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:
Oct. 23, 2012
Filed:
Dec. 19, 2007
Hien Minh Le, Cedar Park, TX (US);
Jason Alan Cox, Raleigh, NC (US);
Robert John Dorsey, Durham, NC (US);
Richard Nicholas, Round Rock, TX (US);
Eric Francis Robinson, Raleigh, NC (US);
Thuong Quang Truong, Austin, TX (US);
Hien Minh Le, Cedar Park, TX (US);
Jason Alan Cox, Raleigh, NC (US);
Robert John Dorsey, Durham, NC (US);
Richard Nicholas, Round Rock, 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 managing data operates in a data processing system with a system memory and a plurality of processing units (PUs), each PU having a cache comprising a plurality of cache lines, each cache line having one of a plurality of coherency states, and each PU coupled to at least another one of the plurality of PUs. A first PU selects a castout cache line of a plurality of cache lines in a first cache of the first PU to be castout of the first cache. The first PU sends a request to a second PU, wherein the second PU is a neighboring PU of the first PU, and the request comprises a first address and first coherency state of the selected castout cache line. The second PU determines whether the first address matches an address of any cache line in the second PU. The second PU sends a response to the first PU based on a coherency state of each of a plurality of cache lines in the second cache and whether there is an address hit. The first PU determines whether to transmit the castout cache line to the second PU based on the response. And, in the event the first PU determines to transmit the castout cache line to the second PU, the first PU transmits the castout cache line to the second PU.