Preliminary evaluations of a FPGA-based-prototype of DIMMnet-2 network interface

Performance improvement of interconnection networks for a PC cluster brings a bottleneck in a standard I/O bus such as PCI bus. DIMMnet is a network interface plugged into a memory slot instead of standard I/O buses. This strategy is one of the solutions in order to balance growing performance with future micro processors. DIMMnet-2 is a prototype which can be plugged into a DDR-DIMM slot to confirm its functions. In this paper, outline of FPGA-based DIMMnet-2 prototype and improvements from DIMMnet-1 to DIMMnet-2 are mentioned. Although the DIMMnet-2 uses an FPGA instead of an ASIC, the latency for writing 8 bytes into remote memory is only 0.948 μs. It is about 3 times fewer latency than that of a high performance commercial network interface QsNET II plugged into PCI-X bus on Intel-based IA32 PC. The delay of CoreLogic part for BOTF sending of FPGA based DIMMnet-2 is 5.75 times as fast as that of DIMMnet-1.