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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C5320C77B6E for ; Wed, 12 Apr 2023 08:56:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229936AbjDLI4A (ORCPT ); Wed, 12 Apr 2023 04:56:00 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46746 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231326AbjDLIz6 (ORCPT ); Wed, 12 Apr 2023 04:55:58 -0400 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 27C94A272 for ; Wed, 12 Apr 2023 01:55:43 -0700 (PDT) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 501D91684; Wed, 12 Apr 2023 01:56:07 -0700 (PDT) Received: from monolith.localdoman (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 29BBB3F587; Wed, 12 Apr 2023 01:55:21 -0700 (PDT) Date: Wed, 12 Apr 2023 09:55:18 +0100 From: Alexandru Elisei To: Andrew Jones Cc: Eric Auger , eric.auger.pro@gmail.com, kvm@vger.kernel.org, kvmarm@lists.linux.dev, maz@kernel.org, will@kernel.org, oliver.upton@linux.dev, ricarkol@google.com, reijiw@google.com Subject: Re: [kvm-unit-tests PATCH 0/6] arm: pmu: Fix random failures of pmu-chain-promotion Message-ID: References: <20230315110725.1215523-1-eric.auger@redhat.com> <968a026e-066e-deea-d02f-f64133295ff1@redhat.com> <7l36wddzolsq7psm5gvra7w6emzlojj5utn7pnrsmwyx6v6jh7@zzrrwbty5zfq> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <7l36wddzolsq7psm5gvra7w6emzlojj5utn7pnrsmwyx6v6jh7@zzrrwbty5zfq> Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Hi, On Wed, Apr 12, 2023 at 09:34:36AM +0200, Andrew Jones wrote: > On Tue, Apr 04, 2023 at 02:47:49PM +0200, Andrew Jones wrote: > > On Tue, Apr 04, 2023 at 08:23:15AM +0200, Eric Auger wrote: > > > Hi, > > > > > > On 3/15/23 12:07, Eric Auger wrote: > > > > On some HW (ThunderXv2), some random failures of > > > > pmu-chain-promotion test can be observed. > > > > > > > > pmu-chain-promotion is composed of several subtests > > > > which run 2 mem_access loops. The initial value of > > > > the counter is set so that no overflow is expected on > > > > the first loop run and overflow is expected on the second. > > > > However it is observed that sometimes we get an overflow > > > > on the first run. It looks related to some variability of > > > > the mem_acess count. This variability is observed on all > > > > HW I have access to, with different span though. On > > > > ThunderX2 HW it looks the margin that is currently taken > > > > is too small and we regularly hit failure. > > > > > > > > although the first goal of this series is to increase > > > > the count/margin used in those tests, it also attempts > > > > to improve the pmu-chain-promotion logs, add some barriers > > > > in the mem-access loop, clarify the chain counter > > > > enable/disable sequence. > > > > > > > > A new 'pmu-memaccess-reliability' is also introduced to > > > > detect issues with MEM_ACCESS event variability and make > > > > the debug easier. > > > > > > > > Obviously one can wonder if this variability is something normal > > > > and does not hide any other bug. I hope this series will raise > > > > additional discussions about this. > > > > > > > > https://github.com/eauger/kut/tree/pmu-chain-promotion-fixes-v1 > > > > > > Gentle ping. > > > > I'd be happy to take this, but I was hoping to see some r-b's and/or t-b's > > from some of the others. > > Any takers? Ricardo? Alexandru? Will try to have a look as soon as I can, and run some tests, am hoping this week (but no promises!). Thanks, Alex > > Thanks, > drew