A Novel Mechanism for Effective Hardware Task Preemption in Dynamically Reconfigurable Systems

Extending the idea of preemptive multitasking to DPRS (Dynamic Partial Reconfiguration Systems) has far-reaching implications as many mechanisms supporting the concept, such as context saving and restoring, have to be built practically from scratch. This paper addresses previously neglected issues, related to design of effective preemption mechanisms for Flip-Flop-based and RAM-based hardware tasks. Furthermore, a very efficient and complete solution to hardware task preemption for Virtex4-based DPRS is presented featuring in bitstream manipulation tool intended for PC and embedded system infrastructure with a DMA-based, instruction-driven reconfiguration/readback controller. Taking advantage of the developed lightweight bus, enhancing management of reconfigurable hardware modules, controller takes care of all essential hardware aspects related to context-switching thereby reducing CPU utilization to necessary minimum.