~/projects/jruby ➔ ../jruby-1.5.2/bin/jruby --1.9 -X+C --server -rbenchmark -e "10.times { puts Benchmark.measure { f = Fiber.new { 1000000.times { Fiber.yield } }; 1000000.times { f.resume } } }"
 13.684000   0.000000  13.684000 ( 13.565000)
 13.076000   0.000000  13.076000 ( 13.076000)
 12.807000   0.000000  12.807000 ( 12.807000)
 12.677000   0.000000  12.677000 ( 12.677000)
 12.774000   0.000000  12.774000 ( 12.774000)
 12.708000   0.000000  12.708000 ( 12.708000)
 12.806000   0.000000  12.806000 ( 12.806000)
 12.688000   0.000000  12.688000 ( 12.688000)
 12.694000   0.000000  12.694000 ( 12.694000)
 12.729000   0.000000  12.729000 ( 12.729000)

~/projects/jruby ➔ jruby --1.9 -X+C --server -rbenchmark -e "10.times { puts Benchmark.measure { f = Fiber.new { 1000000.times { Fiber.yield } }; 1000000.times { f.resume } } }"  0.604000   0.000000   0.604000 (  0.493000)
  0.421000   0.000000   0.421000 (  0.421000)
  0.326000   0.000000   0.326000 (  0.326000)
  0.320000   0.000000   0.320000 (  0.320000)
  0.349000   0.000000   0.349000 (  0.350000)
  0.356000   0.000000   0.356000 (  0.357000)
  0.427000   0.000000   0.427000 (  0.427000)
  0.399000   0.000000   0.399000 (  0.399000)
  0.344000   0.000000   0.344000 (  0.344000)
  0.394000   0.000000   0.394000 (  0.394000)

~/projects/jruby ➔ ../ruby/ruby1.9.2 -rbenchmark -e "10.times { puts Benchmark.measure { f = Fiber.new { 1000000.times { Fiber.yield } }; 1000000.times { f.resume } } }"
  1.520000   0.010000   1.530000 (  1.531244)
  1.500000   0.000000   1.500000 (  1.528080)
  1.490000   0.000000   1.490000 (  1.503375)
  1.480000   0.010000   1.490000 (  1.497984)
  1.500000   0.010000   1.510000 (  1.548153)
  1.500000   0.000000   1.500000 (  1.507885)
  1.500000   0.000000   1.500000 (  1.504895)
  1.510000   0.010000   1.520000 (  1.570512)
  1.490000   0.000000   1.490000 (  1.502377)
  1.490000   0.010000   1.500000 (  1.501016)