Exploiting Hardware-Accelerated Ray Tracing for Monte Carlo Particle Transport with OpenMC

Justin Salmon, Simon N Mcintosh-Smith

Research output: Chapter in Book/Report/Conference proceedingConference Contribution (Conference Proceeding)

3 Citations (Scopus)


OpenMC is a CPU-based Monte Carlo particle transport simulation code recently developed in the Computa- tional Reactor Physics Group at MIT, and which is currently being evaluated by the UK Atomic Energy Authority for use on the ITER fusion reactor project. In this paper we present a novel port of OpenMC to run on the new ray tracing (RT) cores in NVIDIA’s latest Turing GPUs. We show here that the OpenMC GPU port yields up to 9.8x speedup on a single node over a 16-core CPU using the native constructive solid geometry, and up to 13x speedup using approximate triangle mesh geometry. Furthermore, since the expensive 3D geometric operations re- quired during particle transport simulation can be formulated as a ray tracing problem, there is an opportunity to gain even higher performance on triangle meshes by exploiting the RT cores in Turing GPUs to enable hardware-accelerated ray tracing. Extending the GPU port to support RT core acceleration yields between 2x and 20x additional speedup. We note that geometric model complexity has a significant impact on performance, with RT core acceleration yielding comparatively greater speedups as complexity increases. To the best of our knowledge, this is the first work showing that exploitation of RT cores for scientific workloads is possible. We finish by drawing conclusions about RT cores in terms of wider applicability, limitations and performance portability.
Original languageEnglish
Title of host publicationInternational Conference on High Performance Computing, Networks, Storage and Analysis Workshops
Subtitle of host publication2019 IEEE/ACM Performance Modeling, Benchmarking and Simulation of High Performance Computer Systems (PMBS)
PublisherInstitute of Electrical and Electronics Engineers (IEEE)
ISBN (Electronic)978-1-7281-5977-5
Publication statusPublished - Nov 2019


  • HPC, Monte Carlo particle transport, ray tracing, GPUs


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