Plus, threads and processes are essentially the same on unix land – kernel flags will control behavior like shared memory. Which you can still setup manually. Or just use whatever IPC fancies you.
Running on how many CPU cores? Were you writing code for a supercomputing cluster? Otherwise for what kind of system could 10,000 threads possibly be an ok strategy?
Can't wait for 64-core Threadripper to have something similar at home in a little box ;-)
Did he suggest an alternative ?