Github user squito commented on a diff in the pull request:
https://github.com/apache/spark/pull/22612#discussion_r236848338
--- Diff:
core/src/main/scala/org/apache/spark/executor/ProcfsMetricsGetter.scala ---
@@ -0,0 +1,231 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.spark.executor
+
+import java.io._
+import java.nio.charset.Charset
+import java.nio.file.{Files, Paths}
+import java.util.Locale
+
+import scala.collection.mutable
+import scala.collection.mutable.ArrayBuffer
+import scala.util.Try
+
+import org.apache.spark.{SparkEnv, SparkException}
+import org.apache.spark.internal.{config, Logging}
+import org.apache.spark.util.Utils
+
+
+private[spark] case class ProcfsMetrics(
+ jvmVmemTotal: Long,
+ jvmRSSTotal: Long,
+ pythonVmemTotal: Long,
+ pythonRSSTotal: Long,
+ otherVmemTotal: Long,
+ otherRSSTotal: Long)
+
+// Some of the ideas here are taken from the ProcfsBasedProcessTree class
in hadoop
+// project.
+private[spark] class ProcfsMetricsGetter(
+ val procfsDir: String = "/proc/",
+ val pSizeForTest: Long = 0) extends Logging {
+ val procfsStatFile = "stat"
+ val testing = sys.env.contains("SPARK_TESTING") ||
sys.props.contains("spark.testing")
+ val pageSize = computePageSize()
+ var isAvailable: Boolean = isProcfsAvailable
+ private val pid = computePid()
+
+ private lazy val isProcfsAvailable: Boolean = {
+ if (testing) {
+ true
+ }
+ else {
+ val procDirExists = Try(Files.exists(Paths.get(procfsDir))).recover {
+ case ioe: IOException =>
+ logWarning("Exception checking for procfs dir", ioe)
+ false
+ }
+ val shouldLogStageExecutorMetrics =
+ SparkEnv.get.conf.get(config.EVENT_LOG_STAGE_EXECUTOR_METRICS)
+ val shouldLogStageExecutorProcessTreeMetrics =
+ SparkEnv.get.conf.get(config.EVENT_LOG_PROCESS_TREE_METRICS)
+ procDirExists.get && shouldLogStageExecutorProcessTreeMetrics &&
shouldLogStageExecutorMetrics
+ }
+ }
+
+ private def computePid(): Int = {
+ if (!isAvailable || testing) {
+ return -1;
+ }
+ try {
+ // This can be simplified in java9:
+ //
https://docs.oracle.com/javase/9/docs/api/java/lang/ProcessHandle.html
+ val cmd = Array("bash", "-c", "echo $PPID")
+ val out = Utils.executeAndGetOutput(cmd)
+ val pid = Integer.parseInt(out.split("\n")(0))
+ return pid;
+ }
+ catch {
+ case e: SparkException =>
+ logWarning("Exception when trying to compute process tree." +
+ " As a result reporting of ProcessTree metrics is stopped", e)
+ isAvailable = false
+ -1
+ }
+ }
+
+ private def computePageSize(): Long = {
+ if (testing) {
+ return pSizeForTest;
+ }
+ try {
+ val cmd = Array("getconf", "PAGESIZE")
+ val out = Utils.executeAndGetOutput(cmd)
+ Integer.parseInt(out.split("\n")(0))
+ } catch {
+ case e: Exception =>
+ logWarning("Exception when trying to compute pagesize, as a" +
+ " result reporting of ProcessTree metrics is stopped")
+ isAvailable = false
+ 0
+ }
+ }
+
+ private def computeProcessTree(): Set[Int] = {
+ if (!isAvailable || testing) {
+ return Set()
+ }
+ var ptree: Set[Int] = Set()
+ ptree += pid
+ val queue = mutable.Queue.empty[Int]
+ queue += pid
+ while( !queue.isEmpty ) {
+ val p = queue.dequeue()
+ val c = getChildPids(p)
+ if(!c.isEmpty) {
+ queue ++= c
+ ptree ++= c.toSet
+ }
+ }
+ ptree
+ }
+
+ private def getChildPids(pid: Int): ArrayBuffer[Int] = {
+ try {
+ val builder = new ProcessBuilder("pgrep", "-P", pid.toString)
+ val process = builder.start()
+ val childPidsInInt = mutable.ArrayBuffer.empty[Int]
+ def appendChildPid(s: String): Unit = {
+ if (s != "") {
+ logTrace("Found a child pid:" + s)
+ childPidsInInt += Integer.parseInt(s)
+ }
+ }
+ val stdoutThread = Utils.processStreamByLine("read stdout for pgrep",
+ process.getInputStream, appendChildPid)
+ val error = process.getErrorStream
+ var errorString = ""
+ (0 until error.available()).foreach { i =>
--- End diff --
btw -- I realize I'm being somewhat paranoid here.
`Utils.executeAndGetOutput()` has this issue if `redirectStderr = false`.
try this with this script:
```sh
more lotsOfStderr.sh
n=$1
for (( c=1; c<=n; c++ ))
do
echo "stderr $c" 1>&2
if [ $(( $c % 100 )) -eq 0 ] ; then
echo "stdout $c"
fi
done
```
and then in a spark shell
```
scala> val clz = Class.forName("org.apache.spark.util.Utils")
clz: Class[_] = class org.apache.spark.util.Utils
scala> val m = clz.getMethods().filter{_.getName() ==
"executeAndGetOutput"}.head
m: java.lang.reflect.Method = public static java.lang.String
org.apache.spark.util.Utils.executeAndGetOutput(scala.collection.Seq,java.io.File,scala.collection.Map,boolean)
scala> m.invoke(null, Seq("/Users/irashid/lotsOfStderr.sh"), new
java.io.File("."), Map(), false.asInstanceOf[java.lang.Boolean])
[... lots of output]
scala> m.invoke(null, Seq("/Users/irashid/lotsOfStderr.sh", "6000"), new
java.io.File("."), Map(), false.asInstanceOf[java.lang.Boolean])
[blocks forever]
```
so ~5k lines of stderr seems fine, it gets buffered, but at 6K its stuck
waiting for something to read from stderr. That limit will probably vary by
system.
you could just ignore stderr completely, and hope its under whatever the
limit is ...
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