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:
Aug. 15, 1995
Filed:
Dec. 06, 1994
Robert F Bartfai, West Shokan, NY (US);
Barry P Lubart, Hurley, NY (US);
Julian Thomas, Lagrange, NY (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
A system and method for preventing deadlock in a multiprocessor computer system executing instructions requiring multiple resources. The system detects potential deadlock situations where a multi-resource instruction is blocked from obtaining one of the resources. A multi-resource instruction global lock is provided that can be held by at most one processor. Upon conflict detection, the processor attempts to acquire the multi-resource instruction global lock and, if successful, resumes resource acquisition. The use of a global lock serializes multiple resource requests and assures that the processor holding the lock can eventually acquire all required resources without deadlock with another processor. The preferred embodiment acquires the global lock on an exception basis to minimize the overhead impact. However, an alternate embodiment which uses the global lock in each multiple resource instruction could also be implemented. Synonym detection logic is provided to detect the situation where a conflict is caused by address resolution to a synonymous lock by the processor.