From: Juri Lelli <juri.lelli@redhat.com>
To: Quentin Perret <quentin.perret@arm.com>
Cc: Vincent Guittot <vincent.guittot@linaro.org>,
peterz@infradead.org, mingo@kernel.org,
linux-kernel@vger.kernel.org, rjw@rjwysocki.net,
dietmar.eggemann@arm.com, Morten.Rasmussen@arm.com,
viresh.kumar@linaro.org, valentin.schneider@arm.com
Subject: Re: [PATCH v5 05/10] cpufreq/schedutil: get max utilization
Date: Wed, 30 May 2018 10:51:43 +0200 [thread overview]
Message-ID: <20180530085143.GA3320@localhost.localdomain> (raw)
In-Reply-To: <20180530083715.GB2174@e108498-lin.cambridge.arm.com>
On 30/05/18 09:37, Quentin Perret wrote:
> On Tuesday 29 May 2018 at 11:52:03 (+0200), Juri Lelli wrote:
> > On 29/05/18 09:40, Quentin Perret wrote:
> > > Hi Vincent,
> > >
> > > On Friday 25 May 2018 at 15:12:26 (+0200), Vincent Guittot wrote:
> > > > Now that we have both the dl class bandwidth requirement and the dl class
> > > > utilization, we can use the max of the 2 values when agregating the
> > > > utilization of the CPU.
> > > >
> > > > Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
> > > > ---
> > > > kernel/sched/sched.h | 6 +++++-
> > > > 1 file changed, 5 insertions(+), 1 deletion(-)
> > > >
> > > > diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
> > > > index 4526ba6..0eb07a8 100644
> > > > --- a/kernel/sched/sched.h
> > > > +++ b/kernel/sched/sched.h
> > > > @@ -2194,7 +2194,11 @@ static inline void cpufreq_update_util(struct rq *rq, unsigned int flags) {}
> > > > #ifdef CONFIG_CPU_FREQ_GOV_SCHEDUTIL
> > > > static inline unsigned long cpu_util_dl(struct rq *rq)
> > > > {
> > > > - return (rq->dl.running_bw * SCHED_CAPACITY_SCALE) >> BW_SHIFT;
> > > > + unsigned long util = (rq->dl.running_bw * SCHED_CAPACITY_SCALE) >> BW_SHIFT;
> > > > +
> > > > + util = max_t(unsigned long, util, READ_ONCE(rq->avg_dl.util_avg));
> > >
> > > Would it make sense to use a UTIL_EST version of that signal here ? I
> > > don't think that would make sense for the RT class with your patch-set
> > > since you only really use the blocked part of the signal for RT IIUC,
> > > but would that work for DL ?
> >
> > Well, UTIL_EST for DL looks pretty much what we already do by computing
> > utilization based on dl.running_bw. That's why I was thinking of using
> > that as a starting point for dl.util_avg decay phase.
>
> Hmmm I see your point, but running_bw and the util_avg are fundamentally
> different ... I mean, the util_avg doesn't know about the period, which is
> an issue in itself I guess ...
>
> If you have a long running DL task (say 100ms runtime) with a long period
> (say 1s), the running_bw should represent ~1/10 of the CPU capacity, but
> the util_avg can go quite high, which means that you might end up
> executing this task at max OPP. So if we really want to drive OPPs like
> that for deadline, a util_est-like version of this util_avg signal
> should help. Now, you can also argue that going to max OPP for a task
> that _we know_ uses 1/10 of the CPU capacity isn't right ...
Yep, that's my point. :)
next prev parent reply other threads:[~2018-05-30 8:51 UTC|newest]
Thread overview: 99+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-25 13:12 [PATCH v5 00/10] track CPU utilization Vincent Guittot
2018-05-25 13:12 ` [PATCH v5 01/10] sched/pelt: Move pelt related code in a dedicated file Vincent Guittot
2018-05-25 14:26 ` Quentin Perret
2018-05-25 16:14 ` Peter Zijlstra
2018-05-29 8:21 ` Quentin Perret
2018-05-25 18:04 ` Patrick Bellasi
2018-05-29 14:55 ` Quentin Perret
2018-05-29 15:02 ` Vincent Guittot
2018-05-29 15:04 ` Quentin Perret
2018-05-25 13:12 ` [PATCH v5 02/10] sched/rt: add rt_rq utilization tracking Vincent Guittot
2018-05-25 15:54 ` Patrick Bellasi
2018-05-29 13:29 ` Vincent Guittot
2018-05-30 9:32 ` Patrick Bellasi
2018-05-30 10:06 ` Vincent Guittot
2018-05-30 11:01 ` Patrick Bellasi
2018-05-30 14:39 ` Vincent Guittot
2018-05-25 13:12 ` [PATCH v5 03/10] cpufreq/schedutil: add rt " Vincent Guittot
2018-05-30 7:03 ` Viresh Kumar
2018-05-30 8:23 ` Vincent Guittot
2018-05-30 9:40 ` Patrick Bellasi
2018-05-30 9:53 ` Vincent Guittot
2018-05-30 16:46 ` Quentin Perret
2018-05-31 8:46 ` Juri Lelli
2018-06-01 16:23 ` Peter Zijlstra
2018-06-01 17:23 ` Patrick Bellasi
2018-06-04 10:17 ` Quentin Perret
2018-06-04 15:16 ` Patrick Bellasi
2018-05-25 13:12 ` [PATCH v5 04/10] sched/dl: add dl_rq " Vincent Guittot
2018-05-30 10:50 ` Patrick Bellasi
2018-05-30 11:51 ` Vincent Guittot
2018-05-25 13:12 ` [PATCH v5 05/10] cpufreq/schedutil: get max utilization Vincent Guittot
2018-05-28 10:12 ` Juri Lelli
2018-05-28 14:57 ` Vincent Guittot
2018-05-28 15:22 ` Juri Lelli
2018-05-28 16:34 ` Vincent Guittot
2018-05-31 10:27 ` Patrick Bellasi
2018-05-31 13:02 ` Vincent Guittot
2018-06-01 13:53 ` Vincent Guittot
2018-06-01 17:45 ` Joel Fernandes
2018-06-04 6:41 ` Vincent Guittot
2018-06-04 7:04 ` Juri Lelli
2018-06-04 7:14 ` Vincent Guittot
2018-06-04 10:12 ` Juri Lelli
2018-06-04 12:35 ` Vincent Guittot
2018-05-29 5:08 ` Joel Fernandes
2018-05-29 6:31 ` Juri Lelli
2018-05-29 6:48 ` Vincent Guittot
2018-05-29 9:47 ` Juri Lelli
2018-05-29 8:40 ` Quentin Perret
2018-05-29 9:52 ` Juri Lelli
2018-05-30 8:37 ` Quentin Perret
2018-05-30 8:51 ` Juri Lelli [this message]
2018-05-25 13:12 ` [PATCH v5 06/10] sched: remove rt and dl from sched_avg Vincent Guittot
2018-05-25 13:12 ` [PATCH v5 07/10] sched/irq: add irq utilization tracking Vincent Guittot
2018-05-30 15:55 ` Dietmar Eggemann
2018-05-30 18:45 ` Vincent Guittot
2018-05-31 16:54 ` Dietmar Eggemann
2018-06-06 16:06 ` Vincent Guittot
2018-06-07 8:29 ` Dietmar Eggemann
2018-06-07 8:44 ` Vincent Guittot
2018-06-07 9:06 ` Dietmar Eggemann
2018-05-25 13:12 ` [PATCH v5 08/10] cpufreq/schedutil: take into account interrupt Vincent Guittot
2018-05-28 10:41 ` Juri Lelli
2018-05-28 12:06 ` Vincent Guittot
2018-05-28 12:37 ` Juri Lelli
2018-05-25 13:12 ` [PATCH v5 09/10] sched: remove rt_avg code Vincent Guittot
2018-05-25 13:12 ` [PATCH v5 10/10] proc/sched: remove unused sched_time_avg_ms Vincent Guittot
2018-06-04 16:50 ` [PATCH v5 00/10] track CPU utilization Peter Zijlstra
2018-06-04 17:13 ` Quentin Perret
2018-06-04 18:08 ` Vincent Guittot
2018-06-05 14:18 ` Peter Zijlstra
2018-06-05 15:03 ` Juri Lelli
2018-06-05 15:38 ` Patrick Bellasi
2018-06-05 22:27 ` Peter Zijlstra
2018-06-06 9:44 ` Quentin Perret
2018-06-06 9:59 ` Vincent Guittot
2018-06-06 10:02 ` Vincent Guittot
2018-06-06 10:12 ` Quentin Perret
2018-06-05 8:36 ` Vincent Guittot
2018-06-05 10:57 ` Quentin Perret
2018-06-05 11:59 ` Vincent Guittot
2018-06-05 13:12 ` Quentin Perret
2018-06-05 13:18 ` Vincent Guittot
2018-06-05 13:52 ` Quentin Perret
2018-06-05 13:55 ` Vincent Guittot
2018-06-05 14:09 ` Quentin Perret
2018-06-05 14:21 ` Quentin Perret
2018-06-05 12:11 ` Juri Lelli
2018-06-05 13:05 ` Quentin Perret
2018-06-05 13:15 ` Juri Lelli
2018-06-05 14:01 ` Quentin Perret
2018-06-05 14:13 ` Juri Lelli
2018-06-06 13:05 ` Claudio Scordino
2018-06-06 13:20 ` Quentin Perret
2018-06-06 13:53 ` Claudio Scordino
2018-06-06 14:10 ` Quentin Perret
2018-06-06 21:05 ` luca abeni
2018-06-07 8:25 ` Quentin Perret
2018-06-06 20:53 ` luca abeni
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