On-the-fly data compression/decompression mechanism with ExpEther

ExpEther is a virtualization technique that extends PCIe of a host CPU to Ethernet. Since all devices connected by ExpEther can be treated as if they were directly connected to the host, a multi-GPU system called GBU-BOX that connects a number of GPUs virtually to a host can be easily developed. However, the smaller bandwidth of Ethernet compared to PCIe often bottlenecks the system. An on-the-fly data compression/decompression mechanism is proposed for the ExpEther NIC to compensate for the gap in bandwidth between PCIe and Ethernet. Two algorithms, WAH and SECOMPAX, are implemented on an FPGA for compressing bitmap index data. The former reduces the amount of data on Ethernet to 28% while the latter reduces it to 27% when Graph500 BSF is executed on GPU-BOX. Considering the hardware overhead, WAH is a good solution for applications.