Issue #21308 has been updated by radiospiel (Enrico Thierbach). The change in https://github.com/ruby/json/pull/768 was an easy win, because the previous implementation was calling into question`Float#to_s` via `rb_funcall`. The overhead of doing so is so extreme, that any implementation that would skirt that would show a massive improvement already. In fact, a first attempt using dtoa.c already showed a 600% or so performance improvement on a clinical example. I then decided that maybe this would also be a great moment to look at alternative implementations, since the flexibility provided by dtoa.c is not necessary in the context of the json gem. Other motivational factors have been: - dtoa generates output right to left (IIRC), but, at least for an integration with the json gem, generating left to right saves a memcpy, which would add a 5-10% overhead; - more modern algorithms are readily available. I believe integrating a more modern implementation in the ruby runtime certainly is benefitial, but the gains are not as massive as @watson1978 hopes to achieve here, unfortunately. ---------------------------------------- Feature #21308: Replacing the Float#to_s (dtoa.c) implementation with a modern algorithm https://bugs.ruby-lang.org/issues/21308#change-113190 * Author: watson1978 (Shizuo Fujita) * Status: Open ---------------------------------------- This is a feature request to replace Ruby's `Float#to_s` implementation with a modern high-performance float-to-string conversion algorithm such as Grisu. Currently, `Float#to_s` in Ruby uses the BSD-derived implementation in [missing/dtoa.c](https://github.com/ruby/ruby/blob/master/missing/dtoa.c). Meanwhile, `json` gem has adopted a Grisu-based implementation in [ruby/json#768](https://github.com/ruby/json/pull/768), it has been improve the performance of float-to-string conversion dramatically. It appears to have brought about a 10 times improvement in performance. However, the improvement is limited to the `json` gem. If we can use the same implementation in `Float#to_s`, it will introduce the improvement in all float-to-string conversion cases. (In additional, it would be better if an API could be added that could be called directly from the C extension library, it will reduce the overhead of the call.) -- https://bugs.ruby-lang.org/