Re: [RFC][PATCH 1/2] ARM64: add cpu topology definition

From: Vincent Guittot
Date: Mon Jul 29 2013 - 06:28:29 EST

On 29 July 2013 12:15, Sudeep KarkadaNagesha
<Sudeep.KarkadaNagesha@xxxxxxx> wrote:
> On 29/07/13 10:46, Vincent Guittot wrote:
>> On 27 July 2013 12:42, Hanjun Guo <hanjun.guo@xxxxxxxxxx> wrote:
>>> Power aware scheduling needs the cpu topology information to improve the
>>> cpu scheduler decision making.
>> It's not only power aware scheduling. The scheduler already uses
>> topology and cache sharing when CONFIG_SCHED_MC and/or
>> CONFIG_SCHED_SMT are enable. So you should also add these configs for
>> arm64 so the scheduler can use it
> Just for my knowledge, I thought power aware using SCHED_MC/SMT was
> removed. I see commit 8e7fbcbc22c12414bcc9dfdd683637f58fb32759 "sched:
> Remove stale power aware scheduling remnants and dysfunctional knobs"
> I may be missing something here.

It's a common mistake to mixed SCHED_MC and powersaving balance with
SCHED_MC. Only the powersaving policy has been removed but the
SCHED_MC and SCHED_SMT are always in the scheduler and gives perf
improvement on arm 32bits

> Regards,
> Sudeep
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