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.
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.
@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
@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!
Discover the intriguing world of #JVM performance optimization in our latest interview with @chriswhocodes conducted by @bazlur_rahman , we delve into the creation of JITWatch, the future of JVM, and the impact of #AI on this field. #Java #JITWatch
https://foojay.io/today/breaking-the-code-how-chris-newland-is-changing-the-game-in-jvm-performance/
Breaking the Code: How Chris Newland is Changing the Game in JVM Performance!
@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!
RT @chriswhocodes@twitter.com
#JITWatch finally gets a binary release on GitHub!
Version 1.4.0 rolls up all the recent fixes into an executable shaded jar including #OpenJFX for JDK 11+ https://github.com/AdoptOpenJDK/jitwatch/releases/tag/1.4.0 #Java #JVM #JIT
🐦🔗: https://twitter.com/chriswhocodes/status/1321957899548168193
