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 70824C433DB for ; Wed, 20 Jan 2021 05:49:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 45E652313A for ; Wed, 20 Jan 2021 05:49:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727485AbhATFtH (ORCPT ); Wed, 20 Jan 2021 00:49:07 -0500 Received: from mga01.intel.com ([192.55.52.88]:56688 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725816AbhATFtA (ORCPT ); Wed, 20 Jan 2021 00:49:00 -0500 IronPort-SDR: 7Qj265oUfyhxVNOVZ26kSLsUbTQkBdeG6Fzd06CObxvumesFwWB1vD4x5Uqz8YjU9vAgiBqsTn O1UUEzC+mxHA== X-IronPort-AV: E=McAfee;i="6000,8403,9869"; a="197772779" X-IronPort-AV: E=Sophos;i="5.79,360,1602572400"; d="scan'208";a="197772779" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by fmsmga101.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 19 Jan 2021 21:48:19 -0800 IronPort-SDR: cze3eNIFhrm9+YB8Y1pX59WbACbPhMknXaZiQAQf1/WyZfzFuyzptPRl9wjOiAuwuBJAXcg+1y dC6ZHIJXG86g== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.79,360,1602572400"; d="scan'208";a="384433394" Received: from shbuild999.sh.intel.com (HELO localhost) ([10.239.147.98]) by orsmga008.jf.intel.com with ESMTP; 19 Jan 2021 21:48:16 -0800 Date: Wed, 20 Jan 2021 13:48:15 +0800 From: Feng Tang To: Borislav Petkov Cc: "Paul E. McKenney" , kernel test robot , Jonathan Lemon , Tony Luck , LKML , x86@kernel.org, lkp@lists.01.org, lkp@intel.com, ying.huang@intel.com, zhengjun.xing@intel.com Subject: Re: [x86/mce] 7bb39313cd: netperf.Throughput_tps -4.5% regression Message-ID: <20210120054815.GA83476@shbuild999.sh.intel.com> References: <20210112141438.GF13086@zn.tnic> <20210116035251.GB29609@shbuild999.sh.intel.com> <20210116153413.GP2743@paulmck-ThinkPad-P72> <20210116160921.GA101665@shbuild999.sh.intel.com> <20210119042721.GA12664@paulmck-ThinkPad-P72> <20210119100255.GC27433@zn.tnic> <20210119121505.GA111354@shbuild999.sh.intel.com> <20210119131759.GL27433@zn.tnic> <20210119150903.GA21908@shbuild999.sh.intel.com> <20210119153350.GM27433@zn.tnic> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210119153350.GM27433@zn.tnic> User-Agent: Mutt/1.5.24 (2015-08-30) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jan 19, 2021 at 04:33:50PM +0100, Borislav Petkov wrote: > On Tue, Jan 19, 2021 at 11:09:03PM +0800, Feng Tang wrote: > > Yes, that can happen. I started a 4 tasks netperf on a 4C/8T KBL desktop, > > and also saw around 2% improvement. Both the kernel config and the > > platform matters. > > Oh great. ;-\ > > > For the performance changes I have checked, sometimes the change can be > > reproduced on platforms of different generations (the exact delta number > > may differs), sometimes it can only be reproduced on one specific platform, > > like some old generation, or special one like Xeon Phi. > > Probably because that Xeon Phi thing is not as powerful cache-wise as > some newer ones which have bigger caches and smarter hw prefetchers, > etc. Yes, cache size/architecture/policy plays a critical role in these benchmarking, which is our first thing to check for these strange kernel performance changes. Thanks, Feng From mboxrd@z Thu Jan 1 00:00:00 1970 Content-Type: multipart/mixed; boundary="===============7241115839379542276==" MIME-Version: 1.0 From: Feng Tang To: lkp@lists.01.org Subject: Re: [x86/mce] 7bb39313cd: netperf.Throughput_tps -4.5% regression Date: Wed, 20 Jan 2021 13:48:15 +0800 Message-ID: <20210120054815.GA83476@shbuild999.sh.intel.com> In-Reply-To: <20210119153350.GM27433@zn.tnic> List-Id: --===============7241115839379542276== Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable On Tue, Jan 19, 2021 at 04:33:50PM +0100, Borislav Petkov wrote: > On Tue, Jan 19, 2021 at 11:09:03PM +0800, Feng Tang wrote: > > Yes, that can happen. I started a 4 tasks netperf on a 4C/8T KBL deskto= p, > > and also saw around 2% improvement. Both the kernel config and the > > platform matters. > = > Oh great. ;-\ > = > > For the performance changes I have checked, sometimes the change can be > > reproduced on platforms of different generations (the exact delta number > > may differs), sometimes it can only be reproduced on one specific platf= orm, > > like some old generation, or special one like Xeon Phi. > = > Probably because that Xeon Phi thing is not as powerful cache-wise as > some newer ones which have bigger caches and smarter hw prefetchers, > etc. Yes, cache size/architecture/policy plays a critical role in these benchmarking, which is our first thing to check for these strange kernel performance changes. Thanks, Feng --===============7241115839379542276==--