A Domain-Specific On-Chip Network Design for Large Scale Cache Systems

Yuho Jin, Eun Jung Kim, Ki Hwan Yum
2007 2007 IEEE 13th International Symposium on High Performance Computer Architecture  
As circuit integration technology advances, the design of efficient interconnects has become critical. On-chip networks have been adopted to overcome scalability and the poor resource sharing problems of shared buses or dedicated wires. However, using a general on-chip network for a specific domain may cause underutilization of the network resources and huge network delays because the interconnects are not optimized for the domain. Addressing these two issues is challenging because in-depth
more » ... ledges of interconnects and the specific domain are required. Recently proposed Non-Uniform Cache Architectures (NUCAs) use wormhole-routed 2D mesh networks to improve the performance of on-chip L2 caches. We observe that network resources in NUCAs are underutilized and occupy considerable chip area (52% of cache area). Also the network delay is significantly large (63% of cache access time). Motivated by our observations, we investigate how to optimize cache operations and design the network in large scale cache systems. We propose a single-cycle router architecture that can efficiently support multicasting in on-chip caches. Next, we present Fast-LRU replacement, where cache replacement overlaps with data request delivery. Finally we propose a deadlock-free XYX routing algorithm and a new halo network topology to minimize the number of links in the network. Simulation results show that our networked cache system improves the average IPC by 38% over the mesh network design with Multicast Promotion replacement while using only 23% of the interconnection area. Specifically, Multicast Fast-LRU replacement improves the average IPC by 20% compared with Multicast Promotion replacement. A halo topology design additionally improves the average IPC by 18% over a mesh topology.
doi:10.1109/hpca.2007.346209 dblp:conf/hpca/JinKY07 fatcat:uqppu4bfl5dy5agnjkckigrh6m