From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752447AbaJCGXM (ORCPT ); Fri, 3 Oct 2014 02:23:12 -0400 Received: from mail-lb0-f175.google.com ([209.85.217.175]:58593 "EHLO mail-lb0-f175.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750941AbaJCGXK (ORCPT ); Fri, 3 Oct 2014 02:23:10 -0400 Message-ID: <1412317384.5149.19.camel@marge.simpson.net> Subject: Re: [PATCH RFC] sched,idle: teach select_idle_sibling about idle states From: Mike Galbraith To: Rik van Riel Cc: Nicolas Pitre , Peter Zijlstra , Ingo Molnar , Daniel Lezcano , "Rafael J. Wysocki" , linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, linaro-kernel@lists.linaro.org Date: Fri, 03 Oct 2014 08:23:04 +0200 In-Reply-To: <20141002131548.6cd377d5@cuia.bos.redhat.com> References: <1409844730-12273-1-git-send-email-nicolas.pitre@linaro.org> <1409844730-12273-3-git-send-email-nicolas.pitre@linaro.org> <542B277D.7050103@redhat.com> <20141002131548.6cd377d5@cuia.bos.redhat.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.2.3 Content-Transfer-Encoding: 7bit Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 2014-10-02 at 13:15 -0400, Rik van Riel wrote: > Subject: sched,idle: teach select_idle_sibling about idle states > > Change select_idle_sibling to take cpu idle exit latency into > account. First preference is to select the cpu with the lowest > exit latency from a completely idle sched_group inside the CPU; > if that is not available, we pick the CPU with the lowest exit > latency in any sched_group. > > This increases the total search time of select_idle_sibling, > we may want to look into propagating load info up the sched_group > tree in some way. That information would also be useful to prevent > the wake_affine logic from causing a load imbalance between > sched_groups. A generic boo hiss aimed in the general direction of all of this let's go look at every possibility on every wakeup stuff. Less is more. -Mike