The BEAM JIT is all done when .beam files are loaded. It's a runtime JIT, because you can always load new code, but it's not a tracing JIT and it's designed to be pretty fast to do it while loading. For most applications of BEAM, I think the time spent loading code, including JIT, is probably immaterial.

If you have a special need, I haven't seen anyone do it, but I would expect it wouldn't be that hard to run the jit ahead of time. I haven't fully studied it, but I think the expectation is the output from jit should be pretty much the same every run, so it seems doable to generate it once and load many times.

Compile to js target and leverage v8 compiler cache? I dunno, just riffing. You’re probably BEAMing vs js runtime-ing for server workloads, but periodically i compile to node and do stuff