Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753071AbaG2J4E (ORCPT ); Tue, 29 Jul 2014 05:56:04 -0400 Received: from mga03.intel.com ([143.182.124.21]:47368 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751619AbaG2J4B (ORCPT ); Tue, 29 Jul 2014 05:56:01 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.01,756,1400050800"; d="scan'208";a="462621473" Date: Tue, 29 Jul 2014 09:53:44 +0800 From: Yuyang Du To: Peter Zijlstra Cc: Vincent Guittot , "mingo@redhat.com" , linux-kernel , Paul Turner , Benjamin Segall , arjan.van.de.ven@intel.com, Len Brown , rafael.j.wysocki@intel.com, alan.cox@intel.com, "Gross, Mark" , "fengguang.wu@intel.com" Subject: Re: [PATCH 2/2 v4] sched: Rewrite per entity runnable load average tracking Message-ID: <20140729015344.GF5203@intel.com> References: <1405639567-21445-1-git-send-email-yuyang.du@intel.com> <1405639567-21445-3-git-send-email-yuyang.du@intel.com> <20140727173616.GA22986@intel.com> <20140729093911.GU20603@laptop.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140729093911.GU20603@laptop.programming.kicks-ass.net> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jul 29, 2014 at 11:39:11AM +0200, Peter Zijlstra wrote: > > > For task, assuming its load.weight does not change much, yes, we can. But in theory, task's > > > > I would even say that the load_avg of a task should not be impacted by > > an old priority value. Once, the priority of a task is changed, we > > should only take into account this new priority to weight the load_avg > > of the task > > So for tasks I would immediately agree, and I think for groups too, > seeing how the group weight is based off of this avg, if you then > include the old weight we'll get a feedback loop. This might not be > desired as it would counteract the SMP movement of tasks. Including the old weight can we get the *right* feedback. Because say until weight is changed, we are balanced, changed weight leads to imbalance. Without old weight, the imbalance is multiplied by the history, like we have never been balanced. -- 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/