Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754947Ab2FFJP7 (ORCPT ); Wed, 6 Jun 2012 05:15:59 -0400 Received: from casper.infradead.org ([85.118.1.10]:60008 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751360Ab2FFJP6 convert rfc822-to-8bit (ORCPT ); Wed, 6 Jun 2012 05:15:58 -0400 Message-ID: <1338974105.2749.85.camel@twins> Subject: Re: [tip:sched/core] sched/numa: Rewrite the CONFIG_NUMA sched domain support From: Peter Zijlstra To: Alex Shi Cc: mingo@kernel.org, torvalds@linux-foundation.org, cmetcalf@tilera.com, tony.luck@intel.com, sivanich@sgi.com, akpm@linux-foundation.org, ralf@linux-mips.org, greg.pearson@hp.com, ink@jurassic.park.msu.ru, tglx@linutronix.de, rth@twiddle.net, kamezawa.hiroyu@jp.fujitsu.com, paulus@samba.org, linux-kernel@vger.kernel.org, hpa@zytor.com, anton@samba.org, lethal@linux-sh.org, davem@davemloft.net, benh@kernel.crashing.org, dhowells@redhat.com, mattst88@gmail.com, fenghua.yu@intel.com, Alex Shi , linux-tip-commits@vger.kernel.org Date: Wed, 06 Jun 2012 11:15:05 +0200 In-Reply-To: References: Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7BIT X-Mailer: Evolution 3.2.2- Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1171 Lines: 29 On Wed, 2012-06-06 at 15:43 +0800, Alex Shi wrote: > > + /* > > + * O(nr_nodes^2) deduplicating selection sort -- in order to find the > > + * unique distances in the node_distance() table. > > + * > > + * Assumes node_distance(0,j) includes all distances in > > + * node_distance(i,j) in order to avoid cubic time. > > Curious for other platforms node_distance number, actually, this > assumption is right for what I saw Intel platforms. but it is not > match acpispec50.pdf: > > Table 6-152 Example Relative Distances Between Proximity Domains > Proximity Domain 0 1 2 3 > 0 10 15 20 18 > 1 15 10 16 24 > 2 20 16 10 12 > 3 18 24 12 10 Yes I know its allowed, I just haven't seen it in practice. I've got a patch that validates this assumption if you boot with "sched_debug". If we ever run into such a setup we might need to fix this -- it shouldn't be too hard, just expensive. -- 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/