[jdk17u-dev] RFR: 8350285: Shenandoah: Regression caused by ShenandoahLock under extreme contention [v2]

[Goetz Lindenmaier]

On Mon, 30 Jun 2025 16:28:27 GMT, Daniel Huang <duke at openjdk.org> wrote:

>> Backport for ShenandoahLock performance regression issue. The fix involves sleeping for a very short duration every 3 yields, with the number of yields picked through manual testing. 
>> 
>> Clean backport, ran GHA sanity checks and locally tested `tier1`, `tier2`, and `hotspot_gc_shenandoah`. `test/jdk/java/nio/channels/FileChannel/directio/DirectIOTest.java` sometimes fails locally, but it also sometimes failed before the backport.
>> `test/jdk/java/nio/channels/DatagramChannel/SendReceiveMaxSize.java` fails locally, but it also fails locally before the backport.
>
> Daniel Huang 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 three additional commits since the last revision:
> 
>  - Merge branch 'openjdk:master' into backport-JDK-8350285-shenandoahlock
>  - Merge branch 'openjdk:master' into backport-JDK-8350285-shenandoahlock
>  - Backport bd8ad309b59bceb3073a8d6411cca74e73508885

removed the fix request label because it is not yet in 21.

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PR Comment: https://git.openjdk.org/jdk17u-dev/pull/3614#issuecomment-3248192593