From: Patrick Bellasi <patrick.bellasi@arm.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org,
linux-api@vger.kernel.org, Ingo Molnar <mingo@redhat.com>,
Tejun Heo <tj@kernel.org>,
"Rafael J . Wysocki" <rafael.j.wysocki@intel.com>,
Vincent Guittot <vincent.guittot@linaro.org>,
Viresh Kumar <viresh.kumar@linaro.org>,
Paul Turner <pjt@google.com>,
Quentin Perret <quentin.perret@arm.com>,
Dietmar Eggemann <dietmar.eggemann@arm.com>,
Morten Rasmussen <morten.rasmussen@arm.com>,
Juri Lelli <juri.lelli@redhat.com>, Todd Kjos <tkjos@google.com>,
Joel Fernandes <joelaf@google.com>,
Steve Muckle <smuckle@google.com>,
Suren Baghdasaryan <surenb@google.com>
Subject: Re: [PATCH v7 01/15] sched/core: uclamp: Add CPU's clamp buckets refcounting
Date: Thu, 14 Mar 2019 11:45:51 +0000 [thread overview]
Message-ID: <20190314114551.6kfozh6rpw5mornb@e110439-lin> (raw)
In-Reply-To: <20190313194619.GR2482@worktop.programming.kicks-ass.net>
On 13-Mar 20:46, Peter Zijlstra wrote:
> On Wed, Mar 13, 2019 at 03:23:59PM +0000, Patrick Bellasi wrote:
> > On 13-Mar 15:09, Peter Zijlstra wrote:
> > > On Fri, Feb 08, 2019 at 10:05:40AM +0000, Patrick Bellasi wrote:
>
> > > > +static inline void uclamp_rq_update(struct rq *rq, unsigned int clamp_id)
> > > > +{
> > > > + struct uclamp_bucket *bucket = rq->uclamp[clamp_id].bucket;
> > > > + unsigned int max_value = uclamp_none(clamp_id);
> > >
> > > That's 1024 for uclamp_max
> > >
> > > > + unsigned int bucket_id;
> > > > +
> > > > + /*
> > > > + * Both min and max clamps are MAX aggregated, thus the topmost
> > > > + * bucket with some tasks defines the rq's clamp value.
> > > > + */
> > > > + bucket_id = UCLAMP_BUCKETS;
> > > > + do {
> > > > + --bucket_id;
> > > > + if (!rq->uclamp[clamp_id].bucket[bucket_id].tasks)
> > > > + continue;
> > > > + max_value = bucket[bucket_id].value;
> > >
> > > but this will then _lower_ it. That's not a MAX aggregate.
> >
> > For uclamp_max we want max_value=1024 when there are no active tasks,
> > which means: no max clamp enforced on CFS/RT "idle" cpus.
> >
> > If instead there are active RT/CFS tasks then we want the clamp value
> > of the max group, which means: MAX aggregate active clamps.
> >
> > That's what the code above does and the comment says.
>
> That's (obviously) not how I read it.... maybe something like:
>
> static inline void uclamp_rq_update(struct rq *rq, unsigned int clamp_id)
> {
> struct uclamp_bucket *bucket = rq->uclamp[clamp_id].bucket;
> int i;
>
> /*
> * Since both min and max clamps are max aggregated, find the
> * top most bucket with tasks in.
> */
> for (i = UCLMAP_BUCKETS-1; i>=0; i--) {
> if (!bucket[i].tasks)
> continue;
> return bucket[i].value;
> }
>
> /* No tasks -- default clamp value */
> return uclamp_none(clamp_id);
> }
>
> would make it clearer?
Fine for me, I'll then change the name in something else since that's
not more an "_update" by moving the WRITE_ONCE into the caller.
--
#include <best/regards.h>
Patrick Bellasi
next prev parent reply other threads:[~2019-03-14 11:45 UTC|newest]
Thread overview: 84+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-08 10:05 [PATCH v7 00/15] Add utilization clamping support Patrick Bellasi
2019-02-08 10:05 ` [PATCH v7 01/15] sched/core: uclamp: Add CPU's clamp buckets refcounting Patrick Bellasi
2019-03-12 12:52 ` Dietmar Eggemann
2019-03-13 15:15 ` Patrick Bellasi
2019-03-13 21:01 ` Suren Baghdasaryan
2019-03-14 14:54 ` Patrick Bellasi
2019-03-14 15:00 ` Patrick Bellasi
2019-03-12 15:20 ` Peter Zijlstra
2019-03-12 15:50 ` Patrick Bellasi
2019-03-13 8:19 ` Peter Zijlstra
2019-03-13 11:37 ` Patrick Bellasi
2019-03-13 13:40 ` Peter Zijlstra
2019-03-13 16:12 ` Patrick Bellasi
2019-03-13 17:22 ` Peter Zijlstra
2019-03-13 18:22 ` Patrick Bellasi
2019-03-13 19:48 ` Peter Zijlstra
2019-03-14 12:13 ` Patrick Bellasi
2019-03-14 13:32 ` Peter Zijlstra
2019-03-14 15:07 ` Patrick Bellasi
2019-03-14 19:18 ` Peter Zijlstra
2019-03-13 13:52 ` Peter Zijlstra
2019-03-13 15:59 ` Patrick Bellasi
2019-03-13 19:30 ` Peter Zijlstra
2019-03-14 11:03 ` Patrick Bellasi
2019-03-14 13:27 ` Peter Zijlstra
2019-03-13 19:39 ` Peter Zijlstra
2019-03-14 11:18 ` Patrick Bellasi
2019-03-13 21:23 ` Suren Baghdasaryan
2019-03-14 12:43 ` Patrick Bellasi
2019-03-13 14:06 ` Peter Zijlstra
2019-03-13 15:28 ` Patrick Bellasi
2019-03-13 14:09 ` Peter Zijlstra
2019-03-13 15:23 ` Patrick Bellasi
2019-03-13 19:46 ` Peter Zijlstra
2019-03-13 21:08 ` Suren Baghdasaryan
2019-03-14 12:22 ` Patrick Bellasi
2019-03-14 11:45 ` Patrick Bellasi [this message]
2019-03-13 21:32 ` Suren Baghdasaryan
2019-03-14 14:46 ` Patrick Bellasi
2019-03-14 15:29 ` Suren Baghdasaryan
2019-03-14 15:40 ` Patrick Bellasi
2019-03-14 16:39 ` Suren Baghdasaryan
2019-02-08 10:05 ` [PATCH v7 02/15] sched/core: uclamp: Enforce last task UCLAMP_MAX Patrick Bellasi
2019-03-13 14:10 ` Peter Zijlstra
2019-03-13 16:20 ` Patrick Bellasi
2019-03-13 17:29 ` Peter Zijlstra
2019-03-13 18:29 ` Patrick Bellasi
2019-03-13 14:12 ` Peter Zijlstra
2019-03-13 16:16 ` Patrick Bellasi
2019-03-14 0:29 ` Suren Baghdasaryan
2019-03-14 17:06 ` Patrick Bellasi
2019-02-08 10:05 ` [PATCH v7 03/15] sched/core: uclamp: Add system default clamps Patrick Bellasi
2019-03-13 14:32 ` Peter Zijlstra
2019-03-13 17:09 ` Patrick Bellasi
2019-03-13 19:58 ` Peter Zijlstra
2019-03-13 20:10 ` Peter Zijlstra
2019-03-15 13:41 ` Patrick Bellasi
2019-03-13 20:13 ` Peter Zijlstra
2019-03-13 20:18 ` Peter Zijlstra
2019-03-18 12:18 ` Patrick Bellasi
2019-03-18 13:10 ` Peter Zijlstra
2019-03-18 14:21 ` Patrick Bellasi
2019-03-18 14:29 ` Peter Zijlstra
2019-02-08 10:05 ` [PATCH v7 04/15] sched/core: Allow sched_setattr() to use the current policy Patrick Bellasi
2019-02-08 10:05 ` [PATCH v7 05/15] sched/core: uclamp: Extend sched_setattr() to support utilization clamping Patrick Bellasi
2019-02-08 10:05 ` [PATCH v7 06/15] sched/core: uclamp: Reset uclamp values on RESET_ON_FORK Patrick Bellasi
2019-03-13 20:52 ` Peter Zijlstra
2019-03-18 12:58 ` Patrick Bellasi
2019-02-08 10:05 ` [PATCH v7 07/15] sched/core: uclamp: Set default clamps for RT tasks Patrick Bellasi
2019-02-08 10:05 ` [PATCH v7 08/15] sched/cpufreq: uclamp: Add clamps for FAIR and " Patrick Bellasi
2019-02-08 10:05 ` [PATCH v7 09/15] sched/core: uclamp: Add uclamp_util_with() Patrick Bellasi
2019-02-08 10:05 ` [PATCH v7 10/15] sched/fair: uclamp: Add uclamp support to energy_compute() Patrick Bellasi
2019-03-06 17:21 ` Quentin Perret
2019-03-18 15:19 ` Patrick Bellasi
2019-02-08 10:05 ` [PATCH v7 11/15] sched/core: uclamp: Extend CPU's cgroup controller Patrick Bellasi
2019-02-14 15:48 ` Tejun Heo
2019-03-19 10:00 ` Patrick Bellasi
2019-02-08 10:05 ` [PATCH v7 12/15] sched/core: uclamp: Propagate parent clamps Patrick Bellasi
2019-03-14 16:17 ` Suren Baghdasaryan
2019-03-18 16:54 ` Patrick Bellasi
2019-03-18 16:58 ` Suren Baghdasaryan
2019-02-08 10:05 ` [PATCH v7 13/15] sched/core: uclamp: Propagate system defaults to root group Patrick Bellasi
2019-02-08 10:05 ` [PATCH v7 14/15] sched/core: uclamp: Use TG's clamps to restrict TASK's clamps Patrick Bellasi
2019-02-08 10:05 ` [PATCH v7 15/15] sched/core: uclamp: Update CPU's refcount on TG's clamp changes Patrick Bellasi
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=20190314114551.6kfozh6rpw5mornb@e110439-lin \
--to=patrick.bellasi@arm.com \
--cc=dietmar.eggemann@arm.com \
--cc=joelaf@google.com \
--cc=juri.lelli@redhat.com \
--cc=linux-api@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-pm@vger.kernel.org \
--cc=mingo@redhat.com \
--cc=morten.rasmussen@arm.com \
--cc=peterz@infradead.org \
--cc=pjt@google.com \
--cc=quentin.perret@arm.com \
--cc=rafael.j.wysocki@intel.com \
--cc=smuckle@google.com \
--cc=surenb@google.com \
--cc=tj@kernel.org \
--cc=tkjos@google.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).