JITWatch VS JMH

Last time I was this blown away was with jitwatch ( https://github.com/AdoptOpenJDK/jitwatch )

FlowTracker reminds me a little of taint analysis, which is used for tracking unvalidated user inputs or secrets through a program, making sure it is not leaked or used without validation.

search keywords are "dynamic taint tracking/analysis"

https://github.com/gmu-swe/phosphor

https://github.com/soot-oss/SootUp

https://github.com/feliam/klee-taint

You can kind of do the same as DISASSEMBLE in Clojure.

There are some helper projects like https://github.com/Bronsa/tools.decompiler, and on the OpenJDK JitWatch (https://github.com/AdoptOpenJDK/jitwatch), other JVMs have similar tools as well.

It isn't as straightforward as in Lisp, but it is nonetheless doable.

As you have encapsulated the asserts inside methods, these will be called at runtime with the arguments evaluated (for example, creating that lambda). When assertions are disabled, the C1/C2 may inline the empty method call eventually, but I don't know whether it drops the lambda instantiation as well. You can use JITWatch to see what gets inlined. The general notion though is to not worry too much. Lazy log messages are a common pattern.

You can use jitwatch for this. To see the actual assembly code generated you will also need to use a debug build of the jvm.

If you use Oracle's own IDE, it will support it out of the box, as it already did on Sun's days.

Then there are other ways depending on which JVM implementation is used.

On OpenJDK's case you can load runtime plugin to do it

https://github.com/AdoptOpenJDK/jitwatch

We use https://github.com/AdoptOpenJDK/jitwatch for this.

If you already know any JVM or .NET language, the first step would be to understand the full stack, you don't need C for that.

Many of us were doing systems programming with other languages before C went mainstream.

What you need to learn is computer architecture.

Getting back to JVM or .NET, you can get hold of JIT Watch, VS debug mode or play online in SharpLab.

Get to understand how some code gets translated into MSIL/JVM, and how those bytecodes end up being converted into machine code.

https://github.com/AdoptOpenJDK/jitwatch/wiki/Screenshots

https://sharplab.io/

Languages like F# and C# allow you to leave the high level comfort and also do most of the stuff you would be doing in C.

Or just pick D, which provides the same comfort and goes even further in low level capabilities.

Use them to write a toy compiler, userspace driver, talking to GPIO pins in a PI, manipulating B-Tree data stuctures directly from inodes, a TCP/IP userspace driver.

Not advocating not to learn Zig, do it still, the more languages one learns the better.

Only advocating what might be an easier transition path into learning about systems programming concepts.

You can enable a lot of debug information about how the compiler decides what to do with your code using feature flags like -XX:+UnlockDiagnosticVMOptions -XX:+PrintInlining. If you want to dive deeper into the world of the Hotspot JIT Compiler, have a look at JITWatch.

Also, it has an amazing SBT plugin integration.

Take a look at sbt-jhm for doing benchmarks. Java in particular is hard to measure because of optimizations that happen at run-time. jhm runs multiple iterations and gives tools to ensure that function calls and loops that may be optimized away are kept around and tested. You may also find some cases that are faster in node.js because the Javascript V8 engine is highly optimized.

Also, if you really want to know what the performance characteristics are you should use JMH (sbt plugin https://github.com/sbt/sbt-jmh). Not sure how you are evaluating the performance but things like JVM startup and warming can make a big difference. JMH will give you a better idea of real world performance when the JVM is already started and any relevant hot code has been JIT compiled.