stm.scala

import scala.concurrent.stm._

object Test {
  def run(n: Int) = {
    val x = Ref(0)
    val y = Ref(0)

    (1 to n) foreach { i =>
      atomic { implicit tx =>
        val x1 = x()
        val y1 = y()
        if (x() != y()) retry
        x() = x1 + 1
        y() = y1 + 1
      }
    }
  }

  def time(block: => Unit) = {
    val beginTime=System.currentTimeMillis
    block
    val endTime=System.currentTimeMillis
    println(endTime-beginTime)
  }

  time(run(1000000))
}

// scala> time(run(1000000))
// 401