Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964859Ab3DIIGi (ORCPT ); Tue, 9 Apr 2013 04:06:38 -0400 Received: from mga02.intel.com ([134.134.136.20]:35488 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S935595Ab3DIIG3 (ORCPT ); Tue, 9 Apr 2013 04:06:29 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.87,437,1363158000"; d="scan'208";a="292211525" Message-ID: <5163CBE6.4070209@intel.com> Date: Tue, 09 Apr 2013 16:05:58 +0800 From: Alex Shi User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130221 Thunderbird/17.0.3 MIME-Version: 1.0 To: Vincent Guittot CC: "mingo@redhat.com" , Peter Zijlstra , Thomas Gleixner , Andrew Morton , Arjan van de Ven , Borislav Petkov , Paul Turner , Namhyung Kim , Mike Galbraith , Morten Rasmussen , gregkh@linuxfoundation.org, Preeti U Murthy , Viresh Kumar , linux-kernel , Len Brown , rafael.j.wysocki@intel.com, jkosina@suse.cz, clark.williams@gmail.com, "tony.luck@intel.com" , keescook@chromium.org, mgorman@suse.de, riel@redhat.com Subject: Re: [patch v3 6/8] sched: consider runnable load average in move_tasks References: <1364873008-3169-1-git-send-email-alex.shi@intel.com> <1364873008-3169-7-git-send-email-alex.shi@intel.com> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1826 Lines: 47 On 04/09/2013 03:08 PM, Vincent Guittot wrote: > On 2 April 2013 05:23, Alex Shi wrote: >> Except using runnable load average in background, move_tasks is also >> the key functions in load balance. We need consider the runnable load >> average in it in order to the apple to apple load comparison. >> >> Signed-off-by: Alex Shi >> --- >> kernel/sched/fair.c | 11 ++++++++++- >> 1 file changed, 10 insertions(+), 1 deletion(-) >> >> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c >> index 1f9026e..bf4e0d4 100644 >> --- a/kernel/sched/fair.c >> +++ b/kernel/sched/fair.c >> @@ -3966,6 +3966,15 @@ static unsigned long task_h_load(struct task_struct *p); >> >> static const unsigned int sched_nr_migrate_break = 32; >> >> +static unsigned long task_h_load_avg(struct task_struct *p) >> +{ >> + u32 period = p->se.avg.runnable_avg_period; >> + if (!period) >> + return 0; >> + >> + return task_h_load(p) * p->se.avg.runnable_avg_sum / period; > > How do you ensure that runnable_avg_period and runnable_avg_sum are > coherent ? an update of the statistic can occur in the middle of your > sequence. Thanks for your question, Vincent! the runnable_avg_period and runnable_avg_sum, only updated in __update_entity_runnable_avg(). Yes, I didn't see some locks to ensure the coherent of them. but they are updated closely, and it is not big deal even a little incorrect to their value. These data are collected periodically, don't need very very precise at every time. Am I right? :) -- Thanks Alex -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/