Reservation mechanism for nodes with phase constraints

Abstract

A computer chip, a method, and computer program product for providing phase reservations between processing nodes. A computer chip includes a plurality of processing nodes interconnected in an on-chip data transfer network configured in a circular topology. The processing nodes include reservation mechanisms managing reservations made by processing nodes with phase constraints. The reservation policy allows the processing nodes to make a reservation, for a given phase, in any phase window, only once per reservation window. A reservation window can be a bounded amount of time for when a node is guaranteed an opportunity to transmit at least one message. The reservation policy also prevents the processing nodes from making more than one reservation in a phase window. Once a reservation is granted, the corresponding message may progress on the bus unimpeded. Requestors attempting to transmit messages are blocked until the message is transmitted.