While measuring how my search engine scales with thread count (results in the companion article, I threw away my entire first data set. Here's why — and if you ever benchmark anything on a fanless laptop, this is not someone else's problem.
The first data set was clean, and wrong
I measured 1 through 10 threads, in order. The curve looked beautiful, including a shiny record: "11 threads, fastest at 5.2 seconds." Right before writing the article, I re-ran the same conditions as a sanity check.
The same conditions came back up to 54% different. 4 threads: 11.0s became 9.0s. 11 threads: 5.2s became 8.0s. The record run did not reproduce.
No rogue background process. The culprit was the chassis.
