Add a serialisation time column to the StagePage.

core/src/main/scala/org/apache/spark/ui/jobs/StagePage.scala

@@ -86,7 +86,7 @@ private[spark] class StagePage(parent: JobProgressUI) {
 
       val taskHeaders: Seq[String] =
         Seq("Task Index", "Task ID", "Status", "Locality Level", "Executor", "Launch Time") ++
-        Seq("Duration", "GC Time") ++
+        Seq("Duration", "GC Time", "Result Ser Time") ++
         {if (hasShuffleRead) Seq("Shuffle Read")  else Nil} ++
         {if (hasShuffleWrite) Seq("Write Time", "Shuffle Write") else Nil} ++
         Seq("Errors")
@@ -189,6 +189,7 @@ private[spark] class StagePage(parent: JobProgressUI) {
     val formatDuration = if (info.status == "RUNNING") parent.formatDuration(duration)
       else metrics.map(m => parent.formatDuration(m.executorRunTime)).getOrElse("")
     val gcTime = metrics.map(m => m.jvmGCTime).getOrElse(0L)
+    val serializationTime = metrics.map(m => m.resultSerializationTime).getOrElse(0L)
 
     val maybeShuffleRead = metrics.flatMap{m => m.shuffleReadMetrics}.map{s => s.remoteBytesRead}
     val shuffleReadSortable = maybeShuffleRead.map(_.toString).getOrElse("")
@@ -216,6 +217,9 @@ private[spark] class StagePage(parent: JobProgressUI) {
       <td sorttable_customkey={gcTime.toString}>
         {if (gcTime > 0) parent.formatDuration(gcTime) else ""}
       </td>
+      <td sorttable_customkey={serializationTime.toString}>
+        {if (serializationTime > 0) parent.formatDuration(serializationTime) else ""}
+      </td>
       {if (shuffleRead) {
          <td sorttable_customkey={shuffleReadSortable}>
            {shuffleReadReadable}