But I could just offload the CPU bound work to a background thread and prevent the OTHER coroutines ...

# ktor

[Marc Knaup]

But I could just offload the CPU bound work to a background thread and prevent the OTHER coroutines from being blocked, couldn't I?

[elizarov]

Other coroutines will not be blocked. They (usually) run on a thread pool

[Marc Knaup]

I don't know for sure about ktor though. Isn't that internal to ktor? If it uses a thread pool, does it use it's own one? What's the thread limit?

[elizarov]

It is configurable. # of CPU cores by default, so it is designed for CPU-bound tasks.

[Marc Knaup]

So if I have 4 cores and just 4 requests are CPU bound and take a while, no further requests can be handled even if they are very lightweight?

[elizarov]

You are not supposed to block those threads. If all your code is async, you can handle tens of thousands of concurrent requests

[elizarov]

If you have code that blocks thread, then you should consider moving that particular code to a dedicated thread-pool using withContext(myPool) { ... }