HybridOS: Runtime Support for Reconfigurable Accelerators

We present HybridOS, a set of operating system extensions for supporting fine-grained reconfigurable accelerators integrated with general-purpose computing, platforms. HybridOS specifically taracts the application integration, data movement and communication overheads for a CPU/accelerator model when running a commodity operating system. HybridOS provides a simple API for applications and a well-defined hardware interface for reconfigurable accelerators. The goal is to reduce the difficulty in mapping applications into a CPU/accelerator model compared to an unrestrained FPGA platform while achieving whole-application speedups. HybridOS is integrated into a full Linux distribution running on the embedded processor of an FPGA. Application-specific accelerators are implemented in the reconfigurable fabric of the FPGA that are allocated to user applications running on Linux. We have developed and evaluated four methods for accessing the data buffers required by hardware-accelerated applications using our prototype. The results of our work show the feasibility of our system for a case study, JPEG encoding with two accelerators, and an evaluation of HybridOS for varying data movement requirements that can be used as a guide for future applications developers.