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>

diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu b/Documentation/ABI/testing/sysfs-devices-system-cpu
index 2ade5c0..8cdda1c 100644 (file)
--- 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