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From: Quentin Perret <quentin.perret@arm.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Patrick Bellasi <patrick.bellasi@arm.com>,
	Juri Lelli <juri.lelli@redhat.com>,
	linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org,
	Ingo Molnar <mingo@redhat.com>, Tejun Heo <tj@kernel.org>,
	"Rafael J . Wysocki" <rafael.j.wysocki@intel.com>,
	Viresh Kumar <viresh.kumar@linaro.org>,
	Vincent Guittot <vincent.guittot@linaro.org>,
	Paul Turner <pjt@google.com>,
	Dietmar Eggemann <dietmar.eggemann@arm.com>,
	Morten Rasmussen <morten.rasmussen@arm.com>,
	Todd Kjos <tkjos@google.com>, Joel Fernandes <joelaf@google.com>,
	Steve Muckle <smuckle@google.com>,
	Suren Baghdasaryan <surenb@google.com>
Subject: Re: [PATCH v4 14/16] sched/core: uclamp: request CAP_SYS_ADMIN by default
Date: Thu, 27 Sep 2018 11:00:40 +0100
Message-ID: <20180927100021.kpdyol44qpzassup@queper01-lin> (raw)
In-Reply-To: <20180925154956.GA30146@hirez.programming.kicks-ass.net>

On Tuesday 25 Sep 2018 at 17:49:56 (+0200), Peter Zijlstra wrote:
> I really don't see how changing the unit changes anything. Either you
> want to relate to OPPs and those are exposed in 1/1024 unit capacity
> through the EAS files, or you don't and then the knob has no meaning.

FWIW, with the latest versions of the EAS series, we don't expose the
capacity of the various OPPs directly any more. You have 'frequency',
'power' and a more abstract thing called 'cost' (which is useful for
energy computations) in the sysfs files of the EM.

We decided to remove the 'capacity' file to simplify things quite a bit,
and because it wasn't helping much. I'm talking about this discussion w/
Dietmar on v4:

https://lore.kernel.org/lkml/20180717141955.GA4496@e108498-lin.cambridge.arm.com/

But it is also true that we could add back that 'capacity' file if it
makes sense for uclamp. It's just an additional show() function in
energy_model.c, so no problem on that side per se.

The only problem is if you want to use uclamp w/o EAS, I guess ...

Thanks,
Quentin

  parent reply index

Thread overview: 80+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-08-28 13:53 [PATCH v4 00/16] Add utilization clamping support Patrick Bellasi
2018-08-28 13:53 ` [PATCH v4 01/16] sched/core: uclamp: extend sched_setattr to support utilization clamping Patrick Bellasi
2018-09-05 11:01   ` Juri Lelli
2018-08-28 13:53 ` [PATCH v4 02/16] sched/core: uclamp: map TASK's clamp values into CPU's clamp groups Patrick Bellasi
2018-09-05 10:45   ` Juri Lelli
2018-09-06 13:48     ` Patrick Bellasi
2018-09-06 14:13       ` Juri Lelli
2018-09-06  8:17   ` Juri Lelli
2018-09-06 14:00     ` Patrick Bellasi
2018-09-08 23:47   ` Suren Baghdasaryan
2018-09-12 10:32     ` Patrick Bellasi
2018-09-12 13:49   ` Peter Zijlstra
2018-09-12 15:56     ` Patrick Bellasi
2018-09-12 16:12       ` Peter Zijlstra
2018-09-12 17:35         ` Patrick Bellasi
2018-09-12 17:42           ` Peter Zijlstra
2018-09-12 17:52             ` Patrick Bellasi
2018-09-13 19:14               ` Peter Zijlstra
2018-09-14  8:51                 ` Patrick Bellasi
2018-09-12 16:24   ` Peter Zijlstra
2018-09-12 17:42     ` Patrick Bellasi
2018-09-13 19:20       ` Peter Zijlstra
2018-09-14  8:47         ` Patrick Bellasi
2018-08-28 13:53 ` [PATCH v4 03/16] sched/core: uclamp: add CPU's clamp groups accounting Patrick Bellasi
2018-09-12 17:34   ` Peter Zijlstra
2018-09-12 17:44     ` Patrick Bellasi
2018-09-13 19:12   ` Peter Zijlstra
2018-09-14  9:07     ` Patrick Bellasi
2018-09-14 11:52       ` Peter Zijlstra
2018-09-14 13:41         ` Patrick Bellasi
2018-08-28 13:53 ` [PATCH v4 04/16] sched/core: uclamp: update CPU's refcount on clamp changes Patrick Bellasi
2018-08-28 13:53 ` [PATCH v4 05/16] sched/core: uclamp: enforce last task UCLAMP_MAX Patrick Bellasi
2018-08-28 13:53 ` [PATCH v4 06/16] sched/cpufreq: uclamp: add utilization clamping for FAIR tasks Patrick Bellasi
2018-09-14  9:32   ` Peter Zijlstra
2018-09-14 13:19     ` Patrick Bellasi
2018-09-14 13:36       ` Peter Zijlstra
2018-09-14 13:57         ` Patrick Bellasi
2018-09-27 10:23           ` Quentin Perret
2018-08-28 13:53 ` [PATCH v4 07/16] sched/core: uclamp: extend cpu's cgroup controller Patrick Bellasi
2018-08-28 18:29   ` Randy Dunlap
2018-08-29  8:53     ` Patrick Bellasi
2018-08-28 13:53 ` [PATCH v4 08/16] sched/core: uclamp: propagate parent clamps Patrick Bellasi
2018-09-09  3:02   ` Suren Baghdasaryan
2018-09-12 12:51     ` Patrick Bellasi
2018-09-12 15:56       ` Suren Baghdasaryan
2018-09-11 15:18   ` Tejun Heo
2018-09-11 16:26     ` Patrick Bellasi
2018-09-11 16:28       ` Tejun Heo
2018-08-28 13:53 ` [PATCH v4 09/16] sched/core: uclamp: map TG's clamp values into CPU's clamp groups Patrick Bellasi
2018-09-09 18:52   ` Suren Baghdasaryan
2018-09-12 14:19     ` Patrick Bellasi
2018-09-12 15:53       ` Suren Baghdasaryan
2018-08-28 13:53 ` [PATCH v4 10/16] sched/core: uclamp: use TG's clamps to restrict Task's clamps Patrick Bellasi
2018-08-28 13:53 ` [PATCH v4 11/16] sched/core: uclamp: add system default clamps Patrick Bellasi
2018-09-10 16:20   ` Suren Baghdasaryan
2018-09-11 16:46     ` Patrick Bellasi
2018-09-11 19:25       ` Suren Baghdasaryan
2018-08-28 13:53 ` [PATCH v4 12/16] sched/core: uclamp: update CPU's refcount on TG's clamp changes Patrick Bellasi
2018-08-28 13:53 ` [PATCH v4 13/16] sched/core: uclamp: use percentage clamp values Patrick Bellasi
2018-08-28 13:53 ` [PATCH v4 14/16] sched/core: uclamp: request CAP_SYS_ADMIN by default Patrick Bellasi
2018-09-04 13:47   ` Juri Lelli
2018-09-06 14:40     ` Patrick Bellasi
2018-09-06 14:59       ` Juri Lelli
2018-09-06 17:21         ` Patrick Bellasi
2018-09-14 11:10       ` Peter Zijlstra
2018-09-14 14:07         ` Patrick Bellasi
2018-09-14 14:28           ` Peter Zijlstra
2018-09-17 12:27             ` Patrick Bellasi
2018-09-21  9:13               ` Peter Zijlstra
2018-09-24 15:14                 ` Patrick Bellasi
2018-09-24 15:56                   ` Peter Zijlstra
2018-09-24 17:23                     ` Patrick Bellasi
2018-09-24 16:26                   ` Peter Zijlstra
2018-09-24 17:19                     ` Patrick Bellasi
2018-09-25 15:49                   ` Peter Zijlstra
2018-09-26 10:43                     ` Patrick Bellasi
2018-09-27 10:00                     ` Quentin Perret [this message]
2018-09-26 17:51                 ` Patrick Bellasi
2018-08-28 13:53 ` [PATCH v4 15/16] sched/core: uclamp: add clamp group discretization support Patrick Bellasi
2018-08-28 13:53 ` [PATCH v4 16/16] sched/cpufreq: uclamp: add utilization clamping for RT tasks Patrick Bellasi

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