[PATCH] sched: mc/smt power savings sched policy

sysfs entries 'sched_mc_power_savings' and 'sched_smt_power_savings' in
/sys/devices/system/cpu/ control the MC/SMT power savings policy for the
scheduler.

Based on the values (1-enable, 0-disable) for these controls, sched groups
cpu power will be determined for different domains.  When power savings
policy is enabled and under light load conditions, scheduler will minimize
the physical packages/cpu cores carrying the load and thus conserving
power(with a perf impact based on the workload characteristics...  see OLS
2005 CMP kernel scheduler paper for more details..)

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Con Kolivas <kernel@kolivas.org>
Cc: "Chen, Kenneth W" <kenneth.w.chen@intel.com>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 5 insertions, 0 deletions

diff --git a/include/asm-powerpc/topology.h b/include/asm-powerpc/topology.h
index 92f3e5507d22..bbc3844b086f 100644
--- a/include/asm-powerpc/topology.h
+++ b/include/asm-powerpc/topology.h
@@ -93,5 +93,10 @@ static inline void sysfs_remove_device_from_node(struct sys_device *dev,
 
 #endif /* CONFIG_NUMA */
 
+#ifdef CONFIG_SMP
+#include <asm/cputable.h>
+#define smt_capable()           (cpu_has_feature(CPU_FTR_SMT))
+#endif
+
 #endif /* __KERNEL__ */
 #endif  /* _ASM_POWERPC_TOPOLOGY_H */