From 64537223eb2a922fd872741df1a82b1bee325f3e Mon Sep 17 00:00:00 2001 From: Morten Rasmussen Date: Tue, 3 Feb 2015 13:54:11 +0000 Subject: [PATCH 63/92] 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 (cherry picked from commit a5268e57a1b257dee1ffa9cd9d670ee747a4ec88) Signed-off-by: Gaku Inami --- 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 360e922..bc347af 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -9150,12 +9150,13 @@ 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 -- 1.9.1