Erik Österlund

Today, May 22, my book about ZGC is finally ready and available to order! I can recommend reading it if you want to learn more about the magic nature of ZGC. You can order it here (among many places): www.routledge.com/The-Z-Garbag...

Building Project Valhalla is like building a cathedral: craftsmanship, ingenuity, and collective dedication. A single “value” keyword carrying a decade of engineering. The first preview in JDK 28 marks a milestone, with more work ahead. Kudos to the team! youtu.be/D_AmK8-UnZg #java #valhalla

Happy to announce that JEP 546: “Adaptive Heap Sizing for ZGC” and JEP 545: “Faster Startup and Warmup with ZGC” have both been targeted for JDK 28.

Do you trade off startup and warmup by tuning -Xms, -Xmx and -XX:+AlwaysPreTouch appropriately? And did you set -XX:+UseTransparentHugePages together with the appropriate shmem_enabled kernel config? Me neither. ”JEP 545: Faster Startup and Warmup with ZGC” is candidate now: openjdk.org/jeps/545

If you are like me and don’t enjoy configuring JVM heap sizes (e.g. -Xms, -Xmx, -XX:SoftMaxHeapSize) then finally ”JEP 546: Adaptive Heap Sizing for ZGC” just became a candidate JEP: openjdk.org/jeps/546

Java 27 / JDK 27: General Availability: mail.openjdk.org/archives/lis... Features: openjdk.org/projects/jdk... Downloads: jdk.java.net/27/ #Java27 #JDK27 #OpenJDK #Java

The first part of OpenJDK’s Project Valhalla, JEP 401 (Value Objects), has been integrated into JDK 28 as a preview feature and is now available in the early-access builds. More information: openjdk.org/projects/val... #JDK28 #OpenJDK #Java

Wow you got that fast! Hope you enjoy it! Best experienced with a big cup of coffee.

After working on ZGC for a decade, I’m happy to announce that I’m publishing a book about ZGC in JDK 25. It ships 22 May (www.taylorfrancis.com/books/mono/1...) and is being published by Taylor & Francis. You should get a copy if you want to learn more about ZGC. It’s available for pre-order now.

Integrated ”JEP 516: Ahead-of-Time Object Caching with Any GC”! openjdk.org/jeps/516

This is an awesome oak tree close to where I live.

That is a good oak.

JDK 25 has been branched from the main line and is now in Rampdown Phase One: mail.openjdk.org/pipermail/jd... openjdk.org/projects/jdk... #JDK25 #OpenJDK #Java

It’s 5 days left to JavaOne. Go buy a ticket if you haven’t already! And don’t miss my session about what we are cooking in the ZGC project right now: reg.rf.oracle.com/flow/oracle/...

I used to have a bunch of followers on here. Now I can’t find them any more; it just says 404.

Hello, Bluesky!

Looks like Cassandra is getting support for JDK 21 and decided to switch GC to Generational ZGC. Good choice! I like how GC pause warning threshold changed from 1 second to 10 ms and logging threshold from 200 ms to 2 ms. PR: github.com/apache/cassa...

I finally deactivated my ”X” account after a long time of not using it. I simply don’t want to go back there.

I migrated to bluesky rather early. Why? Because I know garbage when I see it.

Helidon 4.1.4 is out now! This release contains important bugfixes and enhancements and is recommended for all users of Helidon 4. github.com/helidon-io/h...

My work on ZGC automatic heap sizing is coming together beautifully. I’m increasingly happy with the GC logs. Feeling optimistic that it can beat carefully tuned manual heap sizing. A static heap size just can’t deal with dynamic behaviour shifts as well; it’s not in its nature.

Twitter was a good ride. Hard to leave 65K followers behind, but hard to stay there too. Let's try things where the sky is blue!

Another pack here: go.bsky.app/F7m9rBy

My JVMLS presentation about automatic heap sizing for ZGC is now available. It’s going to be pretty cool I think. youtube.com/watch?v=wcEN...

NASA Discovers Potential Life On Mars After Giant Eyeball In Middle Of Planet Looks Directly Into Telescope theonion.com/nasa-discove...

Finally Java 23 is out - the first release where Generational ZGC is the default mode of ZGC!

I have worked a lot on automatic heap sizing for ZGC lately (cf. openjdk.org/jeps/8329758). If you find this interesting, I will talk about it at JVMLS this year. See you there!

"In fact, we’ve found for our services and architecture that there is no such trade off. For a given CPU utilization target, ZGC improves both average and P99 latencies with equal or better CPU utilization when compared to G1." writes Netflix' Danny Thomas: netflixtechblog.com/bending-paus...

I ran in to Danny Thomas from Netflix at JVMLS last year. Told him they should try Generational ZGC. They did, and it performed very well. Now they have changed default GC to Generational ZGC at Netflix, and Danny wrote a blog post about their experience: netflixtechblog.com/bending-paus...

I try to remove a lot of unnecessary complicated code before adding a lot of complicated code. I think of it as limiting myself to a “complexity budget”. Now I’m at the point of the cycle where it’s time to add complicated code.

Finally, ICStubs are a distant memory that I will try to suppress. github.com/openjdk/jdk/...

Tired of seeing ”Cleanup” and ”ICBufferFull” safepoint spam in your -Xlog:safepoint output? Finally, I got around to getting rid of this: github.com/openjdk/jdk/...

Happy holidays to all of my two followers!