Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755389Ab3EaPH5 (ORCPT ); Fri, 31 May 2013 11:07:57 -0400 Received: from mga14.intel.com ([143.182.124.37]:64142 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751289Ab3EaPHv (ORCPT ); Fri, 31 May 2013 11:07:51 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.87,779,1363158000"; d="scan'208";a="249130232" Message-ID: <51A8BCB9.2060902@intel.com> Date: Fri, 31 May 2013 23:07:37 +0800 From: Alex Shi User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:15.0) Gecko/20120912 Thunderbird/15.0.1 MIME-Version: 1.0 To: Morten Rasmussen CC: "mingo@redhat.com" , "peterz@infradead.org" , "tglx@linutronix.de" , "akpm@linux-foundation.org" , "bp@alien8.de" , "pjt@google.com" , "namhyung@kernel.org" , "efault@gmx.de" , "vincent.guittot@linaro.org" , "preeti@linux.vnet.ibm.com" , "viresh.kumar@linaro.org" , "linux-kernel@vger.kernel.org" , "mgorman@suse.de" , "riel@redhat.com" , "wangyun@linux.vnet.ibm.com" , Jason Low , Changlong Xie Subject: Re: [patch v7 7/8] sched: consider runnable load average in move_tasks References: <1369897324-16646-1-git-send-email-alex.shi@intel.com> <1369897324-16646-8-git-send-email-alex.shi@intel.com> <20130531101940.GC32728@e103034-lin> In-Reply-To: <20130531101940.GC32728@e103034-lin> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3058 Lines: 94 > > runnable_load_avg is u64, so you need to use div_u64() similar to how it > is already done in task_h_load() further down in this patch. It doesn't > build on ARM as is. > > Fix: > - load /= tg->parent->cfs_rq[cpu]->runnable_load_avg + 1; > + load = div_u64(load, > tg->parent->cfs_rq[cpu]->runnable_load_avg + 1); > > Morten Thank a lot for review! div_u64 or do_div will do force cast u32 on the divisor, so in 64bit machine, the divisor may become incorrect. Since cfs_rq->runnable_load_avg is always smaller the cfs_rq.load.weight. and load.weight is 'unsigned long', we can cast the runnable_load_avg to 'unsigned long' too. Than the div will fit on both 64/32 bit machine and no data concatenate! So the patch changed as following. BTW, Paul & Peter: in cfs_rq, runnable_load_avg, blocked_load_avg, tg_load_contrib are all u64, but their are similar with 'unsigned long' load.weight. So could we change them to 'unsigned long'? --- >From 4a17564363f6d65c9d513ad206b54ebd032d3f46 Mon Sep 17 00:00:00 2001 From: Alex Shi Date: Mon, 3 Dec 2012 23:00:53 +0800 Subject: [PATCH 7/8] sched: consider runnable load average in move_tasks Except using runnable load average in background, move_tasks is also the key functions in load balance. We need consider the runnable load average in it in order to the apple to apple load comparison. Morten catch a div u64 bug on ARM, thanks! Signed-off-by: Alex Shi --- kernel/sched/fair.c | 17 ++++++++++------- 1 files changed, 10 insertions(+), 7 deletions(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index eadd2e7..73e4507 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -4178,11 +4178,14 @@ static int tg_load_down(struct task_group *tg, void *data) long cpu = (long)data; if (!tg->parent) { - load = cpu_rq(cpu)->load.weight; + load = cpu_rq(cpu)->avg.load_avg_contrib; } else { + unsigned long tmp_rla; + tmp_rla = tg->parent->cfs_rq[cpu]->runnable_load_avg + 1; + load = tg->parent->cfs_rq[cpu]->h_load; - load *= tg->se[cpu]->load.weight; - load /= tg->parent->cfs_rq[cpu]->load.weight + 1; + load *= tg->se[cpu]->avg.load_avg_contrib; + load /= tmp_rla; } tg->cfs_rq[cpu]->h_load = load; @@ -4208,12 +4211,12 @@ static void update_h_load(long cpu) static unsigned long task_h_load(struct task_struct *p) { struct cfs_rq *cfs_rq = task_cfs_rq(p); - unsigned long load; + unsigned long load, tmp_rla; - load = p->se.load.weight; - load = div_u64(load * cfs_rq->h_load, cfs_rq->load.weight + 1); + load = p->se.avg.load_avg_contrib * cfs_rq->h_load; + tmp_rla = cfs_rq->runnable_load_avg + 1; - return load; + return load / tmp_rla; } #else static inline void update_blocked_averages(int cpu) -- 1.7.5.4 -- 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/