1000 threads blocking on I/O operations is the same as an epoll() over 1000 file descriptors under the hood, except you also get pre-emption guarantees from the

1000 threads blocking on I/O operations is the same as an epoll() over 1000 file descriptors under the hood, except you also get pre-emption guarantees from the kernel. Yeah, so basically this. Except that "I/O bound" usually implies critical moments of computation too, and pre-emption is really nice here.