Importance

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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.

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First Claim