Performance with short lived processes

I'm trying to run many short lived command-line processes under FEX (a pre-compiled embedded GCC toolchain) and I'm wondering if there are configuration options that I can tune to achieve the best performance.

I saw a -20% improvement with an unpacked RootFS compared to squashfs, but performance is far from native (6s to compile an hello world). Are there other options that can be tuned for this use case?

It's my (limited) understanding that the transpiled ARM binary is not cached between different runs by default, but I'm not sure if it can be enabled. How are these options supposed to be used?

Thanks!