AMD Patch Adds A Third CPU Core Class

AMD has submitted Linux kernel patches that add support for low-power CPU cores in future heterogeneous processors.

The patch separates performance, efficiency and low-power cores, giving Linux a way to classify three AMD core types instead of two.

The disclosure points to a processor design in which AMD can move light workloads away from higher-performance cores.

AMD engineer Vishal Badole described the low-power cores as designed for background and idle tasks where lower energy use matters more than peak performance.

The patch does not introduce a new Linux scheduler policy.

It gives Linux the additional category needed to identify the core type before commercial systems using the design are named.

Linux Reads The Core Type Through CPUID

The patch uses CPUID Function 0x80000026, also called Extended CPU Topology, to identify core classes.

The relevant EBX field uses bits [31:28] for the classification.

AMD previously used the field to distinguish performance and efficiency cores.

The new patch adds a low-power class and connects that class to AMD performance-management support, so the operating system can treat the cores differently from the existing core types.

Laptop Efficiency Is The Near-Term Hardware Question

The move resembles Intel's use of low-power cores in the SoC tile of recent laptop platforms.

Those Intel cores offload light tasks from higher-power CPU cores and are meant to extend battery life.

AMD has not said which future processor will use the new low-power cores.

Future Zen 6 products are a possible candidate because the patch prepares support ahead of commercial hardware, but the patch itself is the disclosed evidence.

AMD also has not said whether the cores will appear first in laptops, desktops or embedded systems.

AMD Still Has To Name The First Product

The kernel work gives software maintainers an early signal before commercial hardware arrives.

It also shows that AMD is preparing Linux for a broader heterogeneous CPU layout, rather than only adding more performance or dense cores.

AMD disclosed the patch behavior and the intended background-task role, but it did not disclose the first processor name, launch date, device category, battery-life target, benchmark data or OEM systems for the low-power core design.