Issue #20112 has been updated by luke-gru (Luke Gruber). This is most likely related to ruby's new M:N thread system. ---------------------------------------- Bug #20112: Ractors not working properly in ruby 3.3.0 https://bugs.ruby-lang.org/issues/20112#change-105960 * Author: ariasdiniz (Aria Diniz) * Status: Open * Priority: Normal * ruby -v: 3.3.0 * Backport: 3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN ---------------------------------------- I recently installed Ruby 3.3.0, and noticed that some of my scripts that use Ractors started to struggle with performance. After doing some benchmarks, I noticed that, while Ractors seem to be working well on Ruby 3.2.2, they're not working properly on 3.3.0. I'm using Ubuntu 22.04.3 LTS Here is the benchmark code: ``` ruby # frozen_string_literal: true require 'benchmark' Ractor.new { :warmup } if defined?(Ractor) Benchmark.bmbm do |x| x.report("Thread: ") do threads = [] 8.times do |i| threads << Thread.new do 20000000.times do |j| ((i * 20000000) + j)**2 end end end threads.each(&:join) end x.report("Ractor: ") do ractors = [] 0..8.times do |i| ractors << Ractor.new(i) do |k| 20000000.times do |j| ((k * 20000000) + j)**2 end end end ractors.map(&:take) end end ``` Here is the results for Ruby 3.2.2: Rehearsal -------------------------------------------- Thread: 7.666909 0.001091 7.668000 ( 7.675266) Ractor: 19.318528 0.012017 19.330545 ( 2.505888) ---------------------------------- total: 26.998545sec user system total real Thread: 7.918141 0.004011 7.922152 ( 7.928772) Ractor: 19.366414 0.003954 19.370368 ( 2.517993) Here is the results for Ruby 3.3.0: Rehearsal -------------------------------------------- Thread: 8.634152 0.010895 8.645047 ( 8.645104) Ractor: 100.172179 0.035985 100.208164 ( 15.213245) --------------------------------- total: 108.853211sec user system total real Thread: 9.451236 0.004002 9.455238 ( 9.460132) Ractor: 118.463294 0.119942 118.583236 ( 18.462157) -- https://bugs.ruby-lang.org/

Issue #20112 has been updated by shadoe (Matthias Mueller). I stumbled across the same problem. Using the example code taken from https://www.honeybadger.io/blog/ractors/ I also get unexpected results using Ractors in Ruby 3.3.0 in contrast to 3.2.2. The code: ``` def tarai(x, y, z) = x <= y ? y : tarai(tarai(x-1, y, z), tarai(y-1, z, x), tarai(z-1, x, y)) require 'benchmark' Benchmark.bm do |x| # sequential version x.report('seq'){ 4.times{ tarai(14, 7, 0) } } # parallel version x.report('par'){ 4.times.map do Ractor.new { tarai(14, 7, 0) } end.each(&:take) } end ``` The results on my machine (Fedora 39, Kernel 6.6.8, AMD Ryzen 3 5300U (4 cores, 8 threads)): ``` Ruby 3.2.2: user system total real seq 70.461697 0.012965 70.474662 ( 71.029432) par 70.103737 0.009663 70.113400 ( 17.677001) Ruby 3.3.0: user system total real seq 74.018553 0.010097 74.028650 ( 74.329446) par381.260338 0.070133 381.330471 ( 96.591537) ``` ---------------------------------------- Bug #20112: Ractors not working properly in ruby 3.3.0 https://bugs.ruby-lang.org/issues/20112#change-106002 * Author: ariasdiniz (Aria Diniz) * Status: Assigned * Priority: Normal * Assignee: ko1 (Koichi Sasada) * ruby -v: 3.3.0 * Backport: 3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN ---------------------------------------- I recently installed Ruby 3.3.0, and noticed that some of my scripts that use Ractors started to struggle with performance. After doing some benchmarks, I noticed that, while Ractors seem to be working well on Ruby 3.2.2, they're not working properly on 3.3.0. I'm using Ubuntu 22.04.3 LTS Here is the benchmark code: ``` ruby # frozen_string_literal: true require 'benchmark' Ractor.new { :warmup } if defined?(Ractor) Benchmark.bmbm do |x| x.report("Thread: ") do threads = [] 8.times do |i| threads << Thread.new do 20000000.times do |j| ((i * 20000000) + j)**2 end end end threads.each(&:join) end x.report("Ractor: ") do ractors = [] 0..8.times do |i| ractors << Ractor.new(i) do |k| 20000000.times do |j| ((k * 20000000) + j)**2 end end end ractors.map(&:take) end end ``` Here is the results for Ruby 3.2.2: Rehearsal -------------------------------------------- Thread: 7.666909 0.001091 7.668000 ( 7.675266) Ractor: 19.318528 0.012017 19.330545 ( 2.505888) ---------------------------------- total: 26.998545sec user system total real Thread: 7.918141 0.004011 7.922152 ( 7.928772) Ractor: 19.366414 0.003954 19.370368 ( 2.517993) Here is the results for Ruby 3.3.0: Rehearsal -------------------------------------------- Thread: 8.634152 0.010895 8.645047 ( 8.645104) Ractor: 100.172179 0.035985 100.208164 ( 15.213245) --------------------------------- total: 108.853211sec user system total real Thread: 9.451236 0.004002 9.455238 ( 9.460132) Ractor: 118.463294 0.119942 118.583236 ( 18.462157) -- https://bugs.ruby-lang.org/