> It is certainly not true that a Linux box with 2000 threads blocked on i/o will be having any sort of bad time.

You and I must have very different perceptions about the way a server is "having a bad time" :)

I was assuming they were at various stages of processing an incoming request, which means they were blocked on either legitimate disk i/o or swapping. It's very difficult to log in even locally in that case, because the login process can't read /etc/passwd in time.

> Also I'm not sure why you think that the kernel thread scheduler is all that good, or why it shouldn't be considered "outside our control.

I was just trying to say that it's dangerous to give non-trusted peers big influence on the way the scheduler behaves.