How many threads are usually used by default for task execution in DefaultDispatcher?

In Kotlin Coroutines, DefaultDispatcher by default uses a number of threads equal to the number of available processor cores (CPU cores), but at least 2. This means that if you have 4 cores, 4 threads will be used, and if 1 core — 2 threads.

This is done for optimal CPU utilization when executing parallel tasks.

Example of obtaining the number of threads in DefaultDispatcher:

import kotlinx.coroutines.*

fun main() = runBlocking {
    println("Default dispatcher parallelism: ${Dispatchers.Default.parallelism}")
}