Specifying an access hint for prefetching partial cache block data in a cache hierarchy

US8140759B2 · kind B2 · utility

Assignee

• International Business Machines Corporation · US

Inventors

• Bradly G. Frey · Austin, US
• Guy L. Guthrie · Austin, US
• Cathy May · Ossining, US
• Ramakrishnan Rajamony · Austin, US
• Balaram Sinharoy · Poughkeepsie, US
• William J. Starke · Round Rock, US
• Peter K. Szwed · Kingston, US

Key dates

• Filing date: Apr 16, 2009
• Grant date: Mar 20, 2012
• Expiry date: Jul 1, 2030

Classification

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

Abstract

A system and method for specifying an access hint for prefetching only a subsection of cache block data, for more efficient system interconnect usage by the processor core. A processing unit receives a data cache block touch (DCBT) instruction containing an access hint and identifying a specific size portion of data to be prefetched. Both the access hint and a value corresponding to an amount of data to be prefetched are contained in separate subfields of the DCBT instruction. In response to detecting that the code point is set to a specific value, only the specific size of data identified in a sub-field of the DCBT and addressed in the DCBT instruction is prefetched into an entry in the lower level cache.