Always look at the source code.
How many times slower than the fastest
How many times slower, the fastest benchmark programs for selected programming language implementations are, compared to the fastest written in any of the programming languages.
Notice which boxes overlap completely. Notice which spread across too large a range of values for confidence.
You can see that the order would be different if it was based on the median scores instead of the [pdf] geometric mean scores.
How much more optimization than average
We don't know how much work was done to optimize each program.
To fix this, regex crate must be updated or replaced. I spent two weekends on this.
We do know that a more than average number of programs have been contributed for some programming languages.
Look at the source code and see which of the faster programs use hand written vectorized SIMD. Look and you might see simpler programs written in the same programming language.
… a pretty solid study on the boredom of performance-oriented software engineers grouped by programming language.