[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, 9 insertions, 1 deletions

diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c
index 3972d8ac9786..4bef76a2f3f2 100644
--- a/drivers/base/cpu.c
+++ b/drivers/base/cpu.c
@@ -143,5 +143,13 @@ EXPORT_SYMBOL_GPL(get_cpu_sysdev);
 
 int __init cpu_dev_init(void)
 {
-        return sysdev_class_register(&cpu_sysdev_class);
+        int err;
+
+        err = sysdev_class_register(&cpu_sysdev_class);
+#if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
+        if (!err)
+                err = sched_create_sysfs_power_savings_entries(&cpu_sysdev_class);
+#endif
+
+        return err;
 }