From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753358AbdARUjp (ORCPT ); Wed, 18 Jan 2017 15:39:45 -0500 Received: from bombadil.infradead.org ([198.137.202.9]:44434 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752846AbdARUhL (ORCPT ); Wed, 18 Jan 2017 15:37:11 -0500 Date: Wed, 18 Jan 2017 12:36:58 -0800 From: Darren Hart To: Srinivas Pandruvada Cc: andriy.shevchenko@intel.com, platform-driver-x86@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] platform: x86: Support Turbo Boost Max 3.0 for non HWP systems Message-ID: <20170118203658.GA3059@f23x64.localdomain> References: <1484764155-183890-1-git-send-email-srinivas.pandruvada@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <1484764155-183890-1-git-send-email-srinivas.pandruvada@linux.intel.com> User-Agent: Mutt/1.7.1 (2016-10-04) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jan 18, 2017 at 10:29:15AM -0800, Srinivas Pandruvada wrote: > On platforms supporting Intel Turbo Boost Max Technology 3.0, the > maximum turbo frequencies (turbo ratio) of some cores in a CPU package > may be higher than the other cores in the same package. In that case, > better performance can be achieved by making the scheduler prefer to run > tasks on the CPUs with higher max turbo frequencies. > > On Intel® Broadwell Xeon systems, it is optional to turn on HWP > (Hardware P-States). When HWP is not turned on, the BIOS doesn't > present required CPPC (Collaborative Processor Performance Control) > tables. This table is used to get the per CPU core maximum performance > ratio and inform scheduler (in cpufreq/intel_pstate driver). > > On such systems the maximum performance ratio can be read via over > clocking (OC) mailbox interface for each CPU. This interface is not > architectural and can change for every model of processors. > > This driver reads maximum performance ratio of each CPU and set up > the scheduler priority metrics. In this way scheduler can prefer CPU > with higher performance to schedule tasks. > > Signed-off-by: Srinivas Pandruvada Queued to testing, thanks Srinivas. -- Darren Hart Intel Open Source Technology Center