[cdh-user] Tracing of Map Reduce Application in Hadoop using Htrace

I am trying to understand how can I get traces for a map reduce application that is executed in Hadoop. Until now what I can find is to get traces of FsShell (http://hadoop.apache.org/docs/stable/hadoop-project-dist/hadoop-common/Tracing.html) but am not clear about application specific traces.

Can anyone guide me plz??