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=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 20F8DC4332B for ; Wed, 10 Mar 2021 22:43:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E400D64FCE for ; Wed, 10 Mar 2021 22:43:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233710AbhCJWnG (ORCPT ); Wed, 10 Mar 2021 17:43:06 -0500 Received: from mga11.intel.com ([192.55.52.93]:25329 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233312AbhCJWms (ORCPT ); Wed, 10 Mar 2021 17:42:48 -0500 IronPort-SDR: 6fNVxwACgFBbacAks+SYZzD3dZjvh5a/HpDSrnVJRVw3uWavVZvHd3myPb2KhOWrmHY1kJW0Nk umBqw6VRO70Q== X-IronPort-AV: E=McAfee;i="6000,8403,9919"; a="185221962" X-IronPort-AV: E=Sophos;i="5.81,238,1610438400"; d="scan'208";a="185221962" Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by fmsmga102.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 10 Mar 2021 14:42:48 -0800 IronPort-SDR: 7QmvimHVZdBPd/6Oxp+gWQo1JczrApAEid/XwVZGVgNxif/6i+gnmW61AaoSAHwAlxmIt98SAd 2A/fsM+h0GpA== X-IronPort-AV: E=Sophos;i="5.81,238,1610438400"; d="scan'208";a="431385953" Received: from dkalra-mobl1.amr.corp.intel.com ([10.212.74.3]) by fmsmga004-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 10 Mar 2021 14:42:47 -0800 Message-ID: <7331f3cc0e78ba2cecdb98c52679a5a5b25ea790.camel@linux.intel.com> Subject: Re: [PATCH V2 1/25] x86/cpufeatures: Enumerate Intel Hybrid Technology feature bit From: Srinivas Pandruvada To: Ricardo Neri , Borislav Petkov Cc: kan.liang@linux.intel.com, 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" Date: Wed, 10 Mar 2021 14:42:47 -0800 In-Reply-To: <20210310222548.GA28393@ranerica-svr.sc.intel.com> 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> Content-Type: text/plain; charset="UTF-8" User-Agent: Evolution 3.34.4 (3.34.4-1.fc31) MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 2021-03-10 at 14:25 -0800, 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? I don't see any need. Thanks, Srinivas > > Thanks and BR, > Ricardo