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:
Jan. 06, 1998
Filed:
May. 12, 1997
Zahir Ebrahim, Mountain View, CA (US);
Satyanarayana Nishtala, Cupertino, CA (US);
William Van Loo, Palo Alto, CA (US);
Kevin Normoyle, Mountain View, CA (US);
Leslie Kohn, Mountain View, CA (US);
Louis F Coffin, III, San Jose, CA (US);
Sun Microsystems, Inc., Mountain View, CA (US);
Abstract
A multi-processor computer system is disclosed that reduces the occurrences of invalidate and copyback operations through a memory interconnect by disabling a first write optimization of a cache coherency protocol for data that is not likely to be written by a requesting processor. Such data include read-only code segments. The code segments, including instructions and data, are shared among the multiple processors. The requesting processor generates a Read to Share Always request upon a cache miss of a read-only datablock, and generates a Read to Share request otherwise. The Read to Share Always request results in the datablock stored in cache memory being labeled as in a 'shared' state, while the Read to Share request results in the datablock being labeled as in an 'exclusive' state.