Ineffective prefetch determination and latency optimization

Abstract

A processor of an information handling system (IHS) initiates an L3 cache prefetch operation in response to a demand load during instruction processing. The processor selects an L3 cache prefetch at random for tracking as a target prefetched instruction. The processor initiates an L1 cache target prefetch operation and stores the resultant target prefetched instruction in the L1 cache. If a demand load arrives, the processor analyzes the target prefetched instruction for effectiveness and determines the source of the prefetch data. If a demand does not arrive, the processor tests to determine if the particular prefetched instruction timed out in the cache and identifies the ineffectiveness of the prefetch operation. The processor samples multiple prefetch operations at random and generates a history of prefetch effectiveness and other useful prefetch information. The processor stores the prefetch effectiveness information to enable reduction or removal of ineffective prefetch operations.