A Survey on Amdahl's Law Extension in Multicore Architectures Bashayer M. Al-Babtain, Fajer J. Al-Kanderi, Maha F. Al-Fahad, and Imtiaz Ahmad Computer Engineering Department, College of Computing Sciences and Engineering Kuwait University, P.O Box 5469, Safat 13060, Kuwait Eng.bashayer@gmail.com, eng.fjk@gmail.com, maha@al-fuhaid.net, imtiaz.ahmad@ku.edu.kw ABSTRACT Multicore architectures represent the future of computing since they provide cost effective solutions to improve throughput and performance of parallel programs while keeping power consumption manageable. Amdahl’s law continues to serve as a guideline for parallel programmers to assess the upper bounds of attainable performance in multicore architectures. In this article, we review the key papers related to the extension of Amdahl’s law for multicore architectures by characterizing them into five categories. For each category we briefly survey the main analytic modeling techniques and discuss their inherent advantages and disadvantages. All the analytic models discussed in this article are compared against a number of attributes hindering the performance enhancement of multicore computing to pinpoint their strengths and weaknesses. Finally, we recommend directions for future work to inspire the research community to invent new ideas to model and evaluate the emerging multicore computing paradigms. KEYWORDS Amdahl's Law, Multicore Architecture, Performance, Analytic Models, Power. 1 INTRODUCTION The hunger for faster performance in the computer domain is never satisfied; every new performance enhancement in processors leads to another level of greater performance demands from businesses and consumers. Today these performance demands are not just for speed, but also for smaller, more powerful mobile devices, longer battery life, better price/performance per watt and lower cooling costs [1]. In the past, processor performance trends were dominated by increasingly complex feature sets, higher clock speeds, and increasing power dissipation. Recently, clock speeds have tapered and power dissipation envelopes have remained flat [2]. However, the demand for increasing performance still continues and as single core processors reaches their physical limits of possible complexity and speed, the movement towards multicore processors begins. A multicore processor is an integrated circuit (IC) to which two or more processors have been attached for enhanced performance, reduced power consumption, and more efficient simultaneous processing of multiple tasks [3]. Multicore architectures have been a major design trend over the past decade, starting with high-end server processors and moving to low-end hand- held mobile devices. These chips provide an effective solution to improve throughput performance of parallel programs while keeping power consumption manageable. They allow for faster execution of applications by taking advantage of parallelism, or the ability to work on multiple problems simultaneously. Computing vendors International Journal of New Computer Architectures and their Applications (IJNCAA) 3(3): 30-46 The Society of Digital Information and Wireless Communications, 2013 (ISSN: 2220-9085) 30