PlanetMath (more info)
 Math for the people, by the people.
Encyclopedia | Requests | Forums | Docs | Wiki | Random | RSS  
Login
create new user
name:
pass:
forget your password?
Main Menu
sections
Encyclopædia
Papers
Books
Expositions

meta
Requests (230)
Orphanage
Unclass'd
Unproven (519)
Corrections (17)
Classification

talkback
Polls
Forums
Feedback
Bug Reports

downloads
Snapshots
PM Book

information
News
Docs
Wiki
ChangeLog
TODO List
Legalese
About
Owner confidence rating: High Entry average rating: No information on entry rating
Amdahl's Law (Theorem)

Amdahl's Law reveals the maximum speedup that can be expected from parallel algorithms given the proportion of parts that must be computed sequentially. It gives the speedup $ S$ as

$\displaystyle S \le \frac{1}{f+(1-f)/N} $

Where $ f$ is the fraction of the problem that must be computed sequentially and $ N$ is the number of processors.

Note that as $ f$ approaches zero, $ S$ nears $ N$, which we'd expect from a perfectly parallelizable algorithm.



"Amdahl's Law" is owned by alozano. [ full author list (2) | owner history (1) ]
(view preamble)

View style:

Keywords:  parallel computation

Attachments:
proof of Amdahl's Law (Proof) by lieven
Log in to rate this entry.
(view current ratings)

Cross-references: parallelizable, nears, number, fraction, Proportion, algorithms, parallel, speedup
There is 1 reference to this entry.

This is version 13 of Amdahl's Law, born on 2001-12-22, modified 2006-10-24.
Object id is 1133, canonical name is AmdahlsLaw.
Accessed 9041 times total.

Classification:
AMS MSC: 68M20 (Computer science :: Computer system organization :: Performance evaluation; queueing; scheduling)
Pending Errata and Addenda
None.
[ View all 1 ]
Discussion
Style: Expand: Order:
forum policy

No messages.

Interact
post | correct | update request | prove | add result | add corollary | add example | add (any)