Intel Adding Interface To Pass Workload Hints To The Linux Kernel For Thermal/Power Purposes

Intel's INT340X thermal code that is used by the likes of the Intel Thermal Daemon "Thermald" for thermal/power management with their modern SoCs will now be able to accept workload hints for making more informed thermal decisions.

With Linux 5.11 the INT340X kernel code is set to see a mailbox driver introduced for handling of workload hints. The intent is to give an indication to the hardware/firmware about what's being run in order to better manage the system power and thermal conditions.

The hints initially supported by the INT340X mailbox code include:

idle
semi_active
bursty [or if you are experimenting with the current "-next" code at the moment, use "burusty"]
sustained
battery_life

Those different hints can be written to /sys/bus/pci/devices/0000:00:04.0/workload_request/workload_type by user-space. The value will affect the power ramp up of the hardware and other power/thermal behavior of the system.

The new driver code is staged in the thermal's "linux-next" branch ahead of Linux 5.11 expected to open next week.

It will be interesting to see what power/performance impact making use of these hints ultimately has on modern Intel laptops. It will also be interesting to see what Linux user-space software may end up offering these options to the user and/or coming up with their own means of seeding the hints automatically.