Issue #18572 has been updated by shugo (Shugo Maeda). Eregon (Benoit Daloze) wrote in #note-9:

From https://bugs.ruby-lang.org/issues/14083#note-3 it seems part of the problem at least is CRuby currently implements what I would call invalid usages of refinements (different set of activates refinements over time for a given call site), and that basically means extra checks and overhead, e.g., for a method which was refined once, even if there are no refinements active in the current scope.

If it's needed to fix the performance issue, it may be acceptable to raise exceptions in some cases (but I don't know the exact condition of such cases). @ko1, @matz What do you think? It's simple to prohibit using calls in blocks, but it will break backward compatibility, e.g., using in module_eval. ---------------------------------------- Bug #18572: Performance regression when invoking refined methods https://bugs.ruby-lang.org/issues/18572#change-103487 * Author: palkan (Vladimir Dementyev) * Status: Assigned * Priority: Normal * Assignee: ko1 (Koichi Sasada) * Backport: 2.6: UNKNOWN, 2.7: UNKNOWN, 3.0: UNKNOWN, 3.1: UNKNOWN ---------------------------------------- Since Ruby 3.0, defining a refinement for a method slows down its execution even if we do not activate the refinement: ```ruby require "benchmark_driver" source = <<~RUBY class Hash def symbolize_keys transform_keys { |key| key.to_sym rescue key } end def refined_symbolize_keys transform_keys { |key| key.to_sym rescue key } end end module HashRefinements refine Hash do def refined_symbolize_keys raise "never called" end end end HASH = {foo: 1, bar: 2, baz: 3} class Foo def original end def refined end end module FooRefinements refine Foo do def refined raise "never called" end end end FOO = Foo.new RUBY Benchmark.driver do |x| x.prelude %Q{ #{source} } x.report "#symbolize_keys original", %{ HASH.symbolize_keys } x.report "#symbolize_keys refined", %{ HASH.refined_symbolize_keys } end Benchmark.driver do |x| x.prelude %Q{ #{source} } x.report "no-op original", %{ FOO.original } x.report "no-op refined", %{ FOO.refined } end ``` The results for Ruby 3.1: ```sh ... Comparison: #symbolize_keys original: 2372420.1 i/s #symbolize_keys refined: 1941019.0 i/s - 1.22x slower ... Comparison: no-op original: 51790974.2 i/s no-op refined: 14456518.9 i/s - 3.58x slower ``` For Ruby 2.6 and 2.7: ```sh Comparison: #symbolize_keys original: 2278339.7 i/s #symbolize_keys refined: 2264153.1 i/s - 1.01x slower ... Comparison: no-op refined: 64178338.5 i/s no-op original: 63357980.1 i/s - 1.01x slower ``` You can find the full code and more results in this [gist](https://gist.github.com/palkan/637dc83edd86d70b5dbf72f2a4d702e5). P.S. The problem was originally noticed by @byroot, see https://github.com/ruby-i18n/i18n/pull/573 -- https://bugs.ruby-lang.org/