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=-3.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED 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 B1CC6C433DF for ; Tue, 25 Aug 2020 11:19:48 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 7C9F820706 for ; Tue, 25 Aug 2020 11:19:48 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=gibson.dropbear.id.au header.i=@gibson.dropbear.id.au header.b="PjxOJqmy" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7C9F820706 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=gibson.dropbear.id.au Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:52530 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kAWzT-0003nc-Ol for qemu-devel@archiver.kernel.org; Tue, 25 Aug 2020 07:19:47 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:41868) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kAWwU-00072U-FX; Tue, 25 Aug 2020 07:16:43 -0400 Received: from ozlabs.org ([2401:3900:2:1::2]:41845) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kAWwS-00053w-55; Tue, 25 Aug 2020 07:16:42 -0400 Received: by ozlabs.org (Postfix, from userid 1007) id 4BbRJc2dthz9sTm; Tue, 25 Aug 2020 21:16:31 +1000 (AEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gibson.dropbear.id.au; s=201602; t=1598354192; bh=EQPdCzGXEohFL8bGkVDNx+u+KUy8Mwb8RMIjqXsIKOE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=PjxOJqmyPQNZQDdgru4qmelsmeO6iJ1MGo6YTFn9kbyN7oCcgrTmTjwneDk/K0l46 oZC59MdlvrThAQvUy2LGLd/uw8ofTn87CDWYyhQd8ExqHLugmUf1qDtwRnBqcC1AS+ Tc6otrfuSjIKH5RkvybhcNEFRo7nj4HKi6mZvPik= Date: Tue, 25 Aug 2020 21:12:08 +1000 From: David Gibson To: Daniel Henrique Barboza Subject: Re: [PATCH 02/10] numa: introduce MachineClass::forbid_asymmetrical_numa Message-ID: <20200825111208.GH4734@yekko.fritz.box> References: <20200820011726.GF271315@yekko.fritz.box> <20200820021128.GC642093@habkost.net> <20200820041504.GN271315@yekko.fritz.box> <20200820165103.GD642093@habkost.net> <20200821105538.6f6b46c8@redhat.com> <20200824060839.GE4734@yekko.fritz.box> <20200824234917.GF4734@yekko.fritz.box> <98728fe4-1262-6be2-8dd1-1b38ffbe81e9@gmail.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="YrlhzR9YrZtruaFS" Content-Disposition: inline In-Reply-To: <98728fe4-1262-6be2-8dd1-1b38ffbe81e9@gmail.com> Received-SPF: pass client-ip=2401:3900:2:1::2; envelope-from=dgibson@ozlabs.org; helo=ozlabs.org X-detected-operating-system: by eggs.gnu.org: No matching host in p0f cache. That's all we know. X-Spam_score_int: -17 X-Spam_score: -1.8 X-Spam_bar: - X-Spam_report: (-1.8 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, HEADER_FROM_DIFFERENT_DOMAINS=0.248, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: qemu-ppc@nongnu.org, Igor Mammedov , John Snow , Eduardo Habkost , qemu-devel@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" --YrlhzR9YrZtruaFS Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Aug 25, 2020 at 06:56:46AM -0300, Daniel Henrique Barboza wrote: >=20 >=20 > On 8/24/20 8:49 PM, David Gibson wrote: > > On Mon, Aug 24, 2020 at 08:45:12AM -0300, Daniel Henrique Barboza wrote: > > >=20 > > >=20 >=20 > [...] >=20 > > > > > LOPAPR support a somewhat asymmetrical NUMA setup in its current > > > > > form, > > > >=20 > > > > Huh, I didn't even realize that. What's the mechanism? > > >=20 > > > LOPAPR mentions that a single resource/node can have multiple associa= tivity > > > arrays. The idea is to contemplate the situations where the node has > > > more than one connection with the board. > > >=20 > > > I say "somewhat" because, right after mentioning that, the spec also = says that > > > the OS should consider that the distance between two nodes must alway= s be > > > the shortest one of all available arrays. I'll copy/paste the except = here > > > (end of section 15.2, "Numa Resource Associativity": > >=20 > > Ah. I didn't think that's what "asymmetric NUMA" meant... but come to > > think of it, I'm not very sure about that. >=20 >=20 > This was a poor attempt of my part to cut PAPR some slack. >=20 > TBH, even if current PAPR allows for some form of NUMA asymmetry, I don't= think > it's worth implementing at all. It'll be more complexity on top of what I > already added here, and the best case scenario will be the kernel ignorin= g it > (worst case - kernel blowing it up because we're adding more associativity > arrays in each CPU and so on). Yes, I agree. --=20 David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_ | _way_ _around_! http://www.ozlabs.org/~dgibson --YrlhzR9YrZtruaFS Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAEBCAAdFiEEdfRlhq5hpmzETofcbDjKyiDZs5IFAl9E8gYACgkQbDjKyiDZ s5I3DRAAtF8dcAIIEBRolOFiMVxR+78skl5PnuCMJ4zasQNedouQEg2KL6HjMgX4 0tgEpAea8UCw/yRRjzev+Gze0Onk6Veadmtb+LF4B4DNKuDaWFXDbqFHvKq5gz+2 Mcpw1PL6ui8Qmh50DN1oQ07w/OVEQFco6tIJ5eop2cPS+P222DtCQ0+QegIAggL8 6k+TjnoGwCqFlYbymPuC8p1wFTAFPo/PKTOHAFETpJJ4QQOzfjdYu1lhl5dTAVRi lz+wimWwXw8dwJbmEDzWpe7pDEm5791gQ4MCwZO4ZhGqoAT/ScObFAu0Zz1z+4uL UqQVnUmZ9TuX0kdM93GT6Ecyz08fCRJZ+SkVSrs/2DC6DRaN7yXfZqfvB1pWUdKA zcxcd54bn0V57ToIW3Q3AbfPea18WnOLua8e3yGqFOOXAjHZhEORRYVeFa6HdySE QLLkKWuw6iUR/AXQsySbx0KoxN/RiJL1lGrIINR/sCbU8WEp3voJDJC/nGPPTbAD 17qriPebXLDH9EOiD4rzyTqWbBQphHg65tUpkae3GHyvHr9b3dZNaKA/tcWrizPs 46E7kMRZD8BCVKKsVo3mdvr1xziX6548SohrkJO42ZYPN3G3D9WHpq/zfcgUL85k lOIIOHmg/6FHXGheBqaSGNuGZFZq1aNlOIBKIuLig7JxlJHxAIc= =lp04 -----END PGP SIGNATURE----- --YrlhzR9YrZtruaFS--