Improved Utilization of NoC Channel Bandwidth by Switch Replication for Cost-Effective Multi-processor Systems-on-Chip

Virtual channels are an appealing flow control technique for on-chip interconnection networks (NoCs), in that they can potentially avoid deadlock and improve link utilization and network throughput. However, their use in the resource constrained multi-processor system-on-chip (MPSoC) domain is still controversial, due to their significant overhead in terms of area, power and cycle time degradation. This paper proposes a simple yet efficient approach to VC implementation, which results in more area- and power-saving solutions than conventional design techniques. While these latter replicate only buffering resources for each physical link, we replicate the entire switch and prove that our solution is counter intuitively more area/power efficient while potentially operating at higher speeds. This result builds on a well-known principle of logic synthesis for combinational circuits (the area-performance trade-off when inferring a logic function into a gate-level netlist), and proves that when a designer is aware of this, novel architecture design techniques can be conceived.