Method and apparatus for distributing interrupts in a symmetric multiprocessor system

摘要

A distributed interrupt controller system for use in a multiprocessor environment, has at least two local programmable interrupt controllers (LOPICs) coupled to at least one central programmable interrupt controller (COPIC) via a dedicated bus. The COPIC functions as a master arbiter, while the LOPICs, each of which may be integrated with its corresponding processing unit, and any other non-master COPICs are treated as bus agents. Bus grant is achieved by a "round robin" arbitration protocol. For distributed delivery of interrupts, the master arbiter compares a current-task-priority-register value associated with each bus agent to determine the agent that is least busy for delivery of the interrupt thereto. <IMAGE>