From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755891AbaKSKl6 (ORCPT ); Wed, 19 Nov 2014 05:41:58 -0500 Received: from mga01.intel.com ([192.55.52.88]:12718 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755806AbaKSKlr (ORCPT ); Wed, 19 Nov 2014 05:41:47 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.07,415,1413270000"; d="scan'208";a="624774737" From: Wanpeng Li To: Ingo Molnar , Peter Zijlstra Cc: Juri Lelli , Kirill Tkhai , linux-kernel@vger.kernel.org, Wanpeng Li Subject: [PATCH 1/2] sched/deadline: reduce overhead if there are no scheduling parameters changed Date: Wed, 19 Nov 2014 18:01:36 +0800 Message-Id: <1416391297-111305-1-git-send-email-wanpeng.li@linux.intel.com> X-Mailer: git-send-email 1.7.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org There is no need to dequeue/enqueue and push/pull if there are no scheduling parameters changed for dl class, actually both fair and rt class have already check if parameters changed for them to avoid unnecessary overhead. This patch add the parameters changed verify for dl class in order to reduce overhead. Signed-off-by: Wanpeng Li --- kernel/sched/core.c | 17 ++++++++++++++++- 1 file changed, 16 insertions(+), 1 deletion(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 603c462..f361867 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -3402,6 +3402,21 @@ static bool check_same_owner(struct task_struct *p) return match; } +static bool dl_param_changed(struct task_struct *p, + const struct sched_attr *attr) +{ + struct sched_dl_entity *dl_se = &p->dl; + + if (dl_se->dl_runtime != attr->sched_runtime || + dl_se->dl_deadline != attr->sched_deadline || + dl_se->dl_period != attr->sched_period || + dl_se->flags != attr->sched_flags || + p->rt_priority != attr->sched_priority) + return true; + + return false; +} + static int __sched_setscheduler(struct task_struct *p, const struct sched_attr *attr, bool user) @@ -3530,7 +3545,7 @@ recheck: goto change; if (rt_policy(policy) && attr->sched_priority != p->rt_priority) goto change; - if (dl_policy(policy)) + if (dl_policy(policy) && dl_param_changed(p, attr)) goto change; p->sched_reset_on_fork = reset_on_fork; -- 1.9.1