From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754116AbaEMXao (ORCPT ); Tue, 13 May 2014 19:30:44 -0400 Received: from mail-wg0-f43.google.com ([74.125.82.43]:64281 "EHLO mail-wg0-f43.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751585AbaEMXam (ORCPT ); Tue, 13 May 2014 19:30:42 -0400 Date: Wed, 14 May 2014 01:30:39 +0200 From: Frederic Weisbecker To: Viresh Kumar Cc: Peter Zijlstra , Thomas Gleixner , Linux Kernel Mailing List , Lists linaro-kernel Subject: Re: [Query]: tick-sched: why don't we stop tick when we are running idle task? Message-ID: <20140513233036.GH13828@localhost.localdomain> References: <20140411151825.GX11096@twins.programming.kicks-ass.net> <20140414110245.GG11096@twins.programming.kicks-ass.net> <20140414114744.GI11096@twins.programming.kicks-ass.net> <20140414120600.GJ11096@twins.programming.kicks-ass.net> <20140415093002.GL1877@localhost.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, May 09, 2014 at 02:14:10PM +0530, Viresh Kumar wrote: > On 23 April 2014 16:42, Viresh Kumar wrote: > > On 15 April 2014 15:00, Frederic Weisbecker wrote: > >> Ok, I'm a bit buzy with a conference right now but I'm going to summarize that > >> soonish. > > Hi Frederic, > > Please see if you can find some time to close this, that would be very > helpful :) > > Thanks I'm generally worried about the accounting in update_curr() that periodically updates stats. I have no idea which of these stats could be read by other CPUs: vruntime, load bandwitdth, etc... Also without tick: * we don't poll anymore on trigger_load_balance() * __update_cpu_load() requires fixed rate periodic polling. Alex Shi had patches for that but I'm not sure if that's going to be merged * rq->rt_avg accounting?