Commit 9ee1cda5 authored Jul 25, 2016 by Morten Rasmussen Committed by Ingo Molnar Aug 18, 2016

sched/core: Enable SD_BALANCE_WAKE for asymmetric capacity systems



A domain with the SD_ASYM_CPUCAPACITY flag set indicate that
sched_groups at this level and below do not include CPUs of all
capacities available (e.g. group containing little-only or big-only CPUs
in big.LITTLE systems). It is therefore necessary to put in more effort
in finding an appropriate CPU at task wake-up by enabling balancing at
wake-up (SD_BALANCE_WAKE) on all lower (child) levels.

Signed-off-by: Morten Rasmussen <morten.rasmussen@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dietmar.eggemann@arm.com
Cc: freedom.tan@mediatek.com
Cc: keita.kobayashi.ym@renesas.com
Cc: mgalbraith@suse.de
Cc: sgurrappadi@nvidia.com
Cc: vincent.guittot@linaro.org
Cc: yuyang.du@intel.com
Link: http://lkml.kernel.org/r/1469453670-2660-8-git-send-email-morten.rasmussen@arm.com


Signed-off-by: Ingo Molnar <mingo@kernel.org>

parent 3676b13e

kernel/sched/core.c

+7 −0

Original line number	Diff line number	Diff line
		@@ -6444,6 +6444,13 @@ sd_init(struct sched_domain_topology_level *tl,
		* Convert topological properties into behaviour.
		*/

		if (sd->flags & SD_ASYM_CPUCAPACITY) {
		struct sched_domain *t = sd;

		for_each_lower_domain(t)
		t->flags \|= SD_BALANCE_WAKE;
		}

		if (sd->flags & SD_SHARE_CPUCAPACITY) {
		sd->flags \|= SD_PREFER_SIBLING;
		sd->imbalance_pct = 110;

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