Joel Sikström

A deep-dive into the details of how to configure, handle and categorize interrupts on AArch64

I’m Joel, a Software Engineer with a MSc in Computer and Information Engineering from Uppsala University (Civilingenjör i Informationsteknologi).

An nmethod, which I’ll refer to as NMethod, is HotSpot’s representation of a natively compiled Java method, the result of a JIT compilation, typically produced by the C1 or C2 compilers.

Details and reflections on how I’ve been using AI to approach OpenJDK development

Deep-dive into cache coherency considerations for JIT compilers on AArch64

Why is my first C++ (m)allocation always 72 KB??

Introduction While digging into Project Valhalla, I encountered a subtle part of the JVM that turned out to be a prime opportunity for optimization.

NUMA-aware relocation is a feature recently added to ZGC, one of the garbage collectors in OpenJDK, with the introduction of JDK-8359683, set to release in JDK 26.

Introduction MADV_COLLAPSE is a madvise(2) advice (added in Linux 6.1) that requests a best-effort, synchronous collapse of native pages in a range into Transparent Huge Pages (THPs).

This post explores how ZGC, one of the garbage collectors in the OpenJDK, allocates memory for the Java heap, focusing on enhancements introduced in JDK-8350441 with the Mapped Cache.

TLDR; If you are experiencing similar issues, upgrade to the latest version of ddclient or change IP-check website to something other than dynamicdns.park-your-domain.com.

Analyzing performance can be challenging, especially when diagnosing regressions.

When I first found out about huge pages I was a bit confused.

Download Start by navigating to https://jdk.java.net/ and download the latest build.

In June 2024 I graduated from the Master’s Programme in Computer and Information Engineering at Uppsala University.

This is a repost of my blog entry about my master thesis at Oracle.