From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Zijlstra Subject: Re: [RFC PATCH v3 05/10] sched/topology: Reference the Energy Model of CPUs when available Date: Tue, 19 Jun 2018 14:26:32 +0200 Message-ID: <20180619122632.GS2458@hirez.programming.kicks-ass.net> References: <20180521142505.6522-1-quentin.perret@arm.com> <20180521142505.6522-6-quentin.perret@arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20180521142505.6522-6-quentin.perret@arm.com> Sender: linux-kernel-owner@vger.kernel.org To: Quentin Perret Cc: rjw@rjwysocki.net, gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, mingo@redhat.com, dietmar.eggemann@arm.com, morten.rasmussen@arm.com, chris.redpath@arm.com, patrick.bellasi@arm.com, valentin.schneider@arm.com, vincent.guittot@linaro.org, thara.gopinath@linaro.org, viresh.kumar@linaro.org, tkjos@google.com, joelaf@google.com, smuckle@google.com, adharmap@quicinc.com, skannan@quicinc.com, pkondeti@codeaurora.org, juri.lelli@redhat.com, edubezval@gmail.com, srinivas.pandruvada@linux.intel.com, currojerez@riseup.net, javi.merino@kernel.org List-Id: linux-pm@vger.kernel.org On Mon, May 21, 2018 at 03:25:00PM +0100, Quentin Perret wrote: > In order to use EAS, the task scheduler has to know about the Energy > Model (EM) of the platform. This commit extends the scheduler topology > code to take references on the frequency domains objects of the EM > framework for all online CPUs. Hence, the availability of the EM for > those CPUs is guaranteed to the scheduler at runtime without further > checks in latency sensitive code paths (i.e. task wake-up). I'm confused by this patch,... what does it do? Why is em_cpu_get() (after you fix it) not sufficient?