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=-2.8 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_NEOMUTT autolearn=unavailable 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 14AB2C28CC0 for ; Thu, 30 May 2019 21:55:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D916426213 for ; Thu, 30 May 2019 21:55:13 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=armlinux.org.uk header.i=@armlinux.org.uk header.b="DLH2JYbe" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727114AbfE3VzN (ORCPT ); Thu, 30 May 2019 17:55:13 -0400 Received: from pandora.armlinux.org.uk ([78.32.30.218]:49572 "EHLO pandora.armlinux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726986AbfE3VzK (ORCPT ); Thu, 30 May 2019 17:55:10 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=armlinux.org.uk; s=pandora-2019; h=Sender:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=cMVlGTvXkUveUITBldNsm2wqtZ0vfwdSAKndguUBaOQ=; b=DLH2JYbeHwq/YpEbWMtT0JGBL spO2pEc/2hmPltlibpNfKJ2Ih/2Rm4G0phN5i2XSKks3aWtbDZz/GjR3JOGCj0DN/EFFNJYoQcgdY KCaXkwyYwGjN4/dPWIvnF995pitZOxwUX3cRQdPGcd08tJMbDelcgzPTaceo+3xiEu6bQ9l0KxDmW A6ERMXUYjHd+RHWZrpMMqsX0zPrTCj1eb0FZ12RnJMUJ3c1CbH3/iBVkW/k/nJ87VxzdpYmPFA/Bj w8HefDp2VNcdyksBGBu0eg9AnsJHYltB0rlhwyOs9x/BKnj7EROswpX3bRDMtwawd5XTsxhzCT215 893fQ6/Cw==; Received: from shell.armlinux.org.uk ([2001:4d48:ad52:3201:5054:ff:fe00:4ec]:56076) by pandora.armlinux.org.uk with esmtpsa (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.90_1) (envelope-from ) id 1hWSpD-0005E4-3f; Thu, 30 May 2019 22:43:03 +0100 Received: from linux by shell.armlinux.org.uk with local (Exim 4.89) (envelope-from ) id 1hWSp5-0005jk-2U; Thu, 30 May 2019 22:42:55 +0100 Date: Thu, 30 May 2019 22:42:54 +0100 From: Russell King - ARM Linux admin To: Morten Rasmussen Cc: "Andrew F. Davis" , Atish Patra , linux-kernel@vger.kernel.org, Sudeep Holla , Rob Herring , Albert Ou , Anup Patel , Catalin Marinas , "David S. Miller" , devicetree@vger.kernel.org, Greg Kroah-Hartman , Ingo Molnar , Jeremy Linton , Linus Walleij , linux-riscv@lists.infradead.org, Mark Rutland , Mauro Carvalho Chehab , Otto Sabart , Palmer Dabbelt , Paul Walmsley , "Peter Zijlstra (Intel)" , "Rafael J. Wysocki" , Rob Herring , Thomas Gleixner , Will Deacon , linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH v6 1/7] Documentation: DT: arm: add support for sockets defining package boundaries Message-ID: <20190530214254.tuxsnyv52a2fyhck@shell.armlinux.org.uk> References: <20190529211340.17087-1-atish.patra@wdc.com> <20190529211340.17087-2-atish.patra@wdc.com> <49f41e62-5354-a674-d95f-5f63851a0ca6@ti.com> <20190530115103.GA10919@e105550-lin.cambridge.arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190530115103.GA10919@e105550-lin.cambridge.arm.com> User-Agent: NeoMutt/20170113 (1.7.2) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, May 30, 2019 at 12:51:03PM +0100, Morten Rasmussen wrote: > On Wed, May 29, 2019 at 07:39:17PM -0400, Andrew F. Davis wrote: > > On 5/29/19 5:13 PM, Atish Patra wrote: > > >From: Sudeep Holla > > > > > >The current ARM DT topology description provides the operating system > > >with a topological view of the system that is based on leaf nodes > > >representing either cores or threads (in an SMT system) and a > > >hierarchical set of cluster nodes that creates a hierarchical topology > > >view of how those cores and threads are grouped. > > > > > >However this hierarchical representation of clusters does not allow to > > >describe what topology level actually represents the physical package or > > >the socket boundary, which is a key piece of information to be used by > > >an operating system to optimize resource allocation and scheduling. > > > > > > > Are physical package descriptions really needed? What does "socket" imply > > that a higher layer "cluster" node grouping does not? It doesn't imply a > > different NUMA distance and the definition of "socket" is already not well > > defined, is a dual chiplet processor not just a fancy dual "socket" or are > > dual "sockets" on a server board "slotket" card, will we need new names for > > those too.. > > Socket (or package) just implies what you suggest, a grouping of CPUs > based on the physical socket (or package). Some resources might be > associated with packages and more importantly socket information is > exposed to user-space. At the moment clusters are being exposed to > user-space as sockets which is less than ideal for some topologies. Please point out a 32-bit ARM system that has multiple "socket"s. As far as I'm aware, all 32-bit systems do not have socketed CPUs (modern ARM CPUs are part of a larger SoC), and the CPUs are always in one package. Even the test systems I've seen do not have socketed CPUs. -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTC broadband for 0.8mile line in suburbia: sync at 12.1Mbps down 622kbps up According to speedtest.net: 11.9Mbps down 500kbps up