[tip:sched/core] sched: Check if we got a shallowest_idle_cpu before searching for least_loaded_cpu
From: tip-bot for Yao Dongdong
Date: Tue Nov 04 2014 - 11:11:26 EST
Commit-ID: 9f96742a13135e6c609cc99a3a458402af3c8f31
Gitweb: http://git.kernel.org/tip/9f96742a13135e6c609cc99a3a458402af3c8f31
Author: Yao Dongdong <yaodongdong@xxxxxxxxxx>
AuthorDate: Tue, 28 Oct 2014 04:08:06 +0000
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Tue, 4 Nov 2014 07:17:51 +0100
sched: Check if we got a shallowest_idle_cpu before searching for least_loaded_cpu
Idle cpu is idler than non-idle cpu, so we needn't search for least_loaded_cpu
after we have found an idle cpu.
Signed-off-by: Yao Dongdong <yaodongdong@xxxxxxxxxx>
Reviewed-by: Srikar Dronamraju <srikar@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/1414469286-6023-1-git-send-email-yaodongdong@xxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
kernel/sched/fair.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index ec32c26d..d03d76d 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -4641,7 +4641,7 @@ find_idlest_cpu(struct sched_group *group, struct task_struct *p, int this_cpu)
latest_idle_timestamp = rq->idle_stamp;
shallowest_idle_cpu = i;
}
- } else {
+ } else if (shallowest_idle_cpu == -1) {
load = weighted_cpuload(i);
if (load < min_load || (load == min_load && i == this_cpu)) {
min_load = load;
--
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