From: Peter Zijlstra <peterz@infradead.org>
To: Juri Lelli <juri.lelli@arm.com>
Cc: mingo@redhat.com, rjw@rjwysocki.net, viresh.kumar@linaro.org,
linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org,
tglx@linutronix.de, vincent.guittot@linaro.org,
rostedt@goodmis.org, luca.abeni@santannapisa.it,
claudio@evidence.eu.com, tommaso.cucinotta@santannapisa.it,
bristot@redhat.com, mathieu.poirier@linaro.org,
tkjos@android.com, joelaf@google.com, andresoportus@google.com,
morten.rasmussen@arm.com, dietmar.eggemann@arm.com,
patrick.bellasi@arm.com
Subject: Re: [PATCH RFC 0/8] SCHED_DEADLINE freq/cpu invariance and OPP selection
Date: Wed, 24 May 2017 13:31:58 +0200 [thread overview]
Message-ID: <20170524113158.qoa3tagiyvtxkd7v@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20170524095053.sp6hy4erpyktcmoi@e106622-lin>
On Wed, May 24, 2017 at 10:50:53AM +0100, Juri Lelli wrote:
> Agreed. However, problem seems to be that
>
> - in my opinion (current implementation) this translated into scaling
> runtime considering current freq and cpu-max-capacity; and this is
> required when frequency scaling is enabled and we still want to meet
> a task's guaranteed bandwidth
Just so. The bandwidth they request is based on instructions/work. We
need to get a certain amount of instructions sorted. Nobody cares we get
an exact 10% at random frequency if they loose they finger because we
didn't get that final instruction out that stops the saw blade.
> - Luca seemed instead to be inclined to say that, if we scale runtime
> for !reclaim tasks, such tasks are basically allowed to run for more
> time (when frequency is lower than max) by using some of the
> bandwidth not allocated to themselves
Yes, that's a wrong view :-) We don't care about 'time', we care about
getting the instruction stream / work completed.
next prev parent reply other threads:[~2017-05-24 11:31 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-05-23 8:53 [PATCH RFC 0/8] SCHED_DEADLINE freq/cpu invariance and OPP selection Juri Lelli
2017-05-23 8:53 ` [PATCH RFC 1/8] sched/cpufreq_schedutil: make use of DEADLINE utilization signal Juri Lelli
2017-05-23 8:53 ` [PATCH RFC 2/8] sched/deadline: move cpu frequency selection triggering points Juri Lelli
2017-05-23 8:53 ` [PATCH RFC 3/8] sched/cpufreq_schedutil: make worker kthread be SCHED_DEADLINE Juri Lelli
2017-05-23 18:52 ` Peter Zijlstra
2017-05-24 9:31 ` Juri Lelli
2017-05-23 8:53 ` [PATCH RFC 4/8] sched/cpufreq_schedutil: split utilization signals Juri Lelli
2017-05-23 19:04 ` Peter Zijlstra
2017-05-24 9:01 ` Juri Lelli
2017-05-23 19:29 ` Peter Zijlstra
2017-05-23 23:30 ` Rafael J. Wysocki
2017-05-24 7:01 ` Peter Zijlstra
2017-05-24 9:01 ` Juri Lelli
2017-05-23 8:53 ` [PATCH RFC 5/8] sched/cpufreq_schedutil: always consider all CPUs when deciding next freq Juri Lelli
2017-05-23 8:53 ` [PATCH RFC 6/8] sched/sched.h: remove sd arch_scale_freq_capacity parameter Juri Lelli
2017-05-23 8:53 ` [PATCH RFC 7/8] sched/sched.h: move arch_scale_{freq,cpu}_capacity outside CONFIG_SMP Juri Lelli
2017-05-23 8:53 ` [PATCH RFC 8/8] sched/deadline: make bandwidth enforcement scale-invariant Juri Lelli
2017-05-23 20:23 ` [PATCH RFC 0/8] SCHED_DEADLINE freq/cpu invariance and OPP selection Peter Zijlstra
2017-05-23 20:29 ` Peter Zijlstra
2017-05-24 9:25 ` Juri Lelli
2017-05-24 9:41 ` Peter Zijlstra
2017-05-24 9:50 ` Juri Lelli
2017-05-24 11:31 ` Peter Zijlstra [this message]
2017-05-24 10:01 ` Luca Abeni
2017-05-24 11:29 ` Peter Zijlstra
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=20170524113158.qoa3tagiyvtxkd7v@hirez.programming.kicks-ass.net \
--to=peterz@infradead.org \
--cc=andresoportus@google.com \
--cc=bristot@redhat.com \
--cc=claudio@evidence.eu.com \
--cc=dietmar.eggemann@arm.com \
--cc=joelaf@google.com \
--cc=juri.lelli@arm.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-pm@vger.kernel.org \
--cc=luca.abeni@santannapisa.it \
--cc=mathieu.poirier@linaro.org \
--cc=mingo@redhat.com \
--cc=morten.rasmussen@arm.com \
--cc=patrick.bellasi@arm.com \
--cc=rjw@rjwysocki.net \
--cc=rostedt@goodmis.org \
--cc=tglx@linutronix.de \
--cc=tkjos@android.com \
--cc=tommaso.cucinotta@santannapisa.it \
--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