sched: Add struct rq::cpu_capacity_orig (ca6d75e6) · Commits · 戴 / test

This new field 'cpu_capacity_orig' reflects the original capacity of a CPU before being altered by rt tasks and/or IRQ The cpu_capacity_orig will be used: - to detect when the capacity of a CPU has been noticeably reduced so we can trig load balance to look for a CPU with better capacity. As an example, we can detect when a CPU handles a significant amount of irq (with CONFIG_IRQ_TIME_ACCOUNTING) but this CPU is seen as an idle CPU by scheduler whereas CPUs, which are really idle, are available. - evaluate the available capacity for CFS tasks Signed-off-by:

Vincent Guittot <vincent.guittot@linaro.org> Signed-off-by:

Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by:

Kamalesh Babulal <kamalesh@linux.vnet.ibm.com> Acked-by:

Morten Rasmussen <morten.rasmussen@arm.com> Cc: Morten.Rasmussen@arm.com Cc: dietmar.eggemann@arm.com Cc: efault@gmx.de Cc: linaro-kernel@lists.linaro.org Cc: nicolas.pitre@linaro.org Cc: preeti@linux.vnet.ibm.com Cc: riel@redhat.com Link: http://lkml.kernel.org/r/1425052454-25797-7-git-send-email-vincent.guittot@linaro.org Signed-off-by:

Ingo Molnar <mingo@kernel.org>

kernel/sched/core.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -7216,7 +7216,7 @@ void __init sched_init(void)
		#ifdef CONFIG_SMP
		rq->sd = NULL;
		rq->rd = NULL;
		rq->cpu_capacity = SCHED_CAPACITY_SCALE;
		rq->cpu_capacity = rq->cpu_capacity_orig = SCHED_CAPACITY_SCALE;
		rq->post_schedule = 0;
		rq->active_balance = 0;
		rq->next_balance = jiffies;

kernel/sched/fair.c

+7 −1

Original line number	Diff line number	Diff line
		@@ -4363,6 +4363,11 @@ static unsigned long capacity_of(int cpu)
		return cpu_rq(cpu)->cpu_capacity;
		}

		static unsigned long capacity_orig_of(int cpu)
		{
		return cpu_rq(cpu)->cpu_capacity_orig;
		}

		static unsigned long cpu_avg_load_per_task(int cpu)
		{
		struct rq *rq = cpu_rq(cpu);
		@@ -6040,6 +6045,7 @@ static void update_cpu_capacity(struct sched_domain *sd, int cpu)

		capacity >>= SCHED_CAPACITY_SHIFT;

		cpu_rq(cpu)->cpu_capacity_orig = capacity;
		sdg->sgc->capacity_orig = capacity;

		capacity *= scale_rt_capacity(cpu);
		@@ -6094,7 +6100,7 @@ void update_group_capacity(struct sched_domain *sd, int cpu)
		* Runtime updates will correct capacity_orig.
		*/
		if (unlikely(!rq->sd)) {
		capacity_orig += capacity_of(cpu);
		capacity_orig += capacity_orig_of(cpu);
		capacity += capacity_of(cpu);
		continue;
		}

kernel/sched/sched.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -615,6 +615,7 @@ struct rq {
		struct sched_domain *sd;

		unsigned long cpu_capacity;
		unsigned long cpu_capacity_orig;

		unsigned char idle_balance;
		/* For active balancing */

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