busy.scala

def busyLoop(time: Int, threads: Int) = Action { implicit r =>
  val started = System.currentTimeMillis()
  val workers =  (0 until threads).map { _ =>
    val out = new Thread({ () =>
      val digest = MessageDigest.getInstance("SHA-256")
      while (started + time * 1000 >= System.currentTimeMillis()) {
        digest.update(UUID.randomUUID().toString.getBytes(StandardCharsets.US_ASCII))
      }
    })
    out.start()
    out
  }
  var count = 0
  while (workers.exists(_.isAlive)) {
    count += 1
  }
  Ok(Json.obj("count" -> count))
}