Efficient On-Chip Task Scheduler and Allocator for Reconfigurable Operating Systems

This letter presents efficient and modular task scheduler and allocator support for dynamically and partially reconfigurable electronic systems. This enables hardware tasks to be preempted and arbitrarily placed at an optimal position on the chip on-the-fly. In particular, we present a novel fault-tolerant allocating algorithm called "best-fit empty area compact (BF-EAC)," and its on-chip implementation on a Xilinx Virtex-4 field-programmable gate array (FPGA), which circumvents emerging faults while maintaining more compact empty areas for emerging tasks. We also present an implementation of the early deadline first (EDF) scheduling heuristic used to optimize the chronological order of execution of hardware tasks to meet real time constraints. Put together, the placement and scheduling architecture efficiently exploits chip resources with a μs-grade computing speed and a lightweight footprint (less than 500 slices).