reduce "module_imports_on_top_of_file" execution time by ~20%

[albertedwardson]

Benchmarks

[sigmavirus24]

I wonder if the new profiler in 3.15 would be worth testing here.

I also really wish it were easy to write "benchmark tests" in Python like it is in Go and Rust. I'd love to be continuously verifying nothing regresses on some of these changes and potentially see changes between python versions etc

[albertedwardson]

New profiler in Python 3.15 does look promising, but I haven't tried it yet.

On the benchmarking side — totally agree. That said, tools like pytest-benchmark and codespeed might help get closer to what you're describing, especially if we ever wanted to track performance across versions or PRs. Could be worth exploring if there’s interest in building out some kind of minimal benchmark harness.

[asottile]

made some further improvements to get it to about ~50%-60% improvement over baseline

[asottile]