From: Dietmar Eggemann <dietmar.eggemann@arm.com>
To: Vincent Guittot <vincent.guittot@linaro.org>,
Quentin Perret <quentin.perret@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
"Rafael J. Wysocki" <rjw@rjwysocki.net>,
linux-kernel <linux-kernel@vger.kernel.org>,
"open list:THERMAL" <linux-pm@vger.kernel.org>,
"gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
Ingo Molnar <mingo@redhat.com>,
Morten Rasmussen <morten.rasmussen@arm.com>,
Chris Redpath <chris.redpath@arm.com>,
Patrick Bellasi <patrick.bellasi@arm.com>,
Valentin Schneider <valentin.schneider@arm.com>,
Thara Gopinath <thara.gopinath@linaro.org>,
viresh kumar <viresh.kumar@linaro.org>,
Todd Kjos <tkjos@google.com>,
Joel Fernandes <joel@joelfernandes.org>,
"Cc: Steve Muckle" <smuckle@google.com>,
adharmap@quicinc.com, "Kannan, Saravana" <skannan@quicinc.com>,
pkondeti@codeaurora.org, Juri Lelli <juri.lelli@redhat.com>,
Eduardo Valentin <edubezval@gmail.com>,
Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>,
currojerez@riseup.net, Javi Merino <javi.merino@kernel.org>
Subject: Re: [PATCH v5 09/14] sched: Add over-utilization/tipping point indicator
Date: Mon, 6 Aug 2018 12:08:07 +0200 [thread overview]
Message-ID: <68689fcb-3cb8-4685-58ef-0bec84be2047@arm.com> (raw)
In-Reply-To: <CAKfTPtBT-p-Z0EneirfOTwUw=5jEeDGa+4_EE4ogi2Ht7GU9Bg@mail.gmail.com>
On 08/06/2018 10:40 AM, Vincent Guittot wrote:
> On Fri, 3 Aug 2018 at 17:55, Quentin Perret <quentin.perret@arm.com> wrote:
>>
>> On Friday 03 Aug 2018 at 15:49:24 (+0200), Vincent Guittot wrote:
>>> On Fri, 3 Aug 2018 at 10:18, Quentin Perret <quentin.perret@arm.com> wrote:
>>>>
>>>> On Friday 03 Aug 2018 at 09:48:47 (+0200), Vincent Guittot wrote:
>>>>> On Thu, 2 Aug 2018 at 18:59, Quentin Perret <quentin.perret@arm.com> wrote:
[...]
>> I think we're discussing two different things right now:
>> 1. Should forkees go in find_energy_efficient_cpu() ?
>> 2. Should forkees have 0 of initial util_avg when EAS is enabled ?
>
> It's the same topic: How EAS should consider a newly created task ?
>
> For now, we let the "performance" mode selects a CPU. This CPU will
> most probably be worst CPU from a EAS pov because it's the idlest CPU
> in the idlest group which is the opposite of what EAS tries to do
>
> The current behavior is :
> For every new task, the cpu selection is done assuming it's a heavy
> task with the max possible load_avg, and it looks for the idlest cpu.
> This means that if the system is lightly loaded, scheduler will select
> most probably a idle big core.
AFAICS, task load doesn't seem to be used for find_idlest_cpu() (
find_idlest_group() and find_idlest_group_cpu()). So the forkee
(SD_BALANCE_FORK) is placed independently of his task load.
Task load (task_h_load(p)) is used in
wake_affine()->wake_affine_weight() but for this to be called it has to
be a wakeup (SD_BALANCE_WAKE).
> The utilization of this new task is then set to half of the remaining
> capacity of the selected CPU which means that the idlest you are, the
> biggest the task will be initialized to. This can easily be half a big
> core which can be bigger than the max capacity of a little like on
> hikey960. Then, util_est will keep track of this value for a while
> which will make this task like a big one.
[...]
next prev parent reply other threads:[~2018-08-06 10:08 UTC|newest]
Thread overview: 72+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-24 12:25 [PATCH v5 00/14] Energy Aware Scheduling Quentin Perret
2018-07-24 12:25 ` [PATCH v5 01/14] sched: Relocate arch_scale_cpu_capacity Quentin Perret
2018-07-24 12:25 ` [PATCH v5 02/14] sched/cpufreq: Factor out utilization to frequency mapping Quentin Perret
2018-07-24 12:25 ` [PATCH v5 03/14] PM: Introduce an Energy Model management framework Quentin Perret
2018-08-09 21:52 ` Rafael J. Wysocki
2018-08-10 8:15 ` Quentin Perret
2018-08-10 8:41 ` Rafael J. Wysocki
2018-08-10 9:12 ` Quentin Perret
2018-08-10 11:13 ` Rafael J. Wysocki
2018-08-10 12:30 ` Quentin Perret
2018-08-12 9:49 ` Rafael J. Wysocki
2018-07-24 12:25 ` [PATCH v5 04/14] PM / EM: Expose the Energy Model in sysfs Quentin Perret
2018-07-24 12:25 ` [PATCH v5 05/14] sched/topology: Reference the Energy Model of CPUs when available Quentin Perret
2018-07-24 12:25 ` [PATCH v5 06/14] sched/topology: Lowest energy aware balancing sched_domain level pointer Quentin Perret
2018-07-26 16:00 ` Valentin Schneider
2018-07-26 17:01 ` Quentin Perret
2018-07-24 12:25 ` [PATCH v5 07/14] sched/topology: Introduce sched_energy_present static key Quentin Perret
2018-07-24 12:25 ` [PATCH v5 08/14] sched/fair: Clean-up update_sg_lb_stats parameters Quentin Perret
2018-07-24 12:25 ` [PATCH v5 09/14] sched: Add over-utilization/tipping point indicator Quentin Perret
2018-08-02 12:26 ` Peter Zijlstra
2018-08-02 13:03 ` Quentin Perret
2018-08-02 13:08 ` Peter Zijlstra
2018-08-02 13:18 ` Quentin Perret
2018-08-02 13:48 ` Vincent Guittot
2018-08-02 14:14 ` Quentin Perret
2018-08-02 15:14 ` Vincent Guittot
2018-08-02 15:30 ` Quentin Perret
2018-08-02 15:55 ` Vincent Guittot
2018-08-02 16:00 ` Quentin Perret
2018-08-02 16:07 ` Vincent Guittot
2018-08-02 16:10 ` Quentin Perret
2018-08-02 16:38 ` Vincent Guittot
2018-08-02 16:59 ` Quentin Perret
2018-08-03 7:48 ` Vincent Guittot
2018-08-03 8:18 ` Quentin Perret
2018-08-03 13:49 ` Vincent Guittot
2018-08-03 14:21 ` Vincent Guittot
2018-08-03 15:55 ` Quentin Perret
2018-08-06 8:40 ` Vincent Guittot
2018-08-06 9:43 ` Quentin Perret
2018-08-06 10:45 ` Vincent Guittot
2018-08-06 11:02 ` Quentin Perret
2018-08-06 10:08 ` Dietmar Eggemann [this message]
2018-08-06 10:33 ` Vincent Guittot
2018-08-06 12:29 ` Dietmar Eggemann
2018-08-06 12:37 ` Vincent Guittot
2018-08-06 13:20 ` Dietmar Eggemann
2018-08-09 9:30 ` Vincent Guittot
2018-08-09 9:38 ` Quentin Perret
2018-07-24 12:25 ` [PATCH v5 10/14] sched/cpufreq: Refactor the utilization aggregation method Quentin Perret
2018-07-30 19:35 ` skannan
2018-07-31 7:59 ` Quentin Perret
2018-07-31 19:31 ` skannan
2018-08-01 7:32 ` Rafael J. Wysocki
2018-08-01 8:23 ` Quentin Perret
2018-08-01 8:35 ` Rafael J. Wysocki
2018-08-01 9:23 ` Quentin Perret
2018-08-01 9:40 ` Rafael J. Wysocki
2018-08-02 13:04 ` Peter Zijlstra
2018-08-02 15:39 ` Quentin Perret
2018-08-03 13:04 ` Quentin Perret
2018-08-02 12:33 ` Peter Zijlstra
2018-08-02 12:45 ` Peter Zijlstra
2018-08-02 15:21 ` Quentin Perret
2018-08-02 17:36 ` Peter Zijlstra
2018-08-03 12:42 ` Quentin Perret
2018-07-24 12:25 ` [PATCH v5 11/14] sched/fair: Introduce an energy estimation helper function Quentin Perret
2018-07-24 12:25 ` [PATCH v5 12/14] sched/fair: Select an energy-efficient CPU on task wake-up Quentin Perret
2018-08-02 13:54 ` Peter Zijlstra
2018-08-02 16:21 ` Quentin Perret
2018-07-24 12:25 ` [PATCH v5 13/14] OPTIONAL: arch_topology: Start Energy Aware Scheduling Quentin Perret
2018-07-24 12:25 ` [PATCH v5 14/14] OPTIONAL: cpufreq: dt: Register an Energy Model Quentin Perret
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