···2233There seems to be some kind of performance regression in Ruby 4.0 which showed up in my project, which I think is centered around regexp matching. I extracted some minimal code from the project, which runs significantly slower on Ruby 4.0 than on 3.4.
4455+#### First version (commit 20923f0028e2c023bd5e48be5118c5f97f4f243a)
66+57Running on my server, with 1000 loops:
6879```
···2325$ RUBYOPT="--enable-yjit" ruby test.rb 1000
24261000 * 940 = 940000 records in 13.457106019 -> 69851.57125706079 records/s
2527```
2828+2929+#### Minimal version (commit ccc62810ac635f3250bebe12a08d79ad5d9dd7f5)
3030+3131+With 2,000,000 loops:
3232+3333+```
3434+$ /tmp/ruby34/bin/ruby test.rb 2000000 0
3535+2000000 loops in 0.752061 -> 2659358.748824896 loops/s
3636+3737+$ /tmp/ruby4/bin/ruby test.rb 2000000 0
3838+2000000 loops in 2.711216 -> 737676.3784220808 loops/s
3939+```