Arm systems are now genuine option for a production HPC system as performance study on Isambard supercomputer shows

Isambard hardware. (c) Simon McIntosh-Smith. 7 Feb 2019 Bristol - The GW4 Isambard project has just published a study analysing the performance of Europe's first Arm based production supercomputer. The study concludes that Arm-based processors are now capable of providing levels of performance competitive with state-of-the-art offerings from the incumbent vendors, while significantly improving performance per euro. The study appeared as "A performance analysis of the first generation of HPC-optimized Arm processors" published in "Concurrency and Computation: Practice and Experience".

The majority of the benchmarks compiled and ran successfully out of the box, and no architecture-specific code tuning was necessary to achieve high performance, the authors write. This represents an important milestone in the maturity of the Arm ecosystem for HPC, where these processors can now be considered as viable contenders for future procurements.

Energy efficiency is often mentioned as reason to go to Arm processors. Although the article does not address energy efficiency, early observations from the authors suggest that the energy efficiency of Arm ThunderX2 chip is in the same ballpark as the x86 CPUs. This is not a surprise - for a given manufacturing technology, a Flop will take a certain number of Joules, and moving a byte a certain distance across a chip will also take a certain amount of energy, they say.

The article descibes in-depth the results of many benchmarks, including mini-apps like STREAM and CloverLeaf, and applications like GROMACS, NEMO and OpenFOAM.

The performance report can be found at:

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