From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kirill Tkhai Subject: [PATCH] sched/rt: Decrease number of calls of push_rt_task() in push_rt_tasks() Date: Mon, 28 Jan 2013 03:46:48 +0400 Message-ID: <2016751359330408@web20f.yandex.ru> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Cc: Steven Rostedt , Ingo Molnar , Peter Zijlstra , linux-rt-users To: "linux-kernel@vger.kernel.org" Return-path: Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-rt-users.vger.kernel.org The patch aims to decrease the number of calls of push_rt_task() in push_rt_tasks(). It's not necessary to push more than 'num_online_cpus() - 1' tasks. If just pushed task doesn't leave its new CPU during our local call of push_rt_tasks() than we won't push another task to the CPU. If it leave or change priority than it will pull new task by itself. Signed-off-by: Kirill V Tkhai CC: Steven Rostedt CC: Ingo Molnar CC: Peter Zijlstra CC: linux-rt-users --- kernel/sched/rt.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c index 4e8f0f4..edf046d 100644 --- a/kernel/sched/rt.c +++ b/kernel/sched/rt.c @@ -1703,8 +1703,10 @@ out: static void push_rt_tasks(struct rq *rq) { + int num_cpus = num_online_cpus() - 1; + /* push_rt_task will return true if it moved an RT */ - while (push_rt_task(rq)) + while (push_rt_task(rq) && --num_cpus > 0) ; }