public static PerfLogger getPerfLogger(boolean resetPerfLogger) {
    SessionState ss = get();
    if (ss == null) {
      return PerfLogger.getPerfLogger(null, resetPerfLogger);
    } else {
      return PerfLogger.getPerfLogger(ss.getConf(), resetPerfLogger);
    }
  }
@param resetPerfLogger
@return  Tries to return an instance of the class whose name is configured in
         hive.exec.perf.logger, but if it can't it just returns an instance of
         the base PerfLogger class
ql/src/java/org/apache/hadoop/hive/ql/session/SessionState.java