The psi-cube: a bus-based cube-type clustering network for high-performance on-chip systems

摘要

This paper proposes a bus-based cube-type network, called psi-cube, that alleviates the two problems, long wires and a limited number of I/O pins, against the on-chip systems through a small diameter and dynamic clusters, respectively. The 2~n-node psi-cube is organized on the sets of node-partitions produced with an extended n-bit Hamming code Ψ(n, k) [M. Takesue, Ψ-Cubes: recursive bused fat-hypercubes for multilevel snoopy caches, in: Proceedings of the International Symposium on Parallel Architectures, Algorithms, and Networks, IEEE CS Press, 1999, pp. 62-67] if we connect the nodes in each partition to the bus owned by the leader of the partition. Owing to the routing between the leaders separated by the distance of 1-3, the diameter equals [n/2] if n≠2~p - 1 or [n/2] otherwise. The maximum bus length is O(2~(p-1)) or O(2~(k-1)) when the psi-cube is mapped onto an array. We dynamically produce separate sets of clusters for different off-chip targets such as memory blocks, so the traffic to the leaders of clusters is much smaller than in static clusters fixed in hardware. From simulation results, the psi-cube outperforms over the mesh if the bus delay is less than 4 times the mesh link's, and the dynamic clusters increase the psi-cube bandwidth by over 60%.