From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S966897AbWKUCSl (ORCPT ); Mon, 20 Nov 2006 21:18:41 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S966900AbWKUCSl (ORCPT ); Mon, 20 Nov 2006 21:18:41 -0500 Received: from mga05.intel.com ([192.55.52.89]:26642 "EHLO fmsmga101.fm.intel.com") by vger.kernel.org with ESMTP id S966897AbWKUCSl (ORCPT ); Mon, 20 Nov 2006 21:18:41 -0500 X-ExtLoop1: 1 X-IronPort-AV: i="4.09,441,1157353200"; d="scan'208"; a="166999881:sNHT34886467" Date: Mon, 20 Nov 2006 17:54:42 -0800 From: "Siddha, Suresh B" To: Christoph Lameter Cc: "Siddha, Suresh B" , mingo@elte.hu, nickpiggin@yahoo.com.au, akpm@osdl.org, linux-kernel@vger.kernel.org, kenneth.w.chen@intel.com Subject: Re: [patch] sched: decrease number of load balances Message-ID: <20061120175441.C17305@unix-os.sc.intel.com> References: <20061120142633.A17305@unix-os.sc.intel.com> <20061120164338.B17305@unix-os.sc.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5.1i In-Reply-To: ; from clameter@sgi.com on Mon, Nov 20, 2006 at 05:39:42PM -0800 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Nov 20, 2006 at 05:39:42PM -0800, Christoph Lameter wrote: > On Mon, 20 Nov 2006, Siddha, Suresh B wrote: > > > My patch is not changing any idle load balancing logic and hence it is no > > less/more aggressive as the current one. > > But you cannot do anything in addition to idle balancing. You can only > draw a process to the cpu you are balancing on. And we are already doing > that. Yes. The above logic is not changed. Once an idle processor('P') picked up some load(based on load differences of groups at level 'X) at level 'X', group of cpus(containing 'P') in level 'X-1' will try to distribute that load among them depending on their groups load at that level. And this repeats till we reach the lowest level.. > So this cuts down the frequency of idle balance? Frequency of idle processor doing balance is same as today but what we reduce is number of processors doing that load balance. > And only the first idle processor of a group of idle processors does balancing? That is correct. If all the cpus in a group are busy, then only the first cpu in the group will do load balance between the groups. We really don't have to calculate who in the group is leastly loaded, as we can assume that load is equally balanced at level 'X-1' while doing load balancing at level 'X'. thanks, suresh