powerpc/numa: Disable NEWIDLE balancing at node level

On big POWER7 boxes we see large amounts of CPU time in system
processes like workqueue and watchdog kernel threads.

We currently rebalance the entire machine each time a task goes
idle and this is very expensive on large machines. Disable newidle
balancing at the node level and rely on the scheduler tick to
rebalance across nodes.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

diff --git a/arch/powerpc/include/asm/topology.h b/arch/powerpc/include/asm/topology.h
index d1c1d312f808be51843ce553a8ed2c2cad1adb31..13efa4d95e769b4260c3f2ba31eb71a27d90e0d8 100644 (file)
--- a/arch/powerpc/include/asm/topology.h
+++ b/arch/powerpc/include/asm/topology.h
@@ -75,7 +75,7 @@ static inline int pcibus_to_node(struct pci_bus *bus)
        .forkexec_idx           = 0,                                    \
                                                                        \
        .flags                  = 1*SD_LOAD_BALANCE                     \
-                               | 1*SD_BALANCE_NEWIDLE                  \
+                               | 0*SD_BALANCE_NEWIDLE                  \
                                | 1*SD_BALANCE_EXEC                     \
                                | 1*SD_BALANCE_FORK                     \
                                | 0*SD_BALANCE_WAKE                     \