Issue #21797 has been updated by osyoyu (Daisuke Aritomo). It'd be nice if `RUBY_MAX_CPU` would be autoconfigured based on this, just like Go 1.25 `GOMAXPROCS`. Its default value is currently fixed to 8, but not many cloud containers have 8 cores worth of processors. https://github.com/ruby/ruby/blob/8efaf5e6b6a25e0d237f3d71b75865661ae98268/t... ---------------------------------------- Feature #21797: Make Etc.nprocessors cgroup-aware on Linux https://bugs.ruby-lang.org/issues/21797#change-115823 * Author: moznion (Taiki Kawakami) * Status: Open ---------------------------------------- Currently, `Etc.nprocessors` ignores cgroup CPU quotas. This causes issues in containers where CPU limits differ from the host CPU count. I have written a gem for this purpose (https://github.com/moznion/maxprocs-ruby), but it would be preferable if the Ruby core implementation respected cgroup configuration. Additionally, concurrent-ruby provides similar functionality, but if the language itself offered this capability, language users would not need to implement it individually. And some parts of the Ruby language handle the number of processors using hard-coded values (e.g., https://github.com/ruby/ruby/blob/8efaf5e6b6a25e0d237f3d71b75865661ae98268/t...), so this could also be useful for Ruby language development. Extending `Etc.nprocessors` to respect cgroups is one option, but that would be a breaking change, so adding a new API (e.g., `Etc.cpu_quota` or something?) might be a better approach. ## Prior Art - Go 1.25: runtime GOMAXPROCS (Issue [#73193](https://github.com/golang/go/issues/73193)) - [uber-go/automaxprocs](https://github.com/uber-go/automaxprocs) - [concurrent-ruby](https://github.com/ruby-concurrency/concurrent-ruby): https://github.com/ruby-concurrency/concurrent-ruby/blob/129cf004294af68ac53... -- https://bugs.ruby-lang.org/