Exclusive control method with each node controlling issue of an exclusive use request to a shared resource, a computer system therefor and a computer system with a circuit for detecting writing of an event flag into a shared main storage

Abstract

A computer system including a plurality of processing nodes, at least one resource provided for use by any of the processing nodes and a plurality of register sets. Each register set is provided in each processing node for storing in parallel use status information indicating whether the resource is in exclusive use status. The computer system includes a plurality of request issue circuits, each being provided in each processing node, for issuing requests for exclusive use of the resource, a message exchanging circuit for serializing requests issued by the request issue circuits into a serialized order and broadcasting the request to the processing nodes and a plurality of status control circuits. Each status control circuit is provided in each processing node to update a corresponding register set depending on use status information and each request received at a corresponding node.