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From: Carsten Emde <Carsten.Emde@osadl.org>
To: Clark Williams <williams@redhat.com>
Cc: John Kacur <jkacur@redhat.com>,
	RT <linux-rt-users@vger.kernel.org>,
	LKML <linux-kernel@vger.kernel.org>
Subject: Re: [RFC] [rt-tests] change to cyclictest behavior
Date: Thu, 07 Jan 2010 08:23:52 +0100	[thread overview]
Message-ID: <4B458C08.8070209@osadl.org> (raw)
In-Reply-To: <20100106162759.1d4d5b57@torg>

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.

  parent reply	other threads:[~2010-01-07  7:30 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-01-06 19:04 [RFC] [rt-tests] change to cyclictest behavior Clark Williams
2010-01-06 19:39 ` John Kacur
2010-01-06 19:39   ` John Kacur
2010-01-06 21:39   ` Carsten Emde
2010-01-06 22:04     ` Clark Williams
2010-01-06 22:24       ` Carsten Emde
2010-01-06 22:27         ` Clark Williams
2010-01-06 22:50           ` Carsten Emde
2010-01-07  0:30             ` Leyendecker, Robert
2010-01-07  7:09               ` Carsten Emde
2010-01-07  7:23           ` Carsten Emde [this message]
2010-01-07 14:47             ` Clark Williams
2010-01-07 14:54               ` Carsten Emde
2010-01-12 16:59 ` Sven-Thorsten Dietrich
2010-01-12 17:04   ` Clark Williams
2010-01-12 17:13     ` Sven-Thorsten Dietrich

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