[jdk21u] RFR: 8307766: Linux: Provide the option to override the timer slack

[Thomas Stuefe]

On Fri, 28 Jul 2023 08:04:56 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

> Clean backport of experimental feature for in-field use.
> 
> Additional testing:
>  - [x] Linux x86_64 fastdebug, new test
>  - [ ] Linux x86_64 fastdebug, `tier1`
>  - [ ] Linux x86_64 fastdebug, `tier2`
>  - [ ] Linux x86_64 fastdebug, `tier3`

Good (and low risk in my opinion, for 21).

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Marked as reviewed by stuefe (Reviewer).

PR Review: https://git.openjdk.org/jdk21u/pull/21#pullrequestreview-1551595957