Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S264461AbUFLA1y (ORCPT ); Fri, 11 Jun 2004 20:27:54 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S264452AbUFLA1y (ORCPT ); Fri, 11 Jun 2004 20:27:54 -0400 Received: from opersys.com ([64.40.108.71]:35341 "EHLO www.opersys.com") by vger.kernel.org with ESMTP id S264461AbUFLA1w (ORCPT ); Fri, 11 Jun 2004 20:27:52 -0400 Message-ID: <40CA4D23.2010006@opersys.com> Date: Fri, 11 Jun 2004 20:24:03 -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: Geoff Levand CC: high-res-timers-discourse@lists.sourceforge.net, linux-kernel@vger.kernel.org, George Anzinger Subject: Re: [ANNOUNCE] high-res-timers patches for 2.6.6 References: <40C7BE29.9010600@am.sony.com> In-Reply-To: <40C7BE29.9010600@am.sony.com> 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: 2308 Lines: 48 Geoff Levand wrote: > For those interested, the set of three patches provide POSIX high-res > timer support for linux-2.6.6. The core and i386 patches are updates of > George Anzinger's hrtimers-2.6.5-1.0.patch available on SourceForge > . The ppc32 port is > not available on SourceForge yet. I've got to ask: Just reading from the Posix 1003.1b section 14 spec referenced by the HRT main project page, I see the following: ------------------------------------------------------------------------------ Realtime applications must be able to operate on data within strict timing constraints in order to schedule application or system events. Timing requirements can be in response to the need for either high system throughput or fast response time. Applications requiring high throughput may process large amounts of data and use a continuous stream of data points equally spaced in time. For example, electrocardiogram research uses a continuous stream of data for qualitative and quantitative analysis. ------------------------------------------------------------------------------ If this is really the goal here, then why not just integrate Adeos into the kernel and make some form of HRT as a loadable module that uses Adeos to provide its services? Currently Adeos runs on x86, ARM (MMU-full and MMU-less), PPC, so portability is not an issue. Plus, the interface provided can either be directly used by drivers to get hard-rt interrupts or it can be used by another layer to provide more elaborate services (like RTAI or, potentially, HRT.) Using the virtual interrupts that can be dynamically allocated at runtime, it's rather easy to send signals between domains. Sure, you may not have the exact Posix 1003.1b API, but I don't remember there being any persistent goal of having the kernel conform to any standard. 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/