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=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 0E779C4321D for ; Tue, 21 Aug 2018 22:09:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B876C20BEC for ; Tue, 21 Aug 2018 22:09:40 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B876C20BEC Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727547AbeHVBbh (ORCPT ); Tue, 21 Aug 2018 21:31:37 -0400 Received: from mga09.intel.com ([134.134.136.24]:20214 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726628AbeHVBbh (ORCPT ); Tue, 21 Aug 2018 21:31:37 -0400 X-Amp-Result: UNSCANNABLE X-Amp-File-Uploaded: False Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by orsmga102.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 21 Aug 2018 15:09:38 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.53,271,1531810800"; d="scan'208";a="82297838" Received: from tassilo.jf.intel.com (HELO tassilo.localdomain) ([10.7.201.126]) by fmsmga004.fm.intel.com with ESMTP; 21 Aug 2018 15:09:37 -0700 Received: by tassilo.localdomain (Postfix, from userid 1000) id 935E7301B91; Tue, 21 Aug 2018 15:09:37 -0700 (PDT) Date: Tue, 21 Aug 2018 15:09:37 -0700 From: Andi Kleen To: Eduardo Valentin Cc: Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , x86@kernel.org, Peter Zijlstra , Kan Liang , Dan Carpenter , Jia Zhang , Greg Kroah-Hartman , linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/1] perf/x86/intel: make error messages less confusing Message-ID: <20180821220937.GV12066@tassilo.jf.intel.com> References: <20180821211528.8575-1-eduval@amazon.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180821211528.8575-1-eduval@amazon.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Aug 21, 2018 at 02:15:28PM -0700, Eduardo Valentin wrote: > On a system with X86_FEATURE_ARCH_PERFMON disabled > and with a model not known by family PMU drivers, > user gets a kernel message log like the following: > [ 0.100114] Performance Events: unsupported p6 CPU model 85 no PMU driver, software events only. > > The "unsupported .. CPU" part may be confusing for some > users. Rewording the messages on the failure path to: > [ 0.667154] Performance Events: unknown p6 PMU on CPU model 85: !X86_FEATURE_ARCH_PERFMON: no PMU driver, software events only. Are you sure users even know what ARCH_PERFMON is? Maybe it is confusing (why exactly?), but it doesn't seem to me that your new message is any better. If you refer to VMs not exposing the PMU perhaps that should be explicitely mentioned. Of course the real fix is to always expose the PMU, not improve the error messages... -Andi