delayed initialization of features for better startup time

[ikitommi]

delayed initialization of features for better startup time

[venantius]

You're not the first person to have asked for this.

I did a bit of profiling myself - Ultra adds about 0.3-0.4s worth of dependencies, and then require-ing th e core ultra ns immediately adds about 2-2.5s on my laptop - even if we don't actually do any "work" in that ns. After a bit of further profiling it seems to boil down to the general cost of namespace loading in Ultra. One option would be to move to a more dynamic namespace loading model, so that if a given feature isn't enabled in the project map then its respective namespace and dependencies aren't loaded.

All of the benefits there would still be predicated on your project map being set up with features disabled, though - otherwise you're still following the ultimate code paths, just in a different order. The plugin uses Leiningen middleware so it would be potentially ugly to selectively enable it only for certain lein tasks (the naive implementation that occurs to me off the top of my head would be some sort of project map manipulation disabling certain features for respective tasks; the REPL middleware when testing or building an uberjar, e.g.).

I also don't know if there's a way of lazily loading features as they're needed, or whether just pushing the activation to separate threads would do the trick - I don't have the greatest insight into Leiningen's startup process.

Thoughts?

[ikitommi]

hi, sorry for not answering, got buried under everything else, thanks for the response and the resolution! Will continue to be a happy Ultra user :)

Tommi

[venantius]

Yeah, I think I may have accidentally screwed up the test configuration path unfortunately. The REPL stuff definitely still works but it looks like there's going to have to be an imminent 0.3.1 release to figure out a proper way of initializing tests.

[ikitommi]

$ time lein run -m clojure.main/main -e "(+ 1 1)"
2
lein run -m clojure.main/main -e "(+ 1 1)"  3.52s user 0.23s system 140% cpu 2.667 total

so it dropped from 3.7sec to 2.6sec --> more than 1sec off the load time (now just 0.2sec extra on my mac). Great work!!

cheers,

Tommi

[venantius]

high five

Related/unrelated: I recommend upgrading to 0.3.2 when you get a chance.