Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751510AbaG3ImY (ORCPT ); Wed, 30 Jul 2014 04:42:24 -0400 Received: from mga11.intel.com ([192.55.52.93]:47908 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750782AbaG3ImW (ORCPT ); Wed, 30 Jul 2014 04:42:22 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.01,762,1400050800"; d="scan'208";a="577567860" Date: Wed, 30 Jul 2014 08:40:07 +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: <20140730004007.GC28673@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> <20140729014343.GE5203@intel.com> <20140729222752.GA28673@intel.com> <20140730083008.GD19379@twins.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140730083008.GD19379@twins.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 Wed, Jul 30, 2014 at 10:30:08AM +0200, Peter Zijlstra wrote: > > > > Isn't the entire effort starting from PJT and Ben up to now to soften the extremely > > dynamic changes (runnable or not, weight change, etc)? Assume task does not change > > weight much, but group entity does as Peter mentioned. > > No, softening isn't the point at all. But an integrator is the only > means of predicting the future given the erratic past. > > The whole point we got into this game is to better compute per cpu group > weights, not to soften stuff, that's just a necessarily evil to more > accurately predict erratic/unknown behaviour. > > Yes, I totally agree. I think what I meant by "soften" is the *effect* of the integrator that takes/averages the infinite history to predict the tufure. -- 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/