linux-kernel - Re: Performance regression from switching lock to rw-sem for anon-vma tree

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, 18 Jun 2013 07:20:16 +0800
From:	Alex Shi <alex.shi@...el.com>
To:	Davidlohr Bueso <davidlohr.bueso@...com>
CC:	Tim Chen <tim.c.chen@...ux.intel.com>, Ingo Molnar <mingo@...e.hu>,
	Rik van Riel <riel@...hat.com>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	Andrea Arcangeli <aarcange@...hat.com>,
	Mel Gorman <mgorman@...e.de>, Andi Kleen <andi@...stfloor.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Michel Lespinasse <walken@...gle.com>,
	"Wilcox, Matthew R" <matthew.r.wilcox@...el.com>,
	Dave Hansen <dave.hansen@...el.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"linux-mm@...ck.org" <linux-mm@...ck.org>
Subject: Re: Performance regression from switching lock to rw-sem for anon-vma
 tree

On 06/18/2013 12:22 AM, Davidlohr Bueso wrote:
> After a lot of benchmarking, I finally got the ideal results for aim7,
> so far: this patch + optimistic spinning with preemption disabled. Just
> like optimistic spinning, this patch by itself makes little to no
> difference, yet combined is where we actually outperform 3.10-rc5. In
> addition, I noticed extra throughput when disabling preemption in
> try_optimistic_spin().
> 
> With i_mmap as a rwsem and these changes I could see performance
> benefits for alltests (+14.5%), custom (+17%), disk (+11%), high_systime
> (+5%), shared (+15%) and short (+4%), most of them after around 500
> users, for fewer users, it made little to no difference.

A pretty good number. what's the cpu number in your machine? :)

-- 
Thanks
    Alex
--
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/