Hardware Architectural Support for Caching Partitioned Reconfigurations in Reconfigurable Systems

The efficiency of the reconfiguration process in modern field-programmable gate arrays (FPGAs) can improve drastically if an on-chip configuration memory is included in the system, because it can reduce both the reconfiguration latency and its energy consumption. However, the FPGA on-chip memory resources are very limited. Thus, it is very important to manage them effectively in order to improve the reconfiguration process as much as possible, even when the size of the on-chip configuration memory is small. This paper presents a hardware implementation of an on-chip configuration memory controller that efficiently manages run-time reconfigurations. In order to optimize the use of the on-chip memory, this controller includes support to deal with configurations that have been divided into blocks of customizable size. When a reconfiguration must be carried out, our controller provides the blocks stored on-chip and looks for the remaining blocks by accessing to the off-chip configuration memory. Moreover, it dynamically decides which blocks must be stored on-chip. To this end, the designed controller implements a simple but efficient technique that allows maximizing the benefits of the on-chip memories. Experimental results will demonstrate that its implementation cost is very affordable and that it introduces negligible run-time management overheads.