linux-kernel - Re: [cgroup] a0f9ec1f181: -4.3% will-it-scale.per_thread

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: <1400137877.5175.147.camel@marge.simpson.net>
Date:	Thu, 15 May 2014 09:11:17 +0200
From:	Mike Galbraith <umgwanakikbuti@...il.com>
To:	Tejun Heo <tj@...nel.org>
Cc:	Fengguang Wu <fengguang.wu@...el.com>,
	Jet Chen <jet.chen@...el.com>,
	LKML <linux-kernel@...r.kernel.org>, lkp@...org
Subject: Re: [cgroup] a0f9ec1f181: -4.3% will-it-scale.per_thread_ops

On Thu, 2014-05-15 at 02:14 -0400, Tejun Heo wrote:

> Hmmm... I'm completely stumped.  The commit in question has nothing to
> do with tmpfs.  It only affects three cgroup files - "tasks",
> "cgroup.procs" and "release_agent".  It can't possibly have any effect
> on tmpfs operation.  Maybe random effect through code alignment?  Even
> that is highly unlikely.

Unlikely, but it happens.  I bisected a tbench regression down to a
completely unrelated driver change, and watched it repeatably drop
throughput 5% despite skeptical "No way, show me that trick again".

-Mike

--
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/