Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753988AbbHJOB3 (ORCPT ); Mon, 10 Aug 2015 10:01:29 -0400 Received: from eu-smtp-delivery-143.mimecast.com ([207.82.80.143]:64354 "EHLO eu-smtp-delivery-143.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751914AbbHJOB2 convert rfc822-to-8bit (ORCPT ); Mon, 10 Aug 2015 10:01:28 -0400 Message-ID: <55C8AEDC.90603@arm.com> Date: Mon, 10 Aug 2015 15:02:04 +0100 From: Juri Lelli User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.7.0 MIME-Version: 1.0 To: Peter Zijlstra , Frederic Weisbecker CC: LKML , Thomas Gleixner , Preeti U Murthy , Christoph Lameter , Ingo Molnar , Viresh Kumar , Rik van Riel Subject: Re: [PATCH 07/10] sched: Migrate sched to use new tick dependency mask model References: <1437669735-8786-1-git-send-email-fweisbec@gmail.com> <1437669735-8786-8-git-send-email-fweisbec@gmail.com> <20150803140046.GK19282@twins.programming.kicks-ass.net> <20150803145031.GD25554@lerouge> <20150803170911.GV25159@twins.programming.kicks-ass.net> <20150803173031.GB26022@lerouge> <20150804074116.GH25159@twins.programming.kicks-ass.net> In-Reply-To: <20150804074116.GH25159@twins.programming.kicks-ass.net> X-OriginalArrivalTime: 10 Aug 2015 14:01:24.0462 (UTC) FILETIME=[0B19D0E0:01D0D375] X-MC-Unique: zQzbzfbWSwuFPlKLkxzCiw-1 Content-Type: text/plain; charset=WINDOWS-1252 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1256 Lines: 35 Hi, On 04/08/15 08:41, Peter Zijlstra wrote: > On Mon, Aug 03, 2015 at 07:30:32PM +0200, Frederic Weisbecker wrote: >>> But you've forgotten about SCHED_DEADLINE, we count those in: >>> rq->dl.dl_nr_running. >> >> Indeed. Hmm, there is no preemption between SCHED_DEALINE tasks, right? >> So I can treat it like SCHED_FIFO. > > Sadly no. Even though EDF has static job priority (once a job is > activated its priority doesn't change anymore) DEADLINE also has a CBS > component and that needs the tick regardless, even with a single task. > > So any deadline task running means we cannot stop the tick. Well, couldn't we stop it when we use hrtick? As start_hrtick_dl() sets the hrtick to fire at tasks runtime depletion instant. Thanks, - Juri > -- > 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/ > -- 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/