linux-kernel - Re: [patch] sched: beef up wake

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Date:	Tue, 14 Jul 2015 15:49:17 +0200
From:	Mike Galbraith <umgwanakikbuti@...il.com>
To:	Peter Zijlstra <peterz@...radead.org>
Cc:	Josef Bacik <jbacik@...com>, riel@...hat.com, mingo@...hat.com,
	linux-kernel@...r.kernel.org, morten.rasmussen@....com,
	kernel-team <Kernel-team@...com>
Subject: Re: [patch] sched: beef up wake_wide()

On Tue, 2015-07-14 at 13:19 +0200, Peter Zijlstra wrote:

> OK, how about something like the below; it tightens things up by
> applying two rules:
> 
>  - We really should not continue looking for a balancing domain once
>    SD_LOAD_BALANCE is not set.
> 
>  - SD (balance) flags should really be set in a single contiguous range,
>    always starting at the bottom.
> 
> The latter means what if !want_affine and the (first) sd doesn't have
> BALANCE_WAKE set, we're done. Getting rid of (most of) that iteration
> junk you didn't like..
> 
> Hmm?

Yeah, that's better.  It's not big hairy deal either way, it just bugged
me to knowingly toss those cycles out the window ;-)

select_idle_sibling() looks kinda funny down there, but otoh when the
day comes (hah) that we can just balance, it's closer to the exit.

	-Mike

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