AMD Is Working on Its Own Hybrid x86 CPU: Patent Filing
It’s become clear that hybrid cores — big.Little in ARM’s parlance — are going to be a feature of mainstream x86 CPUs as well. Intel’s Lakefield combines one Ice Lake “big core” with four Tremont “little” cores. Its upcoming Alder Lake platform will scale the solution up, with (rumored) up to eight low-power cores (Gracemont) and eight high-performance cores (Golden Cove).
A few signs have indicated AMD has its own plans to get into this game, and a new patent filing backs up that idea. AMD has applied for a patent describing methods by which one type of CPU would move work over to another type of CPU:
According to the patent, CPUs would rely on core utilization metrics to determine when it was appropriate to move a workload from one type of CPU to the other. Proposed metrics include the amount of time the CPU has been working at maximum speed, the amount of time the CPU has been using maximum memory, average utilization over a period of time, and a more general category in which a workload is moved from one CPU to the other based on unspecified metrics related to the execution of the task.
When the CPU determines that a workload should move from CPU A to CPU B, the core currently performing the work (CPU A, in this case), is put into an idle or stalled state. The architecture state of CPU A is saved to memory and loaded by CPU B, which continues the process. AMD’s patent describes these shifts as bi-directional — the small core can shift work to the large, or vice-versa.
