What's the state of `<http://Dispatchers.IO|Dispatchers.IO>`? I'm seeing different behavior to the d...

# coroutines

[danny]

What's the state of <http://Dispatchers.IO|Dispatchers.IO>? I'm seeing different behavior to the documentation, and some scheduling weirdness

[danny]

For instance, the docs state that they use the same threads as the default dispatcher, but right now that's still the fork/join pool?

[danny]

And when I do use it, I get ~30 threads burning a bunch of CPU in Thread.yield()

[danny]

CoroutineScheduler-worker-24  Runnable CPU usage on sample: 16ms

[danny]

@ kotlinx.coroutines.scheduling.CoroutineScheduler$Worker.cpuWorkerIdle() CoroutineScheduler.kt:781

[danny]

I'd only launched 8 coroutines in this case, I needed to constraint to a relatively small number of concurrent connections

[dave08]

Just use fan out structure like in the guide (or on Roman's KotlinConf 18 speech)

[elizarov]

What version are you using?

[elizarov]

There were some bugs in the past and there were some changes recently. 0.30.2 should be good tho

[dave08]

@elizarov In 0.30.0 there are still bugs? I'm about to release an android app to production, using it, I can't wait till 1.0.0 and kotlin 1.3, and as far as I understood there's still open issues with gradle 4.10.2 metadata and proguard in 0.30.2, is it safe to use 0.30.0?

[dave08]

Or is there a way to overcome the gradle and proguard issues?

[dave08]

This app has alot of devices depending on it... I can't really take chances...

[elizarov]

Both gradle and proguard issues have workarounds. You can wait a bit for 1.0.0-rc release that has them solved tho.

[dave08]

1.0.0 rc is without kotlin 1.3? I can't wait for more than today or maximum sunday..

[dave08]

And I can't use kotlon 1.3 beta for it either...

[elizarov]

0.30.2 is better than 0.30.0 and has its dispatcher bugs fixed

[elizarov]

Go with 0.30.2

[dave08]

What about the issues? I need proguard, and android studio 3.2 requires grdle over 4.7?

[dave08]

Would it be possible to have 0.30.3 just for these issues?

[elizarov]

You don’t enable experimental Gradle Metadata then it works with any version

[elizarov]

ProGuard issues only manifest if you use AndroidX and you can easily workaround with rules.

[danny]

I thought I upgraded, but maybe not - I'll double check. Thanks for the assist!

[danny]

Oh yeah, I was way back on 0.26.1-eap13