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=-5.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 658DFC433E7 for ; Mon, 19 Oct 2020 13:14:54 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (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 E615822203 for ; Mon, 19 Oct 2020 13:14:53 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="wu3rS8gW" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E615822203 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References:Message-ID: Subject:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=NGcU64lGeplxXsgMJTK26TJwirCYofuotMVhhoRcS2I=; b=wu3rS8gW7jpmxv2qxqx4hM10w P0Hjyj9BrYQjESCxX79TU99mX/fi9aUuWMs7vflc/MwcJt8bWmog+V3LBQcvaa0wnRHklH581cBaR 1T4WlsxF+GVWSXGPPfBGnqH4IyInrE5K0apNHQhYpNNa3szyzDqGyJTZjNDJjaKWfIaO3U4hekjmV qcW1/KMp9DsULQxSPi77rHY/VitiEKfQ/VwLSabgwzxIDaHFdKlRfaEAhoLQULAmfyXYNaXX5tPPD b8HtH7aGbdpP7AuIEmd5o3220Ysgbi+2WRha7z8YxDboT8VAFs7GPHRlGG3zGtm2/mFGwl1HNvgq7 ZbjqgvuPQ==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kUUyt-0007k8-Ol; Mon, 19 Oct 2020 13:13:43 +0000 Received: from foss.arm.com ([217.140.110.172]) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kUUym-0007iW-RQ for linux-arm-kernel@lists.infradead.org; Mon, 19 Oct 2020 13:13:41 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 05118D6E; Mon, 19 Oct 2020 06:13:35 -0700 (PDT) Received: from e123083-lin (usa-sjc-imap-foss1.foss.arm.com [10.121.207.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 043063F719; Mon, 19 Oct 2020 06:13:32 -0700 (PDT) Date: Mon, 19 Oct 2020 15:13:30 +0200 From: Morten Rasmussen To: Peter Zijlstra Subject: Re: [RFC PATCH] topology: Represent clusters of CPUs within a die. Message-ID: <20201019131330.GD8004@e123083-lin> References: <20201016152702.1513592-1-Jonathan.Cameron@huawei.com> <20201019103522.GK2628@hirez.programming.kicks-ass.net> <20201019123226.00006705@Huawei.com> <20201019125053.GM2628@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20201019125053.GM2628@hirez.programming.kicks-ass.net> User-Agent: Mutt/1.9.4 (2018-02-28) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20201019_091336_965081_50FE7EC0 X-CRM114-Status: GOOD ( 24.03 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Len Brown , Sudeep Holla , Greg Kroah-Hartman , x86@kernel.org, guohanjun@huawei.com, linux-kernel@vger.kernel.org, linuxarm@huawei.com, Brice Goglin , linux-acpi@vger.kernel.org, Jonathan Cameron , Will Deacon , valentin.schneider@arm.com, linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Mon, Oct 19, 2020 at 02:50:53PM +0200, Peter Zijlstra wrote: > On Mon, Oct 19, 2020 at 01:32:26PM +0100, Jonathan Cameron wrote: > > On Mon, 19 Oct 2020 12:35:22 +0200 > > Peter Zijlstra wrote: > > > > I'm confused by all of this. The core level is exactly what you seem to > > > want. > > > > It's the level above the core, whether in an multi-threaded core > > or a single threaded core. This may correspond to the level > > at which caches are shared (typically L3). Cores are already well > > represented via thread_siblings and similar. Extra confusion is that > > the current core_siblings (deprecated) sysfs interface, actually reflects > > the package level and ignores anything in between core and > > package (such as die on x86) > > That seems wrong. core-mask should be whatever cores share L3. So on a > Intel Core2-Quad (just to pick an example) you should have 4 CPU in a > package, but only 2 CPUs for the core-mask. > > It just so happens that L3 and package were the same for a long while in > x86 land, although recent chips started breaking that trend. > > And I know nothing about the core-mask being depricated; it's what the > scheduler uses. It's not going anywhere. Don't get confused over the user-space topology and the scheduler topology, they are _not_ the same despite having similar names for some things :-) > So if your 'cluster' is a group of single cores (possibly with SMT) that > do not share cache but have a faster cache connection and you want them > to behave as-if they were a multi-core group that did share cache, then > core-mask it is. In the scheduler, yes. There is no core-mask exposed to user-space. We have to be clear about whether we discuss scheduler or user-space topology :-) _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel