From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lukasz Majewski Subject: Re: [RFC v3 0/5] cpufreq:LAB: Support for LAB governor. Date: Mon, 24 Mar 2014 11:00:32 +0100 Message-ID: <20140324110032.7aeae15e@amdc2363> References: <1367590072-10496-1-git-send-email-jonghwa3.lee@samsung.com> <1393928852-22725-1-git-send-email-l.majewski@samsung.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: Received: from mailout4.samsung.com ([203.254.224.34]:20085 "EHLO mailout4.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752450AbaCXKAm (ORCPT ); Mon, 24 Mar 2014 06:00:42 -0400 In-reply-to: Sender: linux-pm-owner@vger.kernel.org List-Id: linux-pm@vger.kernel.org To: Viresh Kumar Cc: "Rafael J. Wysocki" , "cpufreq@vger.kernel.org" , Linux PM list , Jonghwa Lee , Lukasz Majewski , linux-kernel , Bartlomiej Zolnierkiewicz , Myungjoo Ham , Tomasz Figa , Thomas Abraham , Thomas Abraham , "linux-arm-kernel@lists.infradead.org" , linux-samsung-soc Hi Viresh, > On 4 March 2014 15:57, Lukasz Majewski wrote: > > Despite this patch set is working and applicable on top of 3.14-rc5, > > please regard it solely as a pure RFC. > > Okay, I am trying to do a review here and because you have mentioned > how different it is from the earlier versions, I am trying with a > fresh mind. i.e. with zero memories of earlier discussions :) > > LAB was: Legacy Application Boost ?? Yes, correct. > > Probably mention that in your new threads as well, so that new readers > know the details. Also, like other governors, just name it "boost" > governor. I think, that "LAB" name is with us for some time, so it would be a pity to discard it. > > > This patch provides support for LAB governor build on top of > > ondemand. Previous version of LAB can be found here: > > http://thread.gmane.org/gmane.linux.kernel/1484746/match=cpufreq > > > > LAB short reminder: > > > > LAB uses information about how many cores are in "idle" state (the > > core idleness is represented as the value between 0 and 100) and > > the overall load of the system (from 0 to 100) to decide about > > frequency to be set. It is extremely useful with SoCs like > > Exynos4412, which can set only one frequency for all cores. > > Probably a description of how exactly these two values come into play > would have been more interesting here for all. Always think of new > followers of your patchset and so add all interesting things about it > when you resend it. > > If I remember well the logic was more or less like this: > - More idle cores means run few running cores at high frequency > - Less idle cores means don't run them at very high frequencies > > Right? This is correct. Also, the underlying SoC - Exynos4412 has 4 cores with option to set frequency only on all of them. > > What about making it as simple as: > - changing the ondemand governor only instead of adding a new governor My goal is to not touch the ondemand code. It has matured, so I would like to leave it as it is. > - Keeping the bahavior as is for all platforms not publishing boost > frequencies This is also done - you get the LAB configuration specified in the DT for the particular platform/board. > - If more cores are idle, enable switching to boost frequencies and > take them into consideration all the time. I'm not sure if I have understood you, but something like that is also performed in the code. > - If less cores are idle, disable boost frequencies.. As written above. > > Lets discuss this first and then I will get into the very details of > your implementation. Discussion about above functionalities requires consulting the implementation to be sure that our opinions are the same. -- Best regards, Lukasz Majewski Samsung R&D Institute Poland (SRPOL) | Linux Platform Group