2019-06-09 01:56:35

by Subhra Mazumdar

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Subject: [PATCH v3 5/7] sched: SIS_CORE to disable idle core search

Use SIS_CORE to disable idle core search. For some workloads
select_idle_core becomes a scalability bottleneck, removing it improves
throughput. Also there are workloads where disabling it can hurt latency,
so need to have an option.

Signed-off-by: subhra mazumdar <[email protected]>
---
kernel/sched/fair.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index c1ca88e..6a74808 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -6280,9 +6280,11 @@ static int select_idle_sibling(struct task_struct *p, int prev, int target)
if (!sd)
return target;

- i = select_idle_core(p, sd, target);
- if ((unsigned)i < nr_cpumask_bits)
- return i;
+ if (sched_feat(SIS_CORE)) {
+ i = select_idle_core(p, sd, target);
+ if ((unsigned)i < nr_cpumask_bits)
+ return i;
+ }

i = select_idle_cpu(p, sd, target);
if ((unsigned)i < nr_cpumask_bits)
--
2.9.3