public long perfLogEnd(String callerName, String method) {
    return perfLogEnd(callerName, method, null);
  }
Call this function in correspondence of PerfLogBegin to mark the end of the measurement.
@param callerName
@param method
@return long duration  the difference between now and startTime, or -1 if startTime is null
common/src/java/org/apache/hadoop/hive/ql/log/PerfLogger.java