Reduce import time

[nspope]

The import time (due to numba AOT compilation) is driving me nuts-- I wonder if there's a way we can build an extension optionally on install (e.g. triggered by a flag to pip). Jerome and others have had bad experiences with numba extensions, but 30 to 60 seconds for import really slows down the debug cycle, and if extension-building is turned off by default I don't think it'd be an issue.

[hyanwong]

I agree it's a pain. I'll check with @jeromekelleher and @benjeffery if there is a sensible solution in this case.

[jeromekelleher]

One simple thing is to turn caching on/off using an environment variable. So you turn on caching for dev, and it's off by default: https://github.com/sgkit-dev/sgkit/blob/main/sgkit/accelerate.py

Would this help?

[hyanwong]

That sounds like a great suggestion. Thanks @jeromekelleher

[nspope]

That's a good suggestion @jeromekelleher and should be fine for development, thanks. I'm also pondering moving some of the core routines into a rust extension, in the long term.

[jeromekelleher]

I'm also pondering moving some of the core routines into a rust extension, in the long term.

eek!

[nspope]

It's not that bad, I hope! What I'm trying to say is I'd like to move some of the low-level EP stuff into a compiled language extension, to save on import time, as this is just going to keep creeping up. Rust is great for numerical stuff and plugs in really nicely to Python.

(One of the motivations here is that we're using tsdate in simulation-based-inference contexts where we generate a bunch of simulations in parallel to train a neural network-- waiting >60 sec for import when running tsdate from the CLI is really a huge time sink in this application).

[hyanwong]

Do you want to implement the environment variable caching, or do you want me to, @nspope ?

[jeromekelleher]

Should definitely make caching an option for people who know what they're doing, 60s is horrendous.

If you paste in a profile I can comment on some possible ameliorations - that sounds much worse than it should be

[nspope]

Do you want to implement the environment variable caching

I'll play around with it a bit then ping you both. It's annoying but not super urgent.