Re: [RFC v02 0/5] Power Capping Framework and RAPL Driver

From: Srinivas Pandruvada
Date: Fri Aug 09 2013 - 20:32:15 EST


On 08/07/2013 09:12 AM, Srinivas Pandruvada wrote:
Overview
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 sysfs 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.

Also submitting Intel RAPL driver using power capping framework.


Revisions:
Thanks for everyone for review. I have received enough negative comments, which will require another version.
So please hold off your reviews till next version.

v02:
Sign-offs and reviewed-by tags
Stylistic issues suggested by Joe Perches
Removed "counter" from power_uw documentation as pointed by Jonathan Corbet
Submitting Intel RAPL driver using power capping framework

v01:
Use device model only to register zones and controllers.

v00:
Presented options

Jacob Pan (2):
x86/msr: add 64bit _on_cpu access functions
Introduce Intel RAPL power capping driver

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

Documentation/ABI/testing/sysfs-class-powercap | 165 +++
Documentation/powercap/PowerCappingFramework.txt | 686 ++++++++++++
arch/x86/include/asm/msr.h | 22 +
arch/x86/lib/msr-smp.c | 62 +
drivers/Kconfig | 2 +
drivers/Makefile | 1 +
drivers/powercap/Kconfig | 24 +
drivers/powercap/Makefile | 6 +
drivers/powercap/intel_rapl.c | 1305 ++++++++++++++++++++++
drivers/powercap/powercap_sys.c | 995 +++++++++++++++++
include/linux/powercap.h | 300 +++++
11 files changed, 3568 insertions(+)
create mode 100644 Documentation/ABI/testing/sysfs-class-powercap
create mode 100644 Documentation/powercap/PowerCappingFramework.txt
create mode 100644 drivers/powercap/Kconfig
create mode 100644 drivers/powercap/Makefile
create mode 100644 drivers/powercap/intel_rapl.c
create mode 100644 drivers/powercap/powercap_sys.c
create mode 100644 include/linux/powercap.h


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