From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dirk Brandewie Subject: Re: [PATCH] cpufreq: intel_pstate: Change the calculation of next pstate Date: Thu, 01 May 2014 11:42:05 -0700 Message-ID: <5362957D.3060101@gmail.com> References: <535D80C8.9090906@semaphore.gr> <535FD4A6.3050905@semaphore.gr> <25001203.glgeYCc6ZZ@vostro.rjw.lan> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <25001203.glgeYCc6ZZ@vostro.rjw.lan> Sender: linux-kernel-owner@vger.kernel.org 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 List-Id: linux-pm@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 =CF=80=CE=BC, Viresh Kumar wrote: >>> Cc'd Dirk, >>> >>> On 28 April 2014 03:42, Stratos Karafotis w= rote: >>>> 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 independentl= y >>>> 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 independen= t >> from current one. In my opinion we can't scale the load across diffe= rent >> p-states, because it's not always equivalent. >> >> For example suppose a load of 100% because of a tight for loop in th= e >> 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 improv= ement >> 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 r= eproduce > your results in other workloads. > > And I'm waiting for the intel_pstate developer Dirk Brandewie to comm= ent. Sorry I just returned from dealing with a family emergency and am diggi= ng out of my inbox. I will run this patch through some tests. > > Thanks! >