rough timing of alternate implementation of Rng.fill

gistfile1.scala

import com.nicta.rng.Rng
import org.joda.time.DateTime
import scalaz._
import Scalaz._

object Foo extends App {

  def time[A](f: => A): (Long, Long, Long) = {
    val t0 = System.currentTimeMillis
    val a = f
    val t1 = System.currentTimeMillis
    (t0, t1, t1-t0)
  }

  def fill[A](a: Rng[A], count: Int): Rng[List[A]] =
    Stream.from(0).take(count).traverseU(_ => a).map(_.toList)

  val rng = Rng.int

  Thread.sleep(5000)
  val a1@(s1a, e1a, ms1a) = time(fill(rng, 1000000).run.unsafePerformIO)
  println(s"a1: $ms1a")
  Thread.sleep(5000)
  val b1@(s1b, e1b, ms1b) = time(rng.fill(1000000).run.unsafePerformIO)
  println(s"b1: $ms1b")

  Thread.sleep(5000)
  val a2@(s2a, e2a, ms2a) = time(fill(rng, 1000000).run.unsafePerformIO)
  println(s"a2: $ms2a")
  Thread.sleep(5000)
  val b2@(s2b, e2b, ms2b) = time(rng.fill(1000000).run.unsafePerformIO)
  println(s"b2: $ms2b")

  Thread.sleep(5000)
  val a3@(s3a, e3a, ms3a) = time(fill(rng, 1000000).run.unsafePerformIO)
  println(s"a3: $ms3a")
  Thread.sleep(5000)
  val b3@(s3b, e3b, ms3b) = time(rng.fill(1000000).run.unsafePerformIO)
  println(s"b2: $ms3b")

  def p(t: (Long, Long, Long)): Unit = {
    println(s"s:${new DateTime(t._1)} e:${new DateTime(t._2)} ms: ${t._3}")
  }

  println("-------------------")
  p(a1)
  p(a2)
  p(a3)
  println("")
  p(b1)
  p(b2)
  p(b3)
}
// a1: 18630
// b1: 21453
// a2: 17847
// b2: 26559
// a3: 15243
// b2: 25351
// -------------------
// s:2014-12-18T18:18:45.910-05:00 e:2014-12-18T18:19:04.540-05:00 ms: 18630
// s:2014-12-18T18:19:36.003-05:00 e:2014-12-18T18:19:53.850-05:00 ms: 17847
// s:2014-12-18T18:20:30.417-05:00 e:2014-12-18T18:20:45.660-05:00 ms: 15243

// s:2014-12-18T18:19:09.545-05:00 e:2014-12-18T18:19:30.998-05:00 ms: 21453
// s:2014-12-18T18:19:58.856-05:00 e:2014-12-18T18:20:25.415-05:00 ms: 26559
// s:2014-12-18T18:20:50.666-05:00 e:2014-12-18T18:21:16.017-05:00 ms: 25351