From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Zijlstra Subject: Re: [PATCH v7 05/14] sched: Introduce a sched_feat for Energy Aware Scheduling Date: Wed, 3 Oct 2018 18:24:35 +0200 Message-ID: <20181003162435.GA19252@hirez.programming.kicks-ass.net> References: <20180912091309.7551-1-quentin.perret@arm.com> <20180912091309.7551-6-quentin.perret@arm.com> <20181002123416.GA3439@hirez.programming.kicks-ass.net> <20181002130818.fciw7cmlwggymxrz@queper01-lin> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20181002130818.fciw7cmlwggymxrz@queper01-lin> Sender: linux-kernel-owner@vger.kernel.org To: Quentin Perret Cc: rjw@rjwysocki.net, linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, gregkh@linuxfoundation.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, joel@joelfernandes.org, smuckle@google.com, adharmap@codeaurora.org, skannan@codeaurora.org, 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 Tue, Oct 02, 2018 at 02:08:21PM +0100, Quentin Perret wrote: > On Tuesday 02 Oct 2018 at 14:34:16 (+0200), Peter Zijlstra wrote: > > So these are debug knobs.. I would expect there to be a regular > > static_key that is controlled by the presence of EM data. > > Right, the issue I'm trying to solve with this is basically that _some_ > users will want to have an EM for the thermal stuff, but they will want > EAS disabled. Some people (not very many that's true, but still) use > big.little and don't care much about energy ... > > So, there is a need for an EAS knob on the scheduler side. I don't mind > it being something else than a sched_feat, but I couldn't see a better > option. Another Kconfig (CONFIG_SCHED_ENERGY) ? A sysctl ? Yeah, sysctl, see for example: sysctl.kernel.numa_balancing and the sched_numa_balancing static_key that goes with it. I would default enable EAS if the EM is there and valid, but allow people to disable it.