RIKEN Center for Computational Science

HPCIofTomorrow 将来への取組み

Outline of the Development of the Post-K computer

The post-K computer will be developed based on the following guiding principles:

  • Top priority on problem-solving research
    During development, highest priority will be given to creating a system capable of contributing to the solution of various scientific and societal issues. For this, the hardware and software will be developed in a coordinated way (Co-design), with the aim to make it usable in a variety of fields.
  • World-leading performance
    Create the most advanced general-use system in the world.
  • Improve performance through international cooperation
    While leveraging Japan’s strengths, cooperate internationally to achieve world-leading technologies of the highest quality and become the international standard.
  • Continue the legacy of the K computer
    Make the fullest use of the technologies, human resources, and applications of the K computer project for developing the post-K system.


Architecture Armv8.2-A SVE 512bit
With the following Fujitsu's extensions: Hardware barrier, Sector cache, and Prefetch
Core 48 cores for compute and 2 or 4 cores for OS activities
4 CMGs (NUMA nodes)
DP: 2.7+ TF, SP: 5.4+ TF, HP: 10.8 TF
Cache L1D/core: 64 KiB, 4way, 230+ GB/s (load), 115+ GB/s (store)
L2/CMG: 8 MiB, 16way
L2/node: 3.6+ TB/s
L2/core: 115+ GB/s (load), 57+ GB/s (store)
Memory HBM2 32 GiB, 1024 GB/s
Interconnect Tofu Interconnect D (28 Gbps x 2 lane x 10 port)
I/O PCIe Gen3 x16
Technology 7nm FinFET

SVE: Scalable Vector Extension

SVE: Scalable Vector Extension

・CMG (Core Memory Group), NUMA node
・NOC (Network on Chip)

Storage System

1st Layer
  • Cache for global file system
  • Temporary file systems
    • Local file system for compute node
    • Shared file system for a job
2nd Layer
  • Lustre-based global file system
3rd Layer
  • Storage for archive

Programming Language and Library

Compiler Fortran2008 & Fortran2018 subset
C11 & GNU and Clang extensions
C++14 & C++17 subset and GNU and Clang extensions
OpenMP 4.5 & OpenMP 5.0 subset
Parallel Programming XcalableMP
Script Python + Numpy + Scipy
SSL II (Fujitsu)
EigenEXA, Batched BLAS

System Software

MPIFujitsu MPI (Based on OpenMPI), MPICH
Application-oriented file IO libraries