What the $#@! is Parallelism, Anyhow? (2009)
The article discusses the concept of parallelism in computing, highlighting the confusion surrounding its definition among technologists. It critiques the reliance on Amdahl's Law, which limits the understanding of speedup in parallel computing. The author introduces a more precise model using directed acyclic graphs (DAGs) to better define and measure parallelism.
- ▪Many technologists misuse the term parallelism without understanding its definition.
- ▪Amdahl's Law suggests that the maximum speedup is limited by the serial portion of a computation.
- ▪The article proposes using a DAG model to provide a clearer understanding of multithreaded execution.
Opening excerpt (first ~120 words) tap to expand
by Charles LeisersonI'm constantly amazed how many seemingly well-educated computer technologists bandy about the word parallelism without really knowing what they're talking about. I can't tell you how many articles and books I've read on parallel computing that use the term over and over without ever defining it. Many of these “authoritative” sources cite Amdahl's Law (1), originally proffered by Gene Amdahl in 1967, but they seem blissfully unaware of the more general and precise quantification of parallelism provided by theoretical computer science. Since the theory really isn't all that hard, it curious that it isn't better known. Maybe it needs a better name — “Law” sounds so authoritative.
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Excerpt limited to ~120 words for fair-use compliance. The full article is at Archive.