Hello everyone! Interested in how to use Project Loom to improve Coroutines' performance? See the ar...

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[Halina]

Hello everyone!
Interested in how to use Project Loom to improve Coroutines' performance?
See the article written by Jan Vladimir Mostert 👇
https://kt.academy/article/dispatcher-loom

[Dan Rusu]

Wow, interesting!

Are there any drawbacks to this approach such as IntelliJ debugging issues etc? Does JetBrains plan to migrate coroutines to utilize project loom once that gets released?

[janvladimirmostert]

The debugger might look a little rougher than what you're used to (virtual threads and coroutine threads mixed in the same stacktrace), but it works fine. There was a time when coroutines looked a little rough too, but it got prettified eventually.

Would be nice to have a Dispatchers.LOOM directly in the Coroutines library 😁

[CLOVIS]

JetBrains employees have said multiple times that they are waiting for the full release of Loom before making a decision. Since Loom is Java-only, it's unlikely to cause any API difference, so if they do decide to use it it's unlikely to change much for us.

[CLOVIS]

@janvladimirmostert how did you get the "coroutine stack trace" feature in the debugger working? I never managed to 😕

[mcpiroman]

More precisely, LOOM will be, say, Java 2x-only, meaning coroutines will need to be implemented as they are for earlier JREs and Android.

[janvladimirmostert]

it would make sense if Dispatchers.IO automatically defaulted to Virtual Threads if you compiled with JDK20+ and then defaulted to the Thread Pool for JDK19 and lower.

[janvladimirmostert]

@CLOVIS, my coroutine stacktrace just works in IntelliJ Ultimate, didn't tinker with anything to get it working.

[mcpiroman]

@Halina The counterpart for Thread.sleep in kotlinx.coroutines is delay() function and using it would likely make the comparison much more on pair. And for actual blocking code I would not expect much difference either, maybe so if Loom finally specializes java IO operations.

[Halina]

@mcpiroman let's see what the author @janvladimirmostert thinks of that 🙂

[Dan Rusu]

@mcpiroman since Kotlin allows you to specify the JDK target in the Gradle build, I would assume that it could use loom threads when targeting JDK20+