Low Latency Communication on DIMMnet-1 Network Interface Plugged into a DIMM Slot

Abstract

DIMMnet-1 is a high performance network interface for PC clusters that can be directly plugged into the DIMM slot of a PC. By using both low latency AOTF (Atomic On-The-Fly) sending and high bandwidth BOTF (Block On-The-Fly) sending, it can overcome the overhead caused by standard I/O such as the PCI bus. Two types of DIMMnet-1 prototypeboards (providing optical and electrical network interfaces) containing a Martini network interface controller chip are currently available. They can be plugged into a 100MHz DIMM slot of a PC with a Pentium-3, Pentium-4 or Athlon processor. The round-trip time for AOTF onthis incompletely tuned DIMMnet-1 is 7.5 times faster than Myrinet2000. The barrier synchronization time for AOTF is 4 times faster than that of an SR8000 supercomputer. Theinter-two-node floating sum operation time is 1903 ns. This shows that DIMMnet-1 holds promise for applications in which scalable performance with traditional approaches is difficult because of frequent data exchange.