From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 21C91C4332F for ; Thu, 16 Sep 2021 10:57:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 093F661212 for ; Thu, 16 Sep 2021 10:57:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237485AbhIPK7L (ORCPT ); Thu, 16 Sep 2021 06:59:11 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55150 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236506AbhIPK7J (ORCPT ); Thu, 16 Sep 2021 06:59:09 -0400 Received: from ozlabs.org (bilbo.ozlabs.org [IPv6:2401:3900:2:1::2]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 85614C061574; Thu, 16 Sep 2021 03:57:49 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ellerman.id.au; s=201909; t=1631789866; bh=ZispAWzioAVbjxueTjRm+hiDj1TZC69+PxYkYh1lWBA=; h=From:To:Cc:Subject:In-Reply-To:References:Date:From; b=j+eAgDzFwK8z9d+QuWLV+d7slJps5jsQp4dRysMAI+bc19oxRoC8W4gbJ+tvcEdnd OV2H7AyiQ98cJ1M1hJPOy9WzyJZGxPXetztdknB+TV3itWhfCbwUYqNda2H7F5rKGl v5PQOTfUBCoqPjOcUHDrFXrCHKBTRaWHnRljM57KoahGZ14xe4Sym8HQsqfCoxiGrL yvcZVavQ4K++0YtDp2ga0MRoW53N+PSqS04tLBKAsidBQPPNGm8+aTwzrp5OpyqfRw vzHUXrwm9n8fw2XHX9ZJzr30Rl33MOMtza+QITtUVgXy8QQfXoMkk9SAlT5UJ6ujxi mleoa0SUsg08Q== Received: from authenticated.ozlabs.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by mail.ozlabs.org (Postfix) with ESMTPSA id 4H9DZJ1Ny9z9sW8; Thu, 16 Sep 2021 20:57:44 +1000 (AEST) From: Michael Ellerman To: Peter Zijlstra Cc: Kajol Jain , linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, mingo@redhat.com, acme@kernel.org, jolsa@kernel.org, namhyung@kernel.org, linux-perf-users@vger.kernel.org, ak@linux.intel.com, maddy@linux.ibm.com, atrajeev@linux.vnet.ibm.com, rnsastry@linux.ibm.com, yao.jin@linux.intel.com, ast@kernel.org, daniel@iogearbox.net, songliubraving@fb.com, kan.liang@linux.intel.com, mark.rutland@arm.com, alexander.shishkin@linux.intel.com, paulus@samba.org Subject: Re: [PATCH 1/3] perf: Add macros to specify onchip L2/L3 accesses In-Reply-To: References: <20210904064932.307610-1-kjain@linux.ibm.com> <87ilzbmt7i.fsf@mpe.ellerman.id.au> <87czphnchp.fsf@mpe.ellerman.id.au> <87k0jjl9sp.fsf@mpe.ellerman.id.au> Date: Thu, 16 Sep 2021 20:57:33 +1000 Message-ID: <87fsu4kcte.fsf@mpe.ellerman.id.au> MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Peter Zijlstra writes: > On Tue, Sep 14, 2021 at 08:40:38PM +1000, Michael Ellerman wrote: >> Peter Zijlstra writes: > >> > I'm thinking we ought to keep hops as steps along the NUMA fabric, with >> > 0 hops being the local node. That only gets us: >> > >> > L2, remote=0, hops=HOPS_0 -- our L2 >> > L2, remote=1, hops=HOPS_0 -- L2 on the local node but not ours >> > L2, remote=1, hops!=HOPS_0 -- L2 on a remote node >> >> Hmm. I'm not sure about tying it directly to NUMA hops. I worry we're >> going to see more and more systems where there's a hierarchy within the >> chip/package, in addition to the traditional NUMA hierarchy. >> >> Although then I guess it becomes a question of what exactly is a NUMA >> hop, maybe the answer is that on those future systems those >> intra-chip/package hops should be represented as NUMA hops. >> >> It's not like we have a hard definition of what a NUMA hop is? > > Not really, typically whatever the BIOS/DT/whatever tables tell us. I > think in case of Power you're mostly making things up in software :-) Firmware is software so yes :) > But yeah, I think we have plenty wriggle room there. OK. cheers