[deeperf.com] A Performance Issue Caused by the TSC Clock Source Missing in Linux
From: https://deeperf.com/2019/04/30/tsc-clock-missing-caused-performance-issues/ TL;DR Solution Update Linux kernel to the latest version. Simple Conclusion Early Linux kernel doesn’t support the latest Intel’s CPU architecture very well. The Linux OS uses hpet clock source instead of TSC. It caused low performance and other issues. Issues Servers Overclocked core i9 server which is the new one. Its CPU frequency is more than 4.6 GHz. Other servers’ CPU are E5 2600 v3/v4 series. Generally, the CPU frequency is 3.x GHz. OS Ubuntu 14.04 is running on all of them for convenience. Low Performance on i9 server The same program is supposed to be faster on i9 server. But my test shows the program is much slower on the new i9 server. The key function takes about 1 microsecond on old servers. It takes 10 microseconds on the new server. Troubleshooting According to perf result on i9 server, the key function spent most of CPU time on system call gettimeofday() . I made
