Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935698AbdCVRz4 (ORCPT ); Wed, 22 Mar 2017 13:55:56 -0400 Received: from merlin.infradead.org ([205.233.59.134]:58136 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759512AbdCVRzt (ORCPT ); Wed, 22 Mar 2017 13:55:49 -0400 Date: Wed, 22 Mar 2017 18:55:41 +0100 From: Peter Zijlstra To: Joel Fernandes Cc: LKML , Juri Lelli , Patrick Bellasi , Dietmar Eggemann , Ingo Molnar Subject: Re: [PATCH] sched: write better comments for weight calculations Message-ID: <20170322175541.culjydvydyzy4dza@hirez.programming.kicks-ass.net> References: <20170310204743.12872-1-joelaf@google.com> <20170322141808.icah4ygikteqbqdo@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: NeoMutt/20170113 (1.7.2) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1403 Lines: 36 On Wed, Mar 22, 2017 at 09:25:02AM -0700, Joel Fernandes wrote: > On Wed, Mar 22, 2017 at 7:18 AM, Peter Zijlstra wrote: > > On Fri, Mar 10, 2017 at 12:47:43PM -0800, Joel Fernandes wrote: > >> This patch rewrites comments related task priorities and CPU usage > >> along with an example to show how it works. > > > > To what purpose? Bigger word count? > > The intention is to improve the comments to make it more > understandable (the weight calculations, factor of 1.25 etc). > > On reading through the comments the first time, I felt they could be > improved. Is your concern more about the addition of an example > increasing the word-count? Perhaps you'd rather this be added to > Documentation/ instead? It might just be verbiage; I sometimes have trouble condensing text. That is; some people need repetition, I get stuck trying to figure out if its saying the same or not. In any case; if you want to clarify where the 1.25 comes from, maybe do an abstract example, instead of an explicit one? -10% = .9, +10% = 1.1 -> 1.1/.9 = 1.(2) ~ 1.25 Or, starting with the weight thing: .45 = wa / (wa+wb) -> .45 (wa+wb) = wa -> .45wa + .45wb = wa -> .45wb = .55wa -> wb/wa = .55/.45 = 1.(2) ~ 1.25 That's actually simpler to follow no? Now IIRC the whole thing is backwards anyway, we started with 1.25 and got the ~10% from there.