public void perfLogBegin(String callerName, String method) {
    long startTime = System.currentTimeMillis();
    startTimes.put(method, Long.valueOf(startTime));
    LOG.debug("<PERFLOG method={} from={}>", method, callerName);
    beginMetrics(method);
  }
Call this function when you start to measure time spent by a piece of code.
@param callerName the logging object to be used.
@param method method or ID that identifies this perf log element.
common/src/java/org/apache/hadoop/hive/ql/log/PerfLogger.java