Portable Explicit Threading and Concurrent Programming for MPI Applications

New applications for parallel computing in today's data centers, such as online analytical processing, data mining or information retrieval, require support for concurrency. Due to online query processing and multi-user operation, we need to concurrently maintain and analyze the data. While the Portable Operating System Interface (POSIX) defines a thread interface that is widely available, and while modern implementations of the Message Passing Interface (MPI) support threading, this combination is lacking in safety, security and reliability. The development of such parallel applications is therefore complex, difficult and error-prone. In response to this, we propose an additional layer of middle-ware for threaded MPI applications designed to simplify the development of concurrent parallel programs. We formulate a list of requirements and sketch a design rationale for such a library. Based on a prototype implementation, we evaluate the run-time overhead to estimate the overhead caused by the additional layer of indirection.