From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030386AbWGZFOK (ORCPT ); Wed, 26 Jul 2006 01:14:10 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1030387AbWGZFOK (ORCPT ); Wed, 26 Jul 2006 01:14:10 -0400 Received: from omta04ps.mx.bigpond.com ([144.140.83.156]:25586 "EHLO omta04ps.mx.bigpond.com") by vger.kernel.org with ESMTP id S1030386AbWGZFOJ (ORCPT ); Wed, 26 Jul 2006 01:14:09 -0400 Message-ID: <44C6FA1A.1020709@bigpond.net.au> Date: Wed, 26 Jul 2006 15:14:02 +1000 From: Peter Williams User-Agent: Thunderbird 1.5.0.4 (X11/20060614) MIME-Version: 1.0 To: Al Boldi CC: linux-kernel@vger.kernel.org Subject: Re: [ANNOUNCE][RFC] PlugSched-6.4 for 2.6.18-rc2 References: <200607241857.52389.a1426z@gawab.com> <200607252127.14024.a1426z@gawab.com> <44C6BC76.8010808@bigpond.net.au> <200607260745.45156.a1426z@gawab.com> In-Reply-To: <200607260745.45156.a1426z@gawab.com> Content-Type: text/plain; charset=windows-1256; format=flowed Content-Transfer-Encoding: 7bit X-Authentication-Info: Submitted using SMTP AUTH PLAIN at omta04ps.mx.bigpond.com from [147.10.133.38] using ID pwil3058@bigpond.net.au at Wed, 26 Jul 2006 05:14:03 +0000 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Al Boldi wrote: > Peter Williams wrote: >> Al Boldi wrote: >>> Peter Williams wrote: >>>> Al Boldi wrote: >>>>> Peter Williams wrote: >>>>>> Al Boldi wrote: >> [bits deleted] >> >>>>>>> It may be really great, to allow schedulers perPid parent, thus >>>>>>> allowing the stacking of different scheduler semantics. This could >>>>>>> aid flexibility a lot. >>>>>> I'm don't understand what you mean here. Could you elaborate? >>>>> i.e: Boot the kernel with spa_no_frills, then start X with spa_ws. >>>> It's probably not a good idea to have different schedulers managing the >>>> same resource. The way to do different scheduling per process is to >>>> use the scheduling policy mechanism i.e. SCHED_FIFO, SCHED_RR, etc. >>>> (possibly extended) within each scheduler. On the other hand, on an >>>> SMP system, having a different scheduler on each run queue (or sub set >>>> of queues) might be interesting :-). >>> What's wrong with multiple run-queues on UP? >> A really high likelihood of starvation of some tasks. > > Maybe you are thinking of running independent run-queues, in which case it > would probably be unwise to run multiple RQs on a single CPU. No. I'm thinking about different schedulers on a single run queue. I don't think that it's a good idea. > > But I was more thinking of a run-queue of run-queues, with the masterRQ > scheduling slaveRQs, each RQ possible running its own scheduling semantic. I think that you need to think a bit harder about the consequences of such a system. The word "chaos" springs to mind. Peter -- Peter Williams pwil3058@bigpond.net.au "Learning, n. The kind of ignorance distinguishing the studious." -- Ambrose Bierce