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Aleksey Shipilëv @shipilev.bsky.social · 11h

Ever seen a verbose render how a very small GC operation looks like in the context of larger safepoint? Here it is: (I need to blog about things you can see there)

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Johannes Bechberger @mostlynerdless.de · 12h

Learn how to compare objects from JFR recordings in Java and why this is slightly trickier than you might have expected in this week's blog post: mostlynerdless.de/blog/2025/10...

JFR and Equality: A tale of many objects - Mostly nerdless

Learn how to compare objects from JFR recordings in Java and why this is slightly trickier than you might have expected.

mostlynerdless.de

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Brice Dutheil @bricedutheil.bsky.social · 13h

Wow, just noticed that Netty 5 will have the Java 25 baseline !

github.com/netty/netty/...
#netty #java #java25

bump netty5 java version requirement to 25 by derklaro · Pull Request #15676 · netty/netty

Motivation: With the addition of MemorySegment into the JDK the Unsafe and ByteBuffer based Buffer implementations are no longer needed. Due to a bug on jdk versions before 25 the nio buffers creat...

github.com

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Charles Oliver Nutter @headius.bsky.social · 15d

OMG it makes a huge difference. Without even pinning to tier 1 ("dev" mode) we have a new record base startup of 361ms on my M4 MBA. I'm playing with some other tweaks and a longer training run now.

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Charles Oliver Nutter @headius.bsky.social · 16d

New post: JRuby and JDK 25: Startup Time with AOTCache

Let's take a look at JRuby's startup time journey, all the way up to using JDK 25's AOTCache and Project Leyden features coming to a JDK near you soon.

blog.headius.com/2025/09/jrub...

JRuby and JDK 25: Startup Time with AOTCache

JDK 25 is the newest LTS release since JDK 21, and it ships with a gaggle of amazing VM-level features. This post will cover one of the most important improvements for command-line ecosystems like…

blog.headius.com

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Brice Dutheil @bricedutheil.bsky.social · 15d

Today I learned that since #JDK 11, there is now in thread dumps

- cpu=... : the time the thread spent executing on the CPU.
- elapsed=... : the wall clock time passed since the thread was started.

bugs.openjdk.org/browse/JDK-8...

I’m not proud to have missed that 🤦‍♂️

Loading...

bugs.openjdk.org

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Brice Dutheil @bricedutheil.bsky.social · 14d

Nice engineering blog post on some query filtering at scale. There are some lessons in there.

They used a "bloofi " multidimensional bloom filters.
axiom.co/blog/buildin...
lemire.me/en/publicati...

Haydex: From Zero to 178,600,000,000 rows a second in 30 days

This is the story of how we turned a failed filter prototype into a production system running at 178.6B rows/sec in 30 days.

axiom.co

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Aleksey Shipilëv @shipilev.bsky.social · 16d

New toy, "residence graphs": tracking the compilation level for top method in the stack. On the left, normal JIT mode: compilers are busy, intp -> T2 -> T3 code is hot; T4 code slowly takes over. On the right, normal AOT+JIT (Leyden) mode: AOT code carries most of it, JIT happens to plug the holes.

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Aleksey Shipilëv @shipilev.bsky.social · 18d

"Method Tracing" in async-profiler: github.com/async-profil...

Method Tracing · async-profiler async-profiler · Discussion #1497

Background Async-profiler is often described as a low-overhead sampling profiler for Java. Sampling means the profiler collects statistical information about program execution by periodically inter...

github.com

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Alexander Reelsen @spinscale.bsky.social · 20d

SIMD Within a Register: How I Doubled Hash Table Lookup Performance

Learned about SWAR the first time in the one-billion row challenge. Nice explanation including benchmarks.

SIMD Within a Register: How I Doubled Hash Table Lookup Performance | MALTSEV.SPACE

It started with a simple thought: four bytes in a hash table bucket look just like an integer. Luckily, this one idea led to a deep dive into bit-twiddling and a 2x performance boost.

maltsev.space

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Cliff Click @cliffclick.bsky.social · 20d

youtu.be/q4mRNu6_lpc
C++ debugging, -Og, safepoints, adr sanitization. kefir (from scratch C compile), SCCP in Simple, graph DSL. Strict aliasing, implicit conversions. Pointer comparison. GPU Kernels DSLs (Triton, Gluon, TLX), Object layout, NUMA. Distributed random forest

Coffee Compiler Club, 2025_09_19

YouTube video by Cliff Click

youtu.be

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Brice Dutheil @bricedutheil.bsky.social · 23d

Nice usage of #zstd for tarball via Kelly Sommers on Twitter.

x.com/vmg/status/1...

Vicent Martí on X: "I love Zstd. It is my default goto for anything compression related: it has a sweet spot between availability (it’s now standardized!! RFC8478), complexity, performance and compression ratio. My favorite thing about it are the skippable frames. Just a killer feature. It’s not https://t.co/7hzG2GzMAx" / X

I love Zstd. It is my default goto for anything compression related: it has a sweet spot between availability (it’s now standardized!! RFC8478), complexity, performance and compression ratio. My favorite thing about it are the skippable frames. Just a killer feature. It’s not https://t.co/7hzG2GzMAx

x.com

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Gunnar Morling @gunnarmorling.dev · 23d

📝 Blogged: "Let's Take a Look at... Lower Java Tail Latencies With ZGC"

As #Java 25 got released earlier this week, I took the ZGC garbage collector for a spin, exploring how it lives up to its promise of sub-millisecond GC pause times.

👉 www.morling.dev/blog/lower-j...

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Johannes Bechberger @mostlynerdless.de · 23d

With Java 25, there is finally a CPU-time profiler in the OpenJDK.

You can read more about this new profiler and some implementation details in my blog series starting with mostlynerdless.de/blog/2025/06... #java25

Java 25's new CPU-Time Profiler (1) - Mostly nerdless

Learn all about Java 25's new CPU-time profiler and why it matters in this weeks blog post from the creator himself.

mostlynerdless.de

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Teiva Harsanyi @teivah.dev · 24d

What Makes System Calls Expensive: A Linux Internals Deep Dive.
blog.codingconfessions.com/p/what-makes...

Another great post by @abhi9u.bsky.social. I learned a lot, including vDSO.

What Makes System Calls Expensive: A Linux Internals Deep Dive

An explanation of how Linux handles system calls on x86-64 and why they show up as expensive operations in performance profiles

blog.codingconfessions.com

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JChateau Unconference @jchateauunconf.bsky.social · 23d

JChateau our Unconference organized in France in the area of the Châteaux of the Loire Valley is open for registration at : www.jchateau.org/registration...

JChateau – Registration

JChateau

www.jchateau.org

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Mark Reinhold @mreinhold.org · 24d

Java 25 / JDK 25: General Availability: mail.openjdk.org/pipermail/jd...

Features: openjdk.org/projects/jdk...

Downloads: jdk.java.net/25/

#Java25 #JDK25 #OpenJDK #Java

Java 25 / JDK 25: General Availability

mail.openjdk.org

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Stephan Janssen @stephanjanssen.be · 24d

Oracle detaches #GraalVM from the Java SE train 👀
• JDK 24 = last with Graal JIT / GraalVM in Java SE
• Native Image discontinued for #Java SE (-> Leyden)
• GraalVM team pivots to non-Java (GraalPy, GraalJS)
👉 Java devs: migrate to C2 JIT & track Leyden AOT work
blogs.oracle.com/java/post/de...

blogs.oracle.com

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Cliff Click @cliffclick.bsky.social · 28d

youtu.be/5YIhnjThoK4
Burning Man, boats diving between dust devils. LSP, C backend, debug info, codegen , zydis, ASM. Ryan/quxlang update - literal types, bitwise operators, keywords, functions, containers. LLVM LogicalResult. GCC and LLVM funding, Triton, Cuda, ML , Mojo

Coffee Compiler Club, 2025_09_12

YouTube video by Cliff Click

youtu.be

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Markus Eisele @myfear.com · 29d

Let's Take a Look at... JEP 483: Ahead-of-Time Class Loading & Linking! buff.ly/vXDtFq9
#Java #jdk #jep483

Let's Take a Look at... JEP 483: Ahead-of-Time Class Loading & Linking!

In the "Let’s Take a Look at…!" blog series I am exploring interesting projects, developments and technologies in the data and streaming space. This can be KIPs and FLIPs, open-source projects,…

buff.ly

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JChateau Unconference @jchateauunconf.bsky.social · Sep 10

The date have been confirm to 04-08 march 2026, registration will open soon

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JEP Tracker @jeptracker.bsky.social · Sep 9

🎓 JEP 523 moved to candidate
Title: Make G1 the Default Garbage Collector in All Environments
Type: feature
Component: hotspot / gc
See openjdk.org/jeps/523

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Tanel Poder @tanelpoder.com · Sep 9

The xCapture and xtop eBPF tools are now in beta, with a demo dataset!

With a pre-recorded xcapture dataset from my dev server, now you can play with xtop "thread activity sampling" drilldown even on your laptop, without having to run xcapture yourself!

(link in replies :-)

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Brice Dutheil @bricedutheil.bsky.social · Sep 9

#java JEP 401 on value classes is submitted : openjdk.org/jeps/401

JEP 401: Value Classes and Objects (Preview)

openjdk.org

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Cliff Click @cliffclick.bsky.social · Sep 5

youtu.be/qhfhluIory0
C++/11,20,26; partial -g code; Java vs C++ speed with debugging. x86/arm vs java mem model. x86 intrinsics in Java. LSPs. C++ vs Java containers. Compile-time alloc size. UI frameworks. Teaching programming via games. C++ default copy/move opers

Coffee Compiler Club, 2025_09_05

YouTube video by Cliff Click

youtu.be

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