Adding check if ParallelGc is enabled

Author: ShubhamGupta29

app/com/linkedin/drelephant/spark/heuristics/ExecutorGcHeuristic.scala

@@ -56,7 +56,7 @@ class ExecutorGcHeuristic(private val heuristicConfigurationData: HeuristicConfi
     //adding recommendations to the result, severityTimeA corresponds to the ascending severity calculation
     if (evaluator.severityTimeA.getValue > Severity.LOW.getValue) {
       resultDetails = resultDetails :+ new HeuristicResultDetails("Gc ratio high",
-        "The job is spending too much time on GC. Recommended to increase the executor memory and also can enable ParallelGC using spark.executor.extraJavaOptions or reducing number of UDF calls.")
+        "The job is spending too much time on GC. Recommended to increase the executor memory." + evaluator.parallelGcRecommendation + "Can also try reducing number of UDF calls.")
     }
     //severityTimeD corresponds to the descending severity calculation
     if (evaluator.severityTimeD.getValue > Severity.LOW.getValue) {
@@ -104,6 +104,9 @@ object ExecutorGcHeuristic {
       throw new Exception("No executor information available.")
     }
 
+    val isParallelGcEnabled: Boolean = appConfigurationProperties.getOrElse("spark.executor.extraJavaOptions","").contains("XX:+UseParallelGC")
+    val parallelGcRecommendation: String = if (isParallelGcEnabled)  "" else "Enable ParallelGc using spark.executor.extraJavaOptions."
+
     lazy val appConfigurationProperties: Map[String, String] =
       data.appConfigurationProperties
     var (jvmTime, executorRunTimeTotal) = getTimeValues(executorSummaries)