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=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 44D2BC433DF for ; Mon, 24 Aug 2020 15:48:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 18E68205CB for ; Mon, 24 Aug 2020 15:48:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727858AbgHXPsi (ORCPT ); Mon, 24 Aug 2020 11:48:38 -0400 Received: from mga06.intel.com ([134.134.136.31]:36560 "EHLO mga06.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726374AbgHXPsX (ORCPT ); Mon, 24 Aug 2020 11:48:23 -0400 IronPort-SDR: ZK1JCUw0SgOyHqNhlS2T+86/N1AOFFpAtUAafJDskC8OmaDquyhgdQ/weNM6+cm/AMrjpTbNY6 hbyvAgMNWwZg== X-IronPort-AV: E=McAfee;i="6000,8403,9722"; a="217464446" X-IronPort-AV: E=Sophos;i="5.76,349,1592895600"; d="scan'208";a="217464446" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga006.jf.intel.com ([10.7.209.51]) by orsmga104.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 24 Aug 2020 08:48:23 -0700 IronPort-SDR: jnr+6qjcEgTvvkrseGxF9XNoE+ylVqyWrTlX6PSSkmeE1x9y2/sRY5ZuFhMsWRjCMTaBQ+QP8R 8K22yHgo/jJg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.76,349,1592895600"; d="scan'208";a="298757873" Received: from shbuild999.sh.intel.com (HELO localhost) ([10.239.146.107]) by orsmga006.jf.intel.com with ESMTP; 24 Aug 2020 08:48:21 -0700 Date: Mon, 24 Aug 2020 23:48:18 +0800 From: Feng Tang To: "Luck, Tony" Cc: Borislav Petkov , "Chen, Rong A" , LKML , "lkp@lists.01.org" , Mel Gorman Subject: Re: [LKP] Re: [x86/mce] 1de08dccd3: will-it-scale.per_process_ops -14.1% regression Message-ID: <20200824154818.GB56944@shbuild999.sh.intel.com> References: <20200425114414.GU26573@shao2-debian> <20200425130136.GA28245@zn.tnic> <20200818082943.GA65567@shbuild999.sh.intel.com> <20200818200654.GA21494@agluck-desk2.amr.corp.intel.com> <20200819020437.GA2605@shbuild999.sh.intel.com> <20200821020259.GA90000@shbuild999.sh.intel.com> <20200824151425.GF4794@zn.tnic> <20200824153300.GA56944@shbuild999.sh.intel.com> <6e996ad05e434a6fb13f069ee72b876b@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <6e996ad05e434a6fb13f069ee72b876b@intel.com> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Aug 24, 2020 at 11:38:53PM +0800, Luck, Tony wrote: > > Yes, that's what we suspected. And I just did another try to force the > > percpu mce structure aligned. And the regression seems to be gone (reduced > > from 14.1% to 2%), which further proved it. > > I wonder whether it would be useful for bisection of performance issues > for you to change the global definition of DEFINE_PER_CPU() to make > all per CPU definitions aligned. Just like you switch compiler flags to make > all functions aligned. Thanks for the hint! This will definitely help tracking strange performance changes like this, as a general debug mthod. Thanks, Feng > > -Tony