tree 3a8d6bf8e5aded3c371e5dc090b8874305952d1f
parent ad4b78bbcbab66998b05d422ac6106b645796e54
author Peter Zijlstra <a.p.zijlstra@chello.nl> 1253170880 +0200
committer Ingo Molnar <mingo@elte.hu> 1253176830 +0200

sched: Stop buddies from hogging the system

Clear buddies more agressively.

The (theoretical, haven't actually observed any of this) problem is
that when we do not select either buddy in pick_next_entity()
because they are too far ahead of the left-most task, we do not
clear the buddies.

This means that as soon as we service the left-most task, these
same buddies will be tried again on the next schedule. Now if the
left-most task was a pure hog, it wouldn't have done any wakeups
and it wouldn't have set buddies of its own. That leads to the old
buddies dominating, which would lead to bad latencies.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>