From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753014AbYHRLvy (ORCPT ); Mon, 18 Aug 2008 07:51:54 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752062AbYHRLvq (ORCPT ); Mon, 18 Aug 2008 07:51:46 -0400 Received: from casper.infradead.org ([85.118.1.10]:39945 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751885AbYHRLvp (ORCPT ); Mon, 18 Aug 2008 07:51:45 -0400 Subject: Re: SCHED_FIFO and SCHED_RR broken by cfs From: Peter Zijlstra To: Nick Piggin Cc: "Torvalds, Linus" , Stefani Seibold , linux-kernel@vger.kernel.org, mingo@redhat.com In-Reply-To: <200808182124.17359.nickpiggin@yahoo.com.au> References: <1218880552.11912.9.camel@matrix> <200808182058.07346.nickpiggin@yahoo.com.au> <1219057765.10800.315.camel@twins> <200808182124.17359.nickpiggin@yahoo.com.au> Content-Type: text/plain Date: Mon, 18 Aug 2008 13:51:55 +0200 Message-Id: <1219060315.10800.338.camel@twins> Mime-Version: 1.0 X-Mailer: Evolution 2.22.3.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2008-08-18 at 21:24 +1000, Nick Piggin wrote: > Really, you think the enterprise distros will willingly break POSIX > and their own backwards compatiblity by default? I wouldn't have > thought so, but anyway I guess they are free to make that choice, so > where's the problem? I'm not seeing why you're making such a big fuss over this - IMO its not such a significant breakage. Esp since very few realtime apps will require such large amounts of time to ever run into the throttle. If their usage is 95%+ cpu they must have magic WCET estamates - or like in this case, be a benchmark app which IMHO just abuses the real-time class. It's like running your real-time code on a 5% slower cpu - if it runs correctly on the 5% slower cpu, it will run correctly here too. Note that correctness from a RT pov is making your deadline.