Ruby 3 benchmark for thread/process/Ractor

Ruby 3.0.0 benchmark.rb

def tarai(x, y, z)
  x <= y ? y : tarai(
    tarai(x-1, y, z),
    tarai(y-1, z, x),
    tarai(z-1, x, y)
  )
end

require 'benchmark'

Benchmark.bm do |x|
  x.report('seq') do
    4.times { tarai(14, 7, 0) }
  end
end # => total: 83, real: 83

Benchmark.bm do |x|
  x.report('thd') do
    4.times.map do
      Thread.new { tarai(14, 7, 0) }
    end.each(&:join)
  end
end # => total: 79, real: 79

Benchmark.bm do |x|
  x.report('par') do
    4.times.map do
      Ractor.new { tarai(14, 7, 0) }
    end.each(&:take)
  end
end # => total: 114, real: 29

Benchmark.bm do |x|
  x.report('fork') do
    4.times.map do
      Process.fork { tarai(14, 7, 0) }
    end
    Process.waitall
  end
end # => total: 105, real: 26