Is this a good way to create a dispatcher which runs corouti

Question

Is this a good way to create a dispatcher which runs coroutines on a high priority thread ```import java util concurrent Executors import kotlinx coroutines asCoroutineDispatcher import kotlin concurrent thread fun highPriorityContext = Executors newSingleThreadExecutor runnable gt thread priority = Thread MAX PRIORITY runnable run asCoroutineDispatcher ```

elizarov · Answer

Yes It is as good as it gets

melatonina · Answer

Thanks < elizarov> Unfortunately when I `launch` a coroutine in a CoroutineScope with that context I get this exception ``` java lang IllegalThreadStateException at java util concurrent ThreadPoolExecutor addWorker ThreadPoolExecutor java 964 at java util concurrent ThreadPoolExecutor execute ThreadPoolExecutor java 1382 at java util concurrent Executors$DelegatedExecutorService execute Executors java 630 at kotlinx coroutines ExecutorCoroutineDispatcherBase dispatch Executors kt 94 at kotlinx coroutines internal DispatchedContinuationKt resumeCancellableWith DispatchedContinuation kt 305 at kotlinx coroutines intrinsics CancellableKt startCoroutineCancellable Cancellable kt 30 at kotlinx coroutines BuildersKt Builders commonKt startCoroutineImpl Builders common kt 192 at kotlinx coroutines BuildersKt startCoroutineImpl Unknown Source 1 at kotlinx coroutines AbstractCoroutine start AbstractCoroutine kt 145 at kotlinx coroutines BuildersKt Builders commonKt launch Builders common kt 56 at kotlinx coroutines BuildersKt launch Unknown Source 1 at kotlinx coroutines BuildersKt Builders commonKt launch$default Builders common kt 49 at kotlinx coroutines BuildersKt launch$default Unknown Source 1 ``` If I replace that context with ```newFixedThreadPoolContext 1 ``` I don t get the exception Do you understand what is happening from the stack trace

baxter · Answer

The `thread ` function starts threads immediately unless you pass `start = false` to it Executors don t want threads that have already started

melatonina · Answer

Thanks < baxter> That was the problem indeed

melatonina · Answer

I m using this dispatcher to run an audio playback system loop which synthesizes some audio material and the blocks on the `write` call to a output device After the the blocking `write` call I execute ```if isActive yield ``` In order to allow cooperative cancellation When I want shutdown this playback system I just cancel the corresponding job and If I run on `<http Dispatchers IO|Dispatchers IO>` this works It also works with `newFixedThreadPoolContext 1 ` If I use the high priority dispatcher it doesn t Do you know why this is happening