From: Peter Zijlstra <peterz@infradead.org>
To: Quentin Perret <quentin.perret@arm.com>
Cc: skannan@codeaurora.org, rjw@rjwysocki.net,
linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org,
gregkh@linuxfoundation.org, mingo@redhat.com,
dietmar.eggemann@arm.com, morten.rasmussen@arm.com,
chris.redpath@arm.com, patrick.bellasi@arm.com,
valentin.schneider@arm.com, vincent.guittot@linaro.org,
thara.gopinath@linaro.org, viresh.kumar@linaro.org,
tkjos@google.com, joel@joelfernandes.org, smuckle@google.com,
adharmap@quicinc.com, skannan@quicinc.com,
pkondeti@codeaurora.org, juri.lelli@redhat.com,
edubezval@gmail.com, srinivas.pandruvada@linux.intel.com,
currojerez@riseup.net, javi.merino@kernel.org,
linux-pm-owner@vger.kernel.org
Subject: Re: [PATCH v5 10/14] sched/cpufreq: Refactor the utilization aggregation method
Date: Thu, 2 Aug 2018 19:36:01 +0200 [thread overview]
Message-ID: <20180802173601.GO2494@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20180802152109.2k45jqbfquef6u62@queper01-lin>
On Thu, Aug 02, 2018 at 04:21:11PM +0100, Quentin Perret wrote:
> On Thursday 02 Aug 2018 at 14:45:11 (+0200), Peter Zijlstra wrote:
> > To clarify, it makes absolutely no sense what so ever to attempt EAS
> > when the DVFS control is not coordinated.
>
> I tend to agree with that, but at the same time even if we create a very
> strong dependency on schedutil, we will have no guarantee that the actual
> frequencies used on the platform are the ones we predicted in EAS.
Sure; on x86 for example our micro-code does whatever. But using
schedutil we at least 'guide' it in the general direction we'd expect
with the control that is available.
Using a !schedutil governor doesn't even get us that and we're basically
running on random input without any feedback to close the loop. Not
something I feel we should support or care for.
next prev parent reply other threads:[~2018-08-02 17:36 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
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 [this message]
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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