[patch v5 13/15] sched: no balance for prefer_sibling in power scheduling

Alex Shi
2013-02-18T05:08:10Z

In power aware scheduling, we don't want to balance 'prefer_sibling'
groups just because local group has capacity.
If the local group has no tasks at the time, that is the power
balance hope so.

Signed-off-by: Alex Shi <alex.shi@intel.com>
---
kernel/sched/fair.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index f3abb83..ffdf35d 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -4782,8 +4782,12 @@ static inline void update_sd_lb_stats(struct lb_env *env,
* extra check prevents the case where you always pull from the
* heaviest group when it is already under-utilized (possible
* with a large weight task outweighs the tasks on the system).
+ *
+ * In power aware scheduling, we don't care load weight and
+ * want not to pull tasks just because local group has capacity.
*/
- if (prefer_sibling && !local_group && sds->this_has_capacity)
+ if (prefer_sibling && !local_group && sds->this_has_capacity
+ && env->perf_lb)
sgs.group_capacity = min(sgs.group_capacity, 1UL);

if (local_group) {
--
1.7.12