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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS 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 CBE47C2B9F4 for ; Mon, 28 Jun 2021 06:55:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A7CB7619B5 for ; Mon, 28 Jun 2021 06:55:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232172AbhF1G6C (ORCPT ); Mon, 28 Jun 2021 02:58:02 -0400 Received: from wnew1-smtp.messagingengine.com ([64.147.123.26]:37353 "EHLO wnew1-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229998AbhF1G57 (ORCPT ); Mon, 28 Jun 2021 02:57:59 -0400 Received: from compute3.internal (compute3.nyi.internal [10.202.2.43]) by mailnew.west.internal (Postfix) with ESMTP id 11F982B00A29; Mon, 28 Jun 2021 02:55:32 -0400 (EDT) Received: from mailfrontend1 ([10.202.2.162]) by compute3.internal (MEProxy); Mon, 28 Jun 2021 02:55:33 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kroah.com; h= date:from:to:cc:subject:message-id:references:mime-version :content-type:content-transfer-encoding:in-reply-to; s=fm1; bh=W 0b8I7MW5oHpL7ipkRpkxZLHoV17rO9ZRR9rsaHOszQ=; b=QhDCkGmM/A6CGbwsT /qhliCAlEY9K+olYXIySoB2hzUy4BVx4jd9NK7ucWBhbtGpt2ASap4ZlAymeuYn2 N5jmyoebD2IaIX86nTZYBtI4CvG/3Pxj+V32pFIL6iVvYZHhIU2HWW7aL+SuG2qb yMMbtGLMilm0X4n83eFykiFZ/u2LRvc4iImYH0R91Vr3Qhyz33aRBftDCJ6X4PAP +i7HWOYsuscr1AY7pKmdHBPxWcnCJym+6sw4Q+EudhrO5j2yoQy31KgexXg2k9fJ Q5dn4OCAPSAP32+v6l5OTC6OBc5596sVIuZpqhxqMwikENl6fCh4vOdSHz4Ql3En dtXAA== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:content-transfer-encoding:content-type :date:from:in-reply-to:message-id:mime-version:references :subject:to:x-me-proxy:x-me-proxy:x-me-sender:x-me-sender :x-sasl-enc; s=fm3; bh=W0b8I7MW5oHpL7ipkRpkxZLHoV17rO9ZRR9rsaHOs zQ=; b=nxjsoytoYqBDALMbDhnSQ+UhTEcg1/6fB6pTHIwWHA4gKaNzdBKd1I0iF 9lAwUDtxYPueCMCXIIe4eJxnX6ouCQ6q0WyfiKW/10ezyLTUQELy3aa/PMJVTsbw fx/MMthAsOcUCWCV+8kd/zcTCjc6WntRtIlohhGbn5htoX0iM0pGChye3EyK1ju4 QamyUhsgLZ45L6FxF6QzAd24fAZVrn/l0od8PAOmpZNAVlpvhzUeBFGJZGc3atUj xCKIfmwH+JhgJHbJGhxYd1pILRiTjXRlQwC/sioXxFf7uePX1vyMKds6xC5yTCGU 1QMjebaaHsmjlujBStUZAXPTw19lA== X-ME-Sender: X-ME-Received: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgeduledrfeehfedguddtlecutefuodetggdotefrod ftvfcurfhrohhfihhlvgemucfhrghsthforghilhdpqfgfvfdpuffrtefokffrpgfnqfgh necuuegrihhlohhuthemuceftddtnecusecvtfgvtghiphhivghnthhsucdlqddutddtmd enucfjughrpeffhffvuffkfhggtggugfgjsehtkeertddttddunecuhfhrohhmpefirhgv ghcumffjuceoghhrvghgsehkrhhorghhrdgtohhmqeenucggtffrrghtthgvrhhnpeevtd eileeuteeggefgueefhfevgfdttefgtefgtddvgeejheeiuddvtdekffehffenucevlhhu shhtvghrufhiiigvpedtnecurfgrrhgrmhepmhgrihhlfhhrohhmpehgrhgvgheskhhroh grhhdrtghomh X-ME-Proxy: Received: by mail.messagingengine.com (Postfix) with ESMTPA; Mon, 28 Jun 2021 02:55:30 -0400 (EDT) Date: Mon, 28 Jun 2021 08:55:28 +0200 From: Greg KH To: Andi Kleen 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 Subject: Re: [PATCH 2/7] perf: Create a symlink for a PMU Message-ID: 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> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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? Naming is hard, make it simple and do not change it if your userspace tools are not going to be able to handle the issue. Do NOT paper over your naming scheme with symlinks from the very beginning, as that shows the naming scheme is flawed. thanks, greg k-h