The Tofu Interconnect 2 (Tofu2) is a system interconnect designed for the Fujitsu’s next generation successor to the PRIMEHPC FX10 supercomputer. Tofu2 inherited the 6-dimensional mesh/torus network topology from its predecessor, and it increases the link throughput by two and half times. It is integrated into a newly developed SPARC64
processor chip and takes advantages of system-on-chip implementation by removing off-chip I/O between a processor chip and an interconnect controller. Tofu2 also introduces new features such as the atomic read-modify-write communication functions, the session-mode control queue for the offloading of collective communications, and harmless cache injection technique to reduce communication latency.