Amorphous Dynamic Partial Reconfiguration with Flexible Boundaries to Remove Fragmentation

Abstract: Dynamic partial reconfiguration (DPR) allows one region of an field-programmable gate array (FPGA) fabric to be reconfigured without affecting the operations on the rest of the fabric. To use an FPGA as a dynamically shared compute resource, one could partition and manage an FPGA fabric as multiple DPR partitions that can be independently reconfigured at runtime with different application function units (AFUs). Unfortunately, dividing a fabric into DPR partitions with fixed boundaries causes the available fabric resources to become fragmented. An AFU of a given size cannot be loaded unless a sufficiently large DPR partition was floorplanned at build time. To overcome this inefficiency, we devised an "amorphous" DPR technique that is compatible with current device and tool support but does not require the DPR partition boundaries to be a priori fixed. A collection of AFU bitstreams can be simultaneously loaded on the fabric if their footprints (the actual area used by an AFU) in the fabric do not overlap. We verified the feasibility of amorphous DPR on Xilinx Zynq System-on-Chip (SoC) FPGAs using Vivado. We evaluated the benefits of amorphous DPR in the context of a dynamically reconfigurable vision processing pipeline framework.