linux-kernel - Re: [RFC PATCH v4 00/19] Core scheduling v4

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Message-ID: <20200305043330.GA8755@ziqianlu-desktop.localdomain>
Date:   Thu, 5 Mar 2020 12:33:30 +0800
From:   Aaron Lu <aaron.lwe@...il.com>
To:     "Li, Aubrey" <aubrey.li@...ux.intel.com>
Cc:     Tim Chen <tim.c.chen@...ux.intel.com>,
        Vineeth Remanan Pillai <vpillai@...italocean.com>,
        Aubrey Li <aubrey.intel@...il.com>,
        Julien Desfossez <jdesfossez@...italocean.com>,
        Nishanth Aravamudan <naravamudan@...italocean.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...nel.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Paul Turner <pjt@...gle.com>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Linux List Kernel Mailing <linux-kernel@...r.kernel.org>,
        Dario Faggioli <dfaggioli@...e.com>,
        Frédéric Weisbecker <fweisbec@...il.com>,
        Kees Cook <keescook@...omium.org>,
        Greg Kerr <kerrnel@...gle.com>, Phil Auld <pauld@...hat.com>,
        Valentin Schneider <valentin.schneider@....com>,
        Mel Gorman <mgorman@...hsingularity.net>,
        Pawan Gupta <pawan.kumar.gupta@...ux.intel.com>,
        Paolo Bonzini <pbonzini@...hat.com>
Subject: Re: [RFC PATCH v4 00/19] Core scheduling v4

On Wed, Mar 04, 2020 at 07:54:39AM +0800, Li, Aubrey wrote:
> On 2020/3/3 22:59, Li, Aubrey wrote:
> > On 2020/2/29 7:55, Tim Chen wrote:
...
> >> In Vinnet's fix, we only look at the currently running task's weight in
> >> src and dst rq.  Perhaps the load on the src and dst rq needs to be considered
> >> to prevent too great an imbalance between the run queues?
> > 
> > We are trying to migrate a task, can we just use cfs.h_nr_running? This signal
> > is used to find the busiest run queue as well.
> 
> How about this one? the cgroup weight issue seems fixed on my side.

It doesn't apply on top of your coresched_v4-v5.5.2 branch, so I
manually allied it. Not sure if I missed something.

It's now getting 4 cpus in 2 cores. Better, but not back to normal yet..

Thanks,
Aaron
 
> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> index f42ceec..90024cf 100644
> --- a/kernel/sched/fair.c
> +++ b/kernel/sched/fair.c
> @@ -1767,6 +1767,8 @@ static void task_numa_compare(struct task_numa_env *env,
>  	rcu_read_unlock();
>  }
>  
> +static inline bool sched_core_cookie_match(struct rq *rq, struct task_struct *p);
> +
>  static void task_numa_find_cpu(struct task_numa_env *env,
>  				long taskimp, long groupimp)
>  {
> @@ -5650,6 +5652,44 @@ static struct sched_group *
>  find_idlest_group(struct sched_domain *sd, struct task_struct *p,
>  		  int this_cpu, int sd_flag);
>  
> +#ifdef CONFIG_SCHED_CORE
> +static inline bool sched_core_cookie_match(struct rq *rq, struct task_struct *p)
> +{
> +	struct rq *src_rq = task_rq(p);
> +	bool idle_core = true;
> +	int cpu;
> +
> +	/* Ignore cookie match if core scheduler is not enabled on the CPU. */
> +	if (!sched_core_enabled(rq))
> +		return true;
> +
> +	if (rq->core->core_cookie == p->core_cookie)
> +		return true;
> +
> +	for_each_cpu(cpu, cpu_smt_mask(cpu_of(rq))) {
> +		if (!available_idle_cpu(cpu)) {
> +			idle_core = false;
> +			break;
> +		}
> +	}
> +	/*
> +	 * A CPU in an idle core is always the best choice for tasks with
> +	 * cookies.
> +	 */
> +	if (idle_core)
> +		return true;
> +
> +	/*
> +	 * Ignore cookie match if there is a big imbalance between the src rq
> +	 * and dst rq.
> +	 */
> +	if ((src_rq->cfs.h_nr_running - rq->cfs.h_nr_running) > 1)
> +		return true;
> +
> +	return false;
> +}
> +#endif
> +
>  /*
>   * find_idlest_group_cpu - find the idlest CPU among the CPUs in the group.
>   */
> diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
> index 7ae6858..8c607e9 100644
> --- a/kernel/sched/sched.h
> +++ b/kernel/sched/sched.h
> @@ -1061,28 +1061,6 @@ static inline raw_spinlock_t *rq_lockp(struct rq *rq)
>  	return &rq->__lock;
>  }
>  
> -static inline bool sched_core_cookie_match(struct rq *rq, struct task_struct *p)
> -{
> -	bool idle_core = true;
> -	int cpu;
> -
> -	/* Ignore cookie match if core scheduler is not enabled on the CPU. */
> -	if (!sched_core_enabled(rq))
> -		return true;
> -
> -	for_each_cpu(cpu, cpu_smt_mask(cpu_of(rq))) {
> -		if (!available_idle_cpu(cpu)) {
> -			idle_core = false;
> -			break;
> -		}
> -	}
> -	/*
> -	 * A CPU in an idle core is always the best choice for tasks with
> -	 * cookies.
> -	 */
> -	return idle_core || rq->core->core_cookie == p->core_cookie;
> -}
> -
>  extern void queue_core_balance(struct rq *rq);
>  
>  void sched_core_add(struct rq *rq, struct task_struct *p);