Dynamic Packet Fragmentation for Increased Virtual Channel Utilization in On-Chip Routers

Conventional packet-switched on-chip routers provide good resource sharing while minimizing latencies through various techniques. A virtual channel (VC) is allocated on a per-packet basis and held until the entire packet exits the VC buffer. This sometimes leads to inefficient use of VCs at high network loads. A blocked packet can affect adjacent routers, resulting in a congestion propagation effect. In such a scenario, VC buffers may be empty although they are regarded as fully occupied by a blocked packet. This paper proposes a dynamic packet fragmentation technique which releases empty VC buffers by fragmenting packets and allowing other packets to use the freed VC buffers. Thus, fragmentation increases VC utilization. Simulation experiments show performance improvement in terms of latency and throughput up to 20% and 7.5%, respectively.