From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Zijlstra Subject: Re: [3/11] issue 3: No understanding of potential cpu capacity Date: Tue, 14 Jan 2014 17:51:19 +0100 Message-ID: <20140114165119.GJ7572@laptop.programming.kicks-ass.net> References: <1389111587-5923-1-git-send-email-morten.rasmussen@arm.com> <1389111587-5923-4-git-send-email-morten.rasmussen@arm.com> <3700155.hLuCBAXQoy@vostro.rjw.lan> <20140114163953.GF3000@e103034-lin> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from merlin.infradead.org ([205.233.59.134]:38737 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751621AbaANQv3 (ORCPT ); Tue, 14 Jan 2014 11:51:29 -0500 Content-Disposition: inline In-Reply-To: <20140114163953.GF3000@e103034-lin> Sender: linux-pm-owner@vger.kernel.org List-Id: linux-pm@vger.kernel.org To: Morten Rasmussen Cc: "Rafael J. Wysocki" , "mingo@kernel.org" , "markgross@thegnar.org" , "vincent.guittot@linaro.org" , Catalin Marinas , "linux-pm@vger.kernel.org" , "linux-kernel@vger.kernel.org" On Tue, Jan 14, 2014 at 04:39:54PM +0000, Morten Rasmussen wrote: > Responsiveness is still very important. It is quite hard to control. CFS > doesn't consider latency. The only way to get the best responsiveness is > to go for best performance which comes at a high cost in energy. The big problem is that the normal unix task model doesn't cover his at all -- nice isn't much of a knob. There's ways in which you can adapt CFS to include such a measure (search for the EEVDF patches), but I was kinda hoping that tasks that really desire responsiveness could be made to use SCHED_DEADLINE or such.