sched: Disable SD_PREFER_LOCAL at node level

Yanmin Zhang reported that SD_PREFER_LOCAL induces an order of
magnitude increase in select_task_rq_fair() overhead while
running heavy wakeup benchmarks (tbench and vmark).

Since SD_BALANCE_WAKE is off at node level, turn SD_PREFER_LOCAL
off as well pending further investigation.

Reported-by: Zhang, Yanmin <yanmin_zhang@linux.intel.com>
Signed-off-by: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/arch/x86/include/asm/topology.h b/arch/x86/include/asm/topology.h
index d823c24..40e37b1 100644 (file)
--- a/arch/x86/include/asm/topology.h
+++ b/arch/x86/include/asm/topology.h
@@ -143,7 +143,7 @@ extern unsigned long node_remap_size[];
                                | 1*SD_BALANCE_FORK                     \
                                | 0*SD_BALANCE_WAKE                     \
                                | 1*SD_WAKE_AFFINE                      \
-                               | 1*SD_PREFER_LOCAL                     \
+                               | 0*SD_PREFER_LOCAL                     \
                                | 0*SD_SHARE_CPUPOWER                   \
                                | 0*SD_POWERSAVINGS_BALANCE             \
                                | 0*SD_SHARE_PKG_RESOURCES              \