Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754449AbcCAPEJ (ORCPT ); Tue, 1 Mar 2016 10:04:09 -0500 Received: from casper.infradead.org ([85.118.1.10]:34660 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753513AbcCAPEI (ORCPT ); Tue, 1 Mar 2016 10:04:08 -0500 Date: Tue, 1 Mar 2016 16:04:02 +0100 From: Peter Zijlstra To: Juri Lelli Cc: Vincent Guittot , Steve Muckle , "Rafael J. Wysocki" , "Rafael J. Wysocki" , Linux PM list , Linux Kernel Mailing List , Srinivas Pandruvada , Viresh Kumar , Thomas Gleixner Subject: Re: [PATCH 0/3] cpufreq: Replace timers with utilization update callbacks Message-ID: <20160301150402.GT6356@twins.programming.kicks-ass.net> References: <20160211122429.GM11415@e106622-lin> <20160211152625.GM6357@twins.programming.kicks-ass.net> <20160212140415.GS6357@twins.programming.kicks-ass.net> <20160301135811.GQ6356@twins.programming.kicks-ass.net> <20160301141706.GJ18792@e106622-lin> <20160301142459.GR6356@twins.programming.kicks-ass.net> <20160301142620.GX6375@twins.programming.kicks-ass.net> <20160301144210.GL18792@e106622-lin> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160301144210.GL18792@e106622-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 Content-Length: 1035 Lines: 22 On Tue, Mar 01, 2016 at 02:42:10PM +0000, Juri Lelli wrote: > Agree. My point was actually more about Rafael's schedutil RFC (I should > probably have posted this there, but I thought it fitted well with this > example). I realize that Rafael is starting simple, but I fear that some > aggregation of util coming from the different classes will be needed in > the end; schedfreq has already something along this line. Right, but I'm not sure that's a hard thing to add. But yes, it needs doing. It also very much has a bearing on the OPP state selection. As already pointed out, the nearest OPP thing Rafael did is just wrong for DL. It probably makes sense to pass a CPPC like form into the (software) OPP selector. > IMHO, the general approach would be that every scheduling class has an > interface to communicate its util requirement. Then RT will probably > have to ask for max, but CFS and DL will do better. Right, so on IRC you mentioned that we could also use the global (or cgroup) RT throttle to lower the RT util/OPP.