RFR: 8269851: OperatingSystemMXBean getProcessCpuLoad reports incorrect process cpu usage in containers [v2]

[Severin Gehwolf]

On Wed, 7 Jul 2021 07:50:51 GMT, Yasumasa Suenaga <ysuenaga at openjdk.org> wrote:

> In HotSpot, CPU usage for JVM would be calculated at `get_jvm_tickes()` in os_perf_linux.cpp . It refers `/proc/self/stat` - should we refer it in same way?
> 
> I discussed about similar issue in #4299 , then we came to an agreement that we should refactor that HotSpot and JMX should share the code. Of course you can fix JMX only in this PR, but it still uses different implementation from HotSpot. I prefer to fix it in code consolidation between HotSpot and JMX.

Yes, we need a bug to track this work (or at least decide on a plan of action - if any). I wouldn't conflate this into this bug, though as it's not clear whether or not JFR/thread dumps should report container values. I'll try to create a bug for this consolidation effort today.

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PR: https://git.openjdk.java.net/jdk/pull/4702