RFR: 8203359: Container level resources events [v12]

[Jaroslav Bachorik]

On Wed, 19 May 2021 14:11:40 GMT, Jaroslav Bachorik <jbachorik at openjdk.org> wrote:

>> With this change it becomes possible to surface various cgroup level metrics (available via `jdk.internal.platform.Metrics`) as JFR events.
>> 
>> Only a subset of the metrics exposed by `jdk.internal.platform.Metrics` is turned into JFR events to start with.
>> * CPU related metrics
>> * Memory related metrics
>> * I/O related metrics
>> 
>> For each of those subsystems a configuration data will be emitted as well. The initial proposal is to emit the configuration data events at least once per chunk and the metrics values at 30 seconds interval. 
>> By using these values the emitted events seem to contain useful information without increasing overhead (the metrics values are read from `/proc` filesystem so that should not be done too frequently).
>
> Jaroslav Bachorik has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains 11 additional commits since the last revision:
> 
>  - Fix event metadata
>  - Small fixes
>  - Remove trailing spaces
>  - Doh
>  - Report container type and register events conditionally
>  - Remove unused test files
>  - Initial test support for JFR container events
>  - Update the JFR control files
>  - Split off the CPU throttling metrics
>  - Formatting spaces
>  - ... and 1 more: https://git.openjdk.java.net/jdk/compare/a32c4b70...c3fa274c

Thanks for the review!
I've fixed the outstanding test failures and the patch is in its final form.

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PR: https://git.openjdk.java.net/jdk/pull/3126