From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 11466 invoked by alias); 30 May 2006 08:09:25 -0000 Received: (qmail 11457 invoked by uid 22791); 30 May 2006 08:09:24 -0000 X-Spam-Check-By: sourceware.org Received: from nz-out-0102.google.com (HELO nz-out-0102.google.com) (64.233.162.196) by sourceware.org (qpsmtpd/0.31) with ESMTP; Tue, 30 May 2006 08:09:23 +0000 Received: by nz-out-0102.google.com with SMTP id n29so704814nzf for ; Tue, 30 May 2006 01:09:21 -0700 (PDT) Received: by 10.64.53.8 with SMTP id b8mr1254355qba; Tue, 30 May 2006 01:09:21 -0700 (PDT) Received: by 10.64.199.17 with HTTP; Tue, 30 May 2006 01:09:21 -0700 (PDT) Message-ID: <69dd805e0605300109k5dcf7986of596c0b5f796c6b4@mail.gmail.com> Date: Tue, 30 May 2006 08:09:00 -0000 From: "Fabian Scheler" To: "Wolfgang K?bler" , ecos-discuss@ecos.sourceware.org In-Reply-To: <20060530075335.GG2876@lunn.ch> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <20060530075335.GG2876@lunn.ch> X-IsSubscribed: yes Mailing-List: contact ecos-discuss-help@ecos.sourceware.org; run by ezmlm Precedence: bulk List-Subscribe: List-Archive: List-Post: List-Help: , Sender: ecos-discuss-owner@ecos.sourceware.org Subject: Re: [ECOS] Hard-Realtime behaviour X-SW-Source: 2006-05/txt/msg00238.txt.bz2 > Disable the caches. How long something takes to execute will depend on > what is in the cache. If the code to be executed is still in the cache > from the last time it was executied, it will execute a lot quicker > than if it has to be fetches from RAM/ROM. The same applies to the > data to be processed. So to be deterministic, you need to disable > caches. In order to guarantee deadlines, the worst case has to be deterministic, not the average case! In event-driven systems everything should be fine as long as your worst case response time is beneath your deadline, things get problematic when you use time-discrete algorithms, of course, but in this case you are better of using a time-driven approach, anyway. Ciao, Fabian -- Before posting, please read the FAQ: http://ecos.sourceware.org/fom/ecos and search the list archive: http://ecos.sourceware.org/ml/ecos-discuss