Recently a PRACE preparatory access application on the newly installed JUWELS Booster system at Jülich Supercomputing Centre (JSC) was accepted. The ICON team performed two strong scaling tests using two different horizontal resolutions: R2B7 (20km) and R2B9 (5km) to measure the performance of the code.
The tuning effort for optimization was spent for the high-resolution case R2B9 only and we reached a 75% efficiency using 512 GPUs compared to 256 GPUs.
Through this exercise, we identified a few tuning parameters related to the code performance which will be very useful in the future work. Based on the present performance, we could simulate around 0.32 year per day using 600 GPUs at the resolution R2B9. In addition, simulations running at even higher resolutions (e.g. about 1km) seem possible.
For more information on ICON visit https://code.mpimet.mpg.de/projects/iconpublic.