linux-kernel - Re: [PATCH] sched: wake-affine throttle

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: <51677CB0.606@linux.vnet.ibm.com>
Date:	Fri, 12 Apr 2013 11:17:04 +0800
From:	Michael Wang <wangyun@...ux.vnet.ibm.com>
To:	Peter Zijlstra <peterz@...radead.org>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>
CC:	LKML <linux-kernel@...r.kernel.org>,
	Ingo Molnar <mingo@...nel.org>, Mike Galbraith <efault@....de>,
	Alex Shi <alex.shi@...el.com>,
	Namhyung Kim <namhyung@...nel.org>,
	Paul Turner <pjt@...gle.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	"Nikunj A. Dadhania" <nikunj@...ux.vnet.ibm.com>,
	Ram Pai <linuxram@...ibm.com>
Subject: Re: [PATCH] sched: wake-affine throttle

On 04/10/2013 04:51 PM, Peter Zijlstra wrote:
> On Wed, 2013-04-10 at 11:30 +0800, Michael Wang wrote:
>> | 15 GB   |      32 | 35918 |   | 37632 | +4.77% | 47923 | +33.42% |
>> 52241 | +45.45%
> 
> So I don't get this... is wake_affine() once every milisecond _that_
> expensive?
> 
> Seeing we get a 45%!! improvement out of once every 100ms that would
> mean we're like spending 1/3rd of our time in wake_affine()? that's
> preposterous. So what's happening?

Hi, Peter

I think Mike has very well explained the reason why throttle bring us
benefit and why the benefit looks so significant when interval get
higher, could you please take a look at his mail and see whether it
addressed this concern?

And thanks Mike again for the excellent analysis :)

Regards,
Michael Wang


> 
> 
> 
> --
> 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/
> 

--
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/