JCTools VS Agrona

Install some tool that would help you see the performance of your system, like a graph of the CPU usage, the top processes being used, disk activity/read/write, etc. Every time you run your program, glance at those numbers, eventually you'll develop an intuition. Basically write code and profile. A good exercise would be practicing with data structures, this site has an exhaustive list of them, find some stuff that's interesting then google the implementation, then build it yourself, test it, debug, profile, optimize, and understand the performance constraints. Eventually you'll develop better understanding and can compare between other people's works, optimizing them. If you want to go beyond, read some papers on lock-free algorithms https://github.com/JCTools/JCTools/tree/master/resources then read Brendan Gregg's blog and books. Read about how profiling tools work https://github.com/andikleen/pmu-tools/wiki/toplev-manual

If I fork this implementation's repo and then publish a release (of the forked version) with my own commits via jitpack.io (committing with Android Studio IDE).

In some places I'm using https://github.com/aeron-io/agrona

Strangely this is one of the areas where I want to use project panama so I might re-implement some of the ring buffers constructs.

You allocate off heap memory and dump data into it. With modern Java classes like Arena, MemoryLayout, and VarHandle it's honestly a lot like C structs.

I answered "why" in another post in this thread.

Thanks, I've mostly used fastutil lately because it seems to be best maintained. I'll have to look at carrotlabs though, I like the approach of a clean break with java.util.collections.*.

The Agrona Java library from the Aeron people has some primitive optimized collections too: https://github.com/aeron-io/agrona

Aeron for low latency apps and Agrona is you're using Aeron for data structures

Martin Thompson is one of the leaders in that space: his blog is a really great place to start. His Agrona library is a bunch of high-performance data structures, which you can use directly, but which can also serve as examples of writing such code.

ByteBuffer methods have quite a bit of overhead. You could further try to (1) writing to a byte[] first and then using the put(byte[]) method, or (2) use sun.misc.Unsafe::putByte (maybe try with Agrona's DirectBuffer and copy the necessary lines if need be).