[GR-45919] Add support for Generational ZGC on HotSpot

[fniephaus]

TL;DR

Add support for Generational ZGC (JEP 439) to the Graal compiler.

Goals

JDK 21 added support for Generational ZGC, which

Improve(s) application performance by extending the Z Garbage Collector (ZGC) to maintain separate generations for young and old objects. This will allow ZGC to collect young objects — which tend to die young — more frequently.

We plan to add support for required ZGC barriers along with any relevant performance optimizations to Graal, allowing the use of Generational ZGC when Graal is used as a JIT compiler.

Non-Goals

• Add support for (Generational) ZGC to GraalVM Native Image
• Add support for Shenandoah GC and other GCs

Related issues

• Add support for ZGC on HotSpot #5050

[PhantomG27249]

Hello, are there any estimates or ideas of when this feature will be targeted/released for graal? I am just wondering a general release window or time frame.

[tkrodriguez]

It's targeted at 24.1

[PhantomG27249]

Thank you for letting me know this news has made my day :)

[WowYouCanReallyDance]

Very much looking forward to it

[utkuaydn]

Is including (Generational) ZGC in native-image in discussions at all? If so, what is the timeframe?

[fniephaus]

Is including (Generational) ZGC in native-image in discussions at all?

It's listed as a non-goal of this roadmap item, so no this is not about making ZGC available in native-image. We currently don't have any plans to make ZGC available in native-image.