P-CSI v1.0, an accelerated barotropic solver for the high-resolution ocean model component in the Community Earth System Model v2.0
In the Community Earth System Model (CESM), the ocean model is computationally expensive for high-resolution grids and is often the least scalable component for high-resolution production experiments. The major bottleneck is that the barotropic solver scales poorly at high core counts. We design...
| Main Authors: | , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2016-11-01
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| Series: | Geoscientific Model Development |
| Online Access: | https://www.geosci-model-dev.net/9/4209/2016/gmd-9-4209-2016.pdf |
| Summary: | In the Community Earth System Model (CESM), the ocean model is
computationally expensive for high-resolution grids and is often the least
scalable component for high-resolution production experiments. The major
bottleneck is that the barotropic solver scales poorly at high core counts.
We design a new barotropic solver to accelerate the high-resolution ocean
simulation. The novel solver adopts a Chebyshev-type iterative method to
reduce the global communication cost in conjunction with an effective block
preconditioner to further reduce the iterations. The algorithm and its
computational complexity are theoretically analyzed and compared with other
existing methods. We confirm the significant reduction of the global
communication time with a competitive convergence rate using a series of
idealized tests. Numerical experiments using the CESM 0.1° global
ocean model show that the proposed approach results in a factor of 1.7
speed-up over the original method with no loss of accuracy, achieving 10.5
simulated years per wall-clock day on 16 875 cores. |
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| ISSN: | 1991-959X 1991-9603 |