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=-2.3 required=3.0 tests=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 6A7C3C433E1 for ; Mon, 18 May 2020 22:46:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4AA8620756 for ; Mon, 18 May 2020 22:46:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728547AbgERWqI (ORCPT ); Mon, 18 May 2020 18:46:08 -0400 Received: from mga04.intel.com ([192.55.52.120]:10098 "EHLO mga04.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728509AbgERWqF (ORCPT ); Mon, 18 May 2020 18:46:05 -0400 IronPort-SDR: 5ibcpdW13Ve3t7Lswf56Y6eK2eYzwvhpTI+3BB3NDI2D8EsZT1sAVQdOmnyn8VTOsXXkbXD4pp pF91CFadSf/A== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga005.fm.intel.com ([10.253.24.32]) by fmsmga104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 May 2020 15:46:05 -0700 IronPort-SDR: IDYwSVOlT5S23dmNw1M99e1YyXeqXA8zE5/yY7fxNfCTQPDFTYDbJ0efLMNNm04Vf2TruXVfu8 RytQoxmIIRHg== X-IronPort-AV: E=Sophos;i="5.73,407,1583222400"; d="scan'208";a="465751564" Received: from rchatre-mobl.amr.corp.intel.com (HELO [10.254.66.2]) ([10.254.66.2]) by fmsmga005-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 May 2020 15:46:04 -0700 Subject: Re: [PATCH V4 1/4] x86/resctrl: Enable user to view and select thread throttling mode To: Babu Moger , "tglx@linutronix.de" , "fenghua.yu@intel.com" , "bp@alien8.de" , "tony.luck@intel.com" Cc: "kuo-lang.tseng@intel.com" , "ravi.v.shankar@intel.com" , "mingo@redhat.com" , "hpa@zytor.com" , "x86@kernel.org" , "linux-kernel@vger.kernel.org" References: <667e48a36924c1710f6f2dd0116d388170721528.1589652468.git.reinette.chatre@intel.com> From: Reinette Chatre Message-ID: Date: Mon, 18 May 2020 15:46:02 -0700 User-Agent: Mozilla/5.0 (Windows NT 6.3; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.8.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=windows-1252 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Babu, On 5/18/2020 10:28 AM, Babu Moger wrote: > Hi Reinette, > Looks good most part. Few minor comments. Thank you very much for taking a look. > >> -----Original Message----- >> From: Reinette Chatre >> Sent: Saturday, May 16, 2020 1:29 PM >> To: tglx@linutronix.de; fenghua.yu@intel.com; bp@alien8.de; >> tony.luck@intel.com >> Cc: kuo-lang.tseng@intel.com; ravi.v.shankar@intel.com; mingo@redhat.com; >> Moger, Babu ; hpa@zytor.com; x86@kernel.org; >> linux-kernel@vger.kernel.org; Reinette Chatre >> Subject: [PATCH V4 1/4] x86/resctrl: Enable user to view and select thread >> throttling mode >> ... >> +static void mba_cfg_reconfigure_throttle_mode(struct rdt_resource *r) >> +{ >> + if (!r->alloc_capable) >> + return; >> + >> + if (r == &rdt_resources_all[RDT_RESOURCE_MBA] && >> + r->membw.arch_throttle_mode == THREAD_THROTTLE_MIN_MAX) >> + wrmsrl(MSR_MBA_CFG, mba_cfg_msr); >> +} > > How about this? It is kind of consistent with other checks that are done. > > If (r->alloc_capable && (r == &rdt_resources_all[RDT_RESOURCE_MBA]) && > (r->membw.arch_throttle_mode == THREAD_THROTTLE_MIN_MAX)) > wrmsrl(MSR_MBA_CFG, mba_cfg_msr); > Sure. Will do (with fewer parentheses). >> + >> +/* >> + * Model-specific test to determine if platform where memory bandwidth >> + * control is applied to a core can be configured to apply either the >> + * maximum or minimum of the per-thread delay values. >> + * By default, platforms where memory bandwidth control is applied to a >> + * core will select the maximum delay value of the per-thread CLOS. >> + * >> + * NOTE: delay value programmed to hardware is inverse of bandwidth >> + * percentage configured via user interface. >> + */ >> +static bool mba_cfg_supports_min_max_intel(void) >> +{ >> + switch (boot_cpu_data.x86_model) { >> + case INTEL_FAM6_ATOM_TREMONT_D: >> + case INTEL_FAM6_ICELAKE_X: >> + case INTEL_FAM6_ICELAKE_D: >> + return true; >> + default: >> + return false; >> + } >> + >> + return false; > > Is this last return required? I don't think so. We will never go here. > Indeed. Thank you for catching this. Reinette