linux-kernel - Re: [PATCH RESEND] sched: prefer an idle cpu vs an idle sibling for BALANCE

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <556725CA.6070103@fb.com>
Date:	Thu, 28 May 2015 10:27:22 -0400
From:	Josef Bacik <jbacik@...com>
To:	Peter Zijlstra <peterz@...radead.org>
CC:	<riel@...hat.com>, <mingo@...hat.com>,
	<linux-kernel@...r.kernel.org>, <umgwanakikbuti@...il.com>,
	<morten.rasmussen@....com>
Subject: Re: [PATCH RESEND] sched: prefer an idle cpu vs an idle sibling for
 BALANCE_WAKE

On 05/28/2015 07:05 AM, Peter Zijlstra wrote:
>
> So maybe you want something like the below; that cures the thing Morten
> raised, and we continue looking for sd, even after we found affine_sd.
>
> It also avoids the pointless idle_cpu() check Mike raised by making
> select_idle_sibling() return -1 if it doesn't find anything.
>
> Then it continues doing the full balance IFF sd was set, which is keyed
> off of sd->flags.
>
> And note (as Mike already said), BALANCE_WAKE does _NOT_ look for idle
> CPUs, it looks for the least loaded CPU. And its damn expensive.
>

Sorry I was just assuming based on the commit message when WAKE_IDLE was 
removed, this isn't my area.

>
> Rewriting this entire thing is somewhere on the todo list :/

Thanks I'm building and deploying this so I can run our perf test, I'll 
have results in ~3 hours.

Josef
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/