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linux-yocto/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/ Date: September 2013 KernelVersion: 3.13 Contact: linux-pm@vger.kernel.org Description: A is a unique name under /sys/class/powercap. Here determines how the power is going to be controlled. A can contain multiple power zones.

What: /sys/class/powercap//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// 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 . E.g. intel-rapl:0:1:1.

What: /sys/class/powercap/// 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/...//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/...//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/...//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_uw Date: September 2013 KernelVersion: 3.13 Contact: linux-pm@vger.kernel.org Description: Current power in micro-watts.

What: /sys/class/powercap/...//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/...//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/...//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/...//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//.../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//.../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/...//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/...//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/...//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.