Threadpool is very busy if the inputs aren't ready for a cell

[ethanrublee]

void async_wait_for_input()
should most likely use a condition variable to wait for the inputs to be ready. If my graph is blocked, i see an entire cpu taken up by the scheduler.

[straszheim]

this is fixed in the new multithreaded scheduler. Of course the quest for the ultimate scheduler is by no means over...