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linux-next/Documentation/ABI/testing/sysfs-class-powercap
Srinivas Pandruvada e23feb1668 PowerCap: Documentation
Added power cap framework documentation. This explains the use of power
capping framework, sysfs and programming interface.

There are two documents:
 - Documentation/power/powercap/powercap.txt : Explains use case and APIs.
 - Documentation/ABI/testing/sysfs-class-powercap: Explains ABIs.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Len Brown <len.brown@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-10-17 00:36:06 +02:00

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What: /sys/class/powercap/
Date: September 2013
KernelVersion: 3.13
Contact: linux-pm@vger.kernel.org
Description:
The powercap/ class sub directory belongs to the power cap
subsystem. Refer to
Documentation/power/powercap/powercap.txt for details.
What: /sys/class/powercap/<control type>
Date: September 2013
KernelVersion: 3.13
Contact: linux-pm@vger.kernel.org
Description:
A <control type> is a unique name under /sys/class/powercap.
Here <control type> determines how the power is going to be
controlled. A <control type> can contain multiple power zones.
What: /sys/class/powercap/<control type>/enabled
Date: September 2013
KernelVersion: 3.13
Contact: linux-pm@vger.kernel.org
Description:
This allows to enable/disable power capping for a "control type".
This status affects every power zone using this "control_type.
What: /sys/class/powercap/<control type>/<power zone>
Date: September 2013
KernelVersion: 3.13
Contact: linux-pm@vger.kernel.org
Description:
A power zone is a single or a collection of devices, which can
be independently monitored and controlled. A power zone sysfs
entry is qualified with the name of the <control type>.
E.g. intel-rapl:0:1:1.
What: /sys/class/powercap/<control type>/<power zone>/<child power zone>
Date: September 2013
KernelVersion: 3.13
Contact: linux-pm@vger.kernel.org
Description:
Power zones may be organized in a hierarchy in which child
power zones provide monitoring and control for a subset of
devices under the parent. For example, if there is a parent
power zone for a whole CPU package, each CPU core in it can
be a child power zone.
What: /sys/class/powercap/.../<power zone>/name
Date: September 2013
KernelVersion: 3.13
Contact: linux-pm@vger.kernel.org
Description:
Specifies the name of this power zone.
What: /sys/class/powercap/.../<power zone>/energy_uj
Date: September 2013
KernelVersion: 3.13
Contact: linux-pm@vger.kernel.org
Description:
Current energy counter in micro-joules. Write "0" to reset.
If the counter can not be reset, then this attribute is
read-only.
What: /sys/class/powercap/.../<power zone>/max_energy_range_uj
Date: September 2013
KernelVersion: 3.13
Contact: linux-pm@vger.kernel.org
Description:
Range of the above energy counter in micro-joules.
What: /sys/class/powercap/.../<power zone>/power_uw
Date: September 2013
KernelVersion: 3.13
Contact: linux-pm@vger.kernel.org
Description:
Current power in micro-watts.
What: /sys/class/powercap/.../<power zone>/max_power_range_uw
Date: September 2013
KernelVersion: 3.13
Contact: linux-pm@vger.kernel.org
Description:
Range of the above power value in micro-watts.
What: /sys/class/powercap/.../<power zone>/constraint_X_name
Date: September 2013
KernelVersion: 3.13
Contact: linux-pm@vger.kernel.org
Description:
Each power zone can define one or more constraints. Each
constraint can have an optional name. Here "X" can have values
from 0 to max integer.
What: /sys/class/powercap/.../<power zone>/constraint_X_power_limit_uw
Date: September 2013
KernelVersion: 3.13
Contact: linux-pm@vger.kernel.org
Description:
Power limit in micro-watts should be applicable for
the time window specified by "constraint_X_time_window_us".
Here "X" can have values from 0 to max integer.
What: /sys/class/powercap/.../<power zone>/constraint_X_time_window_us
Date: September 2013
KernelVersion: 3.13
Contact: linux-pm@vger.kernel.org
Description:
Time window in micro seconds. This is used along with
constraint_X_power_limit_uw to define a power constraint.
Here "X" can have values from 0 to max integer.
What: /sys/class/powercap/<control type>/.../constraint_X_max_power_uw
Date: September 2013
KernelVersion: 3.13
Contact: linux-pm@vger.kernel.org
Description:
Maximum allowed power in micro watts for this constraint.
Here "X" can have values from 0 to max integer.
What: /sys/class/powercap/<control type>/.../constraint_X_min_power_uw
Date: September 2013
KernelVersion: 3.13
Contact: linux-pm@vger.kernel.org
Description:
Minimum allowed power in micro watts for this constraint.
Here "X" can have values from 0 to max integer.
What: /sys/class/powercap/.../<power zone>/constraint_X_max_time_window_us
Date: September 2013
KernelVersion: 3.13
Contact: linux-pm@vger.kernel.org
Description:
Maximum allowed time window in micro seconds for this
constraint. Here "X" can have values from 0 to max integer.
What: /sys/class/powercap/.../<power zone>/constraint_X_min_time_window_us
Date: September 2013
KernelVersion: 3.13
Contact: linux-pm@vger.kernel.org
Description:
Minimum allowed time window in micro seconds for this
constraint. Here "X" can have values from 0 to max integer.
What: /sys/class/powercap/.../<power zone>/enabled
Date: September 2013
KernelVersion: 3.13
Contact: linux-pm@vger.kernel.org
Description
This allows to enable/disable power capping at power zone level.
This applies to current power zone and its children.