From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753562AbbAaJ5O (ORCPT ); Sat, 31 Jan 2015 04:57:14 -0500 Received: from bombadil.infradead.org ([198.137.202.9]:37513 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752174AbbAaJ5K (ORCPT ); Sat, 31 Jan 2015 04:57:10 -0500 Date: Sat, 31 Jan 2015 10:56:59 +0100 From: Peter Zijlstra To: Juri Lelli Cc: Luca Abeni , Kirill Tkhai , Ingo Molnar , "linux-kernel@vger.kernel.org" Subject: Re: Another SCHED_DEADLINE bug (with bisection and possible fix) Message-ID: <20150131095659.GD32343@twins.programming.kicks-ass.net> References: <1420633741.12772.10.camel@yandex.ru> <54B4D2DF.9010308@arm.com> <4500351421141200@web2m.yandex.ru> <20150113140436.GI25256@twins.programming.kicks-ass.net> <4632021421239387@web25g.yandex.ru> <54B7A33F.20904@unitn.it> <20150115122323.GU23965@worktop.programming.kicks-ass.net> <54B7C232.8060806@unitn.it> <20150128140803.GF23038@twins.programming.kicks-ass.net> <54CB5E56.9080506@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <54CB5E56.9080506@arm.com> User-Agent: Mutt/1.5.21 (2012-12-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jan 30, 2015 at 10:35:02AM +0000, Juri Lelli wrote: > So, we do the safe thing only in case of throttling. No, even for the !throttle aka running tasks. We only use dl_{runtime,deadline,period} for replenishment, until that time we observe the old runtime/deadline set by the previous replenishment. > I guess is more than > ok for now, while we hopefully find some spare cycle to implement a > complete solution :/. Yeah, I bet the fun part is computing the 0-lag across the entire root domain, per-cpu 0-lag isn't correct afaict.