Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S267345AbUJIUEd (ORCPT ); Sat, 9 Oct 2004 16:04:33 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S267350AbUJIUEc (ORCPT ); Sat, 9 Oct 2004 16:04:32 -0400 Received: from opersys.com ([64.40.108.71]:4366 "EHLO www.opersys.com") by vger.kernel.org with ESMTP id S267345AbUJIUDV (ORCPT ); Sat, 9 Oct 2004 16:03:21 -0400 Message-ID: <416845E4.206@opersys.com> Date: Sat, 09 Oct 2004 16:11:16 -0400 From: Karim Yaghmour Reply-To: karim@opersys.com Organization: Opersys inc. User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.4) Gecko/20030624 Netscape/7.1 X-Accept-Language: en-us, en, fr, fr-be, fr-ca, fr-fr MIME-Version: 1.0 To: Lee Revell CC: stefan.eletzhofer@eletztrick.de, linux-kernel Subject: Re: [ANNOUNCE] Linux 2.6 Real Time Kernel References: <41677E4D.1030403@mvista.com> <416822B7.5050206@opersys.com> <1097346628.1428.11.camel@krustophenia.net> <20041009212614.GA25441@tier.local> <1097350227.1428.41.camel@krustophenia.net> <20041009213817.GB25441@tier.local> <1097351221.1428.46.camel@krustophenia.net> In-Reply-To: <1097351221.1428.46.camel@krustophenia.net> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1168 Lines: 28 Lee Revell wrote: > Yes. The upper bound on the response time of an RT task is a function > of the longest non-preemptible code path in the kernel. Currently this > is the processing of a single packet by netif_receive_skb. And this has been demonstrated mathematically/algorithmically to be true 100% of the time, regardless of the load and the driver set? IOW, if I was building an automated industrial saw (based on a VP+IRQ-thread kernel or a combination of the above-mentioned agregate) with a safety mechanism that depended on the kernel's responsivness to outside events to avoid bodily harm, would you be willing to put your hand beneath it? How about things like a hard-rt deterministic nanosleep() 100% of the time with RTAI/fusion? Karim -- Author, Speaker, Developer, Consultant Pushing Embedded and Real-Time Linux Systems Beyond the Limits http://www.opersys.com || karim@opersys.com || 1-866-677-4546 - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/