Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755473Ab0HCJlb (ORCPT ); Tue, 3 Aug 2010 05:41:31 -0400 Received: from casper.infradead.org ([85.118.1.10]:44477 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754213Ab0HCJla convert rfc822-to-8bit (ORCPT ); Tue, 3 Aug 2010 05:41:30 -0400 Subject: Re: periods and deadlines in SCHED_DEADLINE From: Peter Zijlstra To: Bjoern Brandenburg Cc: Raistlin , linux-kernel , Song Yuan , Dmitry Adamushko , Thomas Gleixner , Nicola Manica , Luca Abeni , Claudio Scordino , Harald Gustafsson , bastoni@cs.unc.edu, Giuseppe Lipari In-Reply-To: References: <1278682707.6083.227.camel@Palantir> <1278685133.1900.201.camel@laptop> <51F8E441-58D7-45E1-B7A0-7A717EDF08B5@email.unc.edu> <1278693304.1900.266.camel@laptop> <1278752489.4390.97.camel@Palantir> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8BIT Date: Tue, 03 Aug 2010 11:41:15 +0200 Message-ID: <1280828475.1923.444.camel@laptop> Mime-Version: 1.0 X-Mailer: Evolution 2.28.3 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1503 Lines: 32 On Sun, 2010-07-11 at 08:42 +0200, Bjoern Brandenburg wrote: > > If you want to do G-EDF with limited and different budgets on each CPU > (e.g., G-EDF tasks may only run for 100 out of 1000 ms on CPU 0, but > for 400 out of 1000 ms on CPU 1), then you are entering the domain of > restricted-supply scheduling, which is significantly more complicated > to analyze (see [1,2]). Without having looked at the refs, won't the soft case still have bounded tardiness? Since the boundedness property mostly depends on u<=1, that is, as long as we can always run everything within the available time we won't start drifting. > As far as I know there is no exiting analysis for "almost G-EDF", > i.e., the case where each task may only migrate among a subset of the > processors (= affinity masks), except for the special case of > clustered EDF (C-EDF), wherein the subsets of processors are > non-overlapping. Right, affinity masks are a pain, hence I proposed to limit that to either 1 cpu (yielding fully paritioned) or the full cluster. That will leave us with only having to stack a partitioned and global scheduler on top of each other, and per the previous point, I think that ought to work out trivially for soft, hard otoh will get 'interesting'. -- 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/