From 5886acba9b692e419cd3e99a452d0f380a26e1da Mon Sep 17 00:00:00 2001 From: Morten Rasmussen Date: Tue, 3 Feb 2015 13:54:11 +0000 Subject: [PATCH] ANDROID: sched: Disable energy-unfriendly nohz kicks With energy-aware scheduling enabled nohz_kick_needed() generates many nohz idle-balance kicks which lead to nothing when multiple tasks get packed on a single cpu to save energy. This causes unnecessary wake-ups and hence wastes energy. Make these conditions depend on !energy_aware() for now until the energy-aware nohz story gets sorted out. cc: Ingo Molnar cc: Peter Zijlstra Signed-off-by: Morten Rasmussen Change-Id: Iba347168ea34c152117d0f139e82d0d92ba2de20 Signed-off-by: Chris Redpath --- kernel/sched/fair.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 3f5a9ef58921..b72a1006f719 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -9403,12 +9403,13 @@ static inline bool nohz_kick_needed(struct rq *rq) if (time_before(now, nohz.next_balance)) return false; - if (rq->nr_running >= 2) + if (rq->nr_running >= 2 && + (!energy_aware() || cpu_overutilized(cpu))) return true; rcu_read_lock(); sds = rcu_dereference(per_cpu(sd_llc_shared, cpu)); - if (sds) { + if (sds && !energy_aware()) { /* * XXX: write a coherent comment on why we do this. * See also: http://lkml.kernel.org/r/20111202010832.602203411@sbsiddha-desk.sc.intel.com -- 2.20.1