From mboxrd@z Thu Jan 1 00:00:00 1970 From: Viresh Kumar Subject: Re: [PATCH V3 1/7] sched: Create sched_select_cpu() to give preferred CPU for power saving Date: Tue, 19 Mar 2013 10:45:07 +0530 Message-ID: References: <9f0fd16f792b9f9b399a4c91c98de37c56067d47.1363617402.git.viresh.kumar@linaro.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Cc: pjt@google.com, paul.mckenney@linaro.org, tglx@linutronix.de, tj@kernel.org, suresh.b.siddha@intel.com, venki@google.com, mingo@redhat.com, peterz@infradead.org, rostedt@goodmis.org, linaro-kernel@lists.linaro.org, robin.randhawa@arm.com, Steve.Bannister@arm.com, Liviu.Dudau@arm.com, charles.garcia-tobin@arm.com, Arvind.Chauhan@arm.com, linux-rt-users@vger.kernel.org, linux-kernel@vger.kernel.org To: Frederic Weisbecker Return-path: Received: from mail-ob0-f178.google.com ([209.85.214.178]:62351 "EHLO mail-ob0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753223Ab3CSFPJ (ORCPT ); Tue, 19 Mar 2013 01:15:09 -0400 Received: by mail-ob0-f178.google.com with SMTP id wd20so68312obb.9 for ; Mon, 18 Mar 2013 22:15:09 -0700 (PDT) In-Reply-To: Sender: linux-rt-users-owner@vger.kernel.org List-ID: On 18 March 2013 21:27, Frederic Weisbecker wrote: > 2013/3/18 Viresh Kumar : >>> It would be nice to have some more precise naming. sched_select_busy_cpu() ? >> >> You are correct that name can be improved but busy may give it a different >> meaning. Maybe sched_select_non_idle_cpu()? > > That works too yeah. Here is the fixup that i applied (it fixes another stupid mistake in sched.h). I have pushed this series here again: http://git.linaro.org/gitweb?p=people/vireshk/linux.git;a=shortlog;h=refs/heads/sched-wq-migration-v3 commit e769ff0d78fd2fb504ae056a44b70bba7c259126 Author: Viresh Kumar Date: Fri Sep 14 15:13:05 2012 +0530 fixup! sched: Create sched_select_cpu() to give preferred CPU for power saving Signed-off-by: Viresh Kumar --- include/linux/sched.h | 19 ++++++++++--------- kernel/sched/core.c | 2 +- 2 files changed, 11 insertions(+), 10 deletions(-) diff --git a/include/linux/sched.h b/include/linux/sched.h index 216fa0d..db6655a 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -231,11 +231,18 @@ extern void init_idle_bootup_task(struct task_struct *idle); extern int runqueue_is_locked(int cpu); #ifdef CONFIG_SMP -extern int sched_select_cpu(unsigned int sd_flags); +extern int sched_select_non_idle_cpu(unsigned int sd_flags); +#else +static inline int sched_select_non_idle_cpu(unsigned int sd_flags) +{ + return smp_processor_id(); +} +#endif -#ifdef CONFIG_NO_HZ +#if defined(CONFIG_SMP) && defined(CONFIG_NO_HZ) extern void nohz_balance_enter_idle(int cpu); extern void set_cpu_sd_state_idle(void); + /* * In the semi idle case, use the nearest busy cpu for migrating timers * from an idle cpu. This is good for power-savings. @@ -244,17 +251,11 @@ extern void set_cpu_sd_state_idle(void); * selecting an idle cpu will add more delays to the timers than intended * (as that cpu's timer base may not be uptodate wrt jiffies etc). */ -#define get_nohz_timer_target() sched_select_cpu(0) +#define get_nohz_timer_target() sched_select_non_idle_cpu(0) #else static inline void nohz_balance_enter_idle(int cpu) { } static inline void set_cpu_sd_state_idle(void) { }