Scheduling and Placement of Hardware/Software Real-Time Relocatable Tasks in Dynamically Partially Reconfigurable Systems

With the gradually fading distinction between hardware and software, it is now possible to relocate tasks from a microprocessor to reconfigurable logic and vice versa. However, existing hardware-software scheduling can rarely cope with such runtime task relocation. In this work, we propose a new Relocatable Hardware-Software Scheduling (RHSS) method that not only can be applied to dynamically relocatable hardware-software tasks, but also increases the reconfigurable hardware resource utilization, reduces the reconfigurable hardware resource fragmentation with realistic placement methods, and makes best efforts at meeting the real-time constraints of tasks. The feasibility of the proposed relocatable hardware-software scheduling algorithm was proved by applying it to some randomly generated examples and a real dynamically reconfigurable network security system example. Compared to the quadratic time complexity of the state-of-the-art Adaptive Hardware-Software Allocation (AHSA) method, RHSS is linear in time complexity, and improves the reconfigurable hardware utilization by as much as 117.8%. The scheduling and placement time and the memory usage are also drastically reduced by as much as 89.5% and 96.4%, respectively.