Re: [PATCH 6/6] sched: final power vs capacity cleanup

From: Peter Zijlstra
Date: Thu May 15 2014 - 03:29:41 EST


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

> 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.

But yes, once we kill the capacity stuff we have now with some
utilization bound, capacity becomes uniquely the compute capacity.

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