Massively parallel computing

Project overview

IBM Research - Zurich has developed over the years a deep and broad competence in the field of parallel and distributed computing. Our internal work on scientific and technical computing is used as a test bed and driver for innovative parallel alghorithms and implementations on diverse computer hardware ranging from general-use high-end supercomputers (p-Series clusters) and Linux clusters (x-Series) to novel, massively parallel computer architectures such as BlueGene (L, P and Q) and heterogeneous architectures.

Our key competencies are:

  • distributed memory parallelization using MPI,
  • shared memory parallelization using OpenMP and direct threading,
  • mixed MPI/SMP schemes
  • parallel programming
CPMD code parallelization and tuning

The CPMD code has been implemented and tuned for the entire generation of IBM supercomputers. This made the code a reference in the world of high-perfomance simulations.

We have recently demonstrated that the extreme threading capability of the Blue Gene/Q Supercomputer in combination with an efficient parallelization of CPMD can render density functional theory, including hybrid exchange functionals, routine in molecular modeling activities.

We demonstrated  scalability up to 1,048,576 threads with a parallel efficiency of 99% for the most intensive computational part, i.e. for the Hartree–Fock exact exchange and of 83% for the overall computational flow for runs on exactly the same models used for the scientific investigation, with a sustained performance of ~0.5 Pflops  (see CPMD performance and scale out).