Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755632Ab3FQAep (ORCPT ); Sun, 16 Jun 2013 20:34:45 -0400 Received: from mga03.intel.com ([143.182.124.21]:15704 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755553Ab3FQAeg (ORCPT ); Sun, 16 Jun 2013 20:34:36 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.87,876,1363158000"; d="scan'208";a="350795001" Message-ID: <51BE5958.6020602@intel.com> Date: Mon, 17 Jun 2013 08:33:28 +0800 From: Alex Shi User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130329 Thunderbird/17.0.5 MIME-Version: 1.0 To: Lei Wen CC: mingo@redhat.com, peterz@infradead.org, tglx@linutronix.de, akpm@linux-foundation.org, bp@alien8.de, pjt@google.com, namhyung@kernel.org, efault@gmx.de, morten.rasmussen@arm.com, vincent.guittot@linaro.org, preeti@linux.vnet.ibm.com, viresh.kumar@linaro.org, linux-kernel@vger.kernel.org, mgorman@suse.de, riel@redhat.com, wangyun@linux.vnet.ibm.com, Jason Low , Changlong Xie , sgruszka@redhat.com, fweisbec@gmail.com Subject: Re: [patch v8 3/9] sched: set initial value of runnable avg for new forked task References: <1370589652-24549-1-git-send-email-alex.shi@intel.com> <1370589652-24549-4-git-send-email-alex.shi@intel.com> <51BB21D8.6000109@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: 1381 Lines: 28 On 06/15/2013 08:09 PM, Lei Wen wrote: >>>>> >>> > and make forking balancing imbalance since incorrect load_avg_contrib. >>>>> >>> > >>>>> >>> > Further more, Morten Rasmussen notice some tasks were not launched at >>>>> >>> > once after created. So Paul and Peter suggest giving a start value for >>>>> >>> > new task runnable avg time same as sched_slice(). >>> >> I am confused at this comment, how set slice to runnable avg would change >>> >> the behavior of "some tasks were not launched at once after created"? >> > >> > I also don't know the details on Morten's machine. but just guess, there >> > are much tasks on in the run queue. the minimum load avg make the new >> > task wait its time... > Is there some possibility that since task structure is allocated without being > set to 0, and it cause the imbalance between runqueues. Then the new forked > is migrated to other cpus, so that it cause its execution being delayed? Is there sth weird happens? The task should be running a while before migration. and periodic load balance also need some time to happen. So generally, it has no such worries. -- 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/