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,NICE_REPLY_A,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 D998FC433DB for ; Wed, 10 Mar 2021 22:33:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B160B64FBB for ; Wed, 10 Mar 2021 22:33:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232254AbhCJWcl (ORCPT ); Wed, 10 Mar 2021 17:32:41 -0500 Received: from mga03.intel.com ([134.134.136.65]:2646 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229563AbhCJWcY (ORCPT ); Wed, 10 Mar 2021 17:32:24 -0500 IronPort-SDR: irAAH4pWqakEVARJUayqUCRj+IdlLjfeCqBk6gxe/kjalmBs1lxpcYQeQ1KappvfHf2WcxojW1 bl0W2A/OxdQg== X-IronPort-AV: E=McAfee;i="6000,8403,9919"; a="188613759" X-IronPort-AV: E=Sophos;i="5.81,238,1610438400"; d="scan'208";a="188613759" Received: from orsmga005.jf.intel.com ([10.7.209.41]) by orsmga103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 10 Mar 2021 14:32:24 -0800 IronPort-SDR: mX/MstW726YNg1QkzwchYQiR2gA2iYiBKFsqImz3R42IklhtA/Br+s2qy+n6ot9cqmWvhIxQOI 8QVlzdATryTQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.81,238,1610438400"; d="scan'208";a="589001786" Received: from linux.intel.com ([10.54.29.200]) by orsmga005.jf.intel.com with ESMTP; 10 Mar 2021 14:32:24 -0800 Received: from [10.251.19.203] (kliang2-MOBL.ccr.corp.intel.com [10.251.19.203]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by linux.intel.com (Postfix) with ESMTPS id 6134A580841; Wed, 10 Mar 2021 14:32:22 -0800 (PST) Subject: Re: [PATCH V2 1/25] x86/cpufeatures: Enumerate Intel Hybrid Technology feature bit To: Ricardo Neri , Borislav Petkov Cc: Srinivas Pandruvada , peterz@infradead.org, mingo@kernel.org, linux-kernel@vger.kernel.org, acme@kernel.org, tglx@linutronix.de, namhyung@kernel.org, jolsa@redhat.com, ak@linux.intel.com, yao.jin@linux.intel.com, alexander.shishkin@linux.intel.com, adrian.hunter@intel.com, "Rafael J. Wysocki" , "Ravi V. Shankar" References: <1615394281-68214-1-git-send-email-kan.liang@linux.intel.com> <1615394281-68214-2-git-send-email-kan.liang@linux.intel.com> <20210310165358.GI23521@zn.tnic> <20210310194644.GA1218@ranerica-svr.sc.intel.com> <20210310200147.GJ23521@zn.tnic> <20210310222548.GA28393@ranerica-svr.sc.intel.com> From: "Liang, Kan" Message-ID: <142a4a09-7e92-506c-d683-fb0dd06c1abc@linux.intel.com> Date: Wed, 10 Mar 2021 17:32:21 -0500 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.8.1 MIME-Version: 1.0 In-Reply-To: <20210310222548.GA28393@ranerica-svr.sc.intel.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 3/10/2021 5:25 PM, Ricardo Neri wrote: > On Wed, Mar 10, 2021 at 09:01:47PM +0100, Borislav Petkov wrote: >> On Wed, Mar 10, 2021 at 11:46:44AM -0800, Ricardo Neri wrote: >>> But this series provides the use case, right? Kan's patches handle PMU counters >>> that may differ cross types of CPUs. In patch 2, get_hybrid_params() >>> needs to check first if X86_FEATURE_HYBRID_CPU is enabled before >>> querying the hybrid parameters. Otherwise, we would need to rely on the >>> maximum level of CPUID, which may not be reliable. >> >> On Wed, Mar 10, 2021 at 11:33:54AM -0800, Srinivas Pandruvada wrote: >>> We are working on changes to P-State driver for hybrid CPUs using this >>> define. They are still work in progress. >>> But this patch can be submitted later with our set of changes. >> >> Answering to both with a single mail: >> >> I don't have a problem with X86_FEATURE_HYBRID_CPU - I simply don't want >> to show "hybrid_cpu" in /proc/cpuinfo unless there's a valid use case >> for userspace to know that it is running on a hybrid CPU. > > Ah, I get your point now. You would like to see > > #define X86_FEATURE_HYBRID_CPU (18*32+15) /* "" This part has CPUs of more than one type */ > > Right? Now your first comment makes sense. > > Srinivas, Kan, I don't think we need to expose "hybrid_cpu" in > /proc/cpuinfo, do we? > Right, Perf doesn't use the "hybrid_cpu" in /proc/cpuinfo. Thanks, Kan