A Modular Heterogeneous Stack for Deploying FPGAs and CPUs in the Data Center.

In this work we present a heterogeneous deployment stack, calledGalapagos, that includes the abstraction of individual nodes (FPGAsand CPUs), the communication protocols between nodes and theorchestration and connection of these nodes into clusters. The stackwe create is also highly modular, allowing users to explore a designspace in the implementation of their cluster such as different net-work protocols or communication layers. The communication layerwe have currently implemented within our hardware stack, calledHUMboldt, handles heterogeneous communication between multi-ple FPGAs and CPUs. We implementHUMboldtusing High-LevelSynthesis (HLS) to ensure functional portability of communicatingkernels, allowing us to prototype hardware kernels in software. Ourresults have shown that our modular approach to this heterogeneousdeployment stack has introduced very little area and latency over-head in the FPGAs and can still perform at line-rate, bottleneckedsolely by the network links connecting the nodes. Our results alsohighlight the scalability of our design as our performance remainslimited by the network links when the cluster size increases.