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=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,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 1EB1BC2B9F4 for ; Mon, 28 Jun 2021 15:33:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EFAE86195B for ; Mon, 28 Jun 2021 15:33:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238125AbhF1PeK (ORCPT ); Mon, 28 Jun 2021 11:34:10 -0400 Received: from mga12.intel.com ([192.55.52.136]:24075 "EHLO mga12.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236583AbhF1PLq (ORCPT ); Mon, 28 Jun 2021 11:11:46 -0400 X-IronPort-AV: E=McAfee;i="6200,9189,10029"; a="187657388" X-IronPort-AV: E=Sophos;i="5.83,306,1616482800"; d="scan'208";a="187657388" Received: from fmsmga005.fm.intel.com ([10.253.24.32]) by fmsmga106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 28 Jun 2021 08:00:05 -0700 X-IronPort-AV: E=Sophos;i="5.83,306,1616482800"; d="scan'208";a="643361063" Received: from ngminuti-mobl.amr.corp.intel.com (HELO [10.212.174.12]) ([10.212.174.12]) by fmsmga005-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 28 Jun 2021 08:00:05 -0700 Subject: Re: [PATCH 2/7] perf: Create a symlink for a PMU To: Greg KH Cc: kan.liang@linux.intel.com, peterz@infradead.org, mingo@redhat.com, linux-kernel@vger.kernel.org, eranian@google.com, namhyung@kernel.org, acme@kernel.org, jolsa@redhat.com References: <1e536604-cf93-0f09-401e-2073924c5582@linux.intel.com> <29d5f315-578f-103c-9523-ae890e29c7e7@linux.intel.com> <540d8a38-da12-56c8-8306-8d3d61ae1d6b@linux.intel.com> From: Andi Kleen Message-ID: Date: Mon, 28 Jun 2021 08:00:05 -0700 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.11.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 6/27/2021 11:55 PM, Greg KH wrote: > On Sun, Jun 27, 2021 at 09:30:53AM -0700, Andi Kleen wrote: >>> Then do not break things by renaming the device name, as you all have >>> now stated that this name is part of the user/kernel api. >> The renaming comes from the fallback mode on future systems. In the fallback >> mode the driver doesn't know the true name, so it has to use  the numeric >> name. If you don't use the fallback mode and have the full driver then yes >> you'll get the same names as always (or at least as they make sense for the >> hardware). >> >> But we would like to have the fallback mode too to allow more people use >> uncore monitoring, and that's where the need to for the second name comes >> in. > So then just always use the "fallback" name if that is going to be the > name you have for this hardware device. Why would you want it to be > renamed later on to a "fancier" name if there is only going to be > one-per-chipset-type anyway? It's an ugly numeric name, difficult to use perf stat -e uncore_0_2// instead of perf stat -e uncore_cha// It wouldn't exactly be an improvement for the full driver. -Andi