Description
The focus will be on power management frameworks, task scheduling in relation to power/energy optimization, and platform power management mechanisms. The goal is to facilitate cross framework and cross platform discussions that can help improve power and energy-awareness in Linux.
An updated proposal for Energy Aware Scheduling has been posted and discussed on LKML during this year [1]. The patch set introduces an independent Energy Model framework holding active power cost of CPUs, and changes the scheduler's wake-up balancing code to use this newly available information when deciding on which CPU a task should run.
This session aims at discussing the open problems...
The Linux scheduler is able to drive frequency selection, when the schedutil cpufreq's governor is in use, based on task utilization aggregated at CPU level. The CPU utilization is then used to select the frequency which better fits the task's generated workload. The current translation of utilization values into a frequency selection is pretty simple: we just go to max for RT tasks or to the...
The venerable menu governor does some thigns that are quite questionable in my view. First, it includes timer wakeups in the pattern detection data and mixes them up with wakeups from other sources which in some cases causes it to expect what essentially would be a timer wakeup in a time frame in which no timer wakeups are possible (becuase it knows the time until the next timer event and...
The Generic PM domains framework (genpd) keeps evolving to deal with new problems. Lately, we have for example seen genpd to incorporate support for active states power management and also support for multiple PM domains per device. Let's walk through these new changes that have been made and discuss their impact.
Due to high performance demands systems tend to be over-provisioned, where it is not possible to run at peak power of each component. Even if each component has capability to report power and set power limits, there is no kernel level framework to achieve that. IPA addresses part of it, but on the systems in question thermal limits usually are not a problem, but sudden power overdraw is a...
Runtime PM allows drivers to automatically suspend devices that have not been used for a defined amount of time. This autosuspend feature is really efficient for handling bursts of activity on a device by optimizing the number of runtime PM suspend/resume calls. However, the runtime PM timers used for that are fully based on jiffies granularity which raises problems for some embedded ARM...
