From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757434Ab2HJHbQ (ORCPT ); Fri, 10 Aug 2012 03:31:16 -0400 Received: from LGEMRELSE1Q.lge.com ([156.147.1.111]:46581 "EHLO LGEMRELSE1Q.lge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756915Ab2HJHbN (ORCPT ); Fri, 10 Aug 2012 03:31:13 -0400 X-AuditID: 9c93016f-b7c98ae0000013b4-a3-5024b8bfb7a5 From: Namhyung Kim To: Ingo Molnar , Peter Zijlstra Cc: LKML , Namhyung Kim , Mike Galbraith , Suresh Siddha Subject: [RFC/PATCH] sched: Honor sync wake up in select_idle_sibling Date: Fri, 10 Aug 2012 16:25:12 +0900 Message-Id: <1344583512-25352-1-git-send-email-namhyung@kernel.org> X-Mailer: git-send-email 1.7.11.2 X-Brightmail-Tracker: AAAAAA== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Namhyung Kim When sync wakeup happens and there's the waker task running alone, select the target cpu as if it's already idle. Cc: Mike Galbraith Cc: Suresh Siddha Signed-off-by: Namhyung Kim --- kernel/sched/fair.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index d0cc03b3e70b..64b68bc82b52 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -2632,7 +2632,7 @@ find_idlest_cpu(struct sched_group *group, struct task_struct *p, int this_cpu) /* * Try and locate an idle CPU in the sched_domain. */ -static int select_idle_sibling(struct task_struct *p, int target) +static int select_idle_sibling(struct task_struct *p, int target, int sync) { int cpu = smp_processor_id(); int prev_cpu = task_cpu(p); @@ -2646,6 +2646,13 @@ static int select_idle_sibling(struct task_struct *p, int target) return cpu; /* + * If the task is going to be woken-up on this cpu and there's only + * the sync-waker running, then it is the right target. + */ + if (target == cpu && sync && this_rq()->nr_running == 1) + return cpu; + + /* * If the task is going to be woken-up on the cpu where it previously * ran and if it is currently idle, then it the right target. */ @@ -2748,7 +2755,7 @@ select_task_rq_fair(struct task_struct *p, int sd_flag, int wake_flags) if (cpu == prev_cpu || wake_affine(affine_sd, p, sync)) prev_cpu = cpu; - new_cpu = select_idle_sibling(p, prev_cpu); + new_cpu = select_idle_sibling(p, prev_cpu, sync); goto unlock; } -- 1.7.11.2