From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 1195 invoked by alias); 30 May 2006 11:12:13 -0000 Received: (qmail 1005 invoked by uid 22791); 30 May 2006 11:12:09 -0000 X-Spam-Check-By: sourceware.org Received: from londo.lunn.ch (HELO londo.lunn.ch) (80.238.139.98) by sourceware.org (qpsmtpd/0.31) with ESMTP; Tue, 30 May 2006 11:11:25 +0000 Received: from lunn by londo.lunn.ch with local (Exim 3.36 #1 (Debian)) id 1Fl280-00070U-00; Tue, 30 May 2006 13:11:12 +0200 Date: Tue, 30 May 2006 11:12:00 -0000 To: R Vamshi Krishna Cc: Andrew Lunn , Fabian Scheler , ecos-discuss@ecos.sourceware.org Message-ID: <20060530111112.GK2876@lunn.ch> Mail-Followup-To: R Vamshi Krishna , Andrew Lunn , Fabian Scheler , ecos-discuss@ecos.sourceware.org References: <20060530075335.GG2876@lunn.ch> <69dd805e0605300109k5dcf7986of596c0b5f796c6b4@mail.gmail.com> <20060530081637.GH2876@lunn.ch> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.11+cvs20060403 From: Andrew Lunn 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/msg00244.txt.bz2 On Tue, May 30, 2006 at 02:36:05PM +0530, R Vamshi Krishna wrote: > > Continuing on the discussion, doesn't pipelining on modern processors add > to our woes. Because then we cannot really determine if a particular > instruction is going to 'x' cycles or 'y' cycles. Realy you need to talk to the silicon vendor, or at least read the data sheet and see what it says. However I think pipelining in itself should not be a problem. It should be deterministic under normal conditions. Only when things go wrong will it be none deterministic, ie interrupts, exceptions, cache misses is you have caches enabled. If you are on a processor with HT like technology then i expect the pipeline becomes none deterministic unless you disable all other "processors". Really, if you are worried about this level of detail, you probably should be using a Z80, or some similar level of processor technology, where you know what it is doing. Andrew -- Before posting, please read the FAQ: http://ecos.sourceware.org/fom/ecos and search the list archive: http://ecos.sourceware.org/ml/ecos-discuss