Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751712AbcDRFvd (ORCPT ); Mon, 18 Apr 2016 01:51:33 -0400 Received: from mail-pa0-f65.google.com ([209.85.220.65]:35614 "EHLO mail-pa0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751174AbcDRFvc (ORCPT ); Mon, 18 Apr 2016 01:51:32 -0400 From: Wanpeng Li X-Google-Original-From: Wanpeng Li To: Ingo Molnar , Peter Zijlstra Cc: "Rafael J. Wysocki" , linux-kernel@vger.kernel.org, Wanpeng Li Subject: [PATCH] sched/cpufreq: don't trigger cpufreq update w/o real rt/deadline tasks running Date: Mon, 18 Apr 2016 13:51:24 +0800 Message-Id: <1460958684-32105-1-git-send-email-wanpeng.li@hotmail.com> X-Mailer: git-send-email 1.9.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2037 Lines: 63 Sometimes update_curr() is called w/o tasks actually running, it is captured by: u64 delta_exec = rq_clock_task(rq) - curr->se.exec_start; We should not trigger cpufreq update in this case for rt/deadline classes, and this patch fix it. Signed-off-by: Wanpeng Li --- kernel/sched/deadline.c | 8 ++++---- kernel/sched/rt.c | 8 ++++---- 2 files changed, 8 insertions(+), 8 deletions(-) diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c index affd97e..8f9b5af 100644 --- a/kernel/sched/deadline.c +++ b/kernel/sched/deadline.c @@ -717,10 +717,6 @@ static void update_curr_dl(struct rq *rq) if (!dl_task(curr) || !on_dl_rq(dl_se)) return; - /* Kick cpufreq (see the comment in linux/cpufreq.h). */ - if (cpu_of(rq) == smp_processor_id()) - cpufreq_trigger_update(rq_clock(rq)); - /* * Consumed budget is computed considering the time as * observed by schedulable tasks (excluding time spent @@ -736,6 +732,10 @@ static void update_curr_dl(struct rq *rq) return; } + /* kick cpufreq (see the comment in linux/cpufreq.h). */ + if (cpu_of(rq) == smp_processor_id()) + cpufreq_trigger_update(rq_clock(rq)); + schedstat_set(curr->se.statistics.exec_max, max(curr->se.statistics.exec_max, delta_exec)); diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c index c41ea7a..19e1306 100644 --- a/kernel/sched/rt.c +++ b/kernel/sched/rt.c @@ -953,14 +953,14 @@ static void update_curr_rt(struct rq *rq) if (curr->sched_class != &rt_sched_class) return; - /* Kick cpufreq (see the comment in linux/cpufreq.h). */ - if (cpu_of(rq) == smp_processor_id()) - cpufreq_trigger_update(rq_clock(rq)); - delta_exec = rq_clock_task(rq) - curr->se.exec_start; if (unlikely((s64)delta_exec <= 0)) return; + /* Kick cpufreq (see the comment in linux/cpufreq.h). */ + if (cpu_of(rq) == smp_processor_id()) + cpufreq_trigger_update(rq_clock(rq)); + schedstat_set(curr->se.statistics.exec_max, max(curr->se.statistics.exec_max, delta_exec)); -- 1.9.1