From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753482AbbCZXVQ (ORCPT ); Thu, 26 Mar 2015 19:21:16 -0400 Received: from mga09.intel.com ([134.134.136.24]:55509 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753355AbbCZXVP (ORCPT ); Thu, 26 Mar 2015 19:21:15 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.11,475,1422950400"; d="scan'208";a="473293550" Date: Fri, 27 Mar 2015 07:03:00 +0800 From: Wanpeng Li To: Juri Lelli Cc: Ingo Molnar , Peter Zijlstra , linux-kernel@vger.kernel.org, Wanpeng Li Subject: Re: [PATCH v2] sched/deadline: reduce rq lock contention by eliminating locking of non-feasible target Message-ID: <20150326230300.GA3658@kernel> Reply-To: Wanpeng Li References: <1427101333-5841-1-git-send-email-wanpeng.li@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1427101333-5841-1-git-send-email-wanpeng.li@linux.intel.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Ping Juri, ;) On Mon, Mar 23, 2015 at 05:02:13PM +0800, Wanpeng Li wrote: >This patch adds checks that prevents futile attempts to move dl tasks to >a CPU with active tasks of equal or earlier deadline. The same behavior as >commit 80e3d87b2c55 ("sched/rt: Reduce rq lock contention by eliminating >locking of non-feasible target") for rt class. > >Signed-off-by: Wanpeng Li >--- >v1 -> v2: > * use dl_time_before macro > > kernel/sched/deadline.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > >diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c >index 19d716e..f48d319 100644 >--- a/kernel/sched/deadline.c >+++ b/kernel/sched/deadline.c >@@ -955,7 +955,9 @@ select_task_rq_dl(struct task_struct *p, int cpu, int sd_flag, int flags) > (p->nr_cpus_allowed > 1)) { > int target = find_later_rq(p); > >- if (target != -1) >+ if (target != -1 && >+ dl_time_before(p->dl.deadline, >+ cpu_rq(target)->dl.earliest_dl.curr)) > cpu = target; > } > rcu_read_unlock(); >-- >1.9.1