linux-kernel - Re: [PATCH] sched/fair: Remove cfs_rq::nr_spread_over and cfs_rq::exec

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Message-ID: <Zpel7oyBNTpkLiPS@linux.ibm.com>
Date: Wed, 17 Jul 2024 16:37:26 +0530
From: Vishal Chourasia <vishalc@...ux.ibm.com>
To: Chuyi Zhou <zhouchuyi@...edance.com>
Cc: mingo@...hat.com, peterz@...radead.org, juri.lelli@...hat.com,
        vincent.guittot@...aro.org, chengming.zhou@...ux.dev,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] sched/fair: Remove cfs_rq::nr_spread_over and
 cfs_rq::exec_clock

On Tue, Jul 16, 2024 at 11:06:34PM +0800, Chuyi Zhou wrote:
> cfs_rq::nr_spread_over and cfs_rq::exec_clock are not used anymore in
> eevdf. Remove them from struct cfs_rq.
> 

nr_spread_over tracks the number of instances where the difference
between a scheduling entity's virtual runtime and the minimum virtual
runtime in the runqueue exceeds three times the scheduler latency,
indicating significant disparity in task scheduling.  
Commit that removed its usage: 5e963f2bd: sched/fair: Commit to EEVDF


cfs_rq->exec_clock was used to account for time spent executing tasks.
Commit that removed its usage: 5d69eca542ee1 sched: Unify runtime
accounting across classes

> Signed-off-by: Chuyi Zhou <zhouchuyi@...edance.com>

Acked-by: Vishal Chourasia <vishalc@...ux.ibm.com>
> ---
>  kernel/sched/debug.c | 4 ----
>  kernel/sched/sched.h | 6 ------
>  2 files changed, 10 deletions(-)
> 
> diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c
> index c1eb9a1afd13..90c4a9998377 100644
> --- a/kernel/sched/debug.c
> +++ b/kernel/sched/debug.c
> @@ -641,8 +641,6 @@ void print_cfs_rq(struct seq_file *m, int cpu, struct cfs_rq *cfs_rq)
>  	SEQ_printf(m, "\n");
>  	SEQ_printf(m, "cfs_rq[%d]:\n", cpu);
>  #endif
> -	SEQ_printf(m, "  .%-30s: %Ld.%06ld\n", "exec_clock",
> -			SPLIT_NS(cfs_rq->exec_clock));
>  
>  	raw_spin_rq_lock_irqsave(rq, flags);
>  	root = __pick_root_entity(cfs_rq);
> @@ -669,8 +667,6 @@ void print_cfs_rq(struct seq_file *m, int cpu, struct cfs_rq *cfs_rq)
>  			SPLIT_NS(right_vruntime));
>  	spread = right_vruntime - left_vruntime;
>  	SEQ_printf(m, "  .%-30s: %Ld.%06ld\n", "spread", SPLIT_NS(spread));
> -	SEQ_printf(m, "  .%-30s: %d\n", "nr_spread_over",
> -			cfs_rq->nr_spread_over);
>  	SEQ_printf(m, "  .%-30s: %d\n", "nr_running", cfs_rq->nr_running);
>  	SEQ_printf(m, "  .%-30s: %d\n", "h_nr_running", cfs_rq->h_nr_running);
>  	SEQ_printf(m, "  .%-30s: %d\n", "idle_nr_running",
> diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
> index 4c36cc680361..8a071022bdec 100644
> --- a/kernel/sched/sched.h
> +++ b/kernel/sched/sched.h
> @@ -599,7 +599,6 @@ struct cfs_rq {
>  	s64			avg_vruntime;
>  	u64			avg_load;
>  
> -	u64			exec_clock;
>  	u64			min_vruntime;
>  #ifdef CONFIG_SCHED_CORE
>  	unsigned int		forceidle_seq;
> @@ -619,10 +618,6 @@ struct cfs_rq {
>  	struct sched_entity	*curr;
>  	struct sched_entity	*next;
>  
> -#ifdef	CONFIG_SCHED_DEBUG
> -	unsigned int		nr_spread_over;
> -#endif
> -
>  #ifdef CONFIG_SMP
>  	/*
>  	 * CFS load tracking
> @@ -1158,7 +1153,6 @@ struct rq {
>  	/* latency stats */
>  	struct sched_info	rq_sched_info;
>  	unsigned long long	rq_cpu_time;
> -	/* could above be rq->cfs_rq.exec_clock + rq->rt_rq.rt_runtime ? */
>  
>  	/* sys_sched_yield() stats */
>  	unsigned int		yld_count;
> -- 
> 2.20.1
>