Documentation: ABI: /sys/devices/system/cpu/sched_[mc|smt]_power_savings

Document sched_[mc|smt]_power_savings by reading existing code and
git logs.

Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Alex Chiang <achiang@hp.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 24 insertions, 0 deletions

diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu b/Documentation/ABI/testing/sysfs-devices-system-cpu
index 2ade5c0809a0..8cdda1c56980 100644
--- a/Documentation/ABI/testing/sysfs-devices-system-cpu
+++ b/Documentation/ABI/testing/sysfs-devices-system-cpu
@@ -9,6 +9,30 @@ Description:
 
                 /sys/devices/system/cpu/cpu#/
 
+What:           /sys/devices/system/cpu/sched_mc_power_savings
+                /sys/devices/system/cpu/sched_smt_power_savings
+Date:           June 2006
+Contact:        Linux kernel mailing list <linux-kernel@vger.kernel.org>
+Description:    Discover and adjust the kernel's multi-core scheduler support.
+
+                Possible values are:
+
+                0 - No power saving load balance (default value)
+                1 - Fill one thread/core/package first for long running threads
+                2 - Also bias task wakeups to semi-idle cpu package for power
+                    savings
+
+                sched_mc_power_savings is dependent upon SCHED_MC, which is
+                itself architecture dependent.
+
+                sched_smt_power_savings is dependent upon SCHED_SMT, which
+                is itself architecture dependent.
+
+                The two files are independent of each other. It is possible
+                that one file may be present without the other.
+
+                Introduced by git commit 5c45bf27.
+
 
 What:           /sys/devices/system/cpu/kernel_max
                 /sys/devices/system/cpu/offline