[ https://issues.apache.org/jira/browse/SPARK-6056?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
SaintBacchus updated SPARK-6056: -------------------------------- Description: No matter set the `preferDirectBufs` or limit the number of thread or not ,spark can not limit the use of offheap memory. At line 269 of the class 'AbstractNioByteChannel' in netty-4.0.23.Final, Netty had allocated a offheap memory buffer with the same size in heap. So how many buffer you want to transfor, the same size offheap memory will be allocated. But once the allocated memory size reach the capacity of the overhead momery set in yarn, this executor will be killed. I wrote a simple code to test it: progress: 1. bin/spark-shell --master yarn-cilent --executor-cores 40 --num-executors 1 2. :load test.scala in spark-shell 3. use comman {pid=$(jps|grep CoarseGrainedExecutorBackend |awk '{print $1}');top -b -p $pid|grep $pid} to catch executor on slave node 4. test_driver(20,100)(test) in spark-shell 5. watch the output of the command on slave node If use multi-thread to get len, the physical memery will soon exceed the limit set by spark.yarn.executor.memoryOverhead was: No matter set the `preferDirectBufs` or limit the number of thread or not ,spark can not limit the use of offheap memory. At line 269 of the class 'AbstractNioByteChannel' in netty-4.0.23.Final, Netty had allocated a offheap memory buffer with the same size in heap. So how many buffer you want to transfor, the same size offheap memory will be allocated. But once the allocated memory size reach the capacity of the overhead momery set in yarn, this executor will be killed. I wrote a simple code to test it: ```test.scala import org.apache.spark.storage._ import org.apache.spark._ val bufferRdd = sc.makeRDD(0 to 10, 10).map(x=>new Array[Byte](10*1024*1024)).persist bufferRdd.count val part = bufferRdd.partitions(0) val sparkEnv = SparkEnv.get val blockMgr = sparkEnv.blockManager def test = { val blockOption = blockMgr.get(RDDBlockId(bufferRdd.id, part.index)) val resultIt = blockOption.get.data.asInstanceOf[Iterator[Array[Byte]]] val len = resultIt.map(_.length).sum } def test_driver(count:Int, parallel:Int)(f: => Unit) = { val tpool = new scala.concurrent.forkjoin.ForkJoinPool(parallel) val taskSupport = new scala.collection.parallel.ForkJoinTaskSupport(tpool) val parseq = (1 to count).par parseq.tasksupport = taskSupport parseq.foreach(x=>f) tpool.shutdown tpool.awaitTermination(100, java.util.concurrent.TimeUnit.SECONDS) } ``` progress: 1. bin/spark-shell --master yarn-cilent --executor-cores 40 --num-executors 1 2. :load test.scala in spark-shell 3. use comman {pid=$(jps|grep CoarseGrainedExecutorBackend |awk '{print $1}');top -b -p $pid|grep $pid} to catch executor on slave node 4. test_driver(20,100)(test) in spark-shell 5. watch the output of the command on slave node If use multi-thread to get len, the physical memery will soon exceed the limit set by spark.yarn.executor.memoryOverhead > Unlimit offHeap memory use cause RM killing the container > --------------------------------------------------------- > > Key: SPARK-6056 > URL: https://issues.apache.org/jira/browse/SPARK-6056 > Project: Spark > Issue Type: Bug > Components: Shuffle, Spark Core > Affects Versions: 1.2.1 > Reporter: SaintBacchus > > No matter set the `preferDirectBufs` or limit the number of thread or not > ,spark can not limit the use of offheap memory. > At line 269 of the class 'AbstractNioByteChannel' in netty-4.0.23.Final, > Netty had allocated a offheap memory buffer with the same size in heap. > So how many buffer you want to transfor, the same size offheap memory will be > allocated. > But once the allocated memory size reach the capacity of the overhead momery > set in yarn, this executor will be killed. > I wrote a simple code to test it: > progress: > 1. bin/spark-shell --master yarn-cilent --executor-cores 40 --num-executors 1 > 2. :load test.scala in spark-shell > 3. use comman {pid=$(jps|grep CoarseGrainedExecutorBackend |awk '{print > $1}');top -b -p $pid|grep $pid} to catch executor on slave node > 4. test_driver(20,100)(test) in spark-shell > 5. watch the output of the command on slave node > If use multi-thread to get len, the physical memery will soon exceed the > limit set by spark.yarn.executor.memoryOverhead -- This message was sent by Atlassian JIRA (v6.3.4#6332) --------------------------------------------------------------------- To unsubscribe, e-mail: issues-unsubscr...@spark.apache.org For additional commands, e-mail: issues-h...@spark.apache.org