Re: [PATCH v2 0/6] sched: expel confusing usage of the term "power"

From: Daniel Lezcano
Date: Tue May 27 2014 - 10:07:10 EST


On 05/27/2014 12:19 AM, Nicolas Pitre wrote:
"Power" is a very bad term in the scheduler context. There are so many
meanings that can be attached to it. And with the upcoming "power
aware" scheduler work, confusion is sure to happen.

The definition of "power" is typically the rate at which work is performed,
energy is converted or electric energy is transferred. The notion of
"compute capacity" is rather at odds with "power" to the point many
comments in the code have to make it explicit that "capacity" is the
actual intended meaning.

So let's make it clear what we man by using "capacity" in place of "power"
directly in the code. That will make the introduction of actual "power
consumption" concepts much clearer later on.

This is based on the latest tip tree to apply correctly on top of existing
scheduler changes already queued there.

Changes from v1:

- capa_factor and SCHED_CAPA_* changed to be spelled "capacity" in full
to save peterz some Chupacabra nightmares

- some minor corrections in commit logs

- rebased on latest tip tree


arch/arm/kernel/topology.c | 54 +++----
include/linux/sched.h | 8 +-
kernel/sched/core.c | 87 ++++++-----
kernel/sched/fair.c | 323 ++++++++++++++++++++-------------------
kernel/sched/sched.h | 18 +--
5 files changed, 246 insertions(+), 244 deletions(-)

Hi Nico,

it is a good initiative to replace the 'power' word by another to prevent confusion for future code. Personally I have a preference to 'strength' instead of 'capacity', in case that matter.

Apart that:

Acked-by: Daniel Lezcano <daniel.lezcano@xxxxxxxxxx>

Thanks
-- Daniel


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