Used to do this sort of thing for computations that needed to run in the 10 microsecond range (HFT stuff), circa 2008. Had very predictable results because:

a) language was not garbage collected (C++)

b) we avoided heap lock contentions in critical paths by pre-allocating object pools at startup

c) I/O operations were offloaded to separate threads, connected by mutex locked linked lists

d) processing thread was bound to its own CPU core

That's about as deterministic as we could get.