From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <peterz@infradead.org>
Received: from merlin.infradead.org (merlin.infradead.org
 [IPv6:2001:8b0:10b:1231::1])
 (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits))
 (No client certificate requested)
 by lists.ozlabs.org (Postfix) with ESMTPS id 420ffG0s08zF31N
 for <linuxppc-dev@lists.ozlabs.org>; Wed, 29 Aug 2018 18:57:57 +1000 (AEST)
Date: Wed, 29 Aug 2018 10:57:38 +0200
From: Peter Zijlstra <peterz@infradead.org>
To: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>, LKML <linux-kernel@vger.kernel.org>,
 Mel Gorman <mgorman@techsingularity.net>, Rik van Riel <riel@surriel.com>,
 Thomas Gleixner <tglx@linutronix.de>,
 Michael Ellerman <mpe@ellerman.id.au>,
 Heiko Carstens <heiko.carstens@de.ibm.com>,
 Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>,
 linuxppc-dev <linuxppc-dev@lists.ozlabs.org>,
 Andre Wild <wild@linux.vnet.ibm.com>
Subject: Re: [PATCH] sched/topology: Use Identity node only if required
Message-ID: <20180829085738.GS24142@hirez.programming.kicks-ass.net>
References: <1533712172-11428-1-git-send-email-srikar@linux.vnet.ibm.com>
 <20180808075840.GO2494@hirez.programming.kicks-ass.net>
 <20180810164533.GB42350@linux.vnet.ibm.com>
 <20180829084348.GO24124@hirez.programming.kicks-ass.net>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
In-Reply-To: <20180829084348.GO24124@hirez.programming.kicks-ass.net>
List-Id: Linux on PowerPC Developers Mail List <linuxppc-dev.lists.ozlabs.org>
List-Unsubscribe: <https://lists.ozlabs.org/options/linuxppc-dev>,
 <mailto:linuxppc-dev-request@lists.ozlabs.org?subject=unsubscribe>
List-Archive: <http://lists.ozlabs.org/pipermail/linuxppc-dev/>
List-Post: <mailto:linuxppc-dev@lists.ozlabs.org>
List-Help: <mailto:linuxppc-dev-request@lists.ozlabs.org?subject=help>
List-Subscribe: <https://lists.ozlabs.org/listinfo/linuxppc-dev>,
 <mailto:linuxppc-dev-request@lists.ozlabs.org?subject=subscribe>

On Wed, Aug 29, 2018 at 10:43:48AM +0200, Peter Zijlstra wrote:
> DIE(j) should be:
> 
> 	cpu_cpu_mask(j) := cpumask_of_node(cpu_to_node(j))

FWIW, I was expecting that to be topology_core_cpumask(), so I'm a
little confused myself just now.

> and NODE(j) should be:
> 
> 	\Union_k cpumask_of_node(k) ; where node_distance(j,k) <= node_distance(0,0)
> 
> which, _should_ reduce to:
> 
> 	cpumask_of_node(j)
> 
> and thus DIE and NODE _should_ be the same here.
> 
> So what's going sideways?