From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757244Ab3BRJPs (ORCPT ); Mon, 18 Feb 2013 04:15:48 -0500 Received: from mga03.intel.com ([143.182.124.21]:35191 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756861Ab3BRJPq (ORCPT ); Mon, 18 Feb 2013 04:15:46 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.84,686,1355126400"; d="scan'208";a="258284299" Message-ID: <5121F15B.50403@intel.com> Date: Mon, 18 Feb 2013 17:16:11 +0800 From: Alex Shi User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:15.0) Gecko/20120912 Thunderbird/15.0.1 MIME-Version: 1.0 To: Joonsoo Kim CC: torvalds@linux-foundation.org, mingo@redhat.com, peterz@infradead.org, tglx@linutronix.de, akpm@linux-foundation.org, arjan@linux.intel.com, bp@alien8.de, pjt@google.com, namhyung@kernel.org, efault@gmx.de, vincent.guittot@linaro.org, gregkh@linuxfoundation.org, preeti@linux.vnet.ibm.com, viresh.kumar@linaro.org, linux-kernel@vger.kernel.org, morten.rasmussen@arm.com Subject: Re: [patch v5 01/15] sched: set initial value for runnable avg of sched entities. References: <1361164062-20111-1-git-send-email-alex.shi@intel.com> <1361164062-20111-2-git-send-email-alex.shi@intel.com> <20130218082843.GA10009@lge.com> In-Reply-To: <20130218082843.GA10009@lge.com> 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 On 02/18/2013 04:28 PM, Joonsoo Kim wrote: > On Mon, Feb 18, 2013 at 01:07:28PM +0800, Alex Shi wrote: >> > We need initialize the se.avg.{decay_count, load_avg_contrib} to zero >> > after a new task forked. >> > Otherwise random values of above variables cause mess when do new task > I think that these are not random values. In arch_dup_task_struct(), > we do '*dst = *src', so, these values come from parent process. If we use > these value appropriately, we can anticipate child process' load easily. > So to initialize the load_avg_contrib to zero is not good idea for me. Um, for a new forked task, calling them random value is appropriate, since uncertain value of decay_count make random behaviour in enqueue_entity_load_avg(). And many comments said new forked task need not follow parent's utilisations, like what's you claimed for exec. -- Thanks Alex