Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757489Ab3FDCp0 (ORCPT ); Mon, 3 Jun 2013 22:45:26 -0400 Received: from mga14.intel.com ([143.182.124.37]:43360 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754544Ab3FDCpX (ORCPT ); Mon, 3 Jun 2013 22:45:23 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.87,796,1363158000"; d="scan'208";a="311838150" Message-ID: <51AD549A.9010903@intel.com> Date: Tue, 04 Jun 2013 10:44:42 +0800 From: Alex Shi User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130329 Thunderbird/17.0.5 MIME-Version: 1.0 To: Michael Wang CC: Peter Zijlstra , Paul Turner , Ingo Molnar , Thomas Gleixner , Andrew Morton , Borislav Petkov , Namhyung Kim , Mike Galbraith , Morten Rasmussen , Vincent Guittot , Preeti U Murthy , Viresh Kumar , LKML , Mel Gorman , Rik van Riel Subject: Re: [DISCUSSION] removing variety rq->cpu_load ? References: <1367804711-30308-1-git-send-email-alex.shi@intel.com> <1367804711-30308-6-git-send-email-alex.shi@intel.com> <20130506101936.GE13861@dyad.programming.kicks-ass.net> <20130506111041.GA15446@dyad.programming.kicks-ass.net> <51889C8A.5000806@intel.com> <51AD46CA.9020609@intel.com> <51AD4808.6020507@intel.com> <51AD51E3.6060307@linux.vnet.ibm.com> In-Reply-To: <51AD51E3.6060307@linux.vnet.ibm.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2243 Lines: 68 On 06/04/2013 10:33 AM, Michael Wang wrote: > Hi, Alex > > On 06/04/2013 09:51 AM, Alex Shi wrote: >> resend with a new subject. > > Forgive me but I'm a little lost on this thread... > > So we are planing to rely on instant 'cpu_load[0]' and decayed > 'runnable_load_avg' only, do we? cpu_load is a kind of time decay for cpu load, but after runnable load introduced, the decay functionality is a kind duplicate with it. So, remove them will make code simple. The idea were mentioned by Paul, Peter and I. the following is Peter's word of this affair. > Agreed, esp. the plethora of weird idx things we currently have. If we need to > re-introduce something it would likely only be the busy case and for that we > can immediately link to the balance interval or so. > > > Regards, > Michael Wang > >> >>> Peter, >>> >>> I just tried to remove the variety rq.cpu_load, by the following patch. >>> Because forkexec_idx and busy_idx are all zero, after the patch system just keep cpu_load[0] >>> and remove other values. >>> I tried the patch base 3.10-rc3 and latest tip/sched/core with benchmark dbench,tbench, >>> aim7,hackbench. and oltp of sysbench. Seems performance doesn't change clear. >>> So, for my tested machines, core2, NHM, SNB, with 2 or 4 CPU sockets, and above tested >>> benchmark. We are fine to remove the variety cpu_load. >>> Don't know if there some other concerns on other scenarios. >>> >>> --- >>> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c >>> index 590d535..f0ca983 100644 >>> --- a/kernel/sched/fair.c >>> +++ b/kernel/sched/fair.c >>> @@ -4626,7 +4626,7 @@ static inline void update_sd_lb_stats(struct lb_env *env, >>> if (child && child->flags & SD_PREFER_SIBLING) >>> prefer_sibling = 1; >>> >>> - load_idx = get_sd_load_idx(env->sd, env->idle); >>> + load_idx = 0; //get_sd_load_idx(env->sd, env->idle); >>> >>> do { >>> int local_group; >>> >>> >> >> > -- Thanks Alex -- 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/