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=-0.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS 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 826EEC43382 for ; Wed, 26 Sep 2018 23:38:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1F06C21533 for ; Wed, 26 Sep 2018 23:38:14 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=comcast.net header.i=@comcast.net header.b="pT2Y8V2E" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1F06C21533 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=comcast.net 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 S1726627AbeI0Fxd (ORCPT ); Thu, 27 Sep 2018 01:53:33 -0400 Received: from resqmta-ch2-09v.sys.comcast.net ([69.252.207.41]:58936 "EHLO resqmta-ch2-09v.sys.comcast.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726298AbeI0Fxd (ORCPT ); Thu, 27 Sep 2018 01:53:33 -0400 Received: from resomta-ch2-20v.sys.comcast.net ([69.252.207.116]) by resqmta-ch2-09v.sys.comcast.net with ESMTP id 5INPglItVhaho5JNjgU1uz; Wed, 26 Sep 2018 23:38:11 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=comcast.net; s=q20161114; t=1538005091; bh=wiOMwTrYq5R9ddsvIt6IAAy7iC7WPxxhcmO/6tmD+P8=; h=Received:Received:Subject:To:From:Message-ID:Date:MIME-Version: Content-Type; b=pT2Y8V2Em2+RCD3XtRJZgSSq7fwZ0LvjREFydJqpnBtyotI0pvin4pQPokzd5ev+W wBDDehvNDQ/0upeVMBjjiTjNEA8tDRMeypnuhXmcA+XDE+dmFCGhGPo2IPR78X9rB9 LKpgyGLcW+27B2kbliHqpP9+4EJhDoNLZGruHDXNdAcRDWrvwiQDmPh2hoUzYZuENm 4CpUbtt/44yNc75bQRD0B1SzY/6CmajeNOiGWSEwAqG5vNYD917B+9Nzwx85RJJCjX XWdoRMmlSX+qek8E4XGMXQvWW08fpELvnOC04kh7si2XFKCcHN6k3/e+DpuxRsS8qM zjCpk3OARjGlg== Received: from [10.1.10.100] ([73.214.254.59]) by resomta-ch2-20v.sys.comcast.net with ESMTPSA id 5JNhgoe7Fi7DZ5JNig4BFB; Wed, 26 Sep 2018 23:38:10 +0000 Subject: Re: AMD Athlon bogus performance value causing RCU stalls? To: Thomas Gleixner Cc: linux-kernel@vger.kernel.org References: <6243f7cc-1a80-db0b-4765-fa12bda9b06a@comcast.net> From: Rob Prowel Message-ID: <38932eb1-921f-55f7-10c8-358f9aae32b2@comcast.net> Date: Wed, 26 Sep 2018 19:38:09 -0400 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=windows-1252; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-CMAE-Envelope: MS4wfMhRBq7tDMgSAFr0dVhVxLzIAV/ZpIK4ohlpupBXtkC1tbHU+aEKT7sGX0vdIiK47t8T4J9rqkiacDDoGhMS2PuZsnJ+JB3Z6opiGQv37JuBIR3JdUtq r7DBvlXMfkiHt+/m/aP7a+RclQ3A3kvbe0+CV9qC1VLrc7Ne+CiNKQ2g/ayMaS2Zh7uXq415ZrX9WHwUP4E2hhK5gMSPhmN8QSg= Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 09/23/18 17:19, Thomas Gleixner wrote: >> >> Other than RTFM, or please build a bunch of kernels from source on your slow >> machine, using differing config options to help track down the cause of >> this...any thoughts about a solution? > > Yes. This was decoded recently as an issue on 32bit due to a calculation > which is based on 'unsigned long' but requires to be 64bit wide. > > It's in the 4.18.8 stable kernel, which should be available from your > fedora repo anytime soon. OK. Followup on AMD performance counter problem in 4.18.7 The Dell machine I was experiencing the problem on had a lot of ACPI issues. One of the invalid ACPI entries was for a system timer. dmesg suggests that the broken timer was used in calculating the Athlon performance value. So no, 32/64 bit math was not the issue. ACPI=off in the kernel boot line fixed the issue completely. Machine still functions well as a file/web/postgresql dev server so it's all good. tanks!