From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Rafael J. Wysocki" Subject: Re: [PATCH v6 10/14] sched/cpufreq: Refactor the utilization aggregation method Date: Mon, 10 Sep 2018 12:25:02 +0200 Message-ID: <26961140.kuCyhvbGLP@aspire.rjw.lan> References: <20180820094420.26590-1-quentin.perret@arm.com> <3619149.Cl0Cp2apok@aspire.rjw.lan> <20180910100719.uan6gskxpgu25dj5@queper01-lin> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7Bit Return-path: In-Reply-To: <20180910100719.uan6gskxpgu25dj5@queper01-lin> Sender: linux-kernel-owner@vger.kernel.org To: Quentin Perret Cc: peterz@infradead.org, 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 Monday, September 10, 2018 12:07:21 PM CEST Quentin Perret wrote: > On Monday 10 Sep 2018 at 11:53:58 (+0200), Rafael J. Wysocki wrote: > > On Monday, August 20, 2018 11:44:16 AM CEST Quentin Perret wrote: > > > Schedutil aggregates the PELT signals of CFS, RT, DL and IRQ in order > > > to decide which frequency to request. Energy Aware Scheduling (EAS) > > > needs to be able to predict those requests to assess the energy impact > > > of scheduling decisions. However, the PELT signals aggregation is only > > > done in schedutil for now, hence making it hard to synchronize it with > > > EAS. > > > > > > To address this issue, introduce schedutil_freq_util() to perform the > > > aforementioned aggregation and make it available to other parts of the > > > scheduler. Since frequency selection and energy estimation still need > > > to deal with RT and DL signals slightly differently, schedutil_freq_util() > > > is called with a different 'type' parameter in those two contexts, and > > > returns an aggregated utilization signal accordingly. > > > > This is complementary to patch [02/14] IMO. > > > > schedutil_freq_util() and map_util_freq() introduced by that patch should > > always be used together as they are two parts of one algorithm in my view. > > I agree. > > > Would it be possible to make that clearer? > > I could squash the two at the beginning of the series in a preparatory > patch that refactors schedutil for EAS all in one go, with a clear > mention of what we intend to do (make EAS depend on sugov) in the commit > message. > > Would that work ? I think so. Thanks, Rafael