sched: Fix vmark regression on big machines

SD_PREFER_SIBLING is set at the CPU domain level if power saving isn't
enabled, leading to many cache misses on large machines as we traverse
looking for an idle shared cache to wake to.  Change the enabler of
select_idle_sibling() to SD_SHARE_PKG_RESOURCES, and enable same at the
sibling domain level.

Reported-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Mike Galbraith <efault@gmx.de>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1262612696.15495.15.camel@marge.simson.net>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/include/linux/topology.h b/include/linux/topology.h
index 57e63579bfdd7f193511675fc9ed26141b586638..5b81156780b17f8bf52608ca7b8230dd638a530a 100644 (file)
--- a/include/linux/topology.h
+++ b/include/linux/topology.h
@@ -99,7 +99,7 @@ int arch_update_cpu_topology(void);
                                | 1*SD_WAKE_AFFINE                      \
                                | 1*SD_SHARE_CPUPOWER                   \
                                | 0*SD_POWERSAVINGS_BALANCE             \
-                               | 0*SD_SHARE_PKG_RESOURCES              \
+                               | 1*SD_SHARE_PKG_RESOURCES              \
                                | 0*SD_SERIALIZE                        \
                                | 0*SD_PREFER_SIBLING                   \
                                ,                                       \

diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index 42ac3c9f66f68868bb651f6c163483d6713b6eea..8fe7ee81c55270dc5893a9e2df94a1dbc7450dd6 100644 (file)
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -1508,7 +1508,7 @@ static int select_task_rq_fair(struct task_struct *p, int sd_flag, int wake_flag
                         * If there's an idle sibling in this domain, make that
                         * the wake_affine target instead of the current cpu.
                         */
-                       if (tmp->flags & SD_PREFER_SIBLING)
+                       if (tmp->flags & SD_SHARE_PKG_RESOURCES)
                                target = select_idle_sibling(p, tmp, target);
 
                        if (target >= 0) {