I'm interested in wiring up some Raspberry Pi Compute Modules together on a custom PCB board with DDR2 SODIMM connector interfaces.
I want to use the compute modules together in a N-body-type simulation where each module acts as a planet or something and interacts with all other modules via MPI. Ideally each module should be able to asynchronously communicate with any other module in the board without interrupting the processing on the other modules.
What is a good hardware solution to high-bandwidth switching for PCB components connected in this fashion? Normally with standard Raspberry Pis I would use an ethernet switch to route packets between the nodes but I'm not so sure here. Would it be feasible to build switching logic + processors directly into the board (or have several of the compute modules serve as switching logic)?
Some research seems to indicate that Blue Gene node cards (it has a similar design to the tray I am proposing above) are connected via tx+rx 12-channel optical fibers, but I'm not sure if that is what I need, as that seems to be missing some kind of switching capability.