From: Peter Zijlstra <peterz@infradead.org>
To: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Morten Rasmussen <morten.rasmussen@arm.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-pm@vger.kernel.org" <linux-pm@vger.kernel.org>,
"mingo@kernel.org" <mingo@kernel.org>,
"vincent.guittot@linaro.org" <vincent.guittot@linaro.org>,
"daniel.lezcano@linaro.org" <daniel.lezcano@linaro.org>,
"preeti@linux.vnet.ibm.com" <preeti@linux.vnet.ibm.com>,
Dietmar Eggemann <Dietmar.Eggemann@arm.com>,
len.brown@intel.com
Subject: Re: [RFC PATCH 06/16] arm: topology: Define TC2 sched energy and provide it to scheduler
Date: Thu, 5 Jun 2014 08:52:05 +0200 [thread overview]
Message-ID: <20140605065205.GA3213@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <2484761.vkWavnsDx3@vostro.rjw.lan>
[-- Attachment #1: Type: text/plain, Size: 1184 bytes --]
On Wed, Jun 04, 2014 at 11:56:55PM +0200, Rafael J. Wysocki wrote:
> On Wednesday, June 04, 2014 07:27:12 PM Peter Zijlstra wrote:
> > Well, we eventually want to go there I think. Although we still needed
> > to come up with something for Intel, because I'm not at all sure how all
> > that works.
>
> Do you mean power numbers or how P-states work on Intel in general?
P-states, I'm still not at all sure how all that works on Intel and what
we can sanely do with them.
Supposedly Intel has a means of setting P-states (there's a driver after
all), but then is completely free to totally ignore it and do something
entirely different anyhow.
And while APERF/MPERF allows observing what it did, its afaik, nigh on
impossible to predict wtf its going to do, and therefore any such energy
computation is going to be a PRNG at best.
Now, given all that I'm not sure what we need that P-state driver for,
so supposedly I'm missing something.
Ideally Len (or someone equally in-the-know) would explain to me how
exactly all that works and what we can rely upon. All I've gotten so far
is, you can't rely on anything, and magik. Which is entirely useless.
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next prev parent reply other threads:[~2014-06-05 6:52 UTC|newest]
Thread overview: 71+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-05-23 18:16 [RFC PATCH 00/16] sched: Energy cost model for energy-aware scheduling Morten Rasmussen
2014-05-23 18:16 ` [RFC PATCH 01/16] sched: Documentation for scheduler energy cost model Morten Rasmussen
2014-06-05 8:49 ` Vincent Guittot
2014-06-05 11:35 ` Morten Rasmussen
2014-06-05 15:02 ` Vincent Guittot
2014-05-23 18:16 ` [RFC PATCH 02/16] sched: Introduce CONFIG_SCHED_ENERGY Morten Rasmussen
2014-06-08 6:03 ` Henrik Austad
2014-06-09 10:20 ` Morten Rasmussen
2014-06-10 9:39 ` Peter Zijlstra
2014-06-10 10:06 ` Morten Rasmussen
2014-06-10 10:23 ` Peter Zijlstra
2014-06-10 11:17 ` Henrik Austad
2014-06-10 12:19 ` Peter Zijlstra
2014-06-10 11:24 ` Morten Rasmussen
2014-06-10 12:24 ` Peter Zijlstra
2014-06-10 14:41 ` Morten Rasmussen
2014-05-23 18:16 ` [RFC PATCH 03/16] sched: Introduce sd energy data structures Morten Rasmussen
2014-05-23 18:16 ` [RFC PATCH 04/16] sched: Allocate and initialize sched energy Morten Rasmussen
2014-05-23 18:16 ` [RFC PATCH 05/16] sched: Add sd energy procfs interface Morten Rasmussen
2014-05-23 18:16 ` [RFC PATCH 06/16] arm: topology: Define TC2 sched energy and provide it to scheduler Morten Rasmussen
2014-05-30 12:04 ` Peter Zijlstra
2014-06-02 14:15 ` Morten Rasmussen
2014-06-03 11:41 ` Peter Zijlstra
2014-06-04 13:49 ` Morten Rasmussen
2014-06-03 11:44 ` Peter Zijlstra
2014-06-04 15:42 ` Morten Rasmussen
2014-06-04 16:16 ` Peter Zijlstra
2014-06-06 13:15 ` Morten Rasmussen
2014-06-06 13:43 ` Peter Zijlstra
2014-06-06 14:29 ` Morten Rasmussen
2014-06-12 15:05 ` Vince Weaver
2014-06-03 11:50 ` Peter Zijlstra
2014-06-04 16:02 ` Morten Rasmussen
2014-06-04 17:27 ` Peter Zijlstra
2014-06-04 21:56 ` Rafael J. Wysocki
2014-06-05 6:52 ` Peter Zijlstra [this message]
2014-06-05 15:03 ` Dirk Brandewie
2014-06-05 20:29 ` Yuyang Du
2014-06-06 8:05 ` Peter Zijlstra
2014-06-06 0:35 ` Yuyang Du
2014-06-06 10:50 ` Peter Zijlstra
2014-06-06 12:13 ` Ingo Molnar
2014-06-06 12:27 ` Ingo Molnar
2014-06-06 14:11 ` Morten Rasmussen
2014-06-07 2:33 ` Nicolas Pitre
2014-06-09 8:27 ` Morten Rasmussen
2014-06-09 13:22 ` Nicolas Pitre
2014-06-11 11:02 ` Eduardo Valentin
2014-06-11 11:42 ` Morten Rasmussen
2014-06-11 11:43 ` Eduardo Valentin
2014-06-11 13:37 ` Morten Rasmussen
2014-06-07 23:53 ` Yuyang Du
2014-06-07 23:26 ` Yuyang Du
2014-06-09 8:59 ` Morten Rasmussen
2014-06-09 2:15 ` Yuyang Du
2014-06-10 10:16 ` Peter Zijlstra
2014-06-10 17:01 ` Nicolas Pitre
2014-06-10 18:35 ` Yuyang Du
2014-06-06 16:27 ` Jacob Pan
2014-06-06 13:03 ` Morten Rasmussen
2014-06-07 2:52 ` Nicolas Pitre
2014-05-23 18:16 ` [RFC PATCH 07/16] sched: Introduce system-wide sched_energy Morten Rasmussen
2014-05-23 18:16 ` [RFC PATCH 08/16] sched: Introduce SD_SHARE_CAP_STATES sched_domain flag Morten Rasmussen
2014-05-23 18:16 ` [RFC PATCH 09/16] sched, cpufreq: Introduce current cpu compute capacity into scheduler Morten Rasmussen
2014-05-23 18:16 ` [RFC PATCH 10/16] sched, cpufreq: Current compute capacity hack for ARM TC2 Morten Rasmussen
2014-05-23 18:16 ` [RFC PATCH 11/16] sched: Energy model functions Morten Rasmussen
2014-05-23 18:16 ` [RFC PATCH 12/16] sched: Task wakeup tracking Morten Rasmussen
2014-05-23 18:16 ` [RFC PATCH 13/16] sched: Take task wakeups into account in energy estimates Morten Rasmussen
2014-05-23 18:16 ` [RFC PATCH 14/16] sched: Use energy model in select_idle_sibling Morten Rasmussen
2014-05-23 18:16 ` [RFC PATCH 15/16] sched: Use energy to guide wakeup task placement Morten Rasmussen
2014-05-23 18:16 ` [RFC PATCH 16/16] sched: Disable wake_affine to broaden the scope of wakeup target cpus Morten Rasmussen
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