From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752645AbbCXNBP (ORCPT ); Tue, 24 Mar 2015 09:01:15 -0400 Received: from casper.infradead.org ([85.118.1.10]:35244 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751941AbbCXNBL (ORCPT ); Tue, 24 Mar 2015 09:01:11 -0400 Date: Tue, 24 Mar 2015 14:00:58 +0100 From: Peter Zijlstra To: Morten Rasmussen Cc: mingo@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, yuyang.du@intel.com, preeti@linux.vnet.ibm.com, mturquette@linaro.org, nico@linaro.org, rjw@rjwysocki.net, juri.lelli@arm.com, linux-kernel@vger.kernel.org Subject: Re: [RFCv3 PATCH 33/48] sched: Energy-aware wake-up task placement Message-ID: <20150324130058.GN23123@twins.programming.kicks-ass.net> References: <1423074685-6336-1-git-send-email-morten.rasmussen@arm.com> <1423074685-6336-34-git-send-email-morten.rasmussen@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1423074685-6336-34-git-send-email-morten.rasmussen@arm.com> User-Agent: Mutt/1.5.21 (2012-12-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Feb 04, 2015 at 06:31:10PM +0000, Morten Rasmussen wrote: > @@ -5138,6 +5224,10 @@ select_task_rq_fair(struct task_struct *p, int prev_cpu, int sd_flag, int wake_f > prev_cpu = cpu; > > if (sd_flag & SD_BALANCE_WAKE) { > + if (energy_aware()) { > + new_cpu = energy_aware_wake_cpu(p); > + goto unlock; > + } > new_cpu = select_idle_sibling(p, prev_cpu); > goto unlock; > } So that is fundamentally wrong I think. We only care about power aware scheduling when U < 1, after that we should do the normal thing. This setup does not allow for that.