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:
Jun. 26, 2009
Haakan E. Zeffer, Enskededalen, SE;
Robert E. Cypher, Saratoga, CA (US);
Haakan E. Zeffer, Enskededalen, SE;
Robert E. Cypher, Saratoga, CA (US);
Oracle America, Inc., Redwood Shores, CA (US);
Abstract
Some embodiments of the present invention provide a system that acquires a lock in a shared memory multiprocessor system. During operation, the system loads the lock into a cache associated with the thread and then reads a value of the lock. If the value indicates that the lock is currently held by another thread, the system periodically executes an instruction that tests a status of the lock. If the status indicates the lock is valid, the system continues to test the status of the lock. Otherwise, if the status indicates that the lock was invalidated by a store, the system attempts to acquire the lock by executing an atomic operation. On the other hand, if the status indicates that the lock was invalidated by an atomic operation, or that the lock is not present in the cache, the system repeats the loading and reading operations.