linux-kernel - Re: AIM7 40% regression with 2.6.26-rc1

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]

Date:	Tue, 6 May 2008 05:18:31 -0600
From:	Matthew Wilcox <matthew@....cx>
To:	"Zhang, Yanmin" <yanmin_zhang@...ux.intel.com>
Cc:	LKML <linux-kernel@...r.kernel.org>
Subject: Re: AIM7 40% regression with 2.6.26-rc1

On Tue, May 06, 2008 at 01:48:24PM +0800, Zhang, Yanmin wrote:
> Comparing with kernel 2.6.25, ???AIM7 (use tmpfs) has ???more than 40% with 2.6.26-rc1
> on my 8-core stoakley, 16-core tigerton, and Itanium Montecito. Bisect located
> below patch.
> 
> 64ac24e738823161693bf791f87adc802cf529ff is first bad commit
> commit 64ac24e738823161693bf791f87adc802cf529ff
> Author: Matthew Wilcox <matthew@....cx>
> Date:   Fri Mar 7 21:55:58 2008 -0500
> 
>     Generic semaphore implementation
> 
> 
> After I manually reverted the patch against 2.6.26-rc1 while fixing lots of
> conflictions/errors, aim7 regression became less than 2%.

40%?!  That's shocking.  Can you tell which semaphore was heavily
contended?  I have a horrible feeling that it's the BKL.

-- 
Intel are signing my paycheques ... these opinions are still mine
"Bill, look, we understand that you're interested in selling us this
operating system, but compare it to ours.  We can't possibly take such
a retrograde step."
--
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/