JMH VS JITWatch

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.

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.

In what concerns HotSpot, one way would be JITWatch.