Hi,
I have revised the previous power scheduler proposal[1] trying to address as many of the comments as possible. The overall idea was discussed at LPC[2,3]. The revised design has removed the power scheduler and replaced it with a high level power driver interface. An interface that allows the scheduler to query the power driver for information and provide hints to guide power management decisions in the power driver.
The power driver is going to be a unified platform power driver that can replace cpufreq and cpuidle drivers. Generic power policies will be optional helper functions called from the power driver. Platforms may choose to implement their own policies as part of their power driver.
This RFC series prototypes a part of the power driver interface (cpu capacity hints) and shows how they can be used from the scheduler. More extensive use of the power driver hints and queries is left for later. The focus for now is the power driver interface. The patch series includes a power driver/cpufreq governor that can use existing cpufreq drivers as backend. It has been tested (not thoroughly) on ARM TC2. The cpufreq governor power driver implementation is rather horrible, but it illustrates how the power driver interface can be used. Native power drivers is on the todo list.
The power driver interface is still missing quite a few calls to handle: Idle, adding extra information to the sched_domain hierarchy to guide scheduling decisions (packing), and possibly scaling of tracked load to compensate for frequency changes and asymmetric systems (big.LITTLE).
This set is based on 3.11. I have done ARM TC2 testing based on linux-linaro 2013.08[4] to get cpufreq support for TC2.
Morten
[1] https://lkml.org/lkml/2013/7/9/314
[2] http://etherpad.osuosl.org/lpc2013-power-efficient-scheduling
[3] http://www.linuxplumbersconf.org/2013/ocw//system/presentations/1263/origina...
[4] http://git.linaro.org/gitweb?p=kernel/linux-linaro-tracking.git
Morten Rasmussen (7): Initial power driver interface infrastructure sched: power: Power driver late callback interface sched: power: go_faster/slower power driver hints sched: power: Remove power capacity hints for kworker threads sched: power: Increase cpu capacity based on rq tracked load sched: power: cpufreq: Initial schedpower cpufreq governor/power driver sched: power: Let the power driver choose the best wake-up cpu
arch/arm/Kconfig | 4 + drivers/cpufreq/Kconfig | 11 ++ drivers/cpufreq/Makefile | 1 + drivers/cpufreq/cpufreq_schedpower.c | 218 ++++++++++++++++++++++++++++++++++ include/linux/sched/power.h | 37 ++++++ kernel/sched/Makefile | 1 + kernel/sched/core.c | 1 + kernel/sched/fair.c | 53 ++++++++- kernel/sched/power.c | 73 ++++++++++++ kernel/sched/sched.h | 32 +++++ 10 files changed, 430 insertions(+), 1 deletion(-) create mode 100644 drivers/cpufreq/cpufreq_schedpower.c create mode 100644 include/linux/sched/power.h create mode 100644 kernel/sched/power.c