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=-0.8 required=3.0 tests=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 9CC1EC43382 for ; Thu, 27 Sep 2018 15:04:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5C68821582 for ; Thu, 27 Sep 2018 15:04:51 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5C68821582 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linutronix.de 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 S1727816AbeI0VX3 (ORCPT ); Thu, 27 Sep 2018 17:23:29 -0400 Received: from Galois.linutronix.de ([146.0.238.70]:52246 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727307AbeI0VX3 (ORCPT ); Thu, 27 Sep 2018 17:23:29 -0400 Received: from p5492e4c1.dip0.t-ipconnect.de ([84.146.228.193] helo=nanos) by Galois.linutronix.de with esmtpsa (TLS1.2:DHE_RSA_AES_256_CBC_SHA256:256) (Exim 4.80) (envelope-from ) id 1g5XqQ-000620-Ix; Thu, 27 Sep 2018 17:04:46 +0200 Date: Thu, 27 Sep 2018 17:04:46 +0200 (CEST) From: Thomas Gleixner To: Rob Prowel cc: linux-kernel@vger.kernel.org Subject: Re: AMD Athlon bogus performance value causing RCU stalls? In-Reply-To: <38932eb1-921f-55f7-10c8-358f9aae32b2@comcast.net> Message-ID: References: <6243f7cc-1a80-db0b-4765-fa12bda9b06a@comcast.net> <38932eb1-921f-55f7-10c8-358f9aae32b2@comcast.net> User-Agent: Alpine 2.21 (DEB 202 2017-01-01) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 26 Sep 2018, Rob Prowel wrote: > 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. Uff. > 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. Thanks for letting me know. I was about to dust of that old X2 I have somewhere. Thanks, tglx