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=-2.5 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS, USER_AGENT_MUTT autolearn=ham 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 8628EC43381 for ; Mon, 4 Mar 2019 18:21:58 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 579EA20663 for ; Mon, 4 Mar 2019 18:21:58 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="XFDeoj9v" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 579EA20663 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-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=bombadil.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=CPFYmmGiU9rS9ecti0C/9i1L4QBNXkm1om7rooBBgzo=; b=XFDeoj9vmJFr63 QLypFOz8tp91tIOT+KwleXor/aiCuJijaw04yRd1Sg3EbWbRzGEIXaxvy7Y46BKgT2Tx1y3Bvt81O QDT1LJzQuHdAtoLUmfNle3DXkEchSp4+vcFy2WxE55aXeH03nwRQBB62ygFiPU8jbAl5mIWMDHyY3 DuXU/cqQSOKf7yWETwZWiYOFor2T59kiakrN8abTkscJo7IhnTjlUSCTL6yPRpObVbe1/A+Ej6zgm erPr/ZUvb6jrvc9+37iMiwE5mhUS1JtYU44DURQJ6mbeZ25sKcJ5e24aJmUQKMmQ4MQI7D2CNe0la jQmNiLGuUitt/5zU2gOw==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1h0sDp-0000by-Vx; Mon, 04 Mar 2019 18:21:53 +0000 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70] helo=foss.arm.com) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1h0sDm-0000bT-Gp for linux-arm-kernel@lists.infradead.org; Mon, 04 Mar 2019 18:21:51 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 3743FA78; Mon, 4 Mar 2019 10:21:46 -0800 (PST) Received: from e107155-lin (e107155-lin.cambridge.arm.com [10.1.196.42]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id B161C3F703; Mon, 4 Mar 2019 10:21:44 -0800 (PST) Date: Mon, 4 Mar 2019 18:21:38 +0000 From: Sudeep Holla To: Chandra Sekhar Lingutla Subject: Re: [PATCH] arch_topology: Update user supplied capacity to possible cpus in cluster Message-ID: <20190304182138.GA7553@e107155-lin> References: <1551354838-29902-1-git-send-email-clingutla@codeaurora.org> <20190228121901.GA26207@e107155-lin> <6d7eb7cc-2453-3a7b-9163-ef9a5389220f@codeaurora.org> <20190228152555.GA13165@e107155-lin> <5785fd91-3d76-78e6-f4c5-7ed07be1a14d@codeaurora.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <5785fd91-3d76-78e6-f4c5-7ed07be1a14d@codeaurora.org> 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-20190304_102150_565863_F02C0ADC X-CRM114-Status: GOOD ( 26.45 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: catalin.marinas@arm.com, will.deacon@arm.com, Jeremy Linton , Morten Rasmussen , Quentin Perret , dietmar.eggemann@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+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Sat, Mar 02, 2019 at 07:00:43PM +0530, Chandra Sekhar Lingutla wrote: > > On 2/28/2019 8:55 PM, Sudeep Holla wrote: > > On Thu, Feb 28, 2019 at 08:08:13PM +0530, Chandra Sekhar Lingutla wrote: > >> Hi Sudeep, > >> > >> On 2/28/2019 5:49 PM, Sudeep Holla wrote: > >>> On Thu, Feb 28, 2019 at 05:23:58PM +0530, Lingutla Chandrasekhar wrote: > >>>> With commit '5bdd2b3f0f8 ("arm64: topology: add support to remove cpu > >>>> topology sibling masks")', when cpu hotplugged out, it resets the cpu > >>>> information in its sibling CPUs. If user changes capacity of any cpu, > >>>> then the new capacity applied to all online cpus in the cluster. > >>>> > >>> Correct but you are now changing to apply the same to all the CPUs > >>> in the package which is wrong. > >>> > >>>> If any hot plugged out cpu in the same cluster comes back to online, > >>>> then that would have different/stale capacity value. > >>>> > >>> Why not save the value ? > >> Sorry, didn't get you, you mean save user supplied value ? > > I meant save the last user set value and reset when CPU comes online. > > But 'cpu_capacity' for hot plugging cpu is not touched, so it would retain > same value. The actual problem is, cpu_capacity_store() tries to change the > capacity for all its 'sibling cpus'. Now the commit '5bdd2b3f0f8' keeps only > online cpus in the sibling mask, so user supplied cpu_capacity would be > applied only online sibling cpus at the time. After that, if any cpu hot > plugged in, it would have different cpu_capacity than its siblings. > OK, I understand the problem. What I was saying is using sibling cpus to update cpu_capacity needs to be changed. That is no longer correct with 2 scenarios I mentioned: DSU and ACPI sockets/physical package. We need to fix physical package id for DT systems but that shouldn't block this issue IMO. > >>>> Fix it by applying user supplied capacity to all possible cpus in the > >>>> cluster. > >>>> > >>> NACK for the change. It changes for all the CPUs in the package/socket. > >>> Though DT platforms have cluster ids as package ids, that's wrong and > >>> must be fixed. So you need to fix this issuw without depending on the > >>> package id. I have removed all the wrong users of the same and this is > >>> also a wrong usage. > >> I presumed all cores with same package-id have same cpu capacity, so > >> depended on it. > > No, > > 1. Package is not cluster, it's the physical socket which on typical > > mobile systems will be the whole SoC. So it includes all the CPUs > > in the system. > > > > 2. How about DSU systems where CPUs can have different capacity within > > cluster ? > So cpus in cpu_topology->core_sibling mask would not need to have same > capacity_cpu ? > Yes, it need not. DSU is simple example. Even normal heterogeneous multi-cluster single socket systems will have all the cpus in the die present in core_siblings. > Then i think, we should update the cpu_capacity for only requested cpu > right? One possible solution and a simpler one. But I am open to any better alternative if it exists/possible. > > ex: 'echo 910 > sys/devices/system/cpu/cpu5/cpu_capacity' should be applied > only to cpu5. Yes something similar. > > >> I think, we can update the capacity of newly online cpu by reading its > >> core_sibling cpu capacity. > > Will that survive scenario where all the CPUs in the so-called cluster > > is hot-plugged out and back in. > > > >> Let me know your opinion on this option ? > >> I was always under the impression that this was in debugfs and will be removed. I did mention this in one of the thread couple of months back. I was wrong and do understand the need for this on system where firmware doesn't provide this capacity value. If possible I want to drop the write capability for the sysfs. -- Regards, Sudeep _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel