Scala actor gc problem

          scala原生的acotor在任务结束之后并不会被回收，这也就是说，我无法无限制的创建actor。例如在一个HTTP服务器中，如果每个请求都创建一个新的actor处理，这样不久之后就会内存溢出。今天对scala和akka的actor内存使用情况做了简单测试

 测试代码如下

import akka.actor.Actor
import akka.actor.Actor.spawn
import akka.actor.PoisonPill
import java.io.FileOutputStream
import java.io.OutputStream
import java.io.OutputStreamWriter

case class Work(val index: Int, val output: OutputStream)
case class Result(val value: Double)

object Task {
  def main(args: Array[String]) {
    Thread.sleep(15000)
    new AkkaActorTask(10000000).execute()
  }
}

trait CalculateTask {
  val output: OutputStream
  val taskCount: Int
  def sendWork(work: Work)
  def execute() {
    for (i <- 1 to taskCount) {
      sendWork(Work(i, output))
    }
  }

}

class AkkaActorTask(val taskCount: Int) extends CalculateTask {
  val output = Work.akkaTaskOutput
  def sendWork(work: Work) {
    spawn {
      Work.doWork(work)
    }
  }

}

class ScalaActorTask(val taskCount: Int) extends CalculateTask {
  override val output = Work.scalaTaskOutput
  def sendWork(work: Work) {
    val actor = new ScalaActorWorker
    actor.start()
    actor ! work
  }

  class ScalaActorWorker extends scala.actors.Actor {
    def act = {
      react {
        case work:Work => Work.doWork(work); exit()
      }
    }
  }
}

object Work {
  val resultName = "result-"
  val akkaTaskOutput = new FileOutputStream(resultName + "akka")
  val scalaTaskOutput = new FileOutputStream(resultName + "scala")

  def doWork(work: Work) {
    work.output.write("log(%d) = %f".format(work.index, math.log(work.index)).getBytes())
    work.output.flush()
  }
}

 

程序说明：

 计算从1到10,000,000的整形的自然对数(math.log)并写入文件

分别选择Scala和Akka的actor实现，(spwan是一种一次性非常轻量级的akka actor)

下面是测试结果，

 

机器配置

CPU：Intel(R) Core(TM)2 Duo CPU     E8400  @ 3.00GHz

RAM ：4G

JAVA_OPTS: Xms100m Xmx100m

 

Akka actor performance

 

 

 

Scala actor performance

没有内存泄漏，100m可以负荷连续不断的

执行没多久就outOfMemory 

 

 

可以很明显看到scala actor gc的问题，即使exit了，也不会被回收。官方的说法是一个actor exit之后甚至可能被重新start。