https://zhuanlan.zhihu.com/p/138378298
https://www.binss.me/blog/linux-time-system-analysis/
https://www.binss.me/blog/linux-time-system-analysis/
[ 0.000004] Calibrating delay loop (skipped), value calculated using timer frequency.. 4787.81 BogoMIPS (lpj=2393905)