Kotlin Coroutines can dispatch on LOOM threads

Nice article!

Have you considered dispatching Kotlin coroutines onto Loom VirtualThreads?

Example idea: https://kt.academy/article/dispatcher-loom

Here just create a simple dispatcher...

val Dispatchers.LOOM: CoroutineDispatcher
    get() = Executors.newVirtualThreadPerTaskExecutor().asCoroutineDispatcher()

And change your async { ... } call to use this dispatcher as

async(Dispatchers.LOOM) { ... }

Note your controlTest can have both a Thread { ... } version and a Thread.startVirtualThread { ... } version since nothing stops Kotlin from using LOOM virtual threads directly.

A lot of this code in the samples can be shared between them as Kotlin has no problem accessing Java classes, and most concepts in Kotlin are readable from Java as well. Unless you are worried about performance of basic code between the two, the total codebase could be reduced.

sample run-local with Java, Kotlin coroutines, Kotlin w/Loom async coroutines

Time	Method	Time Complexity	Space Complexity	Repetitions	Java Duration	Kotlin Duration	Kotlin-Loom Duration	Machine
2023-01-15T15:03:16.502528	wait0Nanos - Wait 0 Nanos - Running - Yielding - Virtual Thread	n/a	n/a	2	8	-1	-1	Prototype
2023-01-15T15:03:16.508950	wait100Mills - Wait 100 Mills - Running - Parking - Yield - Virtual Thread	n/a	n/a	2	101	-1	-1	Prototype
2023-01-15T15:03:16.509022	saveWordsNio - Write to 1 file - Yield - Virtual Thread	n/a	n/a	2	112	-1	-1	Prototype
2023-01-15T15:03:16.509055	saveWordsNio - Write to 1 file - Pinning - Yield - Virtual Thread	n/a	n/a	2	222	-1	-1	Prototype
2023-01-15T15:03:16.509082	findAllUniqueWords - All Unique Words	n/a	n/a	10000	1464	2839	2292	Prototype
2023-01-15T15:03:16.509110	findAllUniqueWordsWithCount - All Words with count	n/a	n/a	10000	1031	2081	1261	Prototype
2023-01-15T15:03:16.509137	revertText - Reverted Text	O(n)	O(1)	10000	324	866	594	Prototype
2023-01-15T15:03:16.509170	contentSplitIterateSubtractAndSum - Double iteration of an array of words	O(n^2)	O(1)	10000	373	1496	1120	Prototype
2023-01-15T15:03:16.509198	repetitionCount - Repetition count	O(n^2)	O(n)	10000	2238	2734	721	Prototype
2023-01-15T15:03:16.509223	createAvlTree - Create AVL Tree	O(log n)	O(n)	10000	1197	749	178	Prototype
2023-01-15T15:03:16.509249	findPrimeSecret - Secret word in Sieve of Eratosthenes	O(n * log(log n))	O(n)	10000	556	1632	519	Prototype
2023-01-15T15:03:16.509277	createSplayTree - Create Splay Tree	O(log n)	O(n)	10000	153	604	215	Prototype
2023-01-15T15:03:16.509303	quickSort - Quick sort	O(n * log n)	O(log n)	10000	1057	3616	2815	Prototype
2023-01-15T15:03:16.509334	makeTextFromWordFlow - Make text from word Flow	n/a	n/a	10000	889	519	147	Prototype
2023-01-15T15:03:16.509367	createIntersectionWordList - Intersection Text Algorithm	O(n)	O(n)	10000	83	956	482	Prototype
2023-01-15T15:03:16.509397	controlTest - N/A	n/a	n/a	10000	742	596	722	Prototype
2023-01-15T15:03:16.509424	generalTest - N/A	n/a	n/a	10000	182	59	173	Prototype
2023-01-15T15:03:16.509450	findAllUniqueWords - wait0Nanos	n/a	n/a	2	-1	12	21	Prototype
2023-01-15T15:03:16.509475	controlTest-Loom - N/A	n/a	n/a	10000	-1	-1	10	Prototype

That last controlTest-Loom is just Kotlin controlTest changed to use VirtualThread

@DelicateCoroutinesApi
        suspend fun controlTestWithVirtualThreads(repeats: Int) {
            log.info("----====>>>> Starting LOOM controlTest <<<<====----")
            val startTimeT = LocalDateTime.now()
            val aiThread = AtomicInteger(0)
            withContext(Dispatchers.IO) {
                (1..repeats).map {
                    Thread.startVirtualThread { aiThread.getAndIncrement() }
                }.forEach { it.join() }
            }
            val endTimeT = LocalDateTime.now()
            log.info("Imma be the main Thread")
            log.info(aiThread.get().toString())
            log.info("It took me {} ms to finish", Duration.between(startTimeT, endTimeT).toMillis())     }

jesperancinha / good-story

Kotlin Coroutines can dispatch on LOOM threads #74