sched: revert recent sync wakeup changes

Intel reported a 10% regression (mysql+sysbench) on a 16-way machine
with these patches:

  1596e29: sched: symmetric sync vs avg_overlap
  d942fb6: sched: fix sync wakeups

Revert them.

Reported-by: "Zhang, Yanmin" <yanmin_zhang@linux.intel.com>
Bisected-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>

1 files changed, 0 insertions, 10 deletions

diff --git a/kernel/sched.c b/kernel/sched.c
index e1fc67d0674c..f11c02b86c73 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -2266,16 +2266,6 @@ static int try_to_wake_up(struct task_struct *p, unsigned int state, int sync)
         if (!sched_feat(SYNC_WAKEUPS))
                 sync = 0;
 
-        if (!sync) {
-                if (current->se.avg_overlap < sysctl_sched_migration_cost &&
-                          p->se.avg_overlap < sysctl_sched_migration_cost)
-                        sync = 1;
-        } else {
-                if (current->se.avg_overlap >= sysctl_sched_migration_cost ||
-                          p->se.avg_overlap >= sysctl_sched_migration_cost)
-                        sync = 0;
-        }
-
 #ifdef CONFIG_SMP
         if (sched_feat(LB_WAKEUP_UPDATE)) {
                 struct sched_domain *sd;