2DECOMP Logo Library for 2D pencil decomposition and distributed Fast Fourier Transform

Benchmarks on JUGENE

This set of benchmarked was performed in May 2010 on JUGENE, the big IBM Blue Gene/P system at J├╝lich Supercomputing Centre in Germany. The system ranked world No. 4 by that time, with a Linpack capability of 825.5 TFLOPs.

The work was made possible with the assistance of high performance computing resources (Tier-0) provided by PRACE. 2DECOMP&FFT was ported onto the Blue Gene/P. One major improvement achieved was the implementation of the FFT interface using ESSL, a high-performance math library native to IBM systems. The FFT interface was then benchmarked on problem sizes up to 8192^3 using up to 131072 cores.

Scaling of the FFT interface on Blue Gene/P JUGENE.

As seen, the code scales extremely well on the system for all problem sizes. The apparent super-linear scaling for the 1024^3 case is understood to be related to the Torus network configurations that favour larger jobs.