@George ThomasYour question too generic, you haven't mentioned for which component you want to do benchmarking.
For mapreduce - you can use the hadoop-mapreduce-client-jobclient-tests.jar
For hive benchmarking - You could use the following github code.
https://github.com/hortonworks/hive-testbench/tree/hdp26
For hbase:-
you could use the default hbase pe utility.
time hbase org.apache.hadoop.hbase.PerformanceEvaluation -nomapred randomWrite 10
or utility like "ycsb"