Simple switch/dispatch microbench

gistfile1.txt

import scala.annotation.tailrec

sealed abstract class A { 
  def i: Int
}

object A { 
  @inline final def tpIdx(a: A) = a match {
    case SA(_) => 0
    case BA(_) => 1
    case LA(_) => 2
    case IA(_) => 3
    case DA(_) => 4
  }

  def main(argv: Array[String]) = { 
    @tailrec def fill(arr: Array[A], i: Int): Array[A] = { 
      if (i < 0) arr else {
        (i % 5) match {
          case 0 => arr(i) = SA(i.toString)
          case 1 => arr(i) = BA(i % 2 == 0)
          case 2 => arr(i) = LA(i)
          case 3 => arr(i) = IA(i)
          case 4 => arr(i) = DA(i)
        }   

        fill(arr, i - 1)
      }   
    }   

    val samples = fill(new Array[A](1000000), 1000000 - 1)

    val runs = 100 
    var i = 0 
    var acc = 0L
    while (i < samples.length * runs) {
      acc += tpIdx(samples(i % samples.length))
      i += 1
    }   

    println("warmup...." + acc)
    val starttpi = System.currentTimeMillis
    i = 0 
    acc = 0L
    while (i < samples.length * runs) {
      acc += tpIdx(samples(i % samples.length))
      i += 1
    }   

    val endtpi = System.currentTimeMillis
    println("tpi: " + acc + " : " + (endtpi - starttpi))

    i = 0 
    acc = 0L
    while (i < samples.length * runs) {
      acc += samples(i % samples.length).i
      i += 1
    }   

    println("warmup...." + acc)
    val startdisp = System.currentTimeMillis
    i = 0 
    acc = 0L
    while (i < samples.length * runs) {
      acc += samples(i % samples.length).i
      i += 1
    }   

    val enddisp = System.currentTimeMillis
    println("disp: " + acc + " : " + (enddisp - startdisp))
  }
}

case class SA(s: String) extends A { 
  final val i = 0 
}

case class BA(b: Boolean) extends A { 
  final val i = 1 
}

case class LA(l: Long) extends A { 
  final val i = 2 
}

case class IA(i0: Int) extends A { 
  final val i = 3 
}

case class DA(d: Double) extends A { 
  final val i = 4 
}