Priority-based prefetch requests scheduling and throttling

Abstract

A method, processor, and data processing system for implementing a framework for priority-based scheduling and throttling of prefetching operations. A prefetch engine (PE) assigns a priority to a first prefetch stream, indicating a relative priority for scheduling prefetch operations of the first prefetch stream. The PE monitors activity within the data processing system and dynamically updates the priority of the first prefetch stream based on the activity (or lack thereof). Low priority streams may be discarded. The PE also schedules prefetching in a priority-based scheduling sequence that corresponds to the priority currently assigned to the scheduled active streams. When there are no prefetches within a prefetch queue, the PE triggers the active streams to provide prefetches for issuing. The PE determines when to throttle prefetching, based on the current usage level of resources relevant to completing the prefetch.