I've begun in earnest to update the http://aggregate.org/ web site now that KLAT2 is up and running. So what is KLAT2? Our research group has been on very friendly terms with AMD, and recently they donated 66 Athlon processors to our project. We turned those into the KLAT2 cluster (Kentucky Linux Athlon Testbed 2), which will hopefully be making the news soon.
We are trying out a bunch of new performance enhancing technologies with KLAT2. The coolest one I think is the genetically engineered Flat Neighborhood Network (FNN) topology Hank & I came up with. It allows a very inexpensive network to very closely approximate a fully connected network. It has a very high crossection bandwidth, and single hop latency between any pair of nodes. I've done a preliminary patch to LAM/MPI to make it work with the FNN. However, it is going to take quite a bit more software hacking to get an MPI to utilize all the data link bandwidth that the FNN supplies. I'll post a pointer when we have a reasonable document up that explains the FNN.