linux-kernel - Re: [PATCH 08/11] sched: schedutil: remove sugov_aggregate

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Date:   Fri, 6 Jul 2018 11:32:02 +0530
From:   Viresh Kumar <viresh.kumar@...aro.org>
To:     Vincent Guittot <vincent.guittot@...aro.org>
Cc:     peterz@...radead.org, mingo@...nel.org,
        linux-kernel@...r.kernel.org, rjw@...ysocki.net,
        juri.lelli@...hat.com, dietmar.eggemann@....com,
        Morten.Rasmussen@....com, valentin.schneider@....com,
        patrick.bellasi@....com, joel@...lfernandes.org,
        daniel.lezcano@...aro.org, quentin.perret@....com,
        luca.abeni@...tannapisa.it, claudio@...dence.eu.com,
        Ingo Molnar <mingo@...hat.com>
Subject: Re: [PATCH 08/11] sched: schedutil: remove sugov_aggregate_util()

On 28-06-18, 17:45, Vincent Guittot wrote:
> There is no reason why sugov_get_util() and sugov_aggregate_util()
> were in fact separate functions.
> 
> Cc: Ingo Molnar <mingo@...hat.com>
> Cc: Peter Zijlstra <peterz@...radead.org>
> Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
> [rebased after adding irq tracking and fixed some compilation errors]
> Signed-off-by: Vincent Guittot <vincent.guittot@...aro.org>
> ---
>  kernel/sched/cpufreq_schedutil.c | 44 ++++++++++++++--------------------------
>  kernel/sched/sched.h             |  2 +-
>  2 files changed, 16 insertions(+), 30 deletions(-)
> 
> diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c
> index b77bfef..d04f941 100644
> --- a/kernel/sched/cpufreq_schedutil.c
> +++ b/kernel/sched/cpufreq_schedutil.c
> @@ -53,12 +53,7 @@ struct sugov_cpu {
>  	unsigned int		iowait_boost_max;
>  	u64			last_update;
>  
> -	/* The fields below are only needed when sharing a policy: */
> -	unsigned long		util_cfs;
> -	unsigned long		util_dl;
>  	unsigned long		bw_dl;
> -	unsigned long		util_rt;
> -	unsigned long		util_irq;
>  	unsigned long		max;
>  
>  	/* The field below is for single-CPU policies only: */
> @@ -182,38 +177,31 @@ static unsigned int get_next_freq(struct sugov_policy *sg_policy,
>  	return cpufreq_driver_resolve_freq(policy, freq);
>  }
>  
> -static void sugov_get_util(struct sugov_cpu *sg_cpu)
> +static unsigned long sugov_get_util(struct sugov_cpu *sg_cpu)
>  {
>  	struct rq *rq = cpu_rq(sg_cpu->cpu);
> +	unsigned long util, irq, max;
>  
> -	sg_cpu->max = arch_scale_cpu_capacity(NULL, sg_cpu->cpu);
> -	sg_cpu->util_cfs = cpu_util_cfs(rq);
> -	sg_cpu->util_dl  = cpu_util_dl(rq);
> -	sg_cpu->bw_dl    = cpu_bw_dl(rq);
> -	sg_cpu->util_rt  = cpu_util_rt(rq);
> -	sg_cpu->util_irq = cpu_util_irq(rq);
> -}
> -
> -static unsigned long sugov_aggregate_util(struct sugov_cpu *sg_cpu)
> -{
> -	struct rq *rq = cpu_rq(sg_cpu->cpu);
> -	unsigned long util, max = sg_cpu->max;
> +	sg_cpu->max = max = arch_scale_cpu_capacity(NULL, sg_cpu->cpu);
> +	sg_cpu->bw_dl = cpu_bw_dl(rq);
>  
>  	if (rq->rt.rt_nr_running)
> -		return sg_cpu->max;
> +		return max;
> +
> +	irq = cpu_util_irq(rq);
>  
> -	if (unlikely(sg_cpu->util_irq >= max))
> +	if (unlikely(irq >= max))
>  		return max;
>  
>  	/* Sum rq utilization */
> -	util = sg_cpu->util_cfs;
> -	util += sg_cpu->util_rt;
> +	util = cpu_util_cfs(rq);
> +	util += cpu_util_rt(rq);
>  
>  	/*
>  	 * Interrupt time is not seen by rqs utilization nso we can compare
>  	 * them with the CPU capacity
>  	 */
> -	if ((util + sg_cpu->util_dl) >= max)
> +	if ((util + cpu_util_dl(rq)) >= max)
>  		return max;
>  
>  	/*
> @@ -231,11 +219,11 @@ static unsigned long sugov_aggregate_util(struct sugov_cpu *sg_cpu)
>  	 */
>  
>  	/* Weight rqs utilization to normal context window */
> -	util *= (max - sg_cpu->util_irq);
> +	util *= (max - irq);
>  	util /= max;
>  
>  	/* Add interrupt utilization */
> -	util += sg_cpu->util_irq;
> +	util += irq;
>  
>  	/* Add DL bandwidth requirement */
>  	util += sg_cpu->bw_dl;
> @@ -418,9 +406,8 @@ static void sugov_update_single(struct update_util_data *hook, u64 time,
>  
>  	busy = sugov_cpu_is_busy(sg_cpu);
>  
> -	sugov_get_util(sg_cpu);
> +	util = sugov_get_util(sg_cpu);
>  	max = sg_cpu->max;
> -	util = sugov_aggregate_util(sg_cpu);
>  	sugov_iowait_apply(sg_cpu, time, &util, &max);
>  	next_f = get_next_freq(sg_policy, util, max);
>  	/*
> @@ -459,9 +446,8 @@ static unsigned int sugov_next_freq_shared(struct sugov_cpu *sg_cpu, u64 time)
>  		struct sugov_cpu *j_sg_cpu = &per_cpu(sugov_cpu, j);
>  		unsigned long j_util, j_max;
>  
> -		sugov_get_util(j_sg_cpu);
> +		j_util = sugov_get_util(j_sg_cpu);
>  		j_max = j_sg_cpu->max;
> -		j_util = sugov_aggregate_util(j_sg_cpu);
>  		sugov_iowait_apply(j_sg_cpu, time, &j_util, &j_max);
>  
>  		if (j_util * max > j_max * util) {
> diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
> index 9438e68..59a633d 100644
> --- a/kernel/sched/sched.h
> +++ b/kernel/sched/sched.h
> @@ -2219,7 +2219,7 @@ static inline unsigned long cpu_util_cfs(struct rq *rq)
>  
>  static inline unsigned long cpu_util_rt(struct rq *rq)
>  {
> -	return rq->avg_rt.util_avg;
> +	return READ_ONCE(rq->avg_rt.util_avg);
>  }
>  
>  #if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING)

Acked-by: Viresh Kumar <viresh.kumar@...aro.org>

-- 
viresh