On-demand reconfiguration for coprocessors in mixed criticality multicore systems

Especially in complex system-of-systems scenarios, where multiple high-performance or real-time processing functions need to co-exist and interact, reconfigurable devices together with virtualization techniques show considerable promise to increase efficiency, ease integration and maintain functional and non-functional properties of the individual functions. In a previous work, we proposed a concept that leverages the advantages of FPGA's partial reconfiguration in heterogeneous mixed criticality multicore systems. The basic idea how to handle the partial reconfiguration transparently for noncritical tasks, while providing full control and a predictable behavior for safety relevant tasks was described. In this paper, we focus on the on-demand partial reconfiguration of coprocessors and its implementation details. Our prototype is implemented on an Intel multicore system and a Xilinx Virtex-7 FPGA connected via PCI Express, taking advantage of the Single-Root I/O Virtualization capabilities in modern PCI Express implementations. Experimental results show that compared to the reference software implementation, our concept achieves significantly shorter reconfiguration time with lower variance under various system load situations.