async

It's adopted by Ruby: <https://github.com/socketry/io-event> which is used by <https://github.com/socketry/async> which is part of the Ruby 3+ Fiber Scheduler for light weight concurrency. It shows promising performance.

i think this announcement https://brunosutic.com/blog/async-ruby & the associated async libraries (https://github.com/socketry/async) do a much better job of showing off the potential for the ruby 3.1+ fiber scheduler. Async gem is powered by a fiber scheduler under the hood, and what you get is un-colored async-ready ruby code. That is to say, you can write a normal rack app with falcon-async as the webserver and get node/event-loop scale co-operative concurrency without changing your code. Its pretty exciting! Unfortunately rails makes heavy use of thread locals which arent compatible with fiber concurrency, so its going to take awhile until its async-ready, but I believe progress is being made (Async ActiveRecord was merged recently).

In a sense the GIL (or actually GVL as it's called in current ruby versions) has already been removed for ruby. It's only the original MRI Ruby that still has it several over Ruby implementations already removed it. e.g. JRuby. Concurrent-Ruby[1] is probably a good place to start if you want to work with GVL free ruby on JRuby. It's quite well supported and is currently used by Rails. If you just want async or non-blocking IO I'd take a look at the Async Gem[2]. It looks pretty solid in Ruby > 3.0 and it's been invited by Matz to be part of the stdlib, which I think is a pretty good endorsement. For MRI itself I don't think it's likely they'll ever remove the GVL. Ractors are probably a better solution for CPU concurrency in the long run, although I think they're pretty experimental currently. 1. https://github.com/ruby-concurrency/co