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=-3.8 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 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 87E9AC433E7 for ; Mon, 19 Oct 2020 12:52:29 +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 DC60C21D81 for ; Mon, 19 Oct 2020 12:52:28 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="wcoD8SS0" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org DC60C21D81 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org 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=02CDm9qxHCPY4MU0SLaWhtN3zBJcGn8ahD5zs8n7mDc=; b=wcoD8SS0jLDefQAMeumU+Igr0 aDxkz3rDLXnyqCrGFotEaNa2ZikORGbq6uHg+R82CkBW+NIWuap+vtqePSVv9ULgICSDqNCbLNImu cydm32JmVCLoDuuOhVKXXK6YAjaTUDgsjincBmSCbQ5NW6Se7Kgyjs+ud+9Mnp/Du1zI8TTgOQzXZ vdA1eQ1vAGA/lW2+onQ99bkc0FGDWyMq/VDxD5fOSUq4ieX3qGC7sD7trWfJXKp5foBGzBvUIKimM +KDHpppb9mQA/8w3kE3+dGbL5zNncAnOEBkrmuIRom+2WxcUraPsKs6clWIQUf30uTXZAclKVCZaw FaK/2oLuA==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kUUcw-0004Uk-NZ; Mon, 19 Oct 2020 12:51:02 +0000 Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1kUUcq-0004UF-0e; Mon, 19 Oct 2020 12:50:56 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 531B1302753; Mon, 19 Oct 2020 14:50:53 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 245FD2038FA18; Mon, 19 Oct 2020 14:50:53 +0200 (CEST) Date: Mon, 19 Oct 2020 14:50:53 +0200 From: Peter Zijlstra To: Jonathan Cameron Subject: Re: [RFC PATCH] topology: Represent clusters of CPUs within a die. Message-ID: <20201019125053.GM2628@hirez.programming.kicks-ass.net> References: <20201016152702.1513592-1-Jonathan.Cameron@huawei.com> <20201019103522.GK2628@hirez.programming.kicks-ass.net> <20201019123226.00006705@Huawei.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20201019123226.00006705@Huawei.com> 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 , Greg Kroah-Hartman , x86@kernel.org, guohanjun@huawei.com, linux-kernel@vger.kernel.org, linuxarm@huawei.com, Brice Goglin , linux-acpi@vger.kernel.org, Sudeep Holla , 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 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. 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. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel