Abstract The Meerkat Multicomputer

Meerkat is a distributed memory multicomputer architecture that scales to hundreds of processors. Meerkat uses a two dimensional passive backplane to connect nodes composed ofprocessors, memory, and I/O devices. The interconnect is conceptually simple, inexpensive to design and build, has low latency, and provides high bandwidth on long messages. However, it does not scale to thousands of processors, does not provide high bandwidth on short messages, and does not provide cache coherent shared memory. Our hypothesis is that many general-purpose, database, and parallel numerical workloads work well on systems with Meerkat's characteristics. We describe the Meerkat architecture, the niche that Meerkat lls, the motivation behind our design choices, and give performance results obtained from our hardware prototype and a calibrated simulator.

Chapter 8 CONCLUSIONS

This thesis has shown the benefits of a hardware-minimalist approach to multicomputer design. By keeping the design simple, we were able to keep design time short and hardware expense low. We used a concrete architecture, Meerkat, to represent our vision and to test our ideas. Meerkat is at the extreme end of the design spectrum: it uses simple hardware and requires efficient, low-level software. We reinforced Meerkat’s minimalist approach with a discussion of specific design choices. The most important choice was to limit scalability. Some parallel computer customers require thousands of processors and can afford the high costs associated with them. Those for whom a few hundred nodes will suffice, however, also require the optimized price/performance achievable from systems designed for their needs. Another tradeoff was to limit the interconnect to two dimensions. This allowed the use of inexpensive, yet high performance, wiring technology. A third tradeoff was to make the interconnect circuit switched rather than packet switched. This allowed a simple implementation with high transfer rates