From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751516Ab3BUFOt (ORCPT ); Thu, 21 Feb 2013 00:14:49 -0500 Received: from e23smtp04.au.ibm.com ([202.81.31.146]:53520 "EHLO e23smtp04.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751002Ab3BUFOs (ORCPT ); Thu, 21 Feb 2013 00:14:48 -0500 Message-ID: <5125AD3D.40400@linux.vnet.ibm.com> Date: Thu, 21 Feb 2013 13:14:37 +0800 From: Michael Wang User-Agent: Mozilla/5.0 (X11; Linux i686; rv:16.0) Gecko/20121011 Thunderbird/16.0.1 MIME-Version: 1.0 To: Peter Zijlstra CC: Ingo Molnar , LKML , Paul Turner , Mike Galbraith , Andrew Morton , alex.shi@intel.com, Ram Pai , "Nikunj A. Dadhania" , Namhyung Kim Subject: Re: [RFC PATCH v3 0/3] sched: simplify the select_task_rq_fair() References: <51079178.3070002@linux.vnet.ibm.com> <20130220104958.GA9152@gmail.com> <1361367148.10155.30.camel@laptop> In-Reply-To: <1361367148.10155.30.camel@laptop> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Content-Scanned: Fidelis XPS MAILER x-cbid: 13022105-9264-0000-0000-000003314A83 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 02/20/2013 09:32 PM, Peter Zijlstra wrote: > On Wed, 2013-02-20 at 11:49 +0100, Ingo Molnar wrote: > >> The changes look clean and reasoable, > > I don't necessarily agree, note that O(n^2) storage requirement that > Michael failed to highlight ;-) Forgive me for not explain this point in cover, but it's really not a big deal in my opinion... And I'm going to apply Mike's suggestion, do allocation when cpu active, that will save some space :) Regards, Michael Wang > >> any ideas exactly *why* it speeds up? > > That is indeed the most interesting part.. There's two parts to > select_task_rq_fair(), the 'regular' affine wakeup path, and the > fork/exec find_idlest_goo() path. At the very least we need to quantify > which of these two parts contributes most to the speedup. > > In the power balancing discussion we already noted that the > find_idlest_goo() is in need of attention. > > -- > 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/ >