Ruby Ractors vs Threads benchmark

ractors.rb

require 'benchmark'
require 'etc'

Ractor.new { :warmup } if defined?(Ractor)

def fibonacci(n)
  return n if (0..1).include? n

  fibonacci(n - 1) + fibonacci(n - 2)
end

NUMBER = 25
TIMES = 400
CPU_CORES = 2
PER_CORE = TIMES / CPU_CORES

raise 'TIMES is not divided evenly by CPU cores' unless TIMES.modulo(CPU_CORES).zero?

Benchmark.bmbm do |x|
  x.report('inline') { TIMES.times { fibonacci(NUMBER) } }

  x.report('thread inline') do
    Thread.new { TIMES.times { fibonacci(NUMBER) } }.join
  end
  x.report("threads per #{CPU_CORES} cores") do
    Array.new(CPU_CORES) do
      Thread.new { PER_CORE.times { fibonacci(NUMBER) } }
    end.each(&:join)
  end
  x.report('per-task threads at once') do
    Array.new(TIMES) do
      Thread.new { fibonacci(NUMBER) }
    end.each(&:join)
  end
  x.report("per-task threads batches per #{CPU_CORES} cores") do
    CPU_CORES.times do
      Array.new(PER_CORE) do
        Thread.new { fibonacci(NUMBER) }
      end.each(&:join)
    end
  end

  if defined?(Ractor)
    x.report('ractor inline') do
      Ractor.new { TIMES.times { fibonacci(NUMBER) } }.take
    end
    x.report("ractors per #{CPU_CORES} cores") do
      Array.new(CPU_CORES) do
        Ractor.new { PER_CORE.times { fibonacci(NUMBER) } }
      end.each(&:take)
    end
    x.report('per-task ractors at once') do
      Array.new(TIMES) do
        Ractor.new { fibonacci(NUMBER) }
      end.each(&:take)
    end
    x.report("per-task ractor batches per #{CPU_CORES} cores") do
      CPU_CORES.times do
        Array.new(PER_CORE) do
          Ractor.new { fibonacci(NUMBER) }
        end.each(&:take)
      end
    end
  end
end