Benchmark ways of getting the time as seconds (Scala/Java)

BenchTime.scala

import java.time.Clock
import java.time.Instant

object BenchTime {
  val clock = Clock.systemUTC

  def bench(fn: () => Unit, iterations: Int = 1000000) = {
    val start = System.nanoTime
    Range(0,iterations).foreach( _ => fn() )
    val end = System.nanoTime
    val millis = (end - start) / 1000000.0
    millis
  }

  def medianBench(title: String, fn: () => Unit) = {
    System.gc()
    Thread.sleep(500)
    val results = Range(0,10).map( _ => bench(fn))
    val median = results.sorted.apply(5)
    println(s"$median ms\t$title")
  }

  // Things to benchmark:
  def systemTime(): Unit = {
    val t = System.currentTimeMillis() / 1000
  }

  def clockTimeMillis(): Unit = {
    val t = clock.millis() / 1000
  }

  def clockTimeInstant(): Unit = {
    val t = clock.instant.getEpochSecond()
  }

  def instantNow(): Unit = {
    val t = Instant.now().getEpochSecond()
  }

  def main(args: Array[String]): Unit = {
    // Warm up the JIT with initial passes..
    bench(systemTime)
    bench(clockTimeMillis)
    bench(clockTimeInstant)
    bench(instantNow)

    medianBench("System.currentTimeMillis()", systemTime)
    medianBench("clock.millis()", clockTimeMillis)
    medianBench("clock.instant.getEpochSecond()", clockTimeInstant)
    medianBench("Instant.now().getEpochSecond()", instantNow)

    // Reverse order to verify
    medianBench("Instant.now().getEpochSecond()", instantNow)
    medianBench("clock.instant.getEpochSecond()", clockTimeInstant)
    medianBench("clock.millis()", clockTimeMillis)
    medianBench("System.currentTimeMillis()", systemTime)
  }

}

The results I get are:

17.578916 ms	System.currentTimeMillis() / 1000
17.284542 ms	clock.millis() / 1000
67.385 ms	clock.instant.getEpochSecond()
68.379417 ms	Instant.now().getEpochSecond()
67.518042 ms	Instant.now().getEpochSecond()
67.609458 ms	clock.instant.getEpochSecond()
17.327542 ms	clock.millis() / 1000
17.311 ms	System.currentTimeMillis() / 1000

(These are time elapsed for a million iterations, so the actual time-per-call is n/1000000)