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 F35AFC10F29 for ; Mon, 9 Mar 2020 22:34:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D0A0F24655 for ; Mon, 9 Mar 2020 22:34:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727399AbgCIWeA (ORCPT ); Mon, 9 Mar 2020 18:34:00 -0400 Received: from mga18.intel.com ([134.134.136.126]:49129 "EHLO mga18.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727143AbgCIWeA (ORCPT ); Mon, 9 Mar 2020 18:34:00 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga006.jf.intel.com ([10.7.209.51]) by orsmga106.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 09 Mar 2020 15:33:59 -0700 X-IronPort-AV: E=Sophos;i="5.70,534,1574150400"; d="scan'208";a="245491074" Received: from rchatre-mobl.amr.corp.intel.com (HELO [10.251.21.24]) ([10.251.21.24]) by orsmga006-auth.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-SHA; 09 Mar 2020 15:33:58 -0700 Subject: Re: [PATCH V1 01/13] selftests/resctrl: Fix feature detection To: "Prakhya, Sai Praneeth" , "shuah@kernel.org" , "linux-kselftest@vger.kernel.org" Cc: "tglx@linutronix.de" , "mingo@redhat.com" , "bp@alien8.de" , "Luck, Tony" , "babu.moger@amd.com" , "james.morse@arm.com" , "Shankar, Ravi V" , "Yu, Fenghua" , "x86@kernel.org" , "linux-kernel@vger.kernel.org" References: <7e3e4b91f5786a489e68eecda21e1d8049b60181.1583657204.git.sai.praneeth.prakhya@intel.com> From: Reinette Chatre Message-ID: Date: Mon, 9 Mar 2020 15:33:57 -0700 User-Agent: Mozilla/5.0 (Windows NT 6.3; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.5.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 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 Sai, On 3/9/2020 3:22 PM, Prakhya, Sai Praneeth wrote: > Hi Reinette, > >> -----Original Message----- >> From: Reinette Chatre >> Sent: Monday, March 9, 2020 2:45 PM >> On 3/6/2020 7:40 PM, Sai Praneeth Prakhya wrote: [SNIP] >> Please note that this is only a partial fix. The current feature detection relies on >> the feature flags found in /proc/cpuinfo. Quirks and kernel boot parameters are >> not taken into account. This fix only addresses the parsing of feature flags. If a >> feature has been disabled via kernel boot parameter or quirk then the resctrl >> tests would still attempt to run the test for it. > > That's a good point and makes sense to me. I think we could fix it in two ways > 1. grep for strings in dmesg but that will still leave ambiguity in deciding b/w mbm and cqm because kernel prints "resctrl: L3 monitoring detected" for both the features > 2. Check in "info" directory > a. For cat_l3, we could search for info/L3 > b. For mba, we could search for info/MB > c. For cqm and mbm, we could search for specified string in info/L3_MON/mon_features > > I think option 2 might be better because it can handle all cases, please let me know what you think. I agree. For the reasons you mention and also that (1) may not be possible if the loglevel prevents those lines from being printed. Reinette