Coroutine example does not run out of memory when run with threads, despite the docs saying that it should

[npryce]

The following is from the Kotlin coroutine docs:

Coroutines ARE light-weight

Run the following code:

import kotlinx.coroutines.*
​

fun main() = runBlocking {
    repeat(100_000) { // launch a lot of coroutines
        launch {
            delay(1000L)
            print(".")
        }
    }
}

It launches 100K coroutines and, after a second, each coroutine prints a dot.

Now, try that with threads. What would happen? (Most likely your code will produce some sort of out-of-memory error)

What happens is that it does not crash. (I'm using MacOS 10.15.5 on a 2020 13" MacBook Pro.)

The delay and/or coroutine count should be increased in the example code.

[elizarov]

See explanation here: https://medium.com/@elizarov/such-concurrency-many-threads-wow-7c81ba9e9ebe
The example needs to be updated.