Bug #19875
Updated by iz (Illia Zub) 8 months ago
`String#count` became slower since Ruby 3.1. Originally found by `@Freaky`: https://github.com/ruby/ruby/pull/4001#issuecomment-1714779781
Compared using the [`benchmark-driver` gem](https://github.com/benchmark-driver/benchmark-driver).
```
$ benchmark-driver tmp/string_count_benchmark_driver.yml --rbenv '3.1.1;3.1.4;2.7.2;3.2.2;3.0.6'
Calculating -------------------------------------
3.1.1 3.1.4 2.7.2 3.2.2 3.0.6
count 465.804 463.741 865.783 462.711 857.395 i/s - 10.000k times in 21.468251s 21.563768s 11.550239s 21.611783s 11.663235s
Comparison:
count
2.7.2: 865.8 i/s
3.0.6: 857.4 i/s - 1.01x slower
3.1.1: 465.8 i/s - 1.86x slower
3.1.4: 463.7 i/s - 1.87x slower
3.2.2: 462.7 i/s - 1.87x slower
```
Benchmark:
```yml
$ cat ./tmp/string_count_benchmark_driver.yml
loop_count: 10_000
prelude: |
html = "\nruby\n" * 1024 * 1024
benchmark:
count: html.count($/)
```
---
*Initially, I noticed the difference between `str.count($/)` and `str.lines.size` when working on the performance improvement: https://serpapi.com/blog/lines-count-failed-deployments/*