Sequencing Of Concurrent Communication Traffic In A Mesh Multicomputer With Virtual Channels

Under the fixed-path e-cube routing in mesh multicomputers, we evaluate the performance of several low-overhead packet sequencing and flit multiplexing methods. In the presence of concurrent inter-node communication traffic, we found that unless proper packet sequencing is employed, adding more communication resources, such as links and buffers, can actually degrade the network performance. A good packet-sequencing policy combined with proper flit multiplexing is shown to improve performance by more than 30%. 1 Introduction The use of virtual channels multiplexed over each physical channel was introduced as a mechanism to accomplish deadlock-freedom by placing routing restrictions at intermediate nodes [1]. Virtual channels were also found to improve the network throughput via the increased sharing of each physical channel and the resulting reduction of packet blocking [2]. That is, when there are multiple virtual channels per physical channel, packets of these virtual channels are al..