Lambda を渡す。 g のほうがわずかに速いか

bench.log

$ # call f
$ for i in `seq 10`; scala Main
366
379
383
372
374
373
376
367
385
386
$ # call g
$ for i in `seq 10`; scala Main
361
384
353
348
349
355
363
353
354
393

Lambda.scala

object Main {
  def main(args: Array[String]) {
    val to_s: Int => String = _.toString
    val start = System.currentTimeMillis()
    (0 until 5000000).foreach { i =>
      f(to_s, i)
      // g(i)
    }
    val end = System.currentTimeMillis()
    println(end - start)
  }

  def f(fun: Int => String, x: Int) = fun(x)
  def g(x: Int) = x.toString
}