Due to the increasing complexity of SoC, we're now seeing lots of thermal sensors on the die to quickly detect hot spots and allow the OS to take steps to mitigate these events - either through better scheduling, frequency throttling, idle injection or other similar techniques.

The Linux thermal framework has a 1:1 mapping between a thermal sensor, thermal zone and governor that make it very hard to have a layered policy to reflect different policy decisions at a SoC-, Cluster-, CPU- and GPU-levels.

We're currently experimenting with a hierarchical arrangement of these sensors and their associated governors to better account for heat contribution of each thermal zone to the overall thermal budget of the device and thereby allow different policies at various levels of the SoC hierarchy.

Attendees are expected to know a little bit about how the current thermal framework works, but don't need to know all the technical details. We will cover the conceptual differences between the current and proposed models as an introduction in the talk.