[PATCH v2 05/13] sched: Enable SD_BALANCE_WAKE for asymmetric capacity systems

From	Morten Rasmussen <morten.rasmussen@arm.com>
Newsgroups	linux.kernel
Subject	[PATCH v2 05/13] sched: Enable SD_BALANCE_WAKE for asymmetric capacity systems
Date	2016-06-22 19:10 +0200
Message-ID	<rMTP5-6im-57@gated-at.bofh.it> (permalink)
References	<rMTP3-6im-5@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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Systems with the SD_ASYM_CPUCAPACITY flag set indicate that sched_groups
at this level or 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).

cc: Ingo Molnar <mingo@redhat.com>
cc: Peter Zijlstra <peterz@infradead.org>

Signed-off-by: Morten Rasmussen <morten.rasmussen@arm.com>
---
 kernel/sched/core.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 351609279341..fe39118ffdfb 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -6397,6 +6397,9 @@ sd_init(struct sched_domain_topology_level *tl, int cpu)
 	 * Convert topological properties into behaviour.
 	 */
 
+	if (sd->flags & SD_ASYM_CPUCAPACITY)
+		sd->flags |= SD_BALANCE_WAKE;
+
 	if (sd->flags & SD_SHARE_CPUCAPACITY) {
 		sd->flags |= SD_PREFER_SIBLING;
 		sd->imbalance_pct = 110;
-- 
1.9.1

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[PATCH v2 00/13] sched: Clean-ups and asymmetric cpu capacity support Morten Rasmussen <morten.rasmussen@arm.com> - 2016-06-22 19:10 +0200
  [PATCH v2 11/13] sched/fair: Avoid pulling tasks from non-overloaded higher capacity groups Morten Rasmussen <morten.rasmussen@arm.com> - 2016-06-22 19:10 +0200
  [PATCH v2 09/13] sched/fair: Consider spare capacity in find_idlest_group() Morten Rasmussen <morten.rasmussen@arm.com> - 2016-06-22 19:10 +0200
  [PATCH v2 12/13] arm: Set SD_ASYM_CPUCAPACITY for big.LITTLE platforms Morten Rasmussen <morten.rasmussen@arm.com> - 2016-06-22 19:10 +0200
  [PATCH v2 05/13] sched: Enable SD_BALANCE_WAKE for asymmetric capacity systems Morten Rasmussen <morten.rasmussen@arm.com> - 2016-06-22 19:10 +0200

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