Method and system for inter-thread communication using processor messaging

Abstract

In shared-memory computer systems, threads may communicate with one another using shared memory. A receiving thread may poll a message target location repeatedly to detect the delivery of a message. Such polling may cause excessive cache coherency traffic and/or congestion on various system buses and/or other interconnects. A method for inter-processor communication may reduce such bus traffic by reducing the number of reads performed and/or the number of cache coherency messages necessary to pass messages. The method may include a thread reading the value of a message target location once, and determining that this value has been modified by detecting inter-processor messages, such as cache coherence messages, indicative of such modification. In systems that support transactional memory, a thread may use transactional memory primitives to detect the cache coherence messages. This may be done by starting a transaction, reading the target memory location, and spinning until the transaction is aborted.