diff options
| author | Morten Rasmussen <morten.rasmussen@arm.com> | 2015-02-03 13:54:11 +0000 |
|---|---|---|
| committer | Robin Randhawa <robin.randhawa@arm.com> | 2015-04-09 12:26:15 +0100 |
| commit | 21f6c84c01da1e7465b538fe66152841b5b92beb (patch) | |
| tree | b468b5193edde462c66ef04d007018fc9effaf81 /kernel/sched/fair.c | |
| parent | 3819fd1d7407d86476e5f88189d0c09a12c030e6 (diff) | |
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 <mingo@redhat.com>
cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Morten Rasmussen <morten.rasmussen@arm.com>
Diffstat (limited to 'kernel/sched/fair.c')
| -rw-r--r-- | kernel/sched/fair.c | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 5e5c6f6e38da..e8e0e2855f5f 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -7636,6 +7636,8 @@ end: clear_bit(NOHZ_BALANCE_KICK, nohz_flags(this_cpu)); } +static int cpu_overutilized(int cpu, struct sched_domain *sd); + /* * Current heuristic for kicking the idle load balancer in the presence * of an idle cpu in the system. @@ -7675,12 +7677,13 @@ static inline bool nohz_kick_needed(struct rq *rq) if (time_before(now, nohz.next_balance)) return false; - if (rq->nr_running >= 2) + sd = rcu_dereference(rq->sd); + if (rq->nr_running >= 2 && (!energy_aware() || cpu_overutilized(cpu, sd))) return true; rcu_read_lock(); sd = rcu_dereference(per_cpu(sd_busy, cpu)); - if (sd) { + if (sd && !energy_aware()) { sgc = sd->groups->sgc; nr_busy = atomic_read(&sgc->nr_busy_cpus); |