说明：  Linux下C语言代码，采集数据其中用到了定时器30S进行一次信息采集，最开始获取cpu对于total使用率，而不是用户和系统相对的使用率
(Linux C language code, which uses a timer to collect data once 30S information collection, beginning to get the total cpu usage, rather than the user and system utilization relative)