linux-kernel - Re: [RFC] [rt-tests] change to cyclictest behavior

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: <4B458C08.8070209@osadl.org>
Date:	Thu, 07 Jan 2010 08:23:52 +0100
From:	Carsten Emde <Carsten.Emde@...dl.org>
To:	Clark Williams <williams@...hat.com>
CC:	John Kacur <jkacur@...hat.com>,
	RT <linux-rt-users@...r.kernel.org>,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: [RFC] [rt-tests] change to cyclictest behavior

Clark,

>> -S      --smp              Standard SMP testing (equals -a -t -n -d0),
>>                            same priority on all threads.
After having done some tests with a quickly hacked cyclictest version, I
have found an issue with including -d0. Apparently, small numbers make
life especially difficult for the scheduler; this is why we often used
-d1. Specifying -d0 seems a special case where all threads are in sync.
Maybe, we may miss some important latency constellations, if we do not
let the tasks slightly interfere. In any case, I would like to be able
to specify a distance _in addition_ to -S. This would create a scenario
where

  cyclictest -d1 -S

results in a distance of 0, and

  cyclictest -S -d1

results in a distance of 1. Would this be acceptable?

	Carsten.
--
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/