diff mbox

[10/14] sched: update the buddy CPU

Message ID 1366910611-20048-11-git-send-email-vincent.guittot@linaro.org (mailing list archive)
State New, archived
Headers show

Commit Message

Vincent Guittot April 25, 2013, 5:23 p.m. UTC
Periodically updates the buddy of a CPU according to the current activity of
the system. A CPU is its own buddy if it participates to the packing effort.
Otherwise, it points to a CPU that participates to the packing effort.

Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
---
 kernel/sched/fair.c |   91 ++++++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 86 insertions(+), 5 deletions(-)

Comments

Francesco Lavra April 28, 2013, 8:20 a.m. UTC | #1
Hi,

On 04/25/2013 07:23 PM, Vincent Guittot wrote:
> Periodically updates the buddy of a CPU according to the current activity of
> the system. A CPU is its own buddy if it participates to the packing effort.
> Otherwise, it points to a CPU that participates to the packing effort.
> 
> Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
> ---
>  kernel/sched/fair.c |   91 ++++++++++++++++++++++++++++++++++++++++++++++++---
>  1 file changed, 86 insertions(+), 5 deletions(-)
> 
> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> index 234ecdd..28f8ea7 100644
> --- a/kernel/sched/fair.c
> +++ b/kernel/sched/fair.c
> @@ -174,11 +174,17 @@ void sched_init_granularity(void)
>  
>  
>  #ifdef CONFIG_SMP
> +static unsigned long power_of(int cpu)
> +{
> +	return cpu_rq(cpu)->cpu_power;
> +}
> +
>  /*
>   * Save the id of the optimal CPU that should be used to pack small tasks
>   * The value -1 is used when no buddy has been found
>   */
>  DEFINE_PER_CPU(int, sd_pack_buddy);
> +DEFINE_PER_CPU(struct sched_domain *, sd_pack_domain);
>  
>  /*
>   * Look for the best buddy CPU that can be used to pack small tasks
> @@ -237,6 +243,68 @@ void update_packing_domain(int cpu)
>  	}
>  
>  	pr_debug("CPU%d packing on CPU%d\n", cpu, id);
> +	per_cpu(sd_pack_domain, cpu) = sd;
> +	per_cpu(sd_pack_buddy, cpu) = id;
> +}
> +
> +void update_packing_buddy(int cpu, int activity)
> +{
> +	struct sched_domain *sd = per_cpu(sd_pack_domain, cpu);
> +	struct sched_group *sg, *pack, *tmp;
> +	int id = cpu;
> +
> +	if (!sd)
> +		return;
> +
> +	/*
> +	 * The sched_domain of a CPU points on the local sched_group
> +	 * and this CPU of this local group is a good candidate
> +	 */
> +	pack = sg = sd->groups;
> +
> +	/* loop the sched groups to find the best one */
> +	for (tmp = sg->next; tmp != sg; tmp = tmp->next) {
> +		if ((tmp->sgp->power * pack->group_weight) >
> +			(pack->sgp->power_available * tmp->group_weight))

The power_available struct member is defined in a subsequent patch
(12/14), so this patch series would break git bisect.

--
Francesco
Vincent Guittot April 29, 2013, 7:32 a.m. UTC | #2
On 28 April 2013 10:20, Francesco Lavra <francescolavra.fl@gmail.com> wrote:
> Hi,
>
> On 04/25/2013 07:23 PM, Vincent Guittot wrote:
>> Periodically updates the buddy of a CPU according to the current activity of
>> the system. A CPU is its own buddy if it participates to the packing effort.
>> Otherwise, it points to a CPU that participates to the packing effort.
>>
>> Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
>> ---
>>  kernel/sched/fair.c |   91 ++++++++++++++++++++++++++++++++++++++++++++++++---
>>  1 file changed, 86 insertions(+), 5 deletions(-)
>>
>> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
>> index 234ecdd..28f8ea7 100644
>> --- a/kernel/sched/fair.c
>> +++ b/kernel/sched/fair.c
>> @@ -174,11 +174,17 @@ void sched_init_granularity(void)
>>
>>
>>  #ifdef CONFIG_SMP
>> +static unsigned long power_of(int cpu)
>> +{
>> +     return cpu_rq(cpu)->cpu_power;
>> +}
>> +
>>  /*
>>   * Save the id of the optimal CPU that should be used to pack small tasks
>>   * The value -1 is used when no buddy has been found
>>   */
>>  DEFINE_PER_CPU(int, sd_pack_buddy);
>> +DEFINE_PER_CPU(struct sched_domain *, sd_pack_domain);
>>
>>  /*
>>   * Look for the best buddy CPU that can be used to pack small tasks
>> @@ -237,6 +243,68 @@ void update_packing_domain(int cpu)
>>       }
>>
>>       pr_debug("CPU%d packing on CPU%d\n", cpu, id);
>> +     per_cpu(sd_pack_domain, cpu) = sd;
>> +     per_cpu(sd_pack_buddy, cpu) = id;
>> +}
>> +
>> +void update_packing_buddy(int cpu, int activity)
>> +{
>> +     struct sched_domain *sd = per_cpu(sd_pack_domain, cpu);
>> +     struct sched_group *sg, *pack, *tmp;
>> +     int id = cpu;
>> +
>> +     if (!sd)
>> +             return;
>> +
>> +     /*
>> +      * The sched_domain of a CPU points on the local sched_group
>> +      * and this CPU of this local group is a good candidate
>> +      */
>> +     pack = sg = sd->groups;
>> +
>> +     /* loop the sched groups to find the best one */
>> +     for (tmp = sg->next; tmp != sg; tmp = tmp->next) {
>> +             if ((tmp->sgp->power * pack->group_weight) >
>> +                     (pack->sgp->power_available * tmp->group_weight))
>
> The power_available struct member is defined in a subsequent patch
> (12/14), so this patch series would break git bisect.

Hi Francesco,

yes, power_available should have been added in patch 13/14.
I will correct that

Thanks
Vincent

>
> --
> Francesco
diff mbox

Patch

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 234ecdd..28f8ea7 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -174,11 +174,17 @@  void sched_init_granularity(void)
 
 
 #ifdef CONFIG_SMP
+static unsigned long power_of(int cpu)
+{
+	return cpu_rq(cpu)->cpu_power;
+}
+
 /*
  * Save the id of the optimal CPU that should be used to pack small tasks
  * The value -1 is used when no buddy has been found
  */
 DEFINE_PER_CPU(int, sd_pack_buddy);
+DEFINE_PER_CPU(struct sched_domain *, sd_pack_domain);
 
 /*
  * Look for the best buddy CPU that can be used to pack small tasks
@@ -237,6 +243,68 @@  void update_packing_domain(int cpu)
 	}
 
 	pr_debug("CPU%d packing on CPU%d\n", cpu, id);
+	per_cpu(sd_pack_domain, cpu) = sd;
+	per_cpu(sd_pack_buddy, cpu) = id;
+}
+
+void update_packing_buddy(int cpu, int activity)
+{
+	struct sched_domain *sd = per_cpu(sd_pack_domain, cpu);
+	struct sched_group *sg, *pack, *tmp;
+	int id = cpu;
+
+	if (!sd)
+		return;
+
+	/*
+	 * The sched_domain of a CPU points on the local sched_group
+	 * and this CPU of this local group is a good candidate
+	 */
+	pack = sg = sd->groups;
+
+	/* loop the sched groups to find the best one */
+	for (tmp = sg->next; tmp != sg; tmp = tmp->next) {
+		if ((tmp->sgp->power * pack->group_weight) >
+			(pack->sgp->power_available * tmp->group_weight))
+			continue;
+
+		if (((tmp->sgp->power * pack->group_weight) ==
+			 (pack->sgp->power * tmp->group_weight))
+		 && (cpumask_first(sched_group_cpus(tmp)) >= id))
+			continue;
+
+		/* we have found a better group */
+		pack = tmp;
+
+		/* Take the 1st CPU of the new group */
+		id = cpumask_first(sched_group_cpus(pack));
+	}
+
+	if ((cpu == id) || (activity <= power_of(id))) {
+		per_cpu(sd_pack_buddy, cpu) = id;
+		return;
+	}
+
+	for (tmp = pack; activity > 0; tmp = tmp->next) {
+		if (tmp->sgp->power > activity) {
+			id = cpumask_first(sched_group_cpus(tmp));
+			activity -= power_of(id);
+			if (cpu == id)
+				activity = 0;
+			while ((activity > 0) && (id < nr_cpu_ids)) {
+				id = cpumask_next(id, sched_group_cpus(tmp));
+				activity -= power_of(id);
+				if (cpu == id)
+					activity = 0;
+			}
+		} else if (cpumask_test_cpu(cpu, sched_group_cpus(tmp))) {
+			id = cpu;
+			activity = 0;
+		} else {
+			activity -= tmp->sgp->power;
+		}
+	}
+
 	per_cpu(sd_pack_buddy, cpu) = id;
 }
 
@@ -3014,11 +3082,6 @@  static unsigned long target_load(int cpu, int type)
 	return max(rq->cpu_load[type-1], total);
 }
 
-static unsigned long power_of(int cpu)
-{
-	return cpu_rq(cpu)->cpu_power;
-}
-
 static unsigned long cpu_avg_load_per_task(int cpu)
 {
 	struct rq *rq = cpu_rq(cpu);
@@ -4740,6 +4803,22 @@  static bool update_sd_pick_busiest(struct lb_env *env,
 	return false;
 }
 
+static void update_plb_buddy(int cpu, int *balance, struct sd_lb_stats *sds,
+		struct sched_domain *sd)
+{
+	int buddy;
+
+	if (sysctl_sched_packing_mode != SCHED_PACKING_FULL)
+		return;
+
+	/* Update my buddy */
+	if (sd == per_cpu(sd_pack_domain, cpu))
+		update_packing_buddy(cpu, sds->total_activity);
+
+	/* Get my new buddy */
+	buddy = per_cpu(sd_pack_buddy, cpu);
+}
+
 /**
  * update_sd_lb_stats - Update sched_domain's statistics for load balancing.
  * @env: The load balancing environment.
@@ -4807,6 +4886,8 @@  static inline void update_sd_lb_stats(struct lb_env *env,
 
 		sg = sg->next;
 	} while (sg != env->sd->groups);
+
+	update_plb_buddy(env->dst_cpu, balance, sds, env->sd);
 }
 
 /**