Nov 13 – 15, 2023
America/New_York timezone

Sensors aggregation

Nov 14, 2023, 2:30 PM
"James River Salon B" (Omni Richmond Hotel)

"James River Salon B"

Omni Richmond Hotel

Power Management and Thermal Control MC Power Management and Thermal Control MC


Alexandre Bailon Daniel Lezcano (Linaro)


On one side a thermal sensor is associated with one thermal zone. On the other side a governor manages one thermal zone. The governor acts on a cooling device.

Some configurations have multiple sensors for the same performance domain. For instance, one sensor per core and a DVFS per group of cores.

When the energy model is used along with the power allocator, having a shared cooling device for all the thermal zones makes very difficult to have a the PID loop to work correctly as all governors can do opposite actions.

The proposal is to aggregate the sensors belonging to the same performance domain into a single thermal zone. Consequently one governor can operate on the temperature returned by the an aggregator function (eg. max or avg).

As a side note, the device tree bindings already describes such a an aggregation but it seems it was never implemented.

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