From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751949AbaEASmM (ORCPT ); Thu, 1 May 2014 14:42:12 -0400 Received: from mail-pa0-f47.google.com ([209.85.220.47]:34234 "EHLO mail-pa0-f47.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750727AbaEASmI (ORCPT ); Thu, 1 May 2014 14:42:08 -0400 Message-ID: <5362957D.3060101@gmail.com> Date: Thu, 01 May 2014 11:42:05 -0700 From: Dirk Brandewie User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.4.0 MIME-Version: 1.0 To: "Rafael J. Wysocki" , Stratos Karafotis CC: dirk.brandewie@gmail.com, Viresh Kumar , Dirk Brandewie , "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> <535FD4A6.3050905@semaphore.gr> <25001203.glgeYCc6ZZ@vostro.rjw.lan> In-Reply-To: <25001203.glgeYCc6ZZ@vostro.rjw.lan> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 04/29/2014 02:52 PM, Rafael J. Wysocki wrote: > On Tuesday, April 29, 2014 07:34:46 PM Stratos Karafotis wrote: >> 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. > > Please do so. > > Also, we need to take your patch to our power lab and see if we can reproduce > your results in other workloads. > > And I'm waiting for the intel_pstate developer Dirk Brandewie to comment. Sorry I just returned from dealing with a family emergency and am digging out of my inbox. I will run this patch through some tests. > > Thanks! >