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.
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| Original publisher | Archive |
| Canonical URL | https://web.archive.org/web/20091103162537/http://software.intel.com/en-us/articles/what-the-is-parallelism-anyhow-1/ |
| Publication time | Sat, 23 May 2026 09:19:32 +0000 |
| Retrieval time | 2026-05-23T09:37:26.609Z |
| Last seen | 2026-05-23T09:37:26.609Z |
| Headline source | Publisher (no WeSearch rewrite) |
| Excerpt source | publisher body |
| Excerpt method | First ~120 words (~800 chars) of extracted publisher body, fair-use limited. |
| Summary | WeSearch · cerebras-chat (WeSearch summarizer) |
| Summary source text | contentText |
| Citation coverage | Summary is a WeSearch-generated derivative; primary citation is the original publisher URL. |
| Cluster | 0Vbojx3_HdBy |
| Cluster logic | Grouped by semantic title/content similarity across sources within a rolling window. Same-publisher template collisions are excluded from coverage comparison. |
| Ranking reason | Story pages are not engagement-ranked. Hub feeds use recency, with optional source-diversified chronological ordering (cap consecutive stories per source). No personalized ranking. |
| Publisher visit | Yes — open original |
| Substitutes article? | No — link-out required for full text |
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| Indexing | May the item be indexed (stored, ranked, made findable)? | Allowed |
| Snippet | May a short excerpt of the publisher's text be shown? | Allowed |
| AI summary | May WeSearch generate its own short summary of the article? | Limited |
| Retrieval / RAG | May the content be exposed for third-party retrieval-augmented generation? | Not asserted |
| Model training | May the content be used to train AI models? | Not asserted |
| Commercial reuse | May the content be reused commercially? | Not permitted |
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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.