From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758800AbYCUO6J (ORCPT ); Fri, 21 Mar 2008 10:58:09 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1758620AbYCUO5s (ORCPT ); Fri, 21 Mar 2008 10:57:48 -0400 Received: from mx2.mail.elte.hu ([157.181.151.9]:57950 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758609AbYCUO5r (ORCPT ); Fri, 21 Mar 2008 10:57:47 -0400 Date: Fri, 21 Mar 2008 15:57:36 +0100 From: Ingo Molnar To: Jack Steiner Cc: ak@suse.de, tglx@linutronix.de, linux-kernel@vger.kernel.org Subject: Re: [PATCH] - Allow NODES_SHIFT to be a config option on x86_64 Message-ID: <20080321145736.GC1545@elte.hu> References: <20080321133425.GA11095@sgi.com> <20080321142648.GB31719@elte.hu> <20080321145401.GA10303@sgi.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20080321145401.GA10303@sgi.com> User-Agent: Mutt/1.5.17 (2007-11-01) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.3 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Jack Steiner wrote: > On Fri, Mar 21, 2008 at 03:26:49PM +0100, Ingo Molnar wrote: > > > > * Jack Steiner wrote: > > > > > Allow the maximum number of nodes in an x86_64 system to be > > > configurable. This patch does NOT change the default value but allows > > > the value to be a config option. > > > > i've applied your patch - but i'm wondering, shouldnt we auto-scale the > > default according to max number of CPUs? (with some sensible scaling > > that happens to meet your expected large-system needs as well ;-) All > > the current manual configuration of nodes shift is ugly. > > I would prefer to auto-scale, too, but our hardware platform allows > too many options to make it easy. The current system configs will > support from 0 to 32 cpus per node (some nodes have memory only). > > However, I'm open to suggestions if you have any ideas.... how about scaling for the worst case, and allowing distros to tune down if they really want? What's the cost of a too large NODE_SHIFT? Ingo