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: <20080930111217.GA21367@elte.hu>
Date:	Tue, 30 Sep 2008 13:12:17 +0200
From:	Ingo Molnar <mingo@...e.hu>
To:	Chris Friesen <cfriesen@...tel.com>
Cc:	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	linux-kernel@...r.kernel.org, Steven Rostedt <rostedt@...dmis.org>
Subject: Re: unpredictability in scheduler test results -- still present


* Chris Friesen <cfriesen@...tel.com> wrote:

> Ingo Molnar wrote:
>> * Chris Friesen <cfriesen@...tel.com> wrote:
>
>>> It turns out that disabling CONFIG_DYNAMIC_FTRACE makes the load  
>>> balancing problem go away and causes all cpus to be used.
>>>
>>> With this option enabled, the problem seems to be present as far back 
>>> as 2.6.27-rc2.  (2.6.27-rc1 doesn't compile on my machine, and 2.6.26 
>>> doesn't have ftrace).
>>>
>>> I have no idea why turning on dynamic ftrace would affect load  
>>> balancing behaviour, but it's very repeatable.  The very first test  
>>> run after booting works fine, and all successive runs fail to balance 
>>> properly.
>
>> OTOH, what does 'truning on dftrace' exactly mean? Just enabling it in  
>> the .config, or also activating it via /debug/tracing/current_tracer?
>
> Just enabling it in the .config is enough to trigger the behaviour 
> change.  I'm not explicitly activating any traces.

ok, that would be a clear ftrace bug i guess?

	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/

Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ