The Energy Model (EM) framework aims to provide information about energy consumption of a given performance domain. The power values stored for each performance level are used during calculation in Energy Aware Scheduler (EAS) or in thermal framework for the CPUfreq cooling device. Recently the EM has been extended to support other devices than CPUs (like GPUs, DSP, etc). It opens new...
An ever-increasing number of embedded devices need fine grain control on their performance in order to limit the power consumption. There are three primary reasons for this: to increase the battery life, to protect the components and to control the temperature.
Due to the increasing complexity of SoCs, we’re now seeing lots of thermal sensors on the die to quickly detect hot spots and allow...
Intel Hardware provides guidance to the Operating System (OS) scheduler to perform optimal workload scheduling through a hardware feedback interface structure in memory. Via this interface Hardware can also provide recommendation to the OS to not schedule any software threads on a CPU, so essentially offline a CPU remotely. There are three methods to implement this, each has its own advantages...
In the current thermal core, occasional spikes can cause thermal
shutdowns or any associated processing. There are several reports in
bug databases. Instead of each thermal driver coming up with its own
mechanism, the thermal core can optionally use running average for
The thermal framework is only designed
to detect and handle hotspot, not coldspot. Some systems need to
increase their performance state or leak power to warm some devices
which are getting too cold (outdoor devices when night comes). The logic
is the mirror of managing hot spots.
There are use cases in which the processor shares power budget with some other data-processing devices, like a GPU. In those cases it may be possible to improve the performance of the system by limiting the maximum frequency of CPUs. We will discuss possible ways to utilize this observation in the Linux kernel.
Over time computers get more and more complicated and there are more and more dependencies between devices in them which affect power management.
We will discuss issues arising from that and possible ways to address them.
See https://firstname.lastname@example.org/T/#mbe0060ea9b225073d63ae3ff8b1acd96985f29d7 for a patch series submission related...
sleepgraph is an open source tool in the pm-graph project:
sleepgraph has helped us improve both Linux suspend/resume quality and performance over the last few years.
In this session we will review the capabilities of the tool, so that you will be able to run it and understand its results. We will also highlight some of the areas where...