linux-kernel - Re: [patch v8 6/9] sched: compute runnable load avg in cpu_load and cpu_avg_load_per

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Date:	Wed, 19 Jun 2013 16:15:54 +0800
From:	Alex Shi <alex.shi@...el.com>
To:	Paul Turner <pjt@...gle.com>
CC:	Ingo Molnar <mingo@...hat.com>,
	Peter Zijlstra <peterz@...radead.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Borislav Petkov <bp@...en8.de>,
	Namhyung Kim <namhyung@...nel.org>,
	Mike Galbraith <efault@....de>,
	Morten Rasmussen <morten.rasmussen@....com>,
	Vincent Guittot <vincent.guittot@...aro.org>,
	Preeti U Murthy <preeti@...ux.vnet.ibm.com>,
	Viresh Kumar <viresh.kumar@...aro.org>,
	LKML <linux-kernel@...r.kernel.org>,
	Mel Gorman <mgorman@...e.de>, Rik van Riel <riel@...hat.com>,
	Michael Wang <wangyun@...ux.vnet.ibm.com>,
	Jason Low <jason.low2@...com>,
	Changlong Xie <changlongx.xie@...el.com>, sgruszka@...hat.com,
	Frédéric Weisbecker <fweisbec@...il.com>
Subject: Re: [patch v8 6/9] sched: compute runnable load avg in cpu_load and
 cpu_avg_load_per_task

On 06/18/2013 05:44 PM, Alex Shi wrote:
> 
>>
>> Paul, could I summary your point here:
>> keep current weighted_cpu_load, but add blocked load avg in
>> get_rq_runnable_load?
>>
>> I will test this change.
> 
> Current testing(kbuild, oltp, aim7) don't show clear different on my NHM EP box
> between the following and the origin patch, 
> the only different is get_rq_runnable_load added blocked_load_avg. in SMP
> will test more cases and more box.

I tested the tip/sched/core, tip/sched/core with old patchset and
tip/schec/core with the blocked_load_avg on Core2 2S, NHM EP, IVB EP,
SNB EP 2S and SNB EP 4S box, with benchmark kbuild, sysbench oltp,
hackbench, tbench, dbench.

blocked_load_avg VS origin patchset, oltp has suspicious 5% and
hackbench has 3% drop on NHM EX; dbench has suspicious 6% drop on NHM
EP. other benchmarks has no clear change on all other machines.

origin patchset VS sched/core, hackbench rise 20% on NHM EX, 60% on SNB
EP 4S, and 30% on IVB EP. others no clear changes.

> 
> ---
>  kernel/sched/fair.c |  5 +++--
>  kernel/sched/proc.c | 17 +++++++++++++++--
>  2 files changed, 18 insertions(+), 4 deletions(-)
> 
> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> index 1e5a5e6..7d5c477 100644
> --- a/kernel/sched/fair.c
> +++ b/kernel/sched/fair.c
> @@ -2968,7 +2968,7 @@ static void dequeue_task_fair(struct rq *rq, struct task_struct *p, int flags)
>  /* Used instead of source_load when we know the type == 0 */
>  static unsigned long weighted_cpuload(const int cpu)
>  {
> -	return cpu_rq(cpu)->load.weight;
> +	return cpu_rq(cpu)->cfs.runnable_load_avg;
>  }
>  
>  /*
> @@ -3013,9 +3013,10 @@ static unsigned long cpu_avg_load_per_task(int cpu)
>  {
>  	struct rq *rq = cpu_rq(cpu);
>  	unsigned long nr_running = ACCESS_ONCE(rq->nr_running);
> +	unsigned long load_avg = rq->cfs.runnable_load_avg;
>  
>  	if (nr_running)
> -		return rq->load.weight / nr_running;
> +		return load_avg / nr_running;
>  
>  	return 0;
>  }
> diff --git a/kernel/sched/proc.c b/kernel/sched/proc.c
> index bb3a6a0..36d7db6 100644
> --- a/kernel/sched/proc.c
> +++ b/kernel/sched/proc.c
> @@ -501,6 +501,18 @@ static void __update_cpu_load(struct rq *this_rq, unsigned long this_load,
>  	sched_avg_update(this_rq);
>  }
>  
> +#ifdef CONFIG_SMP
> +unsigned long get_rq_runnable_load(struct rq *rq)
> +{
> +	return rq->cfs.runnable_load_avg + rq->cfs.blocked_load_avg;
> +}
> +#else
> +unsigned long get_rq_runnable_load(struct rq *rq)
> +{
> +	return rq->load.weight;
> +}
> +#endif
> +
>  #ifdef CONFIG_NO_HZ_COMMON
>  /*
>   * There is no sane way to deal with nohz on smp when using jiffies because the
> @@ -522,7 +534,7 @@ static void __update_cpu_load(struct rq *this_rq, unsigned long this_load,
>  void update_idle_cpu_load(struct rq *this_rq)
>  {
>  	unsigned long curr_jiffies = ACCESS_ONCE(jiffies);
> -	unsigned long load = this_rq->load.weight;
> +	unsigned long load = get_rq_runnable_load(this_rq);
>  	unsigned long pending_updates;
>  
>  	/*
> @@ -568,11 +580,12 @@ void update_cpu_load_nohz(void)
>   */
>  void update_cpu_load_active(struct rq *this_rq)
>  {
> +	unsigned long load = get_rq_runnable_load(this_rq);
>  	/*
>  	 * See the mess around update_idle_cpu_load() / update_cpu_load_nohz().
>  	 */
>  	this_rq->last_load_update_tick = jiffies;
> -	__update_cpu_load(this_rq, this_rq->load.weight, 1);
> +	__update_cpu_load(this_rq, load, 1);
>  
>  	calc_load_account_active(this_rq);
>  }
> 


-- 
Thanks
    Alex
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