linux-kernel - Re: [patch v7 7/8] sched: consider runnable load average in move

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Date:	Fri, 31 May 2013 11:19:40 +0100
From:	Morten Rasmussen <morten.rasmussen@....com>
To:	Alex Shi <alex.shi@...el.com>
Cc:	"mingo@...hat.com" <mingo@...hat.com>,
	"peterz@...radead.org" <peterz@...radead.org>,
	"tglx@...utronix.de" <tglx@...utronix.de>,
	"akpm@...ux-foundation.org" <akpm@...ux-foundation.org>,
	"bp@...en8.de" <bp@...en8.de>, "pjt@...gle.com" <pjt@...gle.com>,
	"namhyung@...nel.org" <namhyung@...nel.org>,
	"efault@....de" <efault@....de>,
	"vincent.guittot@...aro.org" <vincent.guittot@...aro.org>,
	"preeti@...ux.vnet.ibm.com" <preeti@...ux.vnet.ibm.com>,
	"viresh.kumar@...aro.org" <viresh.kumar@...aro.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"mgorman@...e.de" <mgorman@...e.de>,
	"riel@...hat.com" <riel@...hat.com>,
	"wangyun@...ux.vnet.ibm.com" <wangyun@...ux.vnet.ibm.com>,
	Jason Low <jason.low2@...com>,
	Changlong Xie <changlongx.xie@...el.com>
Subject: Re: [patch v7 7/8] sched: consider runnable load average in
 move_tasks

On Thu, May 30, 2013 at 08:02:03AM +0100, Alex Shi wrote:
> 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.
> 
> Signed-off-by: Alex Shi <alex.shi@...el.com>
> ---
>  kernel/sched/fair.c | 10 +++++-----
>  1 file changed, 5 insertions(+), 5 deletions(-)
> 
> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> index eadd2e7..bb2470a 100644
> --- a/kernel/sched/fair.c
> +++ b/kernel/sched/fair.c
> @@ -4178,11 +4178,11 @@ 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 {
>  		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 /= tg->parent->cfs_rq[cpu]->runnable_load_avg + 1;

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

>  	}
>  
>  	tg->cfs_rq[cpu]->h_load = load;
> @@ -4210,8 +4210,8 @@ static unsigned long task_h_load(struct task_struct *p)
>  	struct cfs_rq *cfs_rq = task_cfs_rq(p);
>  	unsigned long load;
>  
> -	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;
> +	load = div_u64(load * cfs_rq->h_load, cfs_rq->runnable_load_avg + 1);
>  
>  	return load;
>  }
> -- 
> 1.7.12
> 
> 

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