Evolution-X-Devices/kernel_google_wahoo
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

sched: Disable energy-unfriendly nohz kicks

Browse Source 
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>
This commit is contained in:
Morten Rasmussen
2015-02-03 13:54:11 +00:00
committed by Leo Yan
parent 52b7b8a37c
commit b71188bd2c
1 changed files with 3 additions and 2 deletions
Download Patch File Download Diff File Expand all files Collapse all files

5
kernel/sched/fair.c
View File

@@ -8259,12 +8259,13 @@ 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();
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);