FY16 ASC ATDM L2 Milestone: PARTISN Research and FleCSI Updates

Womeldorff, Geoffrey Alan¹  Payne, Joshua Estes¹  Bergen, Benjamin Karl¹ 

[1] Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

关键词: PARTISN;    Kokkos;    Interoperability;    FleCSI;   

DOI  :  10.2172/1325686
RP-ID  :  LA-UR--16-27057
PID  :  OSTI ID: 1325686

学科分类：数学（综合）

美国|英语

来源: SciTech Connect

【 摘 要 】

These are slides for a presentation on PARTISN Research and FleCSI Updates. The following topics are covered: SNAP vs PARTISN, Background Research, Production Code (structural design and changes, kernel design and implementation, lessons learned), NuT IMC Proxy, FleCSI Update (design and lessons learned). It can all be summarized in the following manner: Kokkos was shown to be effective in FY15 in implementing a C++ version of SNAP's kernel. This same methodology was applied to a production IC code, PARTISN. This was a much more complex endeavour than in FY15 for many reasons; a C++ kernel embedded in Fortran, overloading Fortran memory allocations, general language interoperability, and a fully fleshed out production code versus a simplified proxy code. Lessons learned are Legion. In no particular order: Interoperability between Fortran and C++ was really not that hard, and a useful engineering effort. Tracking down all necessary memory allocations for a kernel in a production code is pretty hard. Modifying a production code to work for more than a handful of use cases is also pretty hard. Figuring out the toolchain that will allow a successful implementation of design decisions is quite hard, if making use of "bleeding edge" design choices. In terms of performance, production code concurrency architecture can be a virtual showstopper; being too complex to easily rewrite and test in a short period of time, or depending on tool features which do not exist yet. Ultimately, while the tools used in this work were not successful in speeding up the production code, they helped to identify how work would be done, and provide requirements to tools.