The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 12, 2013
Filed:
Dec. 19, 2007
Richard Nicholas, Round Rock, TX (US);
Jason Alan Cox, Raleigh, NC (US);
Robert John Dorsey, Durham, NC (US);
Hien Minh Le, Cedar Park, TX (US);
Eric Francis Robinson, Raleigh, NC (US);
Thuong Quang Truong, Austin, TX (US);
Richard Nicholas, Round Rock, TX (US);
Jason Alan Cox, Raleigh, NC (US);
Robert John Dorsey, Durham, NC (US);
Hien Minh Le, Cedar Park, TX (US);
Eric Francis Robinson, Raleigh, NC (US);
Thuong Quang Truong, Austin, TX (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
A method for maintaining cache coherency operates in a data processing system with a system memory and a plurality of processing units (PUs), each PU having a cache, and each PU coupled to at least another one of the plurality of PUs. A first PU receives a first data block for storage in a first cache of the first PU. The first PU stores the first data block in the first cache. The first PU assigns a first coherency state and a first tag to the first data block, wherein the first coherency state is one of a plurality of coherency states that indicate whether the first PU has accessed the first data block. The plurality of coherency states further indicate whether, in the event the first PU has not accessed the first data block, the first PU received the first data block from a neighboring PU.