From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932549Ab2DKQVl (ORCPT ); Wed, 11 Apr 2012 12:21:41 -0400 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.122]:22626 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932410Ab2DKQVk (ORCPT ); Wed, 11 Apr 2012 12:21:40 -0400 X-Authority-Analysis: v=2.0 cv=Z8Fu7QtA c=1 sm=0 a=ZycB6UtQUfgMyuk2+PxD7w==:17 a=XQbtiDEiEegA:10 a=TWBfIqSxIMQA:10 a=5SG0PmZfjMsA:10 a=Q9fys5e9bTEA:10 a=Q_vRj5AnrVouVOA9BZsA:9 a=6c1vHMHYU-MpCEzpB5oA:7 a=PUjeQqilurYA:10 a=ZycB6UtQUfgMyuk2+PxD7w==:117 X-Cloudmark-Score: 0 X-Originating-IP: 74.67.80.29 Message-ID: <1334161298.23924.263.camel@gandalf.stny.rr.com> Subject: Re: [PATCH 06/16] sched: SCHED_DEADLINE push and pull logic From: Steven Rostedt To: Juri Lelli Cc: peterz@infradead.org, tglx@linutronix.de, mingo@redhat.com, oleg@redhat.com, fweisbec@gmail.com, darren@dvhart.com, johan.eker@ericsson.com, p.faure@akatech.ch, linux-kernel@vger.kernel.org, claudio@evidence.eu.com, michael@amarulasolutions.com, fchecconi@gmail.com, tommaso.cucinotta@sssup.it, nicola.manica@disi.unitn.it, luca.abeni@unitn.it, dhaval.giani@gmail.com, hgu1972@gmail.com, paulmck@linux.vnet.ibm.com, raistlin@linux.it, insop.song@ericsson.com, liming.wang@windriver.com Date: Wed, 11 Apr 2012 12:21:38 -0400 In-Reply-To: <1333696481-3433-7-git-send-email-juri.lelli@gmail.com> References: <1333696481-3433-1-git-send-email-juri.lelli@gmail.com> <1333696481-3433-7-git-send-email-juri.lelli@gmail.com> Content-Type: text/plain; charset="ISO-8859-15" X-Mailer: Evolution 3.2.2-1 Content-Transfer-Encoding: 7bit Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 2012-04-06 at 09:14 +0200, Juri Lelli wrote: > /* > * Only called when both the current and waking task are -deadline > * tasks. > @@ -487,8 +819,20 @@ static void yield_task_dl(struct rq *rq) > static void check_preempt_curr_dl(struct rq *rq, struct task_struct *p, > int flags) > { > - if (dl_time_before(p->dl.deadline, rq->curr->dl.deadline)) > + if (dl_time_before(p->dl.deadline, rq->curr->dl.deadline)) { > resched_task(rq->curr); > + return; > + } > + > +#ifdef CONFIG_SMP > + /* > + * In the unlikely case current and p have the same deadline > + * let us try to decide what's the best thing to do... > + */ > + if ((s64)(p->dl.deadline - rq->curr->dl.deadline) == 0 && > + !need_resched()) OK, maybe I'm thick. But how is: (s64)(p->dl.deadline - rq->curr->dl.deadline) == 0 Better than: p->dl.deadline == rq->curr->dl.deadline ? -- Steve > + check_preempt_equal_dl(rq, p); > +#endif /* CONFIG_SMP */ > } >