From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932207AbVHKXtq (ORCPT ); Thu, 11 Aug 2005 19:49:46 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932282AbVHKXtq (ORCPT ); Thu, 11 Aug 2005 19:49:46 -0400 Received: from smtp206.mail.sc5.yahoo.com ([216.136.129.96]:15211 "HELO smtp206.mail.sc5.yahoo.com") by vger.kernel.org with SMTP id S932207AbVHKXtp (ORCPT ); Thu, 11 Aug 2005 19:49:45 -0400 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.com.au; h=Received:Message-ID:Date:From:User-Agent:X-Accept-Language:MIME-Version:To:CC:Subject:References:In-Reply-To:Content-Type:Content-Transfer-Encoding; b=cuxOYAu/ZPgRQZb64Y6yDvrZrfi2ADyaC43ksH5y3+fo1howUCTnfHSDzCrSQmH9vGuPi2hV6w3+cXzYmWGB7fK2IfhOCSMBx5NXNlra4hI4J3ForaVhkOSG6aiD4+xr38RMmymQJp0IEMZ9T026kqW4rI5/FOMCEdyj3TK04MU= ; Message-ID: <42FBE410.9070809@yahoo.com.au> Date: Fri, 12 Aug 2005 09:49:36 +1000 From: Nick Piggin User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.8) Gecko/20050513 Debian/1.7.8-1 X-Accept-Language: en MIME-Version: 1.0 To: "Siddha, Suresh B" CC: Ingo Molnar , Andrew Morton , lkml , steiner@sgi.com, dvhltc@us.ibm.com, mbligh@mbligh.org Subject: Re: allow the load to grow upto its cpu_power (was Re: [Patch] don't kick ALB in the presence of pinned task) References: <20050801174221.B11610@unix-os.sc.intel.com> <20050802092717.GB20978@elte.hu> <20050809160813.B1938@unix-os.sc.intel.com> <42F94A00.3070504@yahoo.com.au> <20050809190352.D1938@unix-os.sc.intel.com> <1123729750.5188.13.camel@npiggin-nld.site> <20050811111411.A581@unix-os.sc.intel.com> In-Reply-To: <20050811111411.A581@unix-os.sc.intel.com> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Siddha, Suresh B wrote: > On Thu, Aug 11, 2005 at 01:09:10PM +1000, Nick Piggin wrote: > >>I have a variation on the 2nd part of your patch which I think >>I would prefer. IMO it kind of generalises the current imbalance >>calculation to handle this case rather than introducing a new >>special case. > > > There is a difference between our changes. > > When the system is lightly loaded, my patch minimizes the number of > groups picking up that load. This will help in power savings for > example in the context of CMP. There are more changes required > (user or kernel) for complete power savings, but this is a direction > towards that. > > How about this patch? Well, it is a departure from our current idea of balancing. I would prefer to use my patch initially to fix the _bug_ you found, then we can think about changing policy for power savings. Main things I'm worried about: Idle time regressions that pop up any time we put restrictions on balancing. This can tend to unbalance memory controllers (eg. on POWER5, CMP Opteron) which can be a performance problem on those systems. Lastly, complexity in the calculation. -- SUSE Labs, Novell Inc. Send instant messages to your online friends http://au.messenger.yahoo.com