On Fri, 23 Apr 2021 13:33:42 GMT, Hao Tang <github.com+7947546+tanghaot...@openjdk.org> wrote:
> OperatingSystemImpl.getCpuLoad() may return 1.0 in a container, even though > the CPU load is obviously below 100%. > > We created a 5-core container and run 4 "while (true)" loops in the > container. OperatingSystemImpl.getCpuLoad() returned 1.0, which is incorrect > (0.8 is correct). > "systemLoad" in getCpuLoad() is exactly 4.0 before "systemLoad = > Math.min(1.0, systemLoad);". The problem is caused by using the elapsed time > (specified by "cpu.cfs_period_us") instead of the total CPU time (specified > by "cpu.cfs_quota_us"). Therefore, it is more reasonable to divide cpu usage > time by "quotaNanos" instead of "elapsedNanos". @tanghaoth90 There are a couple of ways how CPU restrictions can be enforced. It appears that the current patch fixes the cpuacct controller case (`--cpu-quota`), but doesn't yet address `--cpu-shares` case. I've made a note of that in the bug. ------------- Changes requested by sgehwolf (Reviewer). PR: https://git.openjdk.java.net/jdk/pull/3656
