Nova诊断程序将CPU使用情况显示为CPU时间（以纳秒为单位）。
nova diagnostics vm1 +---------------------------+-----------------+ | Property | Value | +---------------------------+-----------------+ | cpu0_time | 36678580000000 | | cpu1_time | 9997850000000 | | cpu2_time | 165635380000000 | | cpu3_time | 116297040000000 | ------ +---------------------------+-----------------+
如何从上述值中获取CPU利用率百分比？