Reaching Exascale compute performance at an affordable budget requires increasingly heterogeneous HPC systems, which combine general purpose processing units (CPUs) with acceleration devices such as graphics processing units (GPUs) or many-core processors. The Modular Supercomputing Architecture (MSA) developed within the EU-funded DEEP project series breaks with traditional HPC system architectures by orchestrating these heterogeneous computing resources at system-level, organizing them in compute modules with diﬀerent hardware and performance characteristics. Modules with disruptive technologies, such as quantum devices, can also be included in a modular supercomputer to satisfy the needs of speciﬁc user communities. The goal is to provide cost-effective computing at extreme performance scales fitting the needs of a wide range of Computational Sciences.
This approach brings substantial beneﬁts for heterogeneous applications and workﬂows. In a modular supercomputer, each application can dynamically decide which kinds and how many nodes to use, mapping its intrinsic requirements and concurrency patterns onto the hardware. Codes that perform multi-physics or multi-scale simulations can run across compute modules due to a global system-software and programming environment. Application workflows that execute different actions after (or in parallel) to each other can also be distributed in order to run each workflow-component on the best suited hardware, and exchange data either directly (via message-passing communication) or via the filesystem. A modular supercomputing system can supply any combination or ratio of resources across modules and is not bound to fixed associations between, for instance, CPUs and accelerators as will be found in clusters of heterogeneous nodes. It is therefore ideal for supercomputer centers running a heterogeneous mix of applications (higher throughput and energy eﬃciency).
This talk will describe the Modular Supercomputing Architecture – which constitutes the central element in Europe’s roadmap to Exascale computing –, including its history, its role in Europe’s Exascale computing strategy, its hardware and software elements, and experiences from mapping applications and workflows to MSA systems.