Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964893AbaD2Qeu (ORCPT ); Tue, 29 Apr 2014 12:34:50 -0400 Received: from sema.semaphore.gr ([78.46.194.137]:41703 "EHLO sema.semaphore.gr" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S933428AbaD2Qes (ORCPT ); Tue, 29 Apr 2014 12:34:48 -0400 Message-ID: <535FD4A6.3050905@semaphore.gr> Date: Tue, 29 Apr 2014 19:34:46 +0300 From: Stratos Karafotis User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.4.0 MIME-Version: 1.0 To: Viresh Kumar , Dirk Brandewie CC: "Rafael J. Wysocki" , "cpufreq@vger.kernel.org" , "linux-pm@vger.kernel.org" , LKML Subject: Re: [PATCH] cpufreq: intel_pstate: Change the calculation of next pstate References: <535D80C8.9090906@semaphore.gr> In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 29/04/2014 07:58 πμ, Viresh Kumar wrote: > Cc'd Dirk, > > On 28 April 2014 03:42, Stratos Karafotis wrote: >> Currently the driver calculates the next pstate proportional to >> core_busy factor and reverse proportional to current pstate. >> >> Change the above method and calculate the next pstate independently >> of current pstate. > > We must mention why the change is required. > Hi Viresh, Actually, I can't say that it's required. :) I just believe that calculation of next p-state should be independent from current one. In my opinion we can't scale the load across different p-states, because it's not always equivalent. For example suppose a load of 100% because of a tight for loop in the current p-state. It will be also a 100% load in any other p-state. It will be wrong if we scale the load in the calculation formula according to the current p-state. I included the test results in the change log to point out an improvement because of this patch. I will enrich more the change log as you suggested. Thanks, Stratos Karafotis -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/