linux-ext4 - Re: [RFC, PATCH] Avoid hot statistics cache line in ext4 extent cache

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:	Fri, 13 Apr 2012 14:48:23 -0400
From:	Ted Ts'o <tytso@....edu>
To:	Andi Kleen <andi@...stfloor.org>
Cc:	Tim Chen <tim.c.chen@...ux.intel.com>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Vivek Haldar <haldar@...gle.com>,
	Andreas Dilger <adilger@...ger.ca>, linux-ext4@...r.kernel.org
Subject: Re: [RFC, PATCH] Avoid hot statistics cache line in ext4 extent
 cache

On Fri, Apr 13, 2012 at 08:41:58PM +0200, Andi Kleen wrote:
> > The reason why I ask this is we're seeing anything like this with Eric
> > Whitney's 48 CPU scalability testing; we're not CPU bottlenecked, and
> > I don't even see evidence of a larger than usual CPU utilization
> > compared to other file systems.
> 
> I bet Eric didn't test with this statistic counter.

Huh?  You can't turn it off, and he's been doing regular scalability
tests at least once per kernel release.

Can you say a bit more about exactly how you are doing this test and
what are the "other issues" where this is becoming a bottleneck?  If
possible I'd like to ask Eric if he can add it to his regular
scalability tests.

Thanks,

						 - Ted
--
To unsubscribe from this list: send the line "unsubscribe linux-ext4" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html