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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 81DD7C77B6E for ; Wed, 12 Apr 2023 12:42:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:Content-Type: Content-Transfer-Encoding:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:From:References:Cc:To:Subject: MIME-Version:Date:Message-ID:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=0w0QOfjQ2e/hBXyNEcGMk9PO2MGEKiLckYLa4osEjdU=; b=FXFrYuDXMTu6l7 D7pL9qfpIsJ1Wemkcc/ufmH0/Ttc3lngryF/WuIixUR/TudjijRWuRLRs9Vi2SmIm79eUDLCGYC5r UuJE7TMrJOWtPaCo2fmrE5NHaBToRUtom6ojb6quVImkHVHFebeL1622sdbwWnPEkv6OC5qAbnqkU Nrn7y/0yRM3OfmxLOREJSHexY8TJWEKIWecSCsawtinYcLntWPIsv8VEEo7KZsG1fiSd6gaNmMakh xVpleGn9hW8RJv+D/yYQfFU5e/vGaGsoYsQ1MtVILnS6aY5FQa2i6l7A47DzlLkE9EAz8hk3mnjOg h8fto2hUE6b+AiWTtE/g==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1pmZnC-003B4c-2k; Wed, 12 Apr 2023 12:41:42 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1pmZn9-003B1q-2C for linux-arm-kernel@lists.infradead.org; Wed, 12 Apr 2023 12:41:41 +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 0FB8FD75; Wed, 12 Apr 2023 05:42:19 -0700 (PDT) Received: from [10.57.55.240] (unknown [10.57.55.240]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 422CA3F73F; Wed, 12 Apr 2023 05:41:29 -0700 (PDT) Message-ID: <71167f33-1e54-53ed-0101-c7293149d89b@arm.com> Date: Wed, 12 Apr 2023 13:41:27 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; rv:102.0) Gecko/20100101 Thunderbird/102.9.1 Subject: Re: [PATCH 01/32] perf: Allow a PMU to have a parent Content-Language: en-GB To: Jonathan Cameron , Peter Zijlstra Cc: Yicong Yang , Mark Rutland , Ingo Molnar , Arnaldo Carvalho de Melo , Will Deacon , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, gregkh@linuxfoundation.org, yangyicong@hisilicon.com, linuxarm@huawei.com, Dan Williams , Shaokun Zhang , Jiucheng Xu , Khuong Dinh , Robert Richter , Atish Patra , Anup Patel , Andy Gross , Bjorn Andersson , Frank Li , Shuai Xue , Vineet Gupta , Shawn Guo , Fenghua Yu , Dave Jiang , Wu Hao , Tom Rix , linux-fpga@vger.kernel.org, Suzuki K Poulose , Liang Kan References: <20230404134225.13408-1-Jonathan.Cameron@huawei.com> <20230404134225.13408-2-Jonathan.Cameron@huawei.com> <61f8e489-ae76-38d6-2da0-43cf3c17853d@huawei.com> <20230406111607.00007be5@Huawei.com> <20230406124040.GD392176@hirez.programming.kicks-ass.net> <20230406174445.0000235c@Huawei.com> From: Robin Murphy In-Reply-To: <20230406174445.0000235c@Huawei.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230412_054139_766765_A6CB476D X-CRM114-Status: GOOD ( 19.61 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 2023-04-06 17:44, Jonathan Cameron wrote: > On Thu, 6 Apr 2023 14:40:40 +0200 > Peter Zijlstra wrote: > >> On Thu, Apr 06, 2023 at 11:16:07AM +0100, Jonathan Cameron wrote: >> >>> In the long run I agree it would be good. Short term there are more instances of >>> struct pmu that don't have parents than those that do (even after this series). >>> We need to figure out what to do about those before adding checks on it being >>> set. >> >> Right, I don't think you've touched *any* of the x86 PMUs for example, >> and getting everybody that boots an x86 kernel a warning isn't going to >> go over well :-) >> > > It was tempting :) "Warning: Parentless PMU: try a different architecture." > > I'd love some inputs on what the x86 PMU devices parents should be? > CPU counters in general tend to just spin out of deep in the architecture code. > > My overall favorite is an l2 cache related PMU that is spun up in > arch/arm/kernel/irq.c init_IRQ() > > I'm just not going to try and figure out why... I think that's simply because the PMU support was hung off the existing PL310 configuration code, which still supports non-DT boardfiles. The PMU shouldn't strictly need to be registered that early, it would just be a bunch more work to ensure that a platform device is available for it to bind to as a regular driver model driver, which wasn't justifiable at the time. Thanks, Robin. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel