Poster (After Call) FZJ-2025-05000

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Porting the hydrologic model ParFlow to accelerator architectures using eDSL and Kokkos

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2025

deRSE Conference 2025, deRSE25, KarlsruheKarlsruhe, Germany, 25 Feb 2025 - 27 Feb 20252025-02-252025-02-27

Abstract: The ParFlow hydrologic model is an integrated variably saturated groundwater, surfacewater flow simulator that incorporates subsurface energy transport and land surfaceprocesses through the integration of the Common Land Model (CLM) as a module. In addition ParFlow has been coupled to atmospheric models, such as WRF, COSMO and ICON. ParFlow is also integrated in the German climate and weather prediction ICON(-Land) software ecosystem as part of the WarmWorld project and it is an important component of the Terrestrial Systems Modeling Platform (TSMP), which enables integrated simulations from the bedrock, across the land surface to the top of the atmosphere with the coupled ICON/COSMO-CLM-ParFlow modeling system.ParFlow is written in C (with additional Fortran 90 parts (especially if CLM is enabled)) and uses the parallelization methods MPI, OpenMP, native CUDA support and the programming model Kokkos (with the backend CUDA, HIP or OpenMP). As a matter of fact, the parallelism in ParFlow has been abstracted early on in what is called an embedded Domain Specific Language (eDSL) which is leading to a best-practice separation-of-concerns, which means the domain scientist/developer does not see e.g. a single MPI call when programming in ParFlow.Since future hardware will be characterized by varying architectures there was a demand to also enable HIP for AMD architectures. For example, the pre-exascale HPC system LUMI of EuroHPC is based on an accelerator consisting of AMD GPUs. To implement HIP for ParFlow via the eDSL the porting was done using Kokkos because Cuda was already incorporated in Parflow via Kokkos and the Kokkos ecosystem also includes an implementation of the HIP programming model for AMD GPUs and which resulted for ParFlow in a high degree of performance portability. Performance and scalability have been demonstrated on JUWELS Booster (Jülich Supercomputing Centre) for Nvidia GPUs (Nvidia A100) and also on the LUMI supercomputer at CSC (Finland) with AMD MI250X accelerators.In this poster we will present the eDSL of ParFlow and also how Kokkos (with the Cuda and HIP backend) is included in its eDSL and to allow ParFlow to reach performance portability on the basis of the eDSL and Kokkos, especially for Nvidia (Cuda) and on AMD platforms (HIP) with the change of only a limited amount of lines. We will also present scaling plots for different machines and accelerators and how to enable HIP as a Kokkos backend of ParFlow using the eDSL of ParFlow.


Contributing Institute(s):
  1. Jülich Supercomputing Center (JSC)
  2. Agrosphäre (IBG-3)
Research Program(s):
  1. 2A5 - Exascale Earth System Modeling (CARF - CCA) (POF4-2A5) (POF4-2A5)
  2. 5112 - Cross-Domain Algorithms, Tools, Methods Labs (ATMLs) and Research Groups (POF4-511) (POF4-511)
  3. 5122 - Future Computing & Big Data Systems (POF4-512) (POF4-512)
  4. EoCoE-III - Energy oriented Center of Excellence (101143931_16HPC102K) (101143931_16HPC102K)

Appears in the scientific report 2025
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Document types > Presentations > Poster
Institute Collections > IBG > IBG-3
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Institute Collections > JSC
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 Record created 2025-12-05, last modified 2025-12-23


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