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From: Dietmar Eggemann <dietmar.eggemann@arm.com>
To: Vincent Guittot <vincent.guittot@linaro.org>,
	linux-kernel@vger.kernel.org, mingo@redhat.com,
	peterz@infradead.org
Cc: pauld@redhat.com, valentin.schneider@arm.com,
	srikar@linux.vnet.ibm.com, quentin.perret@arm.com,
	Morten.Rasmussen@arm.com, hdanton@sina.com
Subject: Re: [PATCH v3 04/10] sched/fair: rework load_balance
Date: Tue, 1 Oct 2019 10:15:25 +0200	[thread overview]
Message-ID: <46e81a81-f88e-c935-d452-9b746bde492b@arm.com> (raw)
In-Reply-To: <1568878421-12301-5-git-send-email-vincent.guittot@linaro.org>

On 19/09/2019 09:33, Vincent Guittot wrote:


[...]

> @@ -8042,14 +8104,24 @@ static inline void update_sg_lb_stats(struct lb_env *env,
>  		}
>  	}
>  
> -	/* Adjust by relative CPU capacity of the group */
> +	/* Check if dst cpu is idle and preferred to this group */
> +	if (env->sd->flags & SD_ASYM_PACKING &&
> +	    env->idle != CPU_NOT_IDLE &&
> +	    sgs->sum_h_nr_running &&
> +	    sched_asym_prefer(env->dst_cpu, group->asym_prefer_cpu)) {
> +		sgs->group_asym_packing = 1;
> +	}
> +

Since asym_packing check is done per-sg rather per-CPU (like misfit_task), can you
not check for asym_packing in group_classify() directly (like for overloaded) and
so get rid of struct sg_lb_stats::group_asym_packing?

Something like (only compile tested).

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index d0c3aa1dc290..b2848d6f8a2a 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -7692,7 +7692,6 @@ struct sg_lb_stats {
        unsigned int idle_cpus;
        unsigned int group_weight;
        enum group_type group_type;
-       unsigned int group_asym_packing; /* Tasks should be moved to preferred CPU */
        unsigned long group_misfit_task_load; /* A CPU has a task too big for its capacity */
 #ifdef CONFIG_NUMA_BALANCING
        unsigned int nr_numa_running;
@@ -7952,6 +7951,20 @@ group_is_overloaded(struct lb_env *env, struct sg_lb_stats *sgs)
        return false;
 }
 
+static inline bool
+group_has_asym_packing(struct lb_env *env, struct sched_group *sg,
+                      struct sg_lb_stats *sgs)
+{
+       if (env->sd->flags & SD_ASYM_PACKING &&
+           env->idle != CPU_NOT_IDLE &&
+           sgs->sum_h_nr_running &&
+           sched_asym_prefer(env->dst_cpu, sg->asym_prefer_cpu)) {
+               return true;
+       }
+
+       return false;
+}
+
 /*
  * group_smaller_min_cpu_capacity: Returns true if sched_group sg has smaller
  * per-CPU capacity than sched_group ref.
@@ -7983,7 +7996,7 @@ group_type group_classify(struct lb_env *env,
        if (sg_imbalanced(group))
                return group_imbalanced;
 
-       if (sgs->group_asym_packing)
+       if (group_has_asym_packing(env, group, sgs))
                return group_asym_packing;
 
        if (sgs->group_misfit_task_load)
@@ -8076,14 +8089,6 @@ static inline void update_sg_lb_stats(struct lb_env *env,
                }
        }
 
-       /* Check if dst cpu is idle and preferred to this group */
-       if (env->sd->flags & SD_ASYM_PACKING &&
-           env->idle != CPU_NOT_IDLE &&
-           sgs->sum_h_nr_running &&
-           sched_asym_prefer(env->dst_cpu, group->asym_prefer_cpu)) {
-               sgs->group_asym_packing = 1;
-       }
-
        sgs->group_capacity = group->sgc->capacity;

[...]

  parent reply	other threads:[~2019-10-01  8:15 UTC|newest]

Thread overview: 57+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-19  7:33 [PATCH v3 0/8] sched/fair: rework the CFS load balance Vincent Guittot
2019-09-19  7:33 ` [PATCH v3 01/10] sched/fair: clean up asym packing Vincent Guittot
2019-09-27 23:57   ` Rik van Riel
2019-09-19  7:33 ` [PATCH v3 02/10] sched/fair: rename sum_nr_running to sum_h_nr_running Vincent Guittot
2019-09-27 23:59   ` Rik van Riel
2019-10-01 17:11   ` Valentin Schneider
2019-09-19  7:33 ` [PATCH v3 03/10] sched/fair: remove meaningless imbalance calculation Vincent Guittot
2019-09-28  0:05   ` Rik van Riel
2019-10-01 17:12   ` Valentin Schneider
2019-10-02  6:28     ` Vincent Guittot
2019-09-19  7:33 ` [PATCH v3 04/10] sched/fair: rework load_balance Vincent Guittot
2019-09-30  1:12   ` Rik van Riel
2019-09-30  7:44     ` Vincent Guittot
2019-09-30 16:24   ` Dietmar Eggemann
2019-10-01  8:14     ` Vincent Guittot
2019-10-01 16:52       ` Dietmar Eggemann
2019-10-02  6:44         ` Vincent Guittot
2019-10-02  9:21           ` Dietmar Eggemann
2019-10-08 13:02             ` Peter Zijlstra
2019-10-02  8:23         ` Vincent Guittot
2019-10-02  9:24           ` Dietmar Eggemann
2019-10-01  8:15   ` Dietmar Eggemann [this message]
2019-10-01  9:14     ` Vincent Guittot
2019-10-01 16:57       ` Dietmar Eggemann
2019-10-01 17:47   ` Valentin Schneider
2019-10-02  8:30     ` Vincent Guittot
2019-10-02 10:47       ` Valentin Schneider
2019-10-08 14:16         ` Peter Zijlstra
2019-10-08 14:34           ` Valentin Schneider
2019-10-08 15:30             ` Vincent Guittot
2019-10-08 15:48               ` Valentin Schneider
2019-10-08 17:39               ` Peter Zijlstra
2019-10-08 18:45                 ` Vincent Guittot
2019-10-08 16:33             ` Peter Zijlstra
2019-10-08 16:39               ` Valentin Schneider
2019-10-08 17:36                 ` Valentin Schneider
2019-10-08 17:55   ` Peter Zijlstra
2019-10-08 18:47     ` Vincent Guittot
2019-10-16  7:21   ` Parth Shah
2019-10-16 11:56     ` Vincent Guittot
2019-10-18  5:34       ` Parth Shah
2019-09-19  7:33 ` [PATCH v3 05/10] sched/fair: use rq->nr_running when balancing load Vincent Guittot
2019-09-19  7:33 ` [PATCH v3 06/10] sched/fair: use load instead of runnable load in load_balance Vincent Guittot
2019-09-19  7:33 ` [PATCH v3 07/10] sched/fair: evenly spread tasks when not overloaded Vincent Guittot
2019-09-19  7:33 ` [PATCH v3 08/10] sched/fair: use utilization to select misfit task Vincent Guittot
2019-10-01 17:12   ` Valentin Schneider
2019-09-19  7:33 ` [PATCH v3 09/10] sched/fair: use load instead of runnable load in wakeup path Vincent Guittot
2019-10-07 15:14   ` Rik van Riel
2019-10-07 15:27     ` Vincent Guittot
2019-10-07 18:06       ` Rik van Riel
2019-09-19  7:33 ` [PATCH v3 10/10] sched/fair: optimize find_idlest_group Vincent Guittot
2019-10-08 14:32 ` [PATCH v3 0/8] sched/fair: rework the CFS load balance Phil Auld
2019-10-08 15:53   ` Vincent Guittot
2019-10-09 19:33     ` Phil Auld
2019-10-10  8:20       ` Vincent Guittot
2019-10-16  7:21 ` Parth Shah
2019-10-16 11:51   ` Vincent Guittot

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