Cache coherence protocol for home proxy cache on RHiNET and its preliminary performance estimation

LASN (Local Area System Network) is a new class of networks which has the advantages of both SANS and LANs. RHiNET (RWCP high performance network) is the first network designed with the concepts of an LASN. A prototype called RHiNET-1 using 1.33 Gbps optical interconnections is available for research on cluster computing. In the case of implementing distributed shared-memory system on a cluster system, software based cache memory is used in order to reduce the number of accesses to shared-memory and a large amount of communication in the network. We have proposed Home Proxy Cache which keeps copies of pages in home memory in order to avoid I/O bus bottleneck when there are many accesses from the other nodes to the home memory. In this paper, a network interface of RHiNET is introduced and the detailed coherence protocol for a distributed shared-memory system is presented. The protocol will be implemented in the RHiNET network interface. We have estimated effectiveness of Home Proxy Cache with RHiNET-1 and RHiNET-2 in cases of Read Miss and Write Miss to Cache Memory.