Adding license header + README changes

Signed-off-by: Sayed Bilal Bari <[email protected]>

core/src/main/scala/org/apache/spark/rapids/tool/benchmarks/README.md

@@ -19,11 +19,12 @@ Use the java command to run the created benchmark class with the following suppo
 
 #### Running the Benchmark class directly
 ```shell
-java -cp $CLASSPATH:$SPARK_HOME/jars/* \
+java -cp $CLASSPATH:$SPARK_HOME/jars/*:$MAVEN-ARTIFACT-JAR \
 org.apache.spark.rapids.tool.benchmarks.SingleThreadedQualToolBenchmark \
 -i 3 -w 3 -a " $EVENT_LOGS_DIR"
 ```
 * `$CLASSPATH` : Path to the compiled class directory. Ex - `<SPARK_RAPIDS_TOOLS_REPO_PATH>/core/target/*`
+* `$MAVEN-ARTIFACT-JAR` : Path to maven-artifact jar. Download jar from [here](https://mvnrepository.com/artifact/org.apache.maven/maven-artifact/3.9.0)
 * `$EVENT_LOGS_DIR` : Path to the event logs directory
 
 #### Running the Benchmark class using tools jar

core/src/main/scala/org/apache/spark/sql/rapids/tool/util/MemoryMetricsTracker.scala

@@ -1,3 +1,19 @@
+/*
+ * Copyright (c) 2024, NVIDIA CORPORATION.
+ *
+ * Licensed 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.sql.rapids.tool.util
 
 import java.lang.management.ManagementFactory