Was browsing Reddit and found this comment <https://www.reddit.com/r/Kotlin/comments/1aqwe3y/comment...

# coroutines

[Edoardo Luppi]

Was browsing Reddit and found this comment
https://www.reddit.com/r/Kotlin/comments/1aqwe3y/comment/kqghzre/?utm_source=share&amp;u[…]m=web3x&amp;utm_name=web3xcss&amp;utm_term=1&amp;utm_content=share_button
I'm not knowledgeable enough, and haven't used coroutines that extensively, so can't say if this is true or false.

[Sam]

Roman did a talk on Loom virtual threads at KotlinConf that included a couple of performance comparisons

[Edoardo Luppi]

@Sam ah nice, I'll check that!

[Edoardo Luppi]

Although I was mostly referring to the

we found that Kotlin's coroutines had astonishingly high overhead...

part

[Sam]

Yeah, I am curious about that. I would be surprised if coroutines are significantly different in performance to callbacks or futures, so it'd be interesting to see examples where that's not the case

[Sam]

The bit about thread locals is interesting

[Edoardo Luppi]

@Sam I need to get home to log in into Reddit and add a comment about it.
Would be cool to have more insight

[Edoardo Luppi]

The way the comment is written makes it sound like it has been written by someone who understand what he's doing, but you know, it's the internet so

[Sam]

If he is right it does kind of undermine all the work the Kotlin team have done on coroutines for the last however many years

[Sam]

It would certainly be a surprise to learn that they were wrong and one dude on Reddit was right

[ross_a]

We've written a whole FX trading system with Coroutines and overhead is negligible so I'm surprised he found it didn't scale for writing a test framework

[ross_a]

We don't use ThreadLocals though

[Edoardo Luppi]

It might just be the use case he had wasn't one the coroutines foundation and library were optimized for. That's why having more insight would be cool.

[Dmitry Khalanskiy [JB]]

It would certainly be a surprise to learn that they were wrong and one dude on Reddit was right

You don't have to be a chef to be able to say that food tastes bad.