commit 15afe09bf496ae10c989e1a375a6b5da7bd3e16e
author Peter Zijlstra <a.p.zijlstra@chello.nl> Sat Sep 20 23:38:02 2008 +0200
committer Ingo Molnar <mingo@elte.hu> Mon Sep 22 16:28:32 2008 +0200
tree 4565659d1084e357eea42e6321a4d304ac950faa
parent 09b22a2f678ae733801b888c44756d0abd686b8a

sched: wakeup preempt when small overlap

Lin Ming reported a 10% OLTP regression against 2.6.27-rc4.

The difference seems to come from different preemption agressiveness,
which affects the cache footprint of the workload and its effective
cache trashing.

Aggresively preempt a task if its avg overlap is very small, this should
avoid the task going to sleep and find it still running when we schedule
back to it - saving a wakeup.

Reported-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>