Session

DescriptionAs supercomputers become more and more powerful, the number and diversity of applications that can be tackled with these machines grows. Unfortunately, the architectural complexity of these supercomputers grows as well, with heterogeneous processors, multiple levels of memory hierarchy, and many ways to move data and synchronize between processors. The MPI+X programming model, use of which is considered by many to be standard practice, demands that a programmer be expert in both the application domain and the low-level details of the architecture(s) on which that application will be deployed, and the availability of such superhuman programmers is a critical bottleneck. Things become more complicated when evolution and change in the underlying architecture translates into significant re-engineering of the MPI+X code to maintain performance.

Numerous alternatives to the MPI+X model exist, and by raising the level of abstraction on the application domain and/or the target architecture, they offer the ability for “mere mortal” programmers to take advantage of the supercomputing resources that are available to advance science and tackle urgent real-world problems. However, compared to the MPI+X approach, these alternatives generally lack two things. First, they aren’t as well known as MPI+X and a domain scientist may simply not be aware of models that are a good fit to their domain. Second, they are less mature than MPI+X and likely have more functionality or performance “potholes” that need only be identified to be addressed.

PAW-ATM is a forum for discussing HPC applications written in alternatives to MPI+X. Its goal is to bring together application experts and proponents of high-level languages to present concrete example uses of such alternatives, describing their benefits and challenges.