From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arjan van de Ven Subject: Re: [RFC][PATCH v5 00/14] sched: packing tasks Date: Mon, 11 Nov 2013 08:39:45 -0800 Message-ID: <52810851.4090907@linux.intel.com> References: <1382097147-30088-1-git-send-email-vincent.guittot@linaro.org> <20131111163630.GD26898@twins.programming.kicks-ass.net> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20131111163630.GD26898@twins.programming.kicks-ass.net> Sender: linux-kernel-owner@vger.kernel.org To: Peter Zijlstra , Catalin Marinas Cc: Vincent Guittot , Linux Kernel Mailing List , Ingo Molnar , Paul Turner , Morten Rasmussen , Chris Metcalf , Tony Luck , "alex.shi@intel.com" , Preeti U Murthy , linaro-kernel , "len.brown@intel.com" , l.majewski@samsung.com, Jonathan Corbet , "Rafael J. Wysocki" , Paul McKenney , linux-pm@vger.kernel.org List-Id: linux-pm@vger.kernel.org > I think the scheduler simply wants to say: we expect to go idle for X > ns, we want a guaranteed wakeup latency of Y ns -- go do your thing. as long as Y normally is "large" or "infinity" that is ok ;-) (a smaller Y will increase power consumption and decrease system performance) > I think you also raised the point in that we do want some feedback as to > the cost of waking up particular cores to better make decisions on which > to wake. That is indeed so. having a hardware driver give a prefered CPU ordering for wakes can indeed be useful. (I'm doubtful that changing the recommendation for each idle is going to pay off, but proof is in the pudding; there are certainly long term effects where this can help) >