From mboxrd@z Thu Jan 1 00:00:00 1970 From: Carsten Emde Subject: Re: [RFC] [rt-tests] change to cyclictest behavior Date: Thu, 07 Jan 2010 15:54:34 +0100 Message-ID: <4B45F5AA.2020100@osadl.org> References: <20100106130400.7f30ae55@torg> <520f0cf11001061139j2af13403qfcbf567647bdfaa8@mail.gmail.com> <4B4502FD.1000404@osadl.org> <20100106160434.77efc790@torg> <4B450D91.7060403@osadl.org> <20100106162759.1d4d5b57@torg> <4B458C08.8070209@osadl.org> <20100107084700.0fa053a3@torg> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: John Kacur , RT , LKML To: Clark Williams Return-path: Received: from toro.web-alm.net ([62.245.132.31]:35050 "EHLO toro.web-alm.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752342Ab0AGPA0 (ORCPT ); Thu, 7 Jan 2010 10:00:26 -0500 In-Reply-To: <20100107084700.0fa053a3@torg> Sender: linux-rt-users-owner@vger.kernel.org List-ID: On 01/07/2010 03:47 PM, Clark Williams wrote: > On Thu, 07 Jan 2010 08:23:52 +0100 > Carsten Emde wrote: >>>> -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. >> [..] > I don't have a problem not having -d in the -S option. I was looking at > the possibility of synchronous sampling as well so it's probably a good > idea to keep it separate. > The main things we want are implied -t, -a and -n. Yes, let's do it this way.