When application-specific ISA meets FPGAs: a multi-layer virtualization framework for heterogeneous cloud FPGAs

While field-programmable gate arrays (FPGAs) have been widely deployed into cloud platforms, the high programming complexity and the inability to manage FPGA resources in an elastic/scalable manner largely limits the adoption of FPGA acceleration. Existing FPGA virtualization mechanisms partially address these limitations. Application-specific (AS) ISA provides a nice abstraction to enable a simple software programming flow that makes FPGA acceleration accessible by the mainstream software application developers. Nevertheless, existing AS ISA-based approaches can only manage FPGA resources at a per-device granularity, leading to a low resource utilization. Alternatively, hardware-specific (HS) abstraction improves the resource utilization by spatially sharing one FPGA among multiple applications. But it cannot reduce the programming complexity due to the lack of a high-level programming model.