I understand why cold starts happen (Byte code needs to be turned into machine code through JIT compilation). However with all the generated meta data available for binaries these days I do not understand why there isn't a simple tool that automatically takes the byte code and turns ALL PATHS THROUGH THE CODE (auto discovered) into machine code specific for that target platform. That would mean the first request through any path (assume a rest api) would be fast and not require any further Just In Time Compilation.
We can create an automation test suite or load test to JIT all the paths before allowing the machine into the load balancer rotation (good best practice anyway). We can also flip the "always on" setting in cloud hosting providers to keep the warmed application from getting evicted from memory (requiring the entire process over again). However, it seems like such an archaic process to still be having in 2020.
Why isn't there a tool that does this? What is the limitation that prevents us from using meta data, debug symbols and/or other means to understand how to generate machine code that is already warm and ready for users from the start?
So I have been asking some sharp minds around my professional network and no one seems to be able to point out exactly what limitation makes this so hard to do. However, I did get a few tools on my radar that do what i'm looking for to some level.
Crossgen appears to be the most promising but it's far from widely used among the many peers I've spoken to. Will have to take a closer look.
Also several do some sort of startup task that runs some class initialization and also register them as singletons. I wouldn't consider those much different then just running integration or load tests on the application.