From mboxrd@z Thu Jan 1 00:00:00 1970 From: Carsten Emde Subject: Re: [RFC] [rt-tests] change to cyclictest behavior Date: Wed, 06 Jan 2010 23:50:34 +0100 Message-ID: <4B4513BA.5090001@osadl.org> References: <20100106130400.7f30ae55@torg> <520f0cf11001061139j2af13403qfcbf567647bdfaa8@mail.gmail.com> <4B4502FD.1000404@osadl.org> <20100106160434.77efc790@torg> <4B450D91.7060403@osadl.org> <20100106162759.1d4d5b57@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]:52291 "EHLO toro.web-alm.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932380Ab0AFWvZ (ORCPT ); Wed, 6 Jan 2010 17:51:25 -0500 In-Reply-To: <20100106162759.1d4d5b57@torg> Sender: linux-rt-users-owner@vger.kernel.org List-ID: Clark, >> [..] >> May I ask you to also include the -n option which is almost always >> needed? This would then give: >> -S --smp Standard SMP testing (equals -a -t -n -d0), >> same priority on all threads. > Yeah, you read my mind. How about -m (mlockall) as well? Hmm, I think that this one is less obvious. Apparently, there are a bunch of different opinions on mlockall(). I once heard, for example, the opinion that mlockall() may - under some conditions - introduce a performance penalty, but I did not verify that. Many real-time systems do not have a "swap" line in /etc/fstab; mlockall() is not needed in such systems. In addition, most today's systems have so much RAM that swapping became a rather rare event. I hope some other RT-ers who are more knowledgeable about memory management and swapping can comment on this. Cyclictest was in use for years, before someone introduced the -m option. I never used this option. Carsten.