How performance metrics for CPU is calculated in percentage in Rancher?

Hi,

Could anyone please explain how Rancher is displaying container performance metrics in percentage for CPU?

I got the stats of containers from the stats API. But I have no clue how the CPU usage percentage is calculated.

.

Most of the numbers returned by stats are raw always increasing counters of bytes read, nanoseconds run, etc… So to get a useful number you need to compare against the previous data point and the time elapsed.

https://github.com/rancher/ui/blob/master/app/utils/multi-stats.js#L110-229