“cpu\毫秒”计数器可以提供有关-所有任务在cpu上花费的总时间的信息。
“reduce\u shuffle\u bytes”数字越高，n/w利用率越高(更多选项可用（如此）

hadoop中有4类计数器：文件系统、作业、框架和自定义。
您可以使用内置计数器验证：

1.The correct number of bytes was read and written
2.The correct number of tasks was launched and successfully ran
3.The amount of CPU and memory consumed is appropriate for your job and cluster nodes
4.The correct number of records was read and written

提供更多信息@https://www.mapr.com/blog/managing-monitoring-and-testing-mapreduce-jobs-how-work-counters#.vzy9if_vpz4 （**credits-mapr.com）