From: Joel Fernandes <joelaf@google.com>
To: Quentin Perret <quentin.perret@arm.com>
Cc: Patrick Bellasi <patrick.bellasi@arm.com>,
Dietmar Eggemann <dietmar.eggemann@arm.com>,
LKML <linux-kernel@vger.kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Thara Gopinath <thara.gopinath@linaro.org>,
Linux PM <linux-pm@vger.kernel.org>,
Morten Rasmussen <morten.rasmussen@arm.com>,
Chris Redpath <chris.redpath@arm.com>,
Valentin Schneider <valentin.schneider@arm.com>,
"Rafael J . Wysocki" <rjw@rjwysocki.net>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Vincent Guittot <vincent.guittot@linaro.org>,
Viresh Kumar <viresh.kumar@linaro.org>,
Todd Kjos <tkjos@google.com>
Subject: Re: [RFC PATCH 5/6] sched/fair: Select an energy-efficient CPU on task wake-up
Date: Sat, 24 Mar 2018 17:12:20 -0700 [thread overview]
Message-ID: <CAJWu+oqVYFT2fNw6nOE2z4sHLU9+o+ZdyfF3XHNo86K9kZJsUw@mail.gmail.com> (raw)
In-Reply-To: <20180324014757.GC1317@queper01-VirtualBox>
On Fri, Mar 23, 2018 at 6:47 PM, Quentin Perret <quentin.perret@arm.com> wrote:
> On Thursday 22 Mar 2018 at 13:19:03 (-0700), Joel Fernandes wrote:
>> On Thu, Mar 22, 2018 at 11:06 AM, Patrick Bellasi
>> <patrick.bellasi@arm.com> wrote:
>
> [...]
>
>> >> > @@ -6555,6 +6613,14 @@ select_task_rq_fair(struct task_struct *p, int prev_cpu, int sd_flag, int wake_f
>> >> > break;
>> >> > }
>> >> >
>> >> > + /*
>> >> > + * Energy-aware task placement is performed on the highest
>> >> > + * non-overutilized domain spanning over cpu and prev_cpu.
>> >> > + */
>> >> > + if (want_energy && !sd_overutilized(tmp) &&
>> >> > + cpumask_test_cpu(prev_cpu, sched_domain_span(tmp)))
>> >>
>> >> Shouldn't you check for the SD_ASYM_CPUCAPACITY flag here for tmp level?
>> >
>> > ... and this then should be covered by the previous check in
>> > wake_energy(), which sets want_energy.
>>
>> Right, but in a scenario which probably doesn't exist today where we
>> have both SD_ASYM_CPUCAPACITY and !SD_ASYM_CPUCAPACITY domains in the
>> hierarchy for which want_energy = 1, I was thinking if its more future
>> proof to check it and not make assumptions...
>
> So we can definitely have cases where SD_ASYM_CPUCAPACITY is not set at all
> sd levels. Today, on mobile systems, this flag is typically set only at DIE
> level for big.LITTLE platforms, and not at MC level.
> We enable EAS if we find _at least_ one domain that has this flag in the
> hierarchy, just to make sure we don't enable EAS for symmetric platform.
> It's just a way to check a property about the topology when EAS starts, not
> really a way to actually select the sd at which we do scheduling at
> runtime.
Yes Ok you're right we do have the ASYM flag set at some sd levels but
not others at the moment. Sorry about the hasty comment. I understand
what you're doing now, I am Ok with that.
thanks,
- Joel
next prev parent reply other threads:[~2018-03-25 0:12 UTC|newest]
Thread overview: 54+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-20 9:43 [RFC PATCH 0/6] Energy Aware Scheduling Dietmar Eggemann
2018-03-20 9:43 ` [RFC PATCH 1/6] sched/fair: Create util_fits_capacity() Dietmar Eggemann
2018-03-20 9:43 ` [RFC PATCH 2/6] sched: Introduce energy models of CPUs Dietmar Eggemann
2018-03-20 9:52 ` Greg Kroah-Hartman
2018-03-21 0:45 ` Quentin Perret
2018-03-25 13:48 ` Quentin Perret
2018-03-26 22:26 ` Dietmar Eggemann
2018-04-09 12:01 ` Peter Zijlstra
2018-04-09 13:45 ` Quentin Perret
2018-04-09 15:32 ` Peter Zijlstra
2018-04-09 16:42 ` Quentin Perret
2018-04-10 6:55 ` Rafael J. Wysocki
2018-04-10 9:31 ` Quentin Perret
2018-04-10 10:20 ` Rafael J. Wysocki
2018-03-20 9:43 ` [RFC PATCH 3/6] sched: Add over-utilization/tipping point indicator Dietmar Eggemann
2018-04-09 9:40 ` Peter Zijlstra
2018-04-09 9:47 ` Peter Zijlstra
2018-04-09 9:53 ` Dietmar Eggemann
2018-04-09 11:49 ` Peter Zijlstra
2018-03-20 9:43 ` [RFC PATCH 4/6] sched/fair: Introduce an energy estimation helper function Dietmar Eggemann
2018-03-21 9:04 ` Juri Lelli
2018-03-21 12:26 ` Patrick Bellasi
2018-03-21 12:59 ` Juri Lelli
2018-03-21 13:55 ` Quentin Perret
2018-03-21 15:15 ` Juri Lelli
2018-03-21 16:26 ` Morten Rasmussen
2018-03-21 17:02 ` Juri Lelli
2018-03-21 14:02 ` Quentin Perret
2018-03-21 21:15 ` Dietmar Eggemann
2018-03-21 12:39 ` Patrick Bellasi
2018-03-21 14:26 ` Quentin Perret
2018-03-21 14:50 ` Juri Lelli
2018-03-21 15:54 ` Patrick Bellasi
2018-03-22 5:05 ` Quentin Perret
2018-03-20 9:43 ` [RFC PATCH 5/6] sched/fair: Select an energy-efficient CPU on task wake-up Dietmar Eggemann
2018-03-21 15:35 ` Patrick Bellasi
2018-03-22 20:10 ` Joel Fernandes
2018-03-23 15:47 ` Morten Rasmussen
2018-03-24 1:13 ` Joel Fernandes
2018-03-24 1:34 ` Quentin Perret
2018-03-24 6:06 ` Joel Fernandes
2018-03-24 1:22 ` Quentin Perret
2018-03-25 1:52 ` Quentin Perret
2018-03-22 16:27 ` Joel Fernandes
2018-03-22 18:06 ` Patrick Bellasi
2018-03-22 20:19 ` Joel Fernandes
2018-03-24 1:47 ` Quentin Perret
2018-03-25 0:12 ` Joel Fernandes [this message]
2018-03-23 16:00 ` Morten Rasmussen
2018-03-24 0:36 ` Joel Fernandes
2018-03-25 1:38 ` Quentin Perret
2018-03-20 9:43 ` [RFC PATCH 6/6] drivers: base: arch_topology.c: Enable EAS for arm/arm64 platforms Dietmar Eggemann
2018-03-20 9:49 ` Greg Kroah-Hartman
2018-03-20 15:20 ` Dietmar Eggemann
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=CAJWu+oqVYFT2fNw6nOE2z4sHLU9+o+ZdyfF3XHNo86K9kZJsUw@mail.gmail.com \
--to=joelaf@google.com \
--cc=chris.redpath@arm.com \
--cc=dietmar.eggemann@arm.com \
--cc=gregkh@linuxfoundation.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-pm@vger.kernel.org \
--cc=morten.rasmussen@arm.com \
--cc=patrick.bellasi@arm.com \
--cc=peterz@infradead.org \
--cc=quentin.perret@arm.com \
--cc=rjw@rjwysocki.net \
--cc=thara.gopinath@linaro.org \
--cc=tkjos@google.com \
--cc=valentin.schneider@arm.com \
--cc=vincent.guittot@linaro.org \
--cc=viresh.kumar@linaro.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).