~/NetBeansProjects/jruby ➔ cat test/bench/bench_thread_creation.rb
require 'benchmark'

(ARGV[0] || 10).to_i.times do
  Benchmark.bm(20) do |bm|
    bm.report('control loop') { 10_000.times { 1 } }
    bm.report('Thread.new.join loop') { 10_000.times { Thread.new { 1 }.join } }
  end
end
~/NetBeansProjects/jruby ➔ jruby --server test/bench/bench_thread_creation.rb 5
                          user     system      total        real
control loop          0.203000   0.000000   0.203000 (  0.202630)
Thread.new.join loop  3.196000   0.000000   3.196000 (  3.195984)
                          user     system      total        real
control loop          0.006000   0.000000   0.006000 (  0.005816)
Thread.new.join loop  2.729000   0.000000   2.729000 (  2.728205)
                          user     system      total        real
control loop          0.002000   0.000000   0.002000 (  0.002222)
Thread.new.join loop  1.982000   0.000000   1.982000 (  1.981994)
                          user     system      total        real
control loop          0.001000   0.000000   0.001000 (  0.001320)
Thread.new.join loop  2.059000   0.000000   2.059000 (  2.059305)
                          user     system      total        real
control loop          0.001000   0.000000   0.001000 (  0.001289)
Thread.new.join loop  1.955000   0.000000   1.955000 (  1.955280)
~/NetBeansProjects/jruby ➔ jruby -J-Djruby.thread.pool.enabled=true --server test/bench/bench_thread_creation.rb 5
                          user     system      total        real
control loop          0.179000   0.000000   0.179000 (  0.178242)
Thread.new.join loop  1.572000   0.000000   1.572000 (  1.573915)
                          user     system      total        real
control loop          0.012000   0.000000   0.012000 (  0.006952)
Thread.new.join loop  1.082000   0.000000   1.082000 (  1.082589)
                          user     system      total        real
control loop          0.003000   0.000000   0.003000 (  0.003126)
Thread.new.join loop  0.580000   0.000000   0.580000 (  0.580560)
                          user     system      total        real
control loop          0.002000   0.000000   0.002000 (  0.001294)
Thread.new.join loop  0.605000   0.000000   0.605000 (  0.605378)
                          user     system      total        real
control loop          0.003000   0.000000   0.003000 (  0.002854)
Thread.new.join loop  0.543000   0.000000   0.543000 (  0.542308)
~/NetBeansProjects/jruby ➔ /opt/local/bin/ruby test/bench/bench_thread_creation.rb 5
                          user     system      total        real
control loop          0.010000   0.000000   0.010000 (  0.002354)
Thread.new.join loop  0.260000   0.250000   0.510000 (  0.521613)
                          user     system      total        real
control loop          0.000000   0.000000   0.000000 (  0.002005)
Thread.new.join loop  0.270000   0.240000   0.510000 (  0.519673)
                          user     system      total        real
control loop          0.000000   0.000000   0.000000 (  0.001724)
Thread.new.join loop  0.260000   0.250000   0.510000 (  0.519492)
                          user     system      total        real
control loop          0.000000   0.000000   0.000000 (  0.001570)
Thread.new.join loop  0.270000   0.240000   0.510000 (  0.515869)
                          user     system      total        real
control loop          0.000000   0.000000   0.000000 (  0.001550)
Thread.new.join loop  0.260000   0.240000   0.500000 (  0.521391)
~/NetBeansProjects/jruby ➔ ../ruby1.9/ruby -I ../ruby1.9/lib test/bench/bench_thread_creation.rb 5
                          user     system      total        real
control loop          0.000000   0.000000   0.000000 (  0.001757)
Thread.new.join loop  0.280000   0.570000   0.850000 (  0.650961)
                          user     system      total        real
control loop          0.010000   0.000000   0.010000 (  0.001508)
Thread.new.join loop  0.280000   0.570000   0.850000 (  0.633450)
                          user     system      total        real
control loop          0.000000   0.000000   0.000000 (  0.001170)
Thread.new.join loop  0.280000   0.570000   0.850000 (  0.641375)
                          user     system      total        real
control loop          0.000000   0.000000   0.000000 (  0.001144)
Thread.new.join loop  0.280000   0.560000   0.840000 (  0.642496)
                          user     system      total        real
control loop          0.000000   0.000000   0.000000 (  0.001233)
Thread.new.join loop  0.280000   0.570000   0.850000 (  0.639463)
~/NetBeansProjects/jruby ➔ ../rubinius/bin/rbx test/bench/bench_thread_creation.rb 5
                          user     system      total        real
control loop          0.002464   0.000000   0.002464 (  0.002445)
Thread.new.join loop 27.212328   0.000000  27.212328 ( 27.212360)