Enzian: an open, general, CPU/FPGA platform for systems software research

ABSTRACTHybrid computing platforms, comprising CPU cores and FPGA logic, are increasingly used for accelerating data-intensive workloads in cloud deployments, and are a growing topic of interest in systems research. However, from a research perspective, existing hardware platforms are limited: they are often optimized for concrete, narrow use-cases and, therefore lack the flexibility needed to explore other applications and configurations. We show that a research group can design and build a more general, open, and affordable hardware platform for hybrid systems research. The platform, Enzian, is capable of duplicating the functionality of existing CPU/FPGA systems with comparable performance but in an open, flexible system. It couples a large FPGA with a server-class CPU in an asymmetric cache-coherent NUMA system. Enzian also enables research not possible with existing hybrid platforms, through explicit access to coherence messages, extensive thermal and power instrumentation, and an open, programmable baseboard management processor. Enzian is already being used in multiple projects, is open source (both hardware and software), and available for remote use. We present the design principles of Enzian, the challenges in building it, and evaluate it with a range of existing research use-cases alongside other, more specialized platforms, as well as demonstrating research not possible on existing platforms.