Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752510AbWAFRYj (ORCPT ); Fri, 6 Jan 2006 12:24:39 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932636AbWAFRYd (ORCPT ); Fri, 6 Jan 2006 12:24:33 -0500 Received: from pentafluge.infradead.org ([213.146.154.40]:32904 "EHLO pentafluge.infradead.org") by vger.kernel.org with ESMTP id S932733AbWAFRY3 (ORCPT ); Fri, 6 Jan 2006 12:24:29 -0500 Subject: RE: [PATCH] ia64: change defconfig to NR_CPUS==1024 From: Arjan van de Ven To: "Luck, Tony" Cc: hawkes@sgi.com, Tony Luck , Andrew Morton , linux-ia64@vger.kernel.org, linux-kernel@vger.kernel.org, Jack Steiner , Dan Higgins , John Hesterberg , Greg Edwards In-Reply-To: References: Content-Type: text/plain Date: Fri, 06 Jan 2006 18:24:16 +0100 Message-Id: <1136568256.2940.50.camel@laptopd505.fenrus.org> Mime-Version: 1.0 X-Mailer: Evolution 2.2.3 (2.2.3-2.fc4) Content-Transfer-Encoding: 7bit X-Spam-Score: -2.8 (--) X-Spam-Report: SpamAssassin version 3.0.4 on pentafluge.infradead.org summary: Content analysis details: (-2.8 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- -2.8 ALL_TRUSTED Did not pass through any untrusted hosts X-SRS-Rewrite: SMTP reverse-path rewritten from by pentafluge.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1604 Lines: 31 On Fri, 2006-01-06 at 09:19 -0800, Luck, Tony wrote: > >> Increase the generic ia64 config from its current max of 512 CPUs to a > >> new max of 1024 CPUs. > > > >I wonder why this would be seen as a sane thing... > >Very few people have 1024 cpus, and the ones that do sure would know how > >to set 1024 in their kernel config. In fact I would argue to lower it. I > >can see the point of keeping it over 64, to give the > >more-cpus-than-a-long code more testing, but 512 is too high already.. > >most people who have ia64 will not have 512 cpus. > > Would it be impossibly hard to make the >64 cpus case (when the code > switches from a single word to an array) be dependent on a boot-time > variable? If we could, then the defconfig could just say 128, and > users of monster machines would just boot with "maxcpus=4096" to increase > the size of the bitmask arrays. variable size runtime cpu count.. that's beside the point for this change though. The *default* shouldn't be insanely high, but more represent a "typical" setup. The *maximum* is of course an entirely different thing. So.. I'd say lower the default from 512 to 128 (just to get the default to be the "complex case", which has benefits). Going to 1024 for a per user default is silly. Just about everyone will change it anyway to something lower. And distros set their own regardless. - 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/