From: Dietmar Eggemann <dietmar.eggemann@arm.com> To: Vincent Guittot <vincent.guittot@linaro.org> Cc: Quentin Perret <quentin.perret@arm.com>, 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 15:20:27 +0200 [thread overview] Message-ID: <454ee0da-9c6c-6944-25e5-0fbbf89bc3b6@arm.com> (raw) In-Reply-To: <CAKfTPtDZs2_4skbGFJkrtq1Z+G_MWue7xC3tcoLs5xcpsBkNUw@mail.gmail.com> On 08/06/2018 02:37 PM, Vincent Guittot wrote: > On Mon, 6 Aug 2018 at 14:29, Dietmar Eggemann <dietmar.eggemann@arm.com> wrote: >> >> On 08/06/2018 12:33 PM, Vincent Guittot wrote: >>> On Mon, 6 Aug 2018 at 12:08, Dietmar Eggemann <dietmar.eggemann@arm.com> wrote: >>>> >>>> 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. >>> >>> hmm ... so what is used if load or runnable load are not used ? >>> find_idlest_group() uses load and runnable load but skip spare >>> capacity in case of fork >> >> Yes, runnable load and load are used, but from the cpus, not from the task. > > yes that's right, I have skipped the "task" word when reading. > So scheduler looks for the idlest CPU taking into account only CPU > loads. Then the task load starts to highest value until it get a > chance to reduce and stabilize to its final value This could potentially allow us to find a better init value for sa->[runnable]_load_avg. At least we could use the information of the initial task rq. > >> >> [...]
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From: Dietmar Eggemann <dietmar.eggemann@arm.com> To: Vincent Guittot <vincent.guittot@linaro.org> Cc: Quentin Perret <quentin.perret@arm.com>, 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 Subject: Re: [PATCH v5 09/14] sched: Add over-utilization/tipping point indicator Date: Mon, 6 Aug 2018 15:20:27 +0200 [thread overview] Message-ID: <454ee0da-9c6c-6944-25e5-0fbbf89bc3b6@arm.com> (raw) In-Reply-To: <CAKfTPtDZs2_4skbGFJkrtq1Z+G_MWue7xC3tcoLs5xcpsBkNUw@mail.gmail.com> On 08/06/2018 02:37 PM, Vincent Guittot wrote: > On Mon, 6 Aug 2018 at 14:29, Dietmar Eggemann <dietmar.eggemann@arm.com> wrote: >> >> On 08/06/2018 12:33 PM, Vincent Guittot wrote: >>> On Mon, 6 Aug 2018 at 12:08, Dietmar Eggemann <dietmar.eggemann@arm.com> wrote: >>>> >>>> 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. >>> >>> hmm ... so what is used if load or runnable load are not used ? >>> find_idlest_group() uses load and runnable load but skip spare >>> capacity in case of fork >> >> Yes, runnable load and load are used, but from the cpus, not from the task. > > yes that's right, I have skipped the "task" word when reading. > So scheduler looks for the idlest CPU taking into account only CPU > loads. Then the task load starts to highest value until it get a > chance to reduce and stabilize to its final value This could potentially allow us to find a better init value for sa->[runnable]_load_avg. At least we could use the information of the initial task rq. > >> >> [...]
next prev parent reply other threads:[~2018-08-06 13:20 UTC|newest] Thread overview: 108+ 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 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 2018-08-12 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 13:48 ` Vincent Guittot 2018-08-02 14:14 ` Quentin Perret 2018-08-02 14:14 ` Quentin Perret 2018-08-02 15:14 ` Vincent Guittot 2018-08-02 15:14 ` Vincent Guittot 2018-08-02 15:30 ` Quentin Perret 2018-08-02 15:30 ` Quentin Perret 2018-08-02 15:55 ` Vincent Guittot 2018-08-02 15:55 ` Vincent Guittot 2018-08-02 16:00 ` Quentin Perret 2018-08-02 16:00 ` Quentin Perret 2018-08-02 16:07 ` Vincent Guittot 2018-08-02 16:07 ` Vincent Guittot 2018-08-02 16:10 ` Quentin Perret 2018-08-02 16:10 ` Quentin Perret 2018-08-02 16:38 ` Vincent Guittot 2018-08-02 16:38 ` Vincent Guittot 2018-08-02 16:59 ` Quentin Perret 2018-08-02 16:59 ` Quentin Perret 2018-08-03 7:48 ` Vincent Guittot 2018-08-03 7:48 ` Vincent Guittot 2018-08-03 8:18 ` Quentin Perret 2018-08-03 8:18 ` Quentin Perret 2018-08-03 13:49 ` Vincent Guittot 2018-08-03 13:49 ` Vincent Guittot 2018-08-03 14:21 ` Vincent Guittot 2018-08-03 14:21 ` Vincent Guittot 2018-08-03 15:55 ` Quentin Perret 2018-08-03 15:55 ` Quentin Perret 2018-08-06 8:40 ` Vincent Guittot 2018-08-06 8:40 ` Vincent Guittot 2018-08-06 9:43 ` Quentin Perret 2018-08-06 9:43 ` Quentin Perret 2018-08-06 10:45 ` Vincent Guittot 2018-08-06 10:45 ` Vincent Guittot 2018-08-06 11:02 ` Quentin Perret 2018-08-06 11:02 ` Quentin Perret 2018-08-06 10:08 ` Dietmar Eggemann 2018-08-06 10:08 ` Dietmar Eggemann 2018-08-06 10:33 ` Vincent Guittot 2018-08-06 10:33 ` Vincent Guittot 2018-08-06 12:29 ` Dietmar Eggemann 2018-08-06 12:29 ` Dietmar Eggemann 2018-08-06 12:37 ` Vincent Guittot 2018-08-06 12:37 ` Vincent Guittot 2018-08-06 13:20 ` Dietmar Eggemann [this message] 2018-08-06 13:20 ` Dietmar Eggemann 2018-08-09 9:30 ` Vincent Guittot 2018-08-09 9:30 ` Vincent Guittot 2018-08-09 9:38 ` Quentin Perret 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 7:32 ` Rafael J. Wysocki 2018-08-01 8:23 ` Quentin Perret 2018-08-01 8:23 ` Quentin Perret 2018-08-01 8:35 ` Rafael J. Wysocki 2018-08-01 8:35 ` Rafael J. Wysocki 2018-08-01 9:23 ` Quentin Perret 2018-08-01 9:23 ` Quentin Perret 2018-08-01 9:40 ` Rafael J. Wysocki 2018-08-01 9:40 ` Rafael J. Wysocki 2018-08-02 13:04 ` Peter Zijlstra 2018-08-02 13:04 ` Peter Zijlstra 2018-08-02 15:39 ` Quentin Perret 2018-08-02 15:39 ` Quentin Perret 2018-08-03 13:04 ` 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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