Multi-level power monitoring, filtering and throttling at local blocks and globally

Abstract

Power management for a multi-processor chip includes a centralized global power manager that monitors global power for the whole chip, and local power managers. Local power managers manage power for local blocks such as processor cores, caches, and memory controllers. When a local block executes an instruction or accesses memory, an event is generated and looked up in a local power estimate table. A local power estimate for that event is sent to the global power manager, which sums all local power estimates received from all local blocks. An exponential moving average (EMA) is generated and compared to a global power threshold. When global power is over the threshold, local targets are sent to power managers that generate and monitor local power averages that must remain under the local target. The local block is throttled by the local power manager to reduce power when the local target is exceeded.