From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S266476AbUGPFkY (ORCPT ); Fri, 16 Jul 2004 01:40:24 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S266477AbUGPFkY (ORCPT ); Fri, 16 Jul 2004 01:40:24 -0400 Received: from e6.ny.us.ibm.com ([32.97.182.106]:50360 "EHLO e6.ny.us.ibm.com") by vger.kernel.org with ESMTP id S266476AbUGPFkU (ORCPT ); Fri, 16 Jul 2004 01:40:20 -0400 Date: Thu, 15 Jul 2004 22:40:05 -0700 From: "Martin J. Bligh" To: Jesse Barnes , Nick Piggin cc: linux-kernel , John Hawkes Subject: Re: [PATCH] reduce inter-node balancing frequency Message-ID: <2700000.1089956404@[10.10.2.4]> In-Reply-To: <200407152158.17605.jbarnes@engr.sgi.com> References: <200407151829.20069.jbarnes@engr.sgi.com> <200407152038.32755.jbarnes@engr.sgi.com> <40F733D2.2000309@yahoo.com.au> <200407152158.17605.jbarnes@engr.sgi.com> X-Mailer: Mulberry/2.2.1 (Linux/x86) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org --Jesse Barnes wrote (on Thursday, July 15, 2004 21:58:17 -0400): > On Thursday, July 15, 2004 9:48 pm, Nick Piggin wrote: >> Yeah, these numbers actually used to be a lot higher, but someone >> at Intel (I forget who it was right now) found them to be too high >> on even a 32 way SMT system. They could probably be raised a *little* >> bit in the generic code. > > Ok, but I wouldn't want to hurt the performance of small machines at all. If > possible, I'd rather just add another level to the hierarchy if MAX_NUMNODES >> some value. Arch code. Arch code. Arch code ;-) Or at least base it of nr_cpus or numnodes. Seriously ... a 2x or 4x opteron obviously needs different parameters from a 16x x440 or a 512x SGI box ... why we have a flexible infrastructure that can stand on its head and do backflips, and then we don't use it at all is a mystery to me ;-) I'd even go so far as to suggest there should be NO default settings for NUMA, only in arch code - that'd make people actually think about it. If there are, they should be based off the topo infrastructure, not static values. >> > We may have enough information to do that already... I'll look. >> >> The plan is to allow arch overridable SD_CPU/NODE_INIT macros for >> those architectures that just look like a regular SMT+SMP+NUMA, and >> have the generic code set them up. > > Would simply creating a 'supernode' scheduling domain work with the existing > scheduler? My thought was that in the ia64 code we'd create them for every N > regular nodes; its children would be the regular nodes with the existing > defaults. Nick would know better than I, but I think so ... it seems to cope with arbitrary levels, groupings, ... gravitational dimensions, etc ;-) M.