DL_POLY_4 and Xeon Phi: Lessons Learnt

Molecular dynamics techniques grew rapidly in the last twenty years. The growth was fuelled by development of new scalable mathematical algorithms, availability of powerful hardware and better availability of ready to use software packages. DL_POLY is one of these packages, widely adopted by the computational physics and material science communities. DL_POLY started its life in 1992 at Daresbury Laboratory, now part of Science & Technology Facilities Council in United Kingdom, with a first public release in 1993. The main developers for the current version are W Smith and IT Todorov. DL_POLY is a general classical molecular dynamics code and was used to simulate macro molecules (both biological and synthetic), complex fluids, materials and ionic liquids. DL_POLY also plays an important role as sandbox for both development of new methods and algorithms for molecular dynamics and testing of emerging hardware technologies[1] and [2]. The core code is written in Fortran 95/2003 standards and optimised for distributed systems using domain decomposition, also OpenMP and CUDA ports exist as contributions to DL_POLY but not part of the official distribution. DL_POLY is free of use for academics pursuing non-commercial research and available for licensing for the rest. The Intel Xeon Phi co-processor is a novel accelerator technology that provides few attractive features as: many cores, 60 cores with 240 hardware threads for the mid model, low power consumption, the same set of instructions as an Intel CPU, supports popular and standardised programming models as MPI and OpenMP and a theoretical peak of 1 TFlops in double precision. In this communication we present the progress made in porting and optimising DL_POLY to Xeon Phi co-processor. The rest of the paper is organised as follows: a short introduction to the methodology used for port and optimisation, OpenMP implementation results in section III-A, synchronous offload ones in section III-B, MPI symmetric running mode in section III-C.