From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751174AbaFJKX6 (ORCPT ); Tue, 10 Jun 2014 06:23:58 -0400 Received: from casper.infradead.org ([85.118.1.10]:48392 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750805AbaFJKX5 (ORCPT ); Tue, 10 Jun 2014 06:23:57 -0400 Date: Tue, 10 Jun 2014 12:23:53 +0200 From: Peter Zijlstra To: Morten Rasmussen Cc: Henrik Austad , "linux-kernel@vger.kernel.org" , "linux-pm@vger.kernel.org" , "mingo@kernel.org" , "rjw@rjwysocki.net" , "vincent.guittot@linaro.org" , "daniel.lezcano@linaro.org" , "preeti@linux.vnet.ibm.com" , Dietmar Eggemann Subject: Re: [RFC PATCH 02/16] sched: Introduce CONFIG_SCHED_ENERGY Message-ID: <20140610102353.GC6758@twins.programming.kicks-ass.net> References: <1400869003-27769-1-git-send-email-morten.rasmussen@arm.com> <1400869003-27769-3-git-send-email-morten.rasmussen@arm.com> <20140608060316.GA18179@austad.us> <20140609102027.GA29593@e103034-lin> <20140610093943.GA6758@twins.programming.kicks-ass.net> <20140610100641.GB1581@e103034-lin> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="TCH5zSpbvKOKdCih" Content-Disposition: inline In-Reply-To: <20140610100641.GB1581@e103034-lin> 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 --TCH5zSpbvKOKdCih Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Jun 10, 2014 at 11:06:41AM +0100, Morten Rasmussen wrote: > How would you like to disable the energy stuff for users for whom > latency is everything? >=20 > I mean, we are adding some extra load/utilization tracking. While I > think we should do everything possible to minimize the overhead, I think > it is unrealistic to assume that it will be zero. Is a some extra 'if > (energy_enabled)' acceptable? >=20 > I'm open for other suggestions. We have the jump-label stuff to do self modifying code ;-) The only thing we need to be careful with is data-layout. So I'm _hoping_ we can do all this without more CONFIG knobs, because {PREEMPT*SMP*CGROUP^3*NUMA^2} is already entirely annoying to build and run test, not to mention that distro builds will have no other option than to enable everything anyhow. --TCH5zSpbvKOKdCih Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) iQIcBAEBAgAGBQJTlty5AAoJEHZH4aRLwOS66xEP/Ru/QFVrwW9QzSFBB21RaEWg jiGy4mGP3a8LxpXiYqb18hti7bONnpJeokH1gVXxidwICARbcoXhnbxy8sTpo1A1 sZ2JnWXKbRcgLqCd52RnGOWQxTpPY2qBIntS2WR/HYhfoekltqtCr3/EgjzE7kxj gjOo3y5r5iTupd6EnzzEf5Ghv4IhC1ecBn8sMhVpBvEqB1OWSWy5qeBXD+HUWCGQ DWQqhSNan0XToadzwUprKTZaM/8zf+KJ8DKFyc0m2GXM64PFXBWs4SWy5AWmTFXn 9Xoola+LkgSsjEI59qD3a2q+qwxsg7saKa78onbDmsvu5Nl42gBqO409yrKx7d9B pewDmaTl0Rb5ZJn4mla3wath5WZnL/me4CVmK/a4PVGoLsv0w+BTiiMHZLWtOU4S yk397Zq78vEf0XYNSkuMlLi7Da8U4+NAx4KWOG9Ddb7HuL1UdJqcYATiUtRpGGLQ zkvKHjIsDMPYNFpxOjlN1nBoIM0a4/gy0zHUk2NPlnuDcBusnqZNS6gl9rXxAUa6 AG/7cgNj4WJdtvqVhGmDDwG16gyov+eSCqiHtYEM+STj0+5L+p4fsilv+0RoAGoR sOu6RxEaYE38+cZKaHMjAB0ekOJhakt/JWooTbTZepxRfG+9FdQM2mL0ZlOcgNMY DAcn1iA5uDg4lqOsGCoi =7xrz -----END PGP SIGNATURE----- --TCH5zSpbvKOKdCih--