From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751927AbcBKRal (ORCPT ); Thu, 11 Feb 2016 12:30:41 -0500 Received: from bombadil.infradead.org ([198.137.202.9]:56671 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751730AbcBKRaj (ORCPT ); Thu, 11 Feb 2016 12:30:39 -0500 Date: Thu, 11 Feb 2016 18:30:33 +0100 From: Peter Zijlstra To: Steve Muckle Cc: "Rafael J. Wysocki" , "Rafael J. Wysocki" , Linux PM list , Linux Kernel Mailing List , Srinivas Pandruvada , Viresh Kumar , Juri Lelli , Thomas Gleixner Subject: Re: [PATCH 0/3] cpufreq: Replace timers with utilization update callbacks Message-ID: <20160211173033.GP6357@twins.programming.kicks-ass.net> References: <3071836.JbNxX8hU6x@vostro.rjw.lan> <56B93548.9090006@linaro.org> <5387313.xAhVpzgZCg@vostro.rjw.lan> <56BA8C29.4090905@linaro.org> <20160211115959.GI6357@twins.programming.kicks-ass.net> <56BCBF7C.2080404@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <56BCBF7C.2080404@linaro.org> 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 On Thu, Feb 11, 2016 at 09:06:04AM -0800, Steve Muckle wrote: > Hi Peter, > > >> > I think additional hooks such as enqueue/dequeue would be needed in > >> > RT/DL. That is what I reacted to mostly. Enqueue/dequeue hooks don't really make much sense for RT / DL. > Rafael's changes aren't specifying particular frequencies/capacities in > the scheduler hooks. They're just pokes to get cpufreq to run, in order > to eliminate cpufreq's timers. > > My concern above is that pokes are guaranteed to keep occurring when > there is only RT or DL activity so nothing breaks. The hook in their respective tick handler should ensure stuff is called sporadically and isn't stalled.