From owner-freebsd-realtime@FreeBSD.ORG Sun Jul 30 20:13:47 2006 Return-Path: X-Original-To: freebsd-realtime@freebsd.org Delivered-To: freebsd-realtime@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 953B516A4DA for ; Sun, 30 Jul 2006 20:13:47 +0000 (UTC) (envelope-from freebsd@godseyfamily.com) Received: from godseyfamily.com (cws-web.com [204.3.218.143]) by mx1.FreeBSD.org (Postfix) with ESMTP id 2B81B43D46 for ; Sun, 30 Jul 2006 20:13:46 +0000 (GMT) (envelope-from freebsd@godseyfamily.com) Received: from godseyfamily.com (localhost [127.0.0.1]) by godseyfamily.com (8.13.6.20060614/8.13.6) with ESMTP id k6UKDkiu045689 for ; Sun, 30 Jul 2006 14:13:46 -0600 (MDT) Received: from 71.213.169.51 (SquirrelMail authenticated user dave) by godseyfamily.com with HTTP; Sun, 30 Jul 2006 14:13:46 -0600 (MDT) Message-ID: <3945.71.213.169.51.1154290426.squirrel@godseyfamily.com> Date: Sun, 30 Jul 2006 14:13:46 -0600 (MDT) From: "David Godsey" To: freebsd-realtime@freebsd.org User-Agent: SquirrelMail/1.4.5 [CVS] MIME-Version: 1.0 Content-Type: text/plain;charset=iso-8859-1 Content-Transfer-Encoding: 8bit X-Priority: 3 (Normal) Importance: Normal X-Greylist: Sender e-mail whitelisted, not delayed by milter-greylist-1.5.6 (godseyfamily.com [127.0.0.1]); Sun, 30 Jul 2006 14:13:46 -0600 (MDT) Subject: Information Sites X-BeenThere: freebsd-realtime@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: "Realtime extensions per POSIX 1003.4" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 30 Jul 2006 20:13:47 -0000 So I have been combing the internet for information on realtime FreeBSD, but the information is limited. So there must be some more information out there, but I do not know where to look. Can someone direct me please? A positive attitude may not solve all your problems, but it will annoy enough people to make it worth the effort. If there are no stupid questions, then what kind of questions do stupid people ask? Do they get smart just in time to ask questions? David Godsey From owner-freebsd-realtime@FreeBSD.ORG Sun Jul 30 21:11:41 2006 Return-Path: X-Original-To: freebsd-realtime@freebsd.org Delivered-To: freebsd-realtime@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 5509216A4DD for ; Sun, 30 Jul 2006 21:11:41 +0000 (UTC) (envelope-from arne_woerner@yahoo.com) Received: from web30310.mail.mud.yahoo.com (web30310.mail.mud.yahoo.com [68.142.200.103]) by mx1.FreeBSD.org (Postfix) with SMTP id EEF7543D49 for ; Sun, 30 Jul 2006 21:11:40 +0000 (GMT) (envelope-from arne_woerner@yahoo.com) Received: (qmail 24076 invoked by uid 60001); 30 Jul 2006 21:11:40 -0000 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.com; h=Message-ID:Received:Date:From:Subject:To:In-Reply-To:MIME-Version:Content-Type:Content-Transfer-Encoding; b=zkEodGYZe0/Mu1h/Gd/bQ4/lnz9kZxKkW4SLMXiXfDXv/Bi/+9+RE0telE/i+AAgwywRvktwDh/b3UZ0XjgXJvRx5IrjryebkPigZfRJL4OM6DJYG3emoH0qwBxFvHZELycQjdAE9kKJsdYbYH/BGuTmGOOg0Da6q11mzkufivo= ; Message-ID: <20060730211140.24074.qmail@web30310.mail.mud.yahoo.com> Received: from [213.54.79.55] by web30310.mail.mud.yahoo.com via HTTP; Sun, 30 Jul 2006 14:11:40 PDT Date: Sun, 30 Jul 2006 14:11:40 -0700 (PDT) From: "R. B. Riddick" To: David Godsey , freebsd-realtime@freebsd.org In-Reply-To: <3945.71.213.169.51.1154290426.squirrel@godseyfamily.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8bit Cc: Subject: Re: Information Sites X-BeenThere: freebsd-realtime@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: "Realtime extensions per POSIX 1003.4" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 30 Jul 2006 21:11:41 -0000 --- David Godsey wrote: > So I have been combing the internet for information on realtime FreeBSD, > but the information is limited. So there must be some more information > out there, but I do not know where to look. Can someone direct me please? > Hmm... I do not have practical experience in real time operations (just my mostly theoretical studies of task scheduling and control engineering), so I can only hope my contribution is not too useless/stupid... :-) I say, have u read the man page rtprio(2) and polling(4)? I would guess, that u might want to set kern.clockrate to something high (1000..2000) (e. g. via /boot/loader.conf's kern.hz). Furthermore I would recommend, that u do some tests/research/experiments in ur specific environment (remember: real time constraints can be very different (e. g. a simple electronic calculator is ok, when u just want to compute the taxes in a shop or in a restaurant, but when u want to compute the course of Cpt. Picard's Enterprise (StarTrek) u would need something faster (or it might get struck by some kind of lightning or get stuck in a sun))). In this case here it is the question, if u can tolerate fluctuations in scheduling accuracy (response time) due to voluntary/unpredictable/dynamically-scheduled kernel activity (I think polling(4) could just help (a little) with network devices, so that hard disc activity can still hinder real time tasks). >From the point of view of digital control engineering operating systems like *BSD are no real real-time operating systems... Real real-time operating systems are obviously able to guarantee a very high scheduling accuracy... I just did this litte experiment with (avg. about 1.3Mbit/sec, peak about 16Mbit/sec) disc traffic at the same time and a clock rate of 1000Hz: > rtprio rtprio: normal priority > repeat 10 time sleep .2 0.007u 0.015s 0:00.22 4.5% 12+396k 0+0io 0pf+0w 0.000u 0.030s 0:00.23 13.0% 182+1332k 0+0io 0pf+0w 0.000u 0.032s 0:00.23 13.0% 181+1288k 0+0io 0pf+0w 0.010u 0.021s 0:00.23 13.0% 276+2064k 0+0io 0pf+0w 0.006u 0.026s 0:00.24 8.3% 144+1230k 0+0io 0pf+0w 0.000u 0.029s 0:00.23 8.6% 136+966k 0+0io 0pf+0w 0.000u 0.032s 0:00.24 12.5% 185+1420k 0+0io 0pf+0w 0.021u 0.010s 0:00.24 12.5% 182+1332k 0+0io 0pf+0w 0.006u 0.025s 0:00.28 7.1% 278+2130k 0+0io 0pf+0w 0.008u 0.026s 0:00.24 8.3% 276+2064k 0+0io 0pf+0w neo# rtprio 30 -$$ neo# rtprio rtprio: realtime priority 30 neo# repeat 10 time sleep .3 0.000u 0.025s 0:00.33 6.0% 138+1018k 0+0io 0pf+0w 0.000u 0.028s 0:00.33 6.0% 276+2036k 0+0io 0pf+0w 0.000u 0.027s 0:00.33 6.0% 140+1084k 0+0io 0pf+0w 0.000u 0.028s 0:00.33 6.0% 138+1018k 0+0io 0pf+0w 0.006u 0.024s 0:00.32 6.2% 412+2988k 0+0io 0pf+0w 0.000u 0.026s 0:00.32 6.2% 138+1018k 0+0io 0pf+0w 0.006u 0.020s 0:00.47 4.2% 274+1970k 0+0io 0pf+0w 0.006u 0.019s 0:00.32 3.1% 552+4072k 0+0io 0pf+0w 0.000u 0.013s 0:00.31 3.2% 276+2036k 0+0io 0pf+0w 0.000u 0.014s 0:00.31 3.2% 276+2036k 0+0io 0pf+0w -Arne __________________________________________________ Do You Yahoo!? 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Mail has the best spam protection around http://mail.yahoo.com From owner-freebsd-realtime@FreeBSD.ORG Mon Jul 31 22:02:19 2006 Return-Path: X-Original-To: freebsd-realtime@freebsd.org Delivered-To: freebsd-realtime@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id E30AA16A4DA for ; Mon, 31 Jul 2006 22:02:19 +0000 (UTC) (envelope-from freebsd@godseyfamily.com) Received: from godseyfamily.com (cws-web.com [204.3.218.143]) by mx1.FreeBSD.org (Postfix) with ESMTP id 2483E43D60 for ; Mon, 31 Jul 2006 22:02:17 +0000 (GMT) (envelope-from freebsd@godseyfamily.com) Received: from godseyfamily.com (localhost [127.0.0.1]) by godseyfamily.com (8.13.6.20060614/8.13.6) with ESMTP id k6VM2H7D059204 for ; Mon, 31 Jul 2006 16:02:17 -0600 (MDT) Received: from 134.253.26.6 (proxying for 134.253.224.108) (SquirrelMail authenticated user dave) by godseyfamily.com with HTTP; Mon, 31 Jul 2006 16:02:17 -0600 (MDT) Message-ID: <58304.134.253.26.6.1154383337.squirrel@godseyfamily.com> Date: Mon, 31 Jul 2006 16:02:17 -0600 (MDT) From: "David Godsey" To: freebsd-realtime@freebsd.org User-Agent: SquirrelMail/1.4.5 [CVS] MIME-Version: 1.0 Content-Type: text/plain;charset=iso-8859-1 Content-Transfer-Encoding: 8bit X-Priority: 3 (Normal) Importance: Normal X-Greylist: Sender e-mail whitelisted, not delayed by milter-greylist-1.5.6 (godseyfamily.com [127.0.0.1]); Mon, 31 Jul 2006 16:02:17 -0600 (MDT) Subject: Point in the right direction X-BeenThere: freebsd-realtime@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: "Realtime extensions per POSIX 1003.4" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 31 Jul 2006 22:02:20 -0000 So I have been combing the internet for information on realtime FreeBSD, but the information is limited. So there must be some more information out there, but I do not know where to look. Can someone direct me please? A positive attitude may not solve all your problems, but it will annoy enough people to make it worth the effort. A positive attitude may not solve all your problems, but it will annoy enough people to make it worth the effort. If there are no stupid questions, then what kind of questions do stupid people ask? Do they get smart just in time to ask questions? David Godsey