FlexForge: Efficient Reconfigurable Cloud Acceleration via Peripheral Resource Disaggregation

Reconfigurable hardware acceleration in the cloud using Field-Programmable Gate Arrays (FPGAs) is an increasingly popular solution for scaling performance and cost-effectiveness. For efficient utilization of FPGA resources, cloud platforms typically support elastic FPGA resource allocation. However, FPGAs are usually allocated in a homogeneous unit consisting of logic, memory, and PCIe bandwidth. Because user kernels have a wide and varying combination of resource requirements, this can result in high internal fragmentation and underutilization of each resource. To address this issue, we present FlexForge, a platform facilitating high-performance disaggregation of peripheral resources over a network of potentially untrusted FPGAs, aided by a secondary inter-FPGA network. Evaluated on a mix of representative accelerator applications deployed on a prototype cluster, FlexForge improves the overall performance of the cloud by up to 70 % and 20 % on average across all possible combinations without significant additional hardware resource requirements.