Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S937128AbZDCVzo (ORCPT ); Fri, 3 Apr 2009 17:55:44 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S936823AbZDCVzP (ORCPT ); Fri, 3 Apr 2009 17:55:15 -0400 Received: from one.firstfloor.org ([213.235.205.2]:41825 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1763806AbZDCVzO (ORCPT ); Fri, 3 Apr 2009 17:55:14 -0400 To: Yinghai Lu Cc: David Rientjes , Chris Worley , linux-kernel@vger.kernel.org Subject: Re: Off topic: Numactl "distance" wrong From: Andi Kleen References: <87vdpljuqi.fsf@basil.nowhere.org> <86802c440904031448yc6d499ckd9cb969ce136f477@mail.gmail.com> Date: Fri, 03 Apr 2009 23:55:09 +0200 In-Reply-To: <86802c440904031448yc6d499ckd9cb969ce136f477@mail.gmail.com> (Yinghai Lu's message of "Fri, 3 Apr 2009 14:48:31 -0700") Message-ID: <87r609jtc2.fsf@basil.nowhere.org> User-Agent: Gnus/5.1008 (Gnus v5.10.8) Emacs/22.3 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1328 Lines: 33 Yinghai Lu writes: > On Fri, Apr 3, 2009 at 2:43 PM, David Rientjes wrote: >> >> Yinghai, can you elaborate on exactly what type of interface you can >> imagine for modifying the distance for nodes through sysfs? ?It seems like >> you'd have to report the entire physical topology in one write, for which >> we currently don't have an interface for beyond pxms, instead of per-node >> distances to remote nodes. > > acpi_numa_slit_init() in srat_64.c will have one copy (called > acpi_slit) of SLIT, if there is SLIT from ACPI. > > so if numa is enabled, could expose that acpi_slit via sysfs for the > user to update it. That's not enough. You would need to redo all the zone fallback tables in the VM that are initialized based on topology, do new scheduler topologies and all kind of other stuff. Besides I don't know any user space software which actually does anything with the distances. The kernel does, but for it it doesn't make much difference on smaller systems. -Andi -- ak@linux.intel.com -- Speaking for myself only. -- 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/