Improve debugging: How to inspect execution time of function easily in rust and node

[hyf0]

Met a lot of cases that want to simply check how long a function run.

We now could do this manually by adding hard code to print out the time. While it works, it's not friendly to be used.

In rust:

We are already using the tracing crate. Might able to do something with it.

In node

Well, I'm currently blind.

[milesj]

I've wanted to give this a try https://crates.io/crates/tracing-chrome

[hyf0]

We are using it right now and it's indeed quite useful. But I still feel it's too heavy for checking out execution of single function.

rolldown/crates/rolldown_tracing/src/lib.rs

Lines 32 to 46 in f38c27b

	pub fn try_init_tracing_with_chrome_layer() -> Option<FlushGuard> {
	use tracing_chrome::ChromeLayerBuilder;
	use tracing_subscriber::prelude::*;
	if std::env::var("RUST_LOG").is_err() {
	// tracing will slow down the bundling process, so we only enable it when `LOG` is set.
	return None;
	}
	if IS_INITIALIZED.swap(true, std::sync::atomic::Ordering::SeqCst) {
	None
	} else {
	let (chrome_layer, guard) = ChromeLayerBuilder::new().build();
	tracing_subscriber::registry().with(EnvFilter::from_default_env()).with(chrome_layer).init();
	Some(guard)
	}
	}

It needs you to open browser and select files, select directories, and parsing, clicking, scaling and scrolling. :)

[hyf0]

What I imagine is we could simply run RUST_LOG=[some filter syntax] cargo run .... or RUST_LOG=[some filter syntax] pnpm build and the logging would be

calling fn xxxx() takes xxx ms

we just do nothing but add #[instrument] on that function.