Journal cover Journal topic
Geoscientific Model Development An interactive open-access journal of the European Geosciences Union
doi:10.5194/gmd-2017-63
© Author(s) 2017. This work is distributed
under the Creative Commons Attribution 3.0 License.
Development and technical paper
05 Apr 2017
Review status
This discussion paper is under review for the journal Geoscientific Model Development (GMD).
GPU accelerated atmospheric chemical kinetics in the ECHAM/MESSy (EMAC) Earth system model (version 2.52)
Michail Alvanos and Theodoros Christoudias The Cyprus Institute, PO Box 27456, 1645 Nicosia, Cyprus
Abstract. This paper presents an application of GPU accelerators in Earth system modelling. We focus on atmospheric chemical kinetics, one of the most computationally intensive tasks in climate-chemistry model simulations. We developed a software package that automatically generates CUDA kernels to numerically integrate atmospheric chemical kinetics in the global climate model ECHAM/MESSy Atmospheric Chemistry (EMAC), used to study climate change and air quality scenarios. A source-to-source compiler outputs a CUDA compatible kernel, by parsing the FORTRAN code generated by the Kinetic Pre-Processor (KPP) general analysis tool. All Rosenbrock methods that are available in the KPP numerical library are supported.

Performance evaluation, using Fermi and Pascal CUDA-enabled GPU accelerators shows achieved speedups of 4.5× and 22.4× respectively of the kernel execution time. A node-to-node real-world production performance comparison shows a 1.75× speed-up over the non-accelerated application using the KPP 3-stage Rosenbrock solver. We provide a detailed description of the code optimizations used to improve the performance including memory optimizations, control code simplification, and reduction of idle time. The accuracy and correctness of the accelerated implementation are evaluated by comparing to the CPU-only version of the application. The relative difference is found to be less than 0.00005 % when comparing the output of the accelerated kernel the CPU-only code, within the target level of relative accuracy (relative error tolerance) of 0.1 %.

The approach followed, including the computational workload division and the developed GPU solver code can potentially be used as the basis for hardware acceleration of numerous geoscientific models that rely on KPP for atmospheric chemical kinetics applications.


Citation: Alvanos, M. and Christoudias, T.: GPU accelerated atmospheric chemical kinetics in the ECHAM/MESSy (EMAC) Earth system model (version 2.52), Geosci. Model Dev. Discuss., doi:10.5194/gmd-2017-63, in review, 2017.
Michail Alvanos and Theodoros Christoudias
Michail Alvanos and Theodoros Christoudias
Michail Alvanos and Theodoros Christoudias

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Short summary
We present an application of GPU accelerators in Earth system modelling. We developed software that generates CUDA kernels for numerical integration in the global climate model EMAC, used to study climate change and air quality. We focus on atmospheric chemical kinetics, the most computationally intensive task in climate-chemistry simulations. This approach can serve as the basis for hardware acceleration of numerous geoscientific models that rely on KPP for chemical kinetics applications.
We present an application of GPU accelerators in Earth system modelling. We developed software...
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