From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTP id 33CFD70A for ; Tue, 13 May 2014 22:58:03 +0000 (UTC) Received: from v094114.home.net.pl (v094114.home.net.pl [79.96.170.134]) by smtp1.linuxfoundation.org (Postfix) with SMTP id 17D0E201AA for ; Tue, 13 May 2014 22:58:01 +0000 (UTC) From: "Rafael J. Wysocki" To: Morten Rasmussen Date: Wed, 14 May 2014 01:14:48 +0200 Message-ID: <18927107.3rlNmEK8uL@vostro.rjw.lan> In-Reply-To: <20140512153234.GE23253@e103034-lin> References: <20140512153234.GE23253@e103034-lin> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="utf-8" Cc: ksummit-discuss@lists.linuxfoundation.org, Peter Zijlstra , Ingo Molnar Subject: Re: [Ksummit-discuss] Energy-aware Scheduling Workshop List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Monday, May 12, 2014 04:32:34 PM Morten Rasmussen wrote: > Hi, Hi, > Last year's Energy-Aware Scheduling workshop [1,2] was a good > opportunity for interested parties to discuss some of the open issues in > this area face to face. While work is still ongoing on many of the > topics that were discussed, it might be worth having workshop again this > year to follow up, revise the plans if necessary, and discuss topics > that were not covered last year. > > Before submitting a workshop proposal to the Ksummit PC I would like to > probe the interest. IMO, it is important that we have scheduler > maintainers present. > > Workshop topic proposals: > > Test cases > Use-cases for high-end phones (which some of us care about) consist of > rather complex software stacks which are not suitable for quick patch > testing [3]. While we can't avoid testing using the full software stack > in the end, it would be useful to have configurable micro-benchmarks for > initial testing and to reproduce specific scheduling patterns from the > full use-case for debugging purposes. > > Energy Evaluation > A hot topic last year. We need a way to evaluate energy-awareness > patches. Work has started on an idle state analysis tool [4], but we are > not there yet. > > Platform Performance/Energy data > Currently the kernel has quite limited knowledge about energy costs of > the platform where it is running. Without this information it is rather > hard to make energy-efficient scheduling decisions. It seems that > various energy-saving techniques don't work equally well on all > platforms and might even depend on the use-case. Should we give the > kernel enough information to construct a simple energy-model to guide > decisions? > > CPU utilization and cpu_power > The entity load tracking has given us a much better indication of > individual task loadi. However, priority scaling makes it less suitable > for low load scenarios [5] where we care more about actual cpu > utilization per task when trying to figure out an energy-efficient load > balance. Do we need entity utilization tracking as well? Related to this > topic is the representation of cpu compute capacity. The current > representation, cpu_power, can't deal with heterogeneous systems > correctly. Can we come up with a solution that can handle SMT, SMP, and > heterogeneous systems? > > > All comments and topic proposals are welcome. I would be interested in participating in that discussion (which also is related to the energy conservation bias interfaces KS topic proposed by me). Thanks! > [1] http://lwn.net/Articles/571414/ > [2] http://etherpad.osuosl.org/energy-aware-scheduling-ks-2013 > [3] https://lkml.org/lkml/2014/1/7/355 > [4] https://lkml.org/lkml/2014/3/24/363 > [5] https://lkml.org/lkml/2014/1/7/503 -- I speak only for myself. Rafael J. Wysocki, Intel Open Source Technology Center.