linux-kernel - Re: REGRESSION: Performance regressions from switching anon

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: <20110617091319.GA11719@elte.hu>
Date:	Fri, 17 Jun 2011 11:13:19 +0200
From:	Ingo Molnar <mingo@...e.hu>
To:	Andi Kleen <ak@...ux.intel.com>
Cc:	Linus Torvalds <torvalds@...ux-foundation.org>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	Tim Chen <tim.c.chen@...ux.intel.com>,
	Shaohua Li <shaohua.li@...el.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Hugh Dickins <hughd@...gle.com>,
	KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>,
	Benjamin Herrenschmidt <benh@...nel.crashing.org>,
	David Miller <davem@...emloft.net>,
	Martin Schwidefsky <schwidefsky@...ibm.com>,
	Russell King <rmk@....linux.org.uk>,
	Paul Mundt <lethal@...ux-sh.org>,
	Jeff Dike <jdike@...toit.com>,
	Richard Weinberger <richard@....at>,
	"Luck, Tony" <tony.luck@...el.com>,
	KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>,
	Mel Gorman <mel@....ul.ie>, Nick Piggin <npiggin@...nel.dk>,
	Namhyung Kim <namhyung@...il.com>,
	"Shi, Alex" <alex.shi@...el.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"linux-mm@...ck.org" <linux-mm@...ck.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	"Rafael J. Wysocki" <rjw@...k.pl>
Subject: Re: REGRESSION: Performance regressions from switching
 anon_vma->lock to mutex


* Andi Kleen <ak@...ux.intel.com> wrote:

> > I tried to send uli a patch to just add caching. No go. I sent 
> > *another* patch to at least make glibc use a sane interface (and 
> > the cache if it needs to fall back on /proc/stat for some legacy 
> > reason). We'll see what happens.
> 
> FWIW a rerun with this modified LD_PRELOAD that does caching seems 
> to have the same performance as the version that does 
> sched_getaffinity.
> 
> So you're right. Caching indeed helps and my assumption that the 
> child would only do it once was incorrect.

You should have known that your assumption was wrong not just from a 
quick look at the strace output or a quick look at the glibc sources, 
but also because i pointed out the caching angle to you in the 
sysconf() discussion:

  http://lkml.org/lkml/2011/5/14/9

repeatedly:

  http://lkml.org/lkml/2011/5/17/149

and Denys Vlasenko pointed out the caching angle as well:

  http://lkml.org/lkml/2011/5/17/183

But you kept pushing for your new syscall for upstream integration, 
ignoring all contrary evidence and ignoring all contrary feedback, 
without even *once* checking where and how it would integrate into 
glibc ...

Thanks,

	Ingo
--
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/