Evaluating virtual channels for cache-coherent shared-memory multiprocessors
Akhilesh Kumar, Laxmi Narayan Bhuyan · 1996
In this paper, performance of wormhole routed 2-D torus network with virtual channels has been evaluated for cachecoherent shared-memory multiprocessors with executiondriven simulation. The traffic in such systems is very different from the traffic in message-passing environment. We show the impact of number of virtual channels, flit buffers per virtual channel, and internal links. The study shows that 4 virtual channels per link is most efficient for 2-D torus networks. The number of flit buffers per virtual channel has a considerable impact and 2 to 4 flit buffers are usually enough. The number of internal links makes a difference on the performance for applications, such as MP3D, that generate large contention for shared variables. 1 Introduction Large-scale shared-memory multiprocessors are difficult to design but they provide a unified view of the memory for easy programming. These systems are built using processormemory nodes that are connected through an interconnection network...