Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754820Ab2KEUer (ORCPT ); Mon, 5 Nov 2012 15:34:47 -0500 Received: from smtp.getmail.no ([84.208.15.66]:56494 "EHLO smtp.getmail.no" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753889Ab2KEUeq (ORCPT ); Mon, 5 Nov 2012 15:34:46 -0500 MIME-version: 1.0 Content-transfer-encoding: 7BIT Content-type: text/plain; charset=iso-8859-15; format=flowed; delsp=yes To: Martin Subject: Re: sched: SCHED_DEADLINE v6 References: <5098204D.3080002@onlinehome.de> Date: Mon, 05 Nov 2012 21:34:44 +0100 Cc: linux-kernel@vger.kernel.org From: Ove Karlsen Message-id: In-reply-to: <5098204D.3080002@onlinehome.de> User-Agent: Opera Mail/12.02 (Linux) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3534 Lines: 88 On Mon, 05 Nov 2012 21:23:41 +0100, Martin wrote: > On 11/04/2012 09:00 PM, Uwaysi Bin Kareem wrote: >> Nobody knows? This is really obscure for an EDF patch. Making things a >> bit more accessible should be a priority. I think a lot of enthusiasts >> would like to have smooth control over stuff, without windows-jitter. If >> you can do a robot arm, jitter-free with this, then I am very >> interested. >> >> uwaysi@Millennium:~/Kildekode/sched_deadline-schedtool-dl$ ./schedtool >> -E >> -t 500:1000 3718 >> ERROR: could not set PID 3718 to E: SCHED_DEADLINE - Function not >> implemented >> uwaysi@Millennium:~/Kildekode/sched_deadline-schedtool-dl$ >> >> On Sun, 04 Nov 2012 20:02:25 +0100, Uwaysi Bin Kareem >> wrote: >> >>> How does the modified schedtool work? There is no updated >>> documentation. >>> >>> http://gitorious.org/sched_deadline/schedtool-dl/commits/latest/2.6.36-dl-V3 >>> >>> >>> If anyone could give an example of a 1000uS period / 500uS time, with >>> schedtool, or any other relevant information. >>> Most examples online use parameters that are no longer supported. >>> >>> Peace Be With You. >> -- >> 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/ > > Hi, > > I assume the reason nobody answers is that the cpu scheduler is an > emotional subject. > > However, if you really want a smooth desktop and a deadline scheduler > (albeit it might not be as configurable as you seem to want it to be), > try BFS or the whole CK patch. > > http://ck-hack.blogspot.com/ > > I have implemented it on a laptop this weekend, and I was surprised by > the change in user experience yet again. Mostly during 3D game play. > Generally the difference is felt more strongly on low end machines and > taxing workloads. > > Since you are talking about robot arms: note that BFS is not a real time > solution, but is designed around the physiological conditions of the > human perception system (where, I believe, 6 ms is equivalent to real > time). Maybe a similar deadline approach is useful for robot arms, no > idea. > > cu Martin > If you ever saw a robot-arm jitter, you`d think of it as faulty. And that is how people should think of their PC aswell. Just the interrupts, preemption (points), daemons, hopefully cleverly arranged, to reduce jitter, is what I want. I did already try BFS. PS: 90hz timer, is very good with BFS also, but the jitter-extremes are higher. Meaning large jitters last longer, while small jitters, seems smaller. For overall computing CFS actually has less jitter. What would be really interesting would be to try a scheduler that tries to bound latencies, and have accurate timing. There seems to be generally 3 different profiles people tuned for: Server, Mobile, Desktop. Server guiless stationary, Mobile for minimal power desktop, Desktop, for workstation/home low-jitter high-performance. Maybe these profiles even can be combined a bit, having several hz counters, and several scheduling policies. Peace Be With You. -- 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/