-24 21:33   ` [PATCH v2 " Tejun Heo
2017-05-03 18:00     ` Peter Zijlstra
2017-05-03 21:45       ` Tejun Heo
2017-05-04  5:51         ` Peter Zijlstra
2017-05-04  6:21           ` Peter Zijlstra
2017-05-04  9:49             ` Dietmar Eggemann
2017-05-04 10:57               ` Peter Zijlstra
2017-05-04 17:39               ` Tejun Heo
2017-05-05 10:36                 ` Dietmar Eggemann
2017-05-04 10:26       ` Vincent Guittot
2017-04-25  8:35   ` [PATCH " Vincent Guittot
2017-04-25 18:12     ` Tejun Heo
2017-04-26 16:51       ` Vincent Guittot
2017-04-26 22:40         ` Tejun Heo
2017-04-27  7:00           ` Vincent Guittot
2017-05-01 14:17         ` Peter Zijlstra
2017-05-01 14:52           ` Peter Zijlstra
2017-05-01 21:56           ` Tejun Heo
2017-05-02  8:19             ` Peter Zijlstra
2017-05-02  8:30               ` Peter Zijlstra
2017-05-02 20:00                 ` Tejun Heo
2017-05-03  9:10                   ` Peter Zijlstra
2017-04-26 16:14   ` Vincent Guittot
2017-04-26 22:27     ` Tejun Heo
2017-04-27  8:59       ` Vincent Guittot
2017-04-28 17:46         ` Tejun Heo
2017-05-02  7:20           ` Vincent Guittot
2017-04-24 20:14 ` [PATCH 2/2] sched/fair: Always propagate runnable_load_avg Tejun Heo
2017-04-25  8:46   ` Vincent Guittot
2017-04-25  9:05     ` Vincent Guittot
2017-04-25 12:59       ` Vincent Guittot
2017-04-25 18:49         ` Tejun Heo
2017-04-25 20:49           ` Tejun Heo
2017-04-25 21:15             ` Chris Mason
2017-04-25 21:08           ` Tejun Heo
2017-04-26 10:21             ` Vincent Guittot
2017-04-27  0:30               ` Tejun Heo
2017-04-27  8:28                 ` Vincent Guittot
2017-04-28 16:14                   ` Tejun Heo
2017-05-02  6:56                     ` Vincent Guittot
2017-05-02 20:56                       ` Tejun Heo
2017-05-03  7:25                         ` Vincent Guittot
2017-05-03  7:54                           ` Vincent Guittot
2017-04-26 18:12   ` Vincent Guittot
2017-04-26 22:52     ` Tejun Heo
2017-04-27  8:29       ` Vincent Guittot
2017-04-28 20:33         ` Tejun Heo
2017-04-28 20:38           ` Tejun Heo
2017-05-01 15:56           ` Peter Zijlstra
2017-05-02 22:01             ` Tejun Heo
2017-05-02  7:18           ` Vincent Guittot
2017-05-02 13:26             ` Vincent Guittot
2017-05-02 22:37               ` Tejun Heo
2017-05-02 21:50             ` Tejun Heo
2017-05-03  7:34               ` Vincent Guittot
2017-05-03  9:37                 ` Peter Zijlstra
2017-05-03 10:37                   ` Vincent Guittot
2017-05-03 13:09                     ` Peter Zijlstra
2017-05-03 21:49                       ` Tejun Heo
2017-05-04  8:19                         ` Vincent Guittot
2017-05-04 17:43                           ` Tejun Heo
2017-05-04 19:02                             ` Vincent Guittot [this message]
2017-05-04 19:04                               ` Tejun Heo
2017-04-24 21:35 ` [PATCH 3/2] sched/fair: Skip __update_load_avg() on cfs_rq sched_entities Tejun Heo
2017-04-24 21:48   ` Peter Zijlstra
2017-04-24 22:54     ` Tejun Heo
2017-04-25 21:09   ` Tejun Heo

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