Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762181AbZDCWQD (ORCPT ); Fri, 3 Apr 2009 18:16:03 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757324AbZDCWPv (ORCPT ); Fri, 3 Apr 2009 18:15:51 -0400 Received: from rv-out-0506.google.com ([209.85.198.229]:9285 "EHLO rv-out-0506.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756886AbZDCWPv convert rfc822-to-8bit (ORCPT ); Fri, 3 Apr 2009 18:15:51 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; b=nlIWJBlqM+zHuvy7FQtoERKbuNhr7BdXd2/Pl/QVpn3U1c2kC5ItwuFQ/Y5mWeExn7 inFBPRzRMsO5rZLGB/2wjxfDIGDRa/kD7Vb+PFht7CxRyzwJArzRVYCMNwTZk3lLR8oa Q3bI9slTcNj0UsBCX4Kc5Zs+p/Zn/eKXUI2Ag= MIME-Version: 1.0 In-Reply-To: <87r609jtc2.fsf@basil.nowhere.org> References: <87vdpljuqi.fsf@basil.nowhere.org> <86802c440904031448yc6d499ckd9cb969ce136f477@mail.gmail.com> <87r609jtc2.fsf@basil.nowhere.org> Date: Fri, 3 Apr 2009 15:15:48 -0700 Message-ID: <86802c440904031515u22bd2362n884337729282c6c1@mail.gmail.com> Subject: Re: Off topic: Numactl "distance" wrong From: Yinghai Lu To: Andi Kleen Cc: David Rientjes , Chris Worley , linux-kernel@vger.kernel.org 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: 1631 Lines: 37 On Fri, Apr 3, 2009 at 2:55 PM, Andi Kleen wrote: > 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. how the cpu and memory hotplug works when it could change kind of topology? sched: wonder if arch_reinit_sched_domains() is used to rebuild_sched_domains() it will call node_distance() or ACPI asl code could update SLIT table , and let os use slit table. YH -- 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/