Definition
Amdahl’s Law says that if you apply P processors to a task that has serial fraction f, the predicted net speedup is
More generally, it shows the speedup that results from applying any performance enhancement by a factor of P to only one part of a given workload.
A corollary of Amdahl’s Law, often confused with the law itself, is that even when one applies a very large number of processors P (or other performance enhancement) to a problem, the net improvement in speed cannot exceed 1 ∕ f.
Discussion
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Bibliography
Amdahl GM (1967) Validity of the single-processor approach to achieve large scale computing capabilities. AFIPS Joint Spring Conference Proceedings 30 (Atlantic City, NJ, Apr. 18–20), AFIPS Press, Reston VA, pp 483–485, At http://www-inst.eecs.berkeley.edu/~n252/paper/Amdahl.pdf
Bell G (interviewed) (July 1987) An interview with Gordon Bell. IEEE Software, 4(4):102–104
Brooks FP (1975) The mythical man-month: Essays on software engineering. Addison-Wesley, Reading. ISBN 0-201-00650-2
Gustafson JL (April 1990) Fixed time, tiered memory, and superlinear speedup. Proceedings of the 5th distributed memory conference, vol 2, pp 1255–1260. ISBN: 0-8186-2113-3
Gustafson JL, Montry GR, Benner RE (July 1988) Development of parallel methods for a 1024-processor hypercube. SIAM J Sci Statist Comput, 9(4):609–638
Gustafson (May 1988) Reevaluating Amdahl’s law. Commun ACM, 31(5):532–533. DOI = 10.1145/42411.42415
Hennessy JL, Patterson DA (1990, 1996, 2003, 2007) Computer architecture: A quantitative approach. Elsevier Inc.
Hwang K, Briggs F (1990) Computer architecture and parallel processing, McGraw-Hill, New York. ISBN: 0070315566
Karp A (1985) http://www.netlib.org/benchmark/karp-challenge
Lewis TG, El-Rewini H (1992) Introduction to parallel computing, Prentice Hall. ISBN: 0-13-498924-4, 32–33
Seitz CL (1986) Experiments with VLSI ensemble machines. Journal of VLSI and computer systems, vol 1. No. 3, pp 311–334
Slotnick D (1967) Unconventional systems. AFIPS joint spring conference proceedings 30 (Atlantic City, NJ, Apr. 18–20). AFIPS Press, Reston VA, pp 477–481
Sun X-H, Ni L (1993) Scalable problems and memory-bounded speedup. Journal of parallel and distributed computing, vol 19. No 1, pp 22–37
Ware WH (1972) The Ultimate Computer. IEEE spectrum, vol 9. No. 3, pp 84–91
Author information
Authors and Affiliations
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2011 Springer Science+Business Media, LLC
About this entry
Cite this entry
Gustafson, J.L. (2011). Amdahl’s Law. In: Padua, D. (eds) Encyclopedia of Parallel Computing. Springer, Boston, MA. https://doi.org/10.1007/978-0-387-09766-4_77
Download citation
DOI: https://doi.org/10.1007/978-0-387-09766-4_77
Publisher Name: Springer, Boston, MA
Print ISBN: 978-0-387-09765-7
Online ISBN: 978-0-387-09766-4
eBook Packages: Computer ScienceReference Module Computer Science and Engineering