Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751050Ab3HSPsJ (ORCPT ); Mon, 19 Aug 2013 11:48:09 -0400 Received: from mga02.intel.com ([134.134.136.20]:17910 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750996Ab3HSPsG (ORCPT ); Mon, 19 Aug 2013 11:48:06 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.89,913,1367996400"; d="scan'208";a="364961365" Message-ID: <52123E1F.9030204@linux.intel.com> Date: Mon, 19 Aug 2013 08:47:43 -0700 From: Arjan van de Ven User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:17.0) Gecko/20130801 Thunderbird/17.0.8 MIME-Version: 1.0 To: Peter Zijlstra CC: Frederic Weisbecker , Oleg Nesterov , Ingo Molnar , Thomas Gleixner , LKML , Fernando Luis Vazquez Cao , Tetsuo Handa , Andrew Morton Subject: Re: [PATCH 2/4] nohz: Synchronize sleep time stats with seqlock 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> <20130819105817.GD24092@twins.programming.kicks-ass.net> In-Reply-To: <20130819105817.GD24092@twins.programming.kicks-ass.net> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1156 Lines: 25 On 8/19/2013 3:58 AM, Peter Zijlstra wrote: > 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? fwiw only some Intel cpu's use this, and those by and large no longer use cpufreq so this can just go away as far as I am concerned. -- 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/