Adaptive Bubble Scheme with Minimal Buffers in Torus Networks

Bubble flow control is an efficient technique to avoid deadlock for torus networks. Critical bubble scheme can avoid intra-dimension deadlock with just one packet buffer, but has a risk of blocking. In this paper, we present a false packet protocol, design a non-blocking moveable bubble scheme for an adaptive virtual cut-through router, and the result is a fully adaptive router with minimal two virtual channels, one packet buffer per virtual channel. We compare the performance of various bubble-based schemes with simulation. Network simulation results show that moveable bubble scheme outperform traditional bubble scheme, whereas adaptive scheme performs apparently better than the other methods, avoids blocking, reduces latency, displays a throughput improvement of more than 20%, maximally up to 100%, and achieves lower latency.