Exascale supercomputers. Architectural outlines

Architectural aspects of exascale supercomputers are explored. Parameters of the computing environment and interconnect are evaluated. It is shown that reaching exascale performances requires hybrid systems. Processor elements of such systems comprise CPU cores and arithmetic accelerators, implementing the MIMD and SIMD computing disciplines, respectively. Efficient exascale hybrid systems require fundamentally new applications and architectural efficiency scaling solutions, including: process-aware structural reconfiguring of hybrid processor elements by varying the number of MIMD cores and SIMD cores communicating with them to attain as high performance and efficiency as possible under given conditions; application of conflict-free sets of sources and receivers and/or decomposition of the computation to subprocesses and their allocation to environment elements in accordance with their features and communication topology to minimize communication time; application of topological redundancy methods to preserve the topology and overall performance achieved by the above communication time minimization solutions in case of element failure thus maintaining the efficiency reached by the above reconfiguring and communication minimization solutions, i.e. to provide fault-tolerant efficiency scaling. Application of these solutions is illustrated by running molecular dynamics tests and the NPB LU benchmark. The resulting architecture displays dynamic adaptability to program features, which in turn ensures the efficiency of using exascale supercomputers.