Understanding the Requirements Imposed by Programming Model Middlware on a Common Communication Subsystem

In high-performance parallel computing, most programming model middleware libraries and runtime systems use a communication subsystem to abstract the lower level network layer. The functionality required of a communication subsystem depends largely on the particular programming model implemented by the middleware. In order to maximize performance, middleware libraries and runtime systems typically implement their own communication subsystems that are specially tuned for the middleware, rather than use an existing communication subsystem. This leads to duplicated effort and prevents different middleware libraries from being used by the same application in hybrid programming models. In this paper we describe features required by various middleware libraries as well as some desirable features that would make it easier to port a middleware library to the communication subsystem, and allow the middleware to make use of high-performance features provided by some networking layers. We evaluate whether existing communication subsystems support these features efficiently. We show that none of the existing communication subsystems that we evaluated support all of the features.