Linux Patch Pending To Help Lower Alder Lake N & Raptor Lake P Power Consumption
The default tuning patch working its way now to mainline is adjusting the default Energy Performance Bias (EPB) for Alder Lake N and Raptor Lake P models. At the start of the year the Linux kernel added the ability to allow model-specific "normal" EPB values as the default. This change came with Intel finding the default EPB value setup by the hardware is not always suitable, which was first noted with Alder Lake P processors. The Linux kernel ended up adjusting the default energy performance bias from a value of 6 to 7 in order to lower the uncore power consumption while not affecting the performance.
With Alder Lake N and Raptor Lake P updating the default energy performance bias to 7 was also found to help lower the uncore power consumption without hurting performance. In the case of tests carried out by Intel it saved 200~300 mW which is enough to justify the improvement for their low-power mobile platforms. The power-savings and performance under load is not impacted by this EPB change.
This EPB tuning for ADL-N and RPL-P is now picked up by TIP's x86/cpu branch as it awaits going into the mainline kernel.