[Bug]: Why rslib is so slow?

[dingff]

Version

no

Details

https://github.com/Gugustinette/bundler-benchmark

Reproduce link

https://github.com/Gugustinette/bundler-benchmark

Reproduce Steps

no

[chenjiahan]

This is not an apple-to-apple comparison, because these tools have different default behaviors.

tsup and Rslib run tsc type check by default to ensure correctness, while tsdown does not perform type check when isolatedDeclarations is enabled. Although isolatedDeclarations avoids most of the overhead from tsc, you still need to run type check in other stages.

[Timeless0911]

The difference in Rslib build time between these two cases (thousand-functions and thousand-typed-functions) is unexpectedly small. I think there is something wrong with this benchmark case. Let me observe it further.

[chenjiahan]

When tsc is not enabled, Rslib should have good performance. Perhaps this benchmark hits a performance issue in Rspack, we will investigate this soon.

[sxzz]

@chenjiahan I requested tests for both tsc and isolatedDeclarations. See Gugustinette/bundler-benchmark#5

[chenjiahan]

@sxzz Thank you! ❤️ We are glad to see that the community has provided such a great library benchmark, which is very helpful for us to optimize Rslib's performance.

[Gugustinette]

Yes, the benchmark is far from being 100% fair to each bundler.
Do not hesitate to contribute if you have ideas to make it better !

Also, I'd like to say that a tool shouldn't be considered "slow" just because its color bar is higher than another one.
Most of our recent JavaScript tooling really have amazing performances overall : a second to bundle a thousand functions, with all the features bundler offer is still a VERY solid score.

[sxzz]

Thanks to @Gugustinette, new benchmark is released.

[Gugustinette]

Results will now be published on a proper website : https://gugustinette.github.io/bundler-benchmark/

I'll work on more advanced, detailed (and hopefully fair) benchmarks : Gugustinette/bundler-benchmark#6

[Timeless0911]

@Gugustinette Hi, Rslib v0.10.1 has been released which brings a performance optimization PR for cases like this benchmark.

When you have time, you can upgrade the data table generating by running it on your machine.

We will continue to optimize Rspack's performance in bundling module projects.