Efficient runtime support for parallelizing block structured applications

Scientific and engineering applications often involve structured meshes. These meshes may be nested (for multigrid codes) and/or irregularly coupled (called multiblock or irregularly coupled regular mesh problems). In this paper, we describe a runtime library for parallelizing these applications on distributed memory parallel machines in an efficient and machine-independent fashion. This runtime library is currently implemented on several different systems. This library can be used by application programmers to port applications by hand and can also be used by a compiler to handle communication for these applications. Our experimental results show that our primitives have low runtime communication overheads. We have used this library to port a multiblock template and a multigrid code. Effort is also underway to port a complete multiblock computational fluid dynamics code using our library.