The limits of semiconductor technology and oncoming challenges in computer micro architectures and architectures

In the last three decades the world of computers and especially that of mi- croprocessors has been advanced at exponential rates in both productivity and perfor- mance. The integrated circuit industry has followed a steady path of constantly shrink- ing devices geometries and increased functionality that larger chips provide. The technology that enabled this exponential growth is a combination of advancements in process technology, microarchitecture, architecture and design and development tools. Together, these performances and functionality improvements have resulted in a history of new technology generations every two to three years, commonly referred to as iMoore Lawi. Each new generation has approximately doubled logic circuit density and increased performance by about 40%. This paper overviews some of the microarchitectural techniques that are typical for contemporary high-performance mi- croprocessors. The techniques are classied into those that increase the concurrency in instruction processing, while maintaining the appearance of sequential processing (pipelining, super-scalar execution, out-of-order execution, etc.), and those that ex- ploit program behavior (memories hierarchies, branch predictors, trace caches, etc.). In addition, the paper also discusses microarchitectural techniques likely to be used in the near future such as microarchitectures with multiple sequencers and thread-level speculation, and microarchitectural techniques intended for minimization of power consumption.