[RFC v01 0/3] Power Capping Framework

From: Srinivas Pandruvada
Date: Fri Aug 02 2013 - 14:08:43 EST

As suggested
- Didn't use any raw kobject calls, only using device_xx calls.
- No device_create_file/device_remove_file for attributes, so that
user space can see all attributes when notification is received for
device creation.

With the evolution of technologies, which enables power monitoring and limiting,
more and more devices are able to constrain their power consumption under certain
limits. There are several use cases for such technologies:
- Power monitoring: Each device can report its power consumption.
- Power Limiting: Setting power limits on the devices allows users to guard against
platform reaching max system power level.
- Maximize performance: While staying below a power limit, it allows devices to
automatically adjust performance to meet demands
- Dynamic control and re-budgeting: If each device can be constrained to some power,
extra power can redistributed to other devices, which needs additional performance.

One such example of technology is RAPL (Running Average Power Limit) mechanism
available in the latest Intel Processors. Intel is slowly adding many devices under
RAPL control. Also there are other technologies available, for power capping various
devices. Soon it is very likely that other vendors are also adding or considering
such implementation.

Power Capping framework is an effort to have a uniform interface available to Linux
drivers, which will enable
- A uniform sys-fs interface for all devices which can offer power capping
- A common API for drivers, which will avoid code duplication and easy
implementation of client drivers.

Once this framework is approved, we will submit a RAPL client driver using this


Use device model only to register zones and controllers.

Presented options

Srinivas Pandruvada (3):
PowerCap: Documentation
PowerCap: Add class driver
PowerCap: Added to drivers build

Documentation/powercap/PowerCappingFramework.txt | 677 ++++++++++++++++
drivers/Kconfig | 2 +
drivers/Makefile | 1 +
drivers/powercap/Kconfig | 16 +
drivers/powercap/Makefile | 5 +
drivers/powercap/powercap_sys.c | 985 +++++++++++++++++++++++
include/linux/powercap.h | 300 +++++++
7 files changed, 1986 insertions(+)
create mode 100644 Documentation/powercap/PowerCappingFramework.txt
create mode 100644 drivers/powercap/Kconfig
create mode 100644 drivers/powercap/Makefile
create mode 100644 drivers/powercap/powercap_sys.c
create mode 100644 include/linux/powercap.h


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