Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751801Ab3HTPdx (ORCPT ); Tue, 20 Aug 2013 11:33:53 -0400 Received: from mga03.intel.com ([143.182.124.21]:9904 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751249Ab3HTPdw (ORCPT ); Tue, 20 Aug 2013 11:33:52 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.89,921,1367996400"; d="scan'208";a="349050060" Message-ID: <52138C5E.4060705@linux.intel.com> Date: Tue, 20 Aug 2013 08:33:50 -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: Frederic Weisbecker CC: Peter Zijlstra , "Rafael J. Wysocki" , Viresh Kumar , =?ISO-8859-1?Q?Fernando_Luis_?= =?ISO-8859-1?Q?V=E1zquez_Cao?= , Oleg Nesterov , Ingo Molnar , Thomas Gleixner , LKML , 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> <20130819111026.GE24092@twins.programming.kicks-ass.net> <521313D8.9080500@lab.ntt.co.jp> <20130820084405.GC3258@twins.programming.kicks-ass.net> <20130820152910.GB17441@somewhere> In-Reply-To: <20130820152910.GB17441@somewhere> 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: 1090 Lines: 27 On 8/20/2013 8:29 AM, Frederic Weisbecker wrote: >> >> Of course, if we can get away with completely removing all of that >> (which I think Arjan suggested was a real possibility) then that would >> be ever so much better still :-) > > Would be lovely. But I don't know much about cpufreq, I hope somebody who's > familiar with that code can handle this. Then once there are no more users > of get_cpu_iowait_sleep_time() I can simply zap and clean the tick/time related > code. it's just doing the "idle = 100 - busy% - iowait%" calculation. (with the later part only for Intel cpus iirc) in a perfect world the scheduler would be doing that calculation in the first place ;-) removing the later part will impact performance some on specific workloads, but most Intel cpus that this applies to should not be using cpufreq anymore anyway. -- 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/