Software prefetch system and method for predetermining amount of streamed data

US6574712B1 · kind B1 · utility

Assignee

• International Business Machines Corporation · US

Inventors

• James Allan Kahle · Austin, US
• Michael John Mayfield · Austin, US
• Francis Patrick O'Connell · Austin, US
• David Scott Ray · Georgetown, US
• Edward John Silha · Austin, US
• Joel M. Tendler · Austin, US

Key dates

• Filing date: Apr 14, 2000
• Grant date: Jun 3, 2003
• Expiry date: Apr 14, 2020

Classification

• Technology area (CPC G): Physics
• CPC primary: G06F2212/6028
• WIPO field: Computer technology
• WIPO sector: Electrical engineering

Abstract

A data processing system includes a processor having a first level cache and a prefetch engine. Coupled to the processor are a second level cache and a third level cache and a system memory. Prefetching of cache lines is performed into each of the first, second, and third level caches by the prefetch engine. Prefetch requests from the prefetch engine to the second and third level caches is performed over a private prefetch request bus, which is separate from the bus system that transfers data from the various cache levels to the processor. A software instruction is used to accelerate the prefetch process by overriding the normal functionality of the hardware prefetch engine. The instruction also limits the amount of data to be prefetched.