Hardware task scheduling and placement in operating systems for dynamically reconfigurable SoC

Existing operating systems can manage the execution of software tasks efficiently, however the manipulation of hardware tasks is very limited. In the research on the design and implementation of an embedded operating system that manages both software and hardware tasks in the same framework, two major issues are the dynamic scheduling and the dynamic placement of hardware tasks into a reconfigurable logic space in an SoC. The distinguishing criteria for good dynamic scheduling and placement methods include the total schedule length and the amount of fragmentation incurred while tasks are dynamically placed and replaced. Existing methods either do not take fragmentation into consideration or postpone the consideration of fragmentation to a later stage of space allocation. In our method, we try to reduce fragmentation during placement itself. The advantage of such an approach is that not only the reconfigurable space is utilized more efficiently, but the total schedule length is also reduced, that is, hardware tasks complete faster. Experimental results on large random tasks sets have shown that the proposed improvement is as much as 23.3% in total fragmentation and 2.0% in total schedule time.