Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751258Ab3HSK6w (ORCPT ); Mon, 19 Aug 2013 06:58:52 -0400 Received: from merlin.infradead.org ([205.233.59.134]:56994 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751087Ab3HSK6v (ORCPT ); Mon, 19 Aug 2013 06:58:51 -0400 Date: Mon, 19 Aug 2013 12:58:17 +0200 From: Peter Zijlstra To: Frederic Weisbecker Cc: Oleg Nesterov , Ingo Molnar , Thomas Gleixner , LKML , Fernando Luis Vazquez Cao , Tetsuo Handa , Andrew Morton , Arjan van de Ven Subject: Re: [PATCH 2/4] nohz: Synchronize sleep time stats with seqlock Message-ID: <20130819105817.GD24092@twins.programming.kicks-ass.net> References: <1376667753-29014-1-git-send-email-fweisbec@gmail.com> <1376667753-29014-3-git-send-email-fweisbec@gmail.com> <20130816160201.GA31682@redhat.com> <20130816162056.GE24210@somewhere> <20130816162654.GA453@redhat.com> <20130816164626.GH24210@somewhere> <20130816164922.GA1573@redhat.com> <20130816171208.GJ24210@somewhere> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130816171208.GJ24210@somewhere> 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 Content-Length: 951 Lines: 20 On Fri, Aug 16, 2013 at 07:12:09PM +0200, Frederic Weisbecker wrote: > Or may be Peter could tell us as well. Peter, do you have a preference? Still trying to wrap my head around it, but conceptually get_cpu_iowait_time_us() doesn't make any kind of sense. iowait isn't per cpu since effectively tasks that aren't running aren't assigned a cpu (as Oleg already pointed out). The fact that cpufreq 'needs' this just means that cpufreq is broken -- but I think I've said as much previously; cpufreq needs to stop living in the partitioned-mp era and get dragged (kicking and screaming) into the smp era. I'm also not entirely clear on the 'desired' semantics here. Do we count iowait time as idle or not? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/