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From: Nicolas Pitre <nicolas.pitre@linaro.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>,
	Vincent Guittot <vincent.guittot@linaro.org>,
	Daniel Lezcano <daniel.lezcano@linaro.org>,
	Morten Rasmussen <morten.rasmussen@arm.com>,
	"Rafael J. Wysocki" <rjw@rjwysocki.net>,
	linux-kernel@vger.kernel.org, linaro-kernel@lists.linaro.org
Subject: Re: [PATCH 6/6] sched: final power vs capacity cleanup
Date: Thu, 15 May 2014 12:12:40 -0400 (EDT)	[thread overview]
Message-ID: <alpine.LFD.2.11.1405151207170.17310@knanqh.ubzr> (raw)
In-Reply-To: <20140515072929.GZ30445@twins.programming.kicks-ass.net>

On Thu, 15 May 2014, Peter Zijlstra wrote:

> On Wed, May 14, 2014 at 04:57:10PM -0400, Nicolas Pitre wrote:
> > It is better not to think about compute capacity as being equivalent to
> > "CPU power".  The upcoming "power aware" scheduler may create confusion
> > with the notion of energy consumption if "power" is used too liberally.
> > 
> > This contains the architecture visible changes.  Incidentally, only ARM
> > takes advantage of the available pow^H^H^Hcapacity scaling hooks and
> > therefore those changes outside kernel/sched/ are confined to one ARM
> > specific file.  The default arch_scale_smt_power() hook is not overridden
> > by anyone.
> > 
> > Replacements are as follows:
> > 
> > 	arch_scale_freq_power  --> arch_scale_freq_capacity
> > 	arch_scale_smt_power   --> arch_scale_smt_capacity
> > 	SCHED_POWER_SCALE      --> SCHED_CAPA_SCALE
> > 	SCHED_POWER_SHIFT      --> SCHED_POWER_SHIFT
> 
> The patch seems to actually make that CAPA_SHIFT

Huh... right, of course.

> > The local usage of "power" in arch/arm/kernel/topology.c is also changed
> > to "capacity" as appropriate.
> 
> For some reason every time I read: 'capa' I think of some south American
> monster -- http://en.wikipedia.org/wiki/Chupacabra, I'm not at all sure
> why my brain links them.

:-)

capa != paca

I chose that not to make this much longer than "POWER", and since there 
are already "LOAD" related constants, I thought there was some symetry 
to another 4-letter identifier.  Do you have other suggestions?


Nicolas

  reply	other threads:[~2014-05-15 16:12 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-05-14 20:57 [PATCH 0/6] sched: expel confusing usage of the term "power" Nicolas Pitre
2014-05-14 20:57 ` [PATCH 1/6] sched/fair.c: remove "power" from struct numa_stats Nicolas Pitre
2014-05-14 20:57 ` [PATCH 2/6] sched/fair.c: change "has_capacity" to "has_free_capacity" Nicolas Pitre
2014-05-15  7:21   ` Peter Zijlstra
2014-05-15  7:28     ` Vincent Guittot
2014-05-14 20:57 ` [PATCH 3/6] sched/fair.c: disambiguate existing/remaining "capacity" usage Nicolas Pitre
2014-05-15  7:39   ` Vincent Guittot
2014-05-15 16:06     ` Nicolas Pitre
2014-05-14 20:57 ` [PATCH 4/6] sched: let struct sched_group_power care about CPU capacity Nicolas Pitre
2014-05-14 20:57 ` [PATCH 5/6] sched: remove remaining power to the CPU Nicolas Pitre
2014-05-16  9:00   ` Preeti Murthy
2014-05-16 16:34     ` Nicolas Pitre
2014-05-14 20:57 ` [PATCH 6/6] sched: final power vs capacity cleanup Nicolas Pitre
2014-05-15  7:29   ` Peter Zijlstra
2014-05-15 16:12     ` Nicolas Pitre [this message]
2014-05-20  3:05       ` Nicolas Pitre
2014-05-15  7:41 ` [PATCH 0/6] sched: expel confusing usage of the term "power" Vincent Guittot
2014-05-15 16:15   ` Nicolas Pitre

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