I'll have to check my work computer on Monday. It was 8 cpu virtual machine on a m1 Mac. the UMCG and normal threads were 1024 set on the server, the Tokio version was 2 threads per core. Just from the top of my head - the I/O bound requests topped out around 40k/second for the Tokio version, 60k/second for the normal hyper version, and 80k/second for the UMCG hyper version.

I'm pretty close to being done - I'm hoping to publish the entire GitHub repository with tests for the community to validate by next week.

UMCG is essentially an open source version of Google Fibers, which is their internal extension to the linux core for "light weight" threads. It requires you to build a user space scheduler, but that allows you to create different types of schedulers. I can not remember which scheduler showed ^ results but I have at least 6 different UMCG schedulers I was testing.

So essentially you get the benefits of something like tokio where you can have different types of schedulers optimized for different use cases, but the power of kernel threads which means easy cancellation, easy programming (at least in rust). It's still a linux thread with an entire 8mb(?) stack size, but from my testing it's far faster than what Tokio can provide, without the headache of async/await programming.