Fencing data transfers in a parallel active messaging interface of a parallel computer

A computer program product for fencing data transfers in a parallel active messaging interface (‘PAMI’) of a parallel computer, the computer program product disposed on a computer readable storage medium, the computer readable storage medium is not a signal, the computer program product comprising computer program instructions capable, when executed, of causing the parallel computer to function by:

• receiving, at an origin endpoint in the PAMI, a plurality of non-blocking SEND instructions from an application, wherein each of the plurality of SEND instruction specifies a data transfer from the origin endpoint to a target endpoint in the PAMI;
• receiving, at an origin endpoint, a FENCE instruction corresponding to transfers between the origin endpoint and the target endpoint,
• wherein the FENCE instruction advises the application when the transfers between the origin endpoint and the target endpoint are complete,
• wherein the origin endpoint is on an origin compute node and the target endpoint on a target compute node, and
• wherein the transfers between the origin endpoint and the target endpoint occur across a deterministic data communications network;
• posting the plurality of SEND instruction in an ordered sequence in a work queue of the origin endpoint;
• posting the FENCE instruction in the work queue of the origin endpoint at a location in the ordered sequence such that the FENCE instruction is processed after each of the plurality of SEND instructions is processed;
• and
• executing, by the origin endpoint, an advance function comprising initiating execution through the PAMI of instructions in the work queue, such that the FENCE instruction executing only after completion of all SEND instructions initiated prior to the FENCE instruction in the work queue, wherein execution of the FENCE instruction indicates to the application that execution of the SEND instructions is complete.