From: Joel Fernandes <joelaf@google.com>
To: Steve Muckle <smuckle@google.com>
Cc: LKML <linux-kernel@vger.kernel.org>,
Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>,
Len Brown <lenb@kernel.org>,
"Rafael J . Wysocki" <rjw@rjwysocki.net>,
Viresh Kumar <viresh.kumar@linaro.org>,
Ingo Molnar <mingo@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Juri Lelli <juri.lelli@arm.com>,
Patrick Bellasi <patrick.bellasi@arm.com>,
kernel-team@android.com
Subject: Re: [PATCH RFC RESEND v2 0/2] Prevent cpufreq update for only task on rq that sleeps
Date: Thu, 7 Sep 2017 11:58:29 -0700 [thread overview]
Message-ID: <CAJWu+oq0_3kTbPqLXWHPg+yMLbJqmC7753R6wCVUp=_pS+m9Gg@mail.gmail.com> (raw)
In-Reply-To: <069bbd75-f1f8-f30b-cd2a-2f143a065c66@google.com>
Hi Steve,
On Thu, Sep 7, 2017 at 11:10 AM, Steve Muckle <smuckle@google.com> wrote:
> On 09/07/2017 09:14 AM, Joel Fernandes wrote:
>>
>> I'm planning to rebase this series on Linus's master and post it
>> again, but just checking any thoughts about it?
>>
>> Just to add more context, the reason for not updating the frequency:
>>
>> - When a last dequeue of a sleeping task happens, it is sufficient to
>> update utilization without updating the frequency because if other
>> CPUs are busy then their updates will consider the utilization of the
>> idle CPU in the shared policy unless sufficient time has passed.
>>
>> - If the last dequeue of a sleeping task happens while all other CPUs
>> in the cluster are idle, then the cluster will likely enter
>> cluster-idle soon.
>
>
> To clarify - when you say "last dequeue of a sleeping task happens" above,
> you're referring to the dequeue of the last task running on the CPU,
> correct? I.e. the CPU is about to go idle?
Yes that's right, sorry for my poor choice of words. I am referring to
dequeue of a task that is DEQUEUE_SLEEP and is the only task on the
RQ.
> It's been a while since I've looked at this area so would like to hold off
> for a rebased version to review in further detail. But I think the concept
> is valid.
Sure and thanks for making time for the review!
-Joel
prev parent reply other threads:[~2017-09-07 18:58 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-03 20:15 [PATCH RFC RESEND v2 0/2] Prevent cpufreq update for only task on rq that sleeps Joel Fernandes
2017-09-03 20:15 ` [PATCH RFC v2 1/2] Revert "sched/fair: Drop always true parameter of update_cfs_rq_load_avg()" Joel Fernandes
2017-09-03 20:15 ` [PATCH RFC v2 2/2] sched/fair: Skip frequency update if CPU about to idle Joel Fernandes
2017-09-07 16:14 ` [PATCH RFC RESEND v2 0/2] Prevent cpufreq update for only task on rq that sleeps Joel Fernandes
2017-09-07 18:10 ` Steve Muckle
2017-09-07 18:58 ` Joel Fernandes [this message]
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+oq0_3kTbPqLXWHPg+yMLbJqmC7753R6wCVUp=_pS+m9Gg@mail.gmail.com' \
--to=joelaf@google.com \
--cc=juri.lelli@arm.com \
--cc=kernel-team@android.com \
--cc=lenb@kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@redhat.com \
--cc=patrick.bellasi@arm.com \
--cc=peterz@infradead.org \
--cc=rjw@rjwysocki.net \
--cc=smuckle@google.com \
--cc=srinivas.pandruvada@linux.intel.com \
--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).