android/android_kernel_asus_sm8350
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sched: turn off the TTWU_QUEUE feature

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While the feature TTWU_QUEUE has the advantage of reducing cache
bouncing of runqueue locks, it has the side effect that runqueue
statistics are not updated until the remote CPU has a chance to
enqueue the task. Since there is no upper bound on the amount of
time it can take the remote CPU to enqueue the task, several
sequential wakeups can result in suboptimal task placement based
on the stale statistics. Turn off the feature as the cost of
sub-optimal placement is much higher than the cost of cache bouncing
spinlocks for msm based systems.

Change-Id: I0b85c0225237b2bc44f54934769f5e3750c0f3d6
Signed-off-by: Syed Rameez Mustafa <rameezmustafa@codeaurora.org>
[satyap@codeaurora.org: fix trivial merge conflict]
Signed-off-by: Satya Durga Srinivasu Prabhala <satyap@codeaurora.org>
This commit is contained in:
Syed Rameez Mustafa 2015-07-13 11:03:02 -07:00 committed by Satya Durga Srinivasu Prabhala
parent 3ab58753c8
commit 61f31539cf
1 changed files with 1 additions and 1 deletions
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kernel/sched/features.h
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@ -49,7 +49,7 @@ SCHED_FEAT(NONTASK_CAPACITY, true)
* Queue remote wakeups on the target CPU and process them
* using the scheduler IPI. Reduces rq->lock contention/bounces.
*/
SCHED_FEAT(TTWU_QUEUE, true)
SCHED_FEAT(TTWU_QUEUE, false)
/*
* When doing wakeups, attempt to limit superfluous scans of the LLC domain.