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 6640FC433DF for ; Wed, 19 Aug 2020 03:21:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4B65F207BB for ; Wed, 19 Aug 2020 03:21:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727959AbgHSDVB (ORCPT ); Tue, 18 Aug 2020 23:21:01 -0400 Received: from mga04.intel.com ([192.55.52.120]:10777 "EHLO mga04.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726605AbgHSDVA (ORCPT ); Tue, 18 Aug 2020 23:21:00 -0400 IronPort-SDR: GBkVNO0CONaO1USmPbNkojQ3JYgA7nnb4rZoj8KbsAM7eq5l8z/j3yrV+YJULQk/qcJb4t0hAZ AT+meMvGUJUQ== X-IronPort-AV: E=McAfee;i="6000,8403,9717"; a="152456150" X-IronPort-AV: E=Sophos;i="5.76,329,1592895600"; d="scan'208";a="152456150" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga008.jf.intel.com ([10.7.209.65]) by fmsmga104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 Aug 2020 20:21:00 -0700 IronPort-SDR: HF5Pud7n/Rwwx0gV7uLRLo15yUbgdHlxzuSQBLgPDrXIgyvlq7ylQNNTYOcbruKyu1fjuf/QNL G56ig0xNVPvA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.76,329,1592895600"; d="scan'208";a="326938632" Received: from feng-iot.sh.intel.com (HELO localhost) ([10.239.13.114]) by orsmga008.jf.intel.com with ESMTP; 18 Aug 2020 20:20:58 -0700 Date: Wed, 19 Aug 2020 11:04:02 +0800 From: Feng Tang To: "Luck, Tony" Cc: Borislav Petkov , "Chen, Rong A" , LKML , "lkp@lists.01.org" Subject: Re: [LKP] Re: [x86/mce] 1de08dccd3: will-it-scale.per_process_ops -14.1% regression Message-ID: <20200819030402.GA7840@feng-iot> 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> <149e0cfb5b7e48dfb9bea966c7741336@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <149e0cfb5b7e48dfb9bea966c7741336@intel.com> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Aug 19, 2020 at 10:23:11AM +0800, Luck, Tony wrote: > 0000000000019260 D pqr_state > > Do you have /sys/fs/resctrl mounted? This variable is read on every context switch. > If your benchmark does a lot of context switching and this now shares a cache line > with something different (especially something that is sometimes modified from another > CPU) that could cause some cache line bouncing. No, the kernel doesn't has /sys/fs/resctrl mounted. And the test case is not context switch intensive. It just forks a task for each CPU which loops running malloc/free and counts the number of complted operations for 300 seconds. Thanks, Feng