#jitwatch — Public Fediverse posts

A couple of nice PRs received for JITWatch, a program for understanding the decisions made by the HotSpot JVM JIT Compiler(s) as they optimised your program at runtime.

New functionality includes tooltip support for disassembled ARM code, and Korean localisation.

New release 1.5 available at https://github.com/AdoptOpenJDK/jitwatch

#jvm #jit #jitwatch #java #compiler #opensource

Vladimir Dvorak has created a fascinating deep dive into the startup times of JetBrains' IntelliJ IDEA.

https://blog.jetbrains.com/platform/2025/01/jitwatch4i-analyzing-intellij-idea-s-startup/

In doing so he created a modified version of JITWatch called JITWatch4i which addresses several shortcomings in the tool.

#java #JITWatch #performance

Thanks to René Kraneis for this new JITWatch example demonstrating vectorisation of a loop incrementing an array with Valhalla-enabled JDK23.

JITWatch is a free and open-source program for inspecting the Just In Time (JIT) compiler decisions made by the JVM as it dynamically optimised your program at runtime.

https://github.com/AdoptOpenJDK/jitwatch

#java #performance #Valhalla #JITWatch

@galderz This is the latest talk I did on #JITWatch https://www.youtube.com/watch?v=p7ipmAa9_9E :)

@sasuke___420 Hi, have you already submitted a solution? After #AdventOfCode I decided not to get nerd-sniped by #1brc but I did run a few of the earlier leading OpenJDK-based solutions through #JITWatch and found you could squeeze out some single digit percentage gains by changing the JVM options that control inlining.

I've just released #JITWatch 1.4.9 binaries which rolls up a lot of fixes and makes the sandbox easier to use with external source files (such as #1brc).

https://github.com/AdoptOpenJDK/jitwatch/releases/tag/1.4.9

Learn about how the #Java #JVM JIT compilers optimise your program at runtime using techniques like inlining, intrinsics, escape analysis, DCE, lock elision, loop unrolling, vectorisation, and lots more :)

Thanks for the mention!

Reasons you might want to follow me are:

#VMOptionsExplorer - Learn about all the switches that control the JVM: https://chriswhocodes.com/

#JaCoLine - Java Command Line Inspector - check your Java command line works with later versions https://jacoline.dev/inspect

#JEPSearch - Check JEP activity https://chriswhocodes.com/jepsearch.html

#ByteMe - Explore Java bytecode https://byte-me.dev/

#JITWatch - Understand JIT compiler decisions made by the JVM https://github.com/AdoptOpenJDK/jitwatch

Thanks for the mention!

Reasons you might want to follow me are:

#VMOptionsExplorer - Learn about all the switches that control the JVM: https://chriswhocodes.com/

#JaCoLine - Java Command Line Inspector - check your Java command line works with later versions https://jacoline.dev/inspect

#JEPSearch - Check JEP activity https://chriswhocodes.com/jepsearch.html

#ByteMe - Explore Java bytecode https://byte-me.dev/

#JITWatch - Understand JIT compiler decisions made by the JVM https://github.com/AdoptOpenJDK/jitwatch

Thanks for the mention!

Reasons you might want to follow me are:

#VMOptionsExplorer - Learn about all the switches that control the JVM: https://chriswhocodes.com/

#JaCoLine - Java Command Line Inspector - check your Java command line works with later versions https://jacoline.dev/inspect

#JEPSearch - Check JEP activity https://chriswhocodes.com/jepsearch.html

#ByteMe - Explore Java bytecode https://byte-me.dev/

#JITWatch - Understand JIT compiler decisions made by the JVM https://github.com/AdoptOpenJDK/jitwatch

Thanks for the mention!

Reasons you might want to follow me are:

#VMOptionsExplorer - Learn about all the switches that control the JVM: https://chriswhocodes.com/

#JaCoLine - Java Command Line Inspector - check your Java command line works with later versions https://jacoline.dev/inspect

#JEPSearch - Check JEP activity https://chriswhocodes.com/jepsearch.html

#ByteMe - Explore Java bytecode https://byte-me.dev/

#JITWatch - Understand JIT compiler decisions made by the JVM https://github.com/AdoptOpenJDK/jitwatch

Thanks for the mention!

Reasons you might want to follow me are:

#VMOptionsExplorer - Learn about all the switches that control the JVM: https://chriswhocodes.com/

#JaCoLine - Java Command Line Inspector - check your Java command line works with later versions https://jacoline.dev/inspect

#JEPSearch - Check JEP activity https://chriswhocodes.com/jepsearch.html

#ByteMe - Explore Java bytecode https://byte-me.dev/

#JITWatch - Understand JIT compiler decisions made by the JVM https://github.com/AdoptOpenJDK/jitwatch

@tarczynski Thanks! I needed a new class library for #JITWatch so I created https://github.com/chriswhocodes/ClassAct and then built Byte-Me as a simple test harness which got a bit out of control and became its own project :) Building your own tools is a great way to learn!

Breaking the Code: How Chris Newland is Changing the Game in JVM Performance!

#java #jitwatch #jvm

https://foojay.io/today/breaking-the-code-how-chris-newland-is-changing-the-game-in-jvm-performance/?utm_medium=erik.in&utm_source=mastodon

@geoffreydesmet Once you've fixed all the low hanging fruit, Java performance == JIT performance so take a look at the #JIT compiler decisions made by the VM using free visualisation tools like #JITWatch (https://github.com/AdoptOpenJDK/jitwatch) (full disclosure, I'm the author :)

Hey new Mastodon friends! Here's a little #introduction :)

* 25 years of #Java, mostly in realtime market data but also some fun R&D stuff.

* Java Champion who loves digging deep into the #JVM and sharing what I learn.

* Creator of open source tools like #JITWatch, #VMOptionsExplorer, #JaCoLine, #JEPSearch (https://chriswhocodes.com)

* Co-wrote a book on Java Performance (Optimizing Java).

* Love retro hardware, synths, and the #Demoscene!

Appreciate boosts to make new connections here!

Hey new Mastodon friends! Here's a little #introduction :)

* 25 years of #Java, mostly in realtime market data but also some fun R&D stuff.

* Java Champion who loves digging deep into the #JVM and sharing what I learn.

* Creator of open source tools like #JITWatch, #VMOptionsExplorer, #JaCoLine, #JEPSearch (https://chriswhocodes.com)

* Co-wrote a book on Java Performance (Optimizing Java).

* Love retro hardware, synths, and the #Demoscene!

Appreciate boosts to make new connections here!

Hey new Mastodon friends! Here's a little #introduction :)

* 25 years of #Java, mostly in realtime market data but also some fun R&D stuff.

* Java Champion who loves digging deep into the #JVM and sharing what I learn.

* Creator of open source tools like #JITWatch, #VMOptionsExplorer, #JaCoLine, #JEPSearch (https://chriswhocodes.com)

* Co-wrote a book on Java Performance (Optimizing Java).

* Love retro hardware, synths, and the #Demoscene!

Appreciate boosts to make new connections here!

Hey new Mastodon friends! Here's a little #introduction :)

* 25 years of #Java, mostly in realtime market data but also some fun R&D stuff.

* Java Champion who loves digging deep into the #JVM and sharing what I learn.

* Creator of open source tools like #JITWatch, #VMOptionsExplorer, #JaCoLine, #JEPSearch (https://chriswhocodes.com)

* Co-wrote a book on Java Performance (Optimizing Java).

* Love retro hardware, synths, and the #Demoscene!

Appreciate boosts to make new connections here!

Hey new Mastodon friends! Here's a little #introduction :)

* 25 years of #Java, mostly in realtime market data but also some fun R&D stuff.

* Java Champion who loves digging deep into the #JVM and sharing what I learn.

* Creator of open source tools like #JITWatch, #VMOptionsExplorer, #JaCoLine, #JEPSearch (https://chriswhocodes.com)

* Co-wrote a book on Java Performance (Optimizing Java).

* Love retro hardware, synths, and the #Demoscene!

Appreciate boosts to make new connections here!