Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754688AbdC3U2L (ORCPT ); Thu, 30 Mar 2017 16:28:11 -0400 Received: from cloudserver094114.home.net.pl ([79.96.170.134]:53430 "EHLO cloudserver094114.home.net.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754322AbdC3U2J (ORCPT ); Thu, 30 Mar 2017 16:28:09 -0400 From: "Rafael J. Wysocki" To: Vikram Mulukutla , Mark Brown Cc: Juri Lelli , Peter Zijlstra , mingo@redhat.com, viresh.kumar@linaro.org, linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, tglx@linutronix.de, vincent.guittot@linaro.org, rostedt@goodmis.org, luca.abeni@santannapisa.it, claudio@evidence.eu.com, tommaso.cucinotta@santannapisa.it, bristot@redhat.com, mathieu.poirier@linaro.org, tkjos@android.com, joelaf@google.com, andresoportus@google.com, morten.rasmussen@arm.com, dietmar.eggemann@arm.com, patrick.bellasi@arm.com, Ingo Molnar , linux-kernel-owner@vger.kernel.org Subject: Re: [RFD PATCH 3/5] sched/cpufreq_schedutil: make worker kthread be SCHED_DEADLINE Date: Thu, 30 Mar 2017 22:22:24 +0200 Message-ID: <2683548.WpoELJxfrb@aspire.rjw.lan> User-Agent: KMail/4.14.10 (Linux/4.10.0+; KDE/4.14.9; x86_64; ; ) In-Reply-To: References: <20170324140900.7334-1-juri.lelli@arm.com> <1721120.3Th1GMboUn@aspire.rjw.lan> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1287 Lines: 39 On Thursday, March 30, 2017 08:50:11 AM Vikram Mulukutla wrote: > > > OK > > > > So there are two pieces here. > > > > One is that if we want *all* drivers to work with schedutil, we need to > > keep > > the kthread for the ones that will never be reworked (because nobody > > cares > > etc). But then perhaps the kthread implementation may be left alone > > (because > > nobody cares etc). > > > > The second one is that there are drivers operating in-context that work > > with > > schedutil already, so I don't see major obstacles to making more > > drivers work > > that way. That would be only a matter of reworking the drivers in > > question. > > > > Thanks, > > Rafael > > There are some MSM platforms that do need a kthread and would love to > use > schedutil. This is all mainly due to the point that Vincent raised; > having > to actually wait for voltage transitions before clock switches. I can't > speak about the future, but that's the situation right now. Leaving the > kthread alone for now would be appreciated! I was not arguing for removing the kthread (quite opposite rather). My point was that *if* it is viable to rework drivers to operate in-context, that would be the way to go IMO instead of messing up with the kthread thing. Thanks, Rafael