Its possible now, with current hardware and address space size. With coroutines you could to that 15 years ago on 32 bit machines.

> so they scale the same way

The difference is the within user space context switch vs kernel space/user space context switch.

Just microbenchmarking thread creation is different case, the issue is usually letting OS scheduler to decide what to run and when while coroutines give you explicit access. Coroutines are quite a different thing than OS-level schedulable entities.

> Coroutines are basically just user-space threads

Except you don't have preemption, so you may get e.g. latency issues.

Whereas with threads you don't get latency issues?

With threads, latency problems are spread out more evenly by design.

Ah well, experience tells us that scheduling latency under load with Linux is a difficult topic.