The Connection Machine CM-5, Moore's Law, and the Future of Computational Performance

In June 1993, the Connection Machine Model CM-5 Supercomputer [6] manufactured by Thinking Machines Corporation was the most powerful computer in the world [10]. At the time, Moore's Law [8, 9] was about halfway through its roughly 60-year reign, and indeed, your smartphone today is likely more powerful than the CM-5, no matter how you want to measure it: FLOPS, bisection bandwidth, storage, etc. As one of the earliest commercially successful parallel supercomputers, the CM-5 network architecture introduced many innovations: a user-level network interface, a fat-tree [5] data network, a global synchronization network, and a system-wide parallel diagnostic network. The CM-5 architecture delivered unprecedented computing power for its day while also simplifying the process of coding for parallel performance. The CM-5 inspired the development of significant software and algorithmic technology still in use today, including work/span analysis [2, Chapter 26], the LogP performance model [3], data-parallel computing [4], task-parallel computing [2, Chapter 26], and workstealing algorithms [1]. Indeed, although the focus at the time was on the CM-5's hardware innovations, its legacy in the areas of programming models, algorithms, and software performance engineering may be the CM-5's greater contribution. The recent end of Moore's Law [7]-and with it, the attenuation of exponential gains in hardware performance-portends increased relevance of research in these areas, especially in software performance engineering.