Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S263199AbTHWQ5Y (ORCPT ); Sat, 23 Aug 2003 12:57:24 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263321AbTHWQ5X (ORCPT ); Sat, 23 Aug 2003 12:57:23 -0400 Received: from e5.ny.us.ibm.com ([32.97.182.105]:10169 "EHLO e5.ny.us.ibm.com") by vger.kernel.org with ESMTP id S263485AbTHWOck (ORCPT ); Sat, 23 Aug 2003 10:32:40 -0400 From: Andrew Theurer Reply-To: habanero@us.ibm.com To: Nick Piggin Subject: Re: [Lse-tech] Re: [patch] scheduler fix for 1cpu/node case Date: Sat, 23 Aug 2003 09:32:24 -0500 User-Agent: KMail/1.5 Cc: Bill Davidsen , "Martin J. Bligh" , Erich Focht , linux-kernel , LSE , Andi Kleen , torvalds@osdl.org, mingo@elte.hu References: <200308221912.38184.habanero@us.ibm.com> <3F46B561.7060706@cyberone.com.au> In-Reply-To: <3F46B561.7060706@cyberone.com.au> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200308230932.24832.habanero@us.ibm.com> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1449 Lines: 29 > >AMD is 1 because there's no need to balance within a node, so I want the > >inter-node balance frequency to be as often as it was with just O(1). > > This interval would not work well with other NUMA boxes, so that's the > > main reason to have arch specific intervals. > > OK, I misread the patch. IIRC AMD has 1 CPU per node? If so, why doesn't > this simply prevent balancing within a node? Yes, one cpu/node. Oh, it does prevent it, but with the current intervals, we end up not really balancing as often (since we need a inter-node balance), and when we call load_balance in schedule when idle, we don't balance at all since it's only a node local balance. > > And, as a general guideline, boxes with > >different local-remote latency ratios will probably benefit from different > >inter-node balance intervals. I don't know what these ratios are, but I'd > >like the kernel to have the ability to change for one arch and not affect > >another. > > I fully appreciate there are huge differences... I am curious if > you can see much improvements in practice. I think AMD would be the first good test. Maybe Andi has some results on numasched vs O(1), which would be a good indication. - 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/