一种动态权值输入缓存Crossbar多播调度算法

Multicast scheduling algorithm with a dynamic weight for the input buffered Crossbar

针对输入缓存Crossbar结构,提出一种权值动态计算的多播调度算法.该算法使用地址拷贝的方法将多播信元按照目的端口区分存储,以达到减少队头阻塞的目的.在调度多播信元时,与现有调度算法每次迭代时多播信元的权值都保持固定不同,新算法在每轮迭代中根据多播信元的扇出分割情况动态地为信元计算权值,以确保为扇出分割小的信元提供更多优先输出机会.减少多播信元的扇出分割,可以有效地防止路由器在多播业务量大时的输入端口拥塞.为了验证新算法的性能,提出一种只存在少数最佳匹配的多播业务模式.仿真结果表明,新算法在这种苛刻的业务模式以及其他常见的业务模式下都有很好的吞吐率.

A multicast scheduling algorithm with a dynamic weight is proposed for the input buffered crossbar. The address of the multicast cell is copied and saved according to its destination ports to decrease the effect of head of line blocking. When a multicast cell is scheduled, its weight is computed in each iteration according to its fanout splitting dynamically to give more chances for the low fanout splitting cells to export. This scheme can decrease the fanout splitting of multicast cells. The input port congestion under a heavy multicast traffic load can be effectively avoided if multicast fannout splitting is decreased. To verify the performance of the proposed scheduling algorithm, a multicast traffic mode with few perfect matchings is proposed. Simulation results show that the new scheduling algorithm has a good throughput under this rigorous traffic mode and other traditional traffic modes.