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=-0.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 E0765C35240 for ; Wed, 29 Jan 2020 23:16:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C06A42082E for ; Wed, 29 Jan 2020 23:16:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726885AbgA2XQm (ORCPT ); Wed, 29 Jan 2020 18:16:42 -0500 Received: from Galois.linutronix.de ([193.142.43.55]:52018 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726618AbgA2XQm (ORCPT ); Wed, 29 Jan 2020 18:16:42 -0500 Received: from 51.26-246-81.adsl-static.isp.belgacom.be ([81.246.26.51] helo=nanos.tec.linutronix.de) by Galois.linutronix.de with esmtpsa (TLS1.2:DHE_RSA_AES_256_CBC_SHA256:256) (Exim 4.80) (envelope-from ) id 1iwwZV-0007Ms-KU; Thu, 30 Jan 2020 00:16:34 +0100 Received: by nanos.tec.linutronix.de (Postfix, from userid 1000) id 26CA7105CFD; Thu, 30 Jan 2020 00:16:28 +0100 (CET) From: Thomas Gleixner To: Evan Green Cc: Rajat Jain , Bjorn Helgaas , linux-pci , Linux Kernel Mailing List , x86@kernel.org, Marc Zyngier Subject: Re: [PATCH v2] PCI/MSI: Avoid torn updates to MSI pairs In-Reply-To: References: <20200117162444.v2.1.I9c7e72144ef639cc135ea33ef332852a6b33730f@changeid> <87y2tytv5i.fsf@nanos.tec.linutronix.de> <87eevqkpgn.fsf@nanos.tec.linutronix.de> <87d0b82a9o.fsf@nanos.tec.linutronix.de> <878slwmpu9.fsf@nanos.tec.linutronix.de> <87imkv63yf.fsf@nanos.tec.linutronix.de> <87pnf342pr.fsf@nanos.tec.linutronix.de> <877e1a2d11.fsf@nanos.tec.linutronix.de> Date: Thu, 30 Jan 2020 00:16:28 +0100 Message-ID: <874kwd3lbn.fsf@nanos.tec.linutronix.de> MIME-Version: 1.0 Content-Type: text/plain 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 Evan, Evan Green writes: > On Wed, Jan 29, 2020 at 1:01 PM Thomas Gleixner wrote: > >> Could you please add some instrumentation to see how often this stuff >> actually triggers spurious interrupts? > > In about 10 minutes of this script running, I got 142 hits. My script > can toggle the HT cpus on and off about twice per second. > Here's my diff (sorry it's mangled by gmail). If you're looking for > something else, let me know, or I can run a patch. > No, that's good data. Your testing is hiting the critical path and as you did not complain about negative side effects it seems to hold up to the expectations. I'm going to convert this to real patch with a proper changelog tomorrow. Thanks for your help! tglx