Saving power in the command processor using queue based watermarks

Abstract

Systems, apparatuses, and methods for dynamically adjusting the power consumption of prefetch engines are disclosed. In one embodiment, a processor includes one or more prefetch engines, a draw completion engine, and a queue in between the one or more prefetch engines and the draw completion engine. If the number of packets stored in the queue is greater than a high watermark, then the processor reduces the power state of the prefetch engine(s). By decreasing the power state of the prefetch engine(s), power consumption is reduced. Additionally, this power consumption reduction is achieved without affecting performance, since the queue has a high occupancy and the draw completion engine can continue to read packets out of the queue. If the number of packets stored in the queue is less than a low watermark, then the processor increases the power state of the prefetch engine(s).