Physically-aware exploitation of component reuse in a partially reconfigurable architecture

The major drawback of partial dynamic reconfiguration is the reconfiguration delay overhead. To reduce the reconfiguration bitstream between two consecutive implementations, design components are reused. However, this incurs additional physical constraints to design which can lead to unroutability and congestion in design. In this paper, we propose a physically-aware component reuse strategy. We propose a floorplanning algorithm to support two-dimensional partial reconfiguration. The proposed floorplanning tool enables a wide design space exploration for component reuse. Key features are selection of the fixed modules, location of the fixed modules, mapping to the fixed modules, and interconnect planning between the fixed and reconfigurable modules. We implemented a sequence of dataflow graphs on Xilinx Virtex 4 devices using our tool for component reuse. When reuse is exploited, the experimental results report more than 50% reduction in the number of reconfiguration frames compared to the flow during which component reuse is not applied. Our proposed floorplan-aware matching technique (to map the modules to fixed components) can reduce the reconfiguration frames by 10% on average compared to dependency-based matching algorithm. In addition, we show that by different placement of the modules for two consecutive tasks, the variation in the number of reconfiguration frames can be between 25%-60% or it may even lead to unroutability of the circuits. The results imply that there is a need to tune the physical design tools for minimizing runtime reconfiguration delay overhead.